USGS



BIOLOGICAL AND ECOTOXICOLOGICAL CHARACTERISTICS OF TERRESTRIAL VERTEBRATE SPECIES RESIDING IN ESTUARIES

Herring Gull Herring Gull photo by J.A. Spendelow
(Photo by J.A. Spendelow)
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Biological Characteristics

Species

Larus argentatus is 58-66 cm in length, and females are smaller (800-1000 g) than males (1000-1300 g) (Bull and Ferrand, 1977; McVey et al., 1993). The adult gull is white with a light gray back and black-tipped wings. First-year birds are brown (Bull and Ferrand, 1977).

Status in Estuaries

The herring gull is common in nearly all aquatic habitats. Nesting occurs in colonies, often with other gull or tern species, though some pairs will nest solitarily if habitat is too poor to sustain a colony. Nests are usually found on islands with low, sparse vegetation and are composed of masses of seaweed or grass on the ground or in cliffs. Territorial nest defense is mainly carried out by males, while females perform most incubation (McVey et al., 1993). A typical clutch consists of 2-4 heavily spotted olive-brown eggs (Bull and Ferrand, 1977; Spendelow and Patton, 1988). Young are semiprecocial (Ehrlich et al., 1988). The maximum age of a herring gull recorded in nature is 27 years (Clapp et al., 1983).

Abundance and Range

Typical breeding range is from Alaska and Greenland south to the Carolinas (Bull and Ferrand, 1977). Atlantic Coast gulls migrate to southern points along the Atlantic and Gulf coasts, while adults in the Great Lakes tend to be year-round residents (McVey et al., 1993). More than 246,000 breeders are estimated in North America (NACWCP, 2001).

Site Fidelity

Gulls form life-long pair bonds and tend to return to the same site and often the same nest. Site fidelity increases with age (Ehrlich et al., 1988).

Ease of Census

Simple

Feeding Habits

A scavenger often associated with garbage dumps, the herring gull is also an opportunistic predator on adult birds, the eggs and young of other gulls, and aquatic and marine animals found along the beach.   Females have been observed to take smaller prey and feed less on garbage than males. Foraging distance varies widely between breeding gulls, with some observed making extended trips as far as 30 km (McVey et al., 1993).


Herring Gull Contaminant Exposure Data

I.

Organochlorine Contaminants

A.

Concentrations in Adults and Juveniles

1.

Five herring gulls were collected in 1966 from Lincoln, Sagadahoc, and Washington counties, Maine (Wiemeyer et al., 1978). DDE, dieldrin, and PCBs were detected in all birds, with concentrations ranging from 1.7-5.9, 0.05-0.24, and 2.8-17 mg/g wet weight, respectively. Concentrations of DDD and oxychlordane (detected in four birds), heptachlor epoxide and mirex (three birds), and DDT and cis-nonachlor (one bird only) were <0.32 mg/g.

2.

In 1967, 15 adult herring gulls were captured from Bellow Island in Grand Traverse Bay, Lake Michigan , and transported to a large outdoor cage (Ludwig and Ludwig, 1969). Eight gulls died en route from the colony as a result of heat prostration and had mean organochlorine concentrations in the brain of 2.34 mg/g wet weight DDT, 1.00 mg/g DDD, 22.7 mg/g DDE and 0.22 mg/g dieldrin. Birds maintained on water alone for up to 9 days had average concentrations in the brain at the time of death of 11.88 mg/g DDT, 5.64 mg/g DDD, 183.6 mg/g DDE, and 1.65 mg/g dieldrin, representing an overall average increase of 6.6 times the brain concentrations of birds that had not been starved. Concentrations in starved birds were also measured in muscle, blood, ovary, and testes, at the following concentrations (mg/g), respectively: 9.91, 0.71, 40.2, 11.8 DDT; 3.34, 0.28, 16.37, 6.13 DDD; 124.2, 8.79, 473.7, 291.8 DDE; and 1.65, 0.83, 0.051, 4.07, 0.83 dieldrin.

3.

Herring gulls were collected from the Bay of Fundy in the Gulf of Maine area (Zitko et al., 1972a; 1972b; Zitko and Hutzinger, 1972). Mean concentrations of PCB (Aroclor 1254) were 5.06 mg/g wet weight in muscle, 6.50 mg/g in liver, and 75 mg/g in subcutaneous fat. Mean concentrations of DDE were 2.07 mg/g in muscle, 2.08 mg/g in liver, and 26 mg/g in subcutaneous fat. Polychlorinated terphenyls (Aroclor 5460) in fatty tissue were at a mean concentration of 1.4 mg/g. Chlorinated dibenzodioxins and dibenzofurans were not detected.

4.

The dynamics of storage of organochlorine compounds was evaluated both in wild adult birds collected in 1966-1967 on the Wisconsin shore of Lake Michigan and by a 322-day feeding study with caged juvenile gulls maintained on Lake Michigan alewives containing about 3 mg/g DDE, 2 mg/g DDT +TDE, and 2 mg/g PCBs (Anderson and Hickey, 1976). Since dieldrin, though detected in all samples, accounted for only 0.19% of the total organochlorine residues, emphasis was placed on the DDT family and PCBs. Total carcass DDE residues of wild birds initially measured about 200 mg/g in June of 1966, varied between about 180-210 mg/g until mid-December and increased thereafter to about 300 mg/g by the end of May, 1967. Less variation occurred in PCB concentrations, measuring about 190 mg/g initially in June, dropping to between about 170-180 mg/g from August until January and then increasing to about 220 mg/g by mid-May. Residues of DDT+TDE showed little variation and were generally <10 mg/g. In the feeding study, initial total body burdens of DDE, 2.33 mg in the body at the start of the trial in August, 1966, increased slowly thereafter to 15.34 mg in April, 1967, and then decreased slightly to 9.29 mg in May. Total burdens of DDT + TDE, 0.05 mg in August, increased to 1.77 mg in March but decreased thereafter to 0.99 and 0.56 mg in April and May, respectively. Maximum concentrations attained in this feeding study were 290 mg/g DDE, 19 mg/g DDT + TDE, and 200 mg/g apparent PCBs. Apparent PCBs and DDE were highly accumulative, although DDE residues resulted from dietary DDE as well as metabolism from DDT.

5.

Two herring gulls collected between 1969 and 1972 from Lake Ontario contained geometric mean brain concentrations of DDE and PCB of 22.8 and 91.0 mg/g dry weight, respectively (Gilbertson and Reynolds, 1974).

6.

Gulls were collected from the Faroe Islands, E. Scotland, Madeira in Portugal , and Gibraltar between 1971-1975, and tissues analyzed for organochlorine pesticides and PCBs (Bourne and Bogan 1976). Mean hepatic concentrations of DDE and PCBs ranged from 0.05-3.15 and 0.2-12.6 µg/g wet weight, respectively.  Mean muscle concentrations of DDE and PCBs ranged from 0.1-3.35 and 0.2-13.4 µg/g. 

7.

Adult herring gulls were collected during the 1973 breeding season from Pigeon Island in Lake Ontario , south of Kingston , Ontario (Fox et al., 1975). Organochlorines detected (mg/g lipid weight) included PCB as Arochlor 1260 (3530 mg/g lipid weight); mirex (220 mg/g); photomirex (84 mg/g); HCB (6.7 mg/g); b-BHC (34.6 mg/g); DDT (3.4 mg/g); DDE (310 mg/g); DDD (1.8 mg/g); heptachlor epoxide (1.0 mg/g); and dieldrin (5.6 mg/g). Pesticides identified but not quantified included cis-chlordane, trans-chlordane, photo-cis-nonachlor, oxychlordane, monodechlorinated oxychlordane, and methoxychlor. In addition, 14 polynuclear hydrocarbons (PAHs), some of which are known carcinogens, were detected in fat. The total concentration of carcinogenic PAHs was approximated to be 100 mg/g.

8.

Organochlorines were measured in lipid of adult gulls breeding on Lake Ontario (Hallett et al., 1977). PCBs were found in the greatest concentrations, 3530 mg/g, followed by DDE, 310 mg/g; mirex, 220 mg/g; photomirex, 84 mg/g; BHC, 34.6 mg/g; HCB, 6.7 mg/g; dieldrin, 5.6 mg/g, DDT, 3.4 mg/g; and DDE, 1.8 mg/g. Concentrations of cis-chlordane, trans-nonachlor, photo cis-nonachlor, oxychlordane, heptachlor epoxide, monohydro oxychlordane, and methoxychlor were <1.0 mg/g.

9.

Adult herring gulls were collected from 9 sites in the Bay of Fundy, the Great Lakes, and the Detroit River between 1974-1993 (Fox et al., 1998).  Mean total PCBs in pooled liver was generally lower in the 1990s than in earlier decades, and declined at all sites except at Middle Island in Lake Erie, where mean concentration increased from 40.0 µg/g wet weight in 1985 to 44.3 µg/g in 1991.  The lowest mean concentration of total PCBs occurred at Kent Island in the Bay of Fundy in 1991, at 3.81 µg/g  The highest mean concentration of total PCBs occurred at Scotch Bonnet Island in Lake Ontario in 1974, at 101 µg/g   Mean hepatic DDE was generally lower in the 1990s than in earlier decades, and declined at all sites except at Saginaw Bay, where mean concentrations increased from 4.10 µg/g in 1985 to 6.50 µg/g in 1991, and at Middle Island, where mean concentration increased from 1.70 µg/g in 1985 to 2.20 µg/g in 1991.  The lowest mean concentration of DDE (0.59 µg/g) occurred at Kent Island in 1991, and the highest (14.5 µg/g) at Scotch Bonnet Island in 1974.  Mean hepatic dieldrin concentrations were generally lower in the 1990s than in earlier decades, and declined at all sites except at Granite Island in Lake Superior, where concentration were 0.11, 0.25, and 0.13 µg/g in 1980, 1982, and 1991, respectively.  The lowest mean concentration of dieldrin (0.02 µg/g) occurred at Kent Island , and the highest (0.72 µg/g) at Green Bay in Lake Michigan in 1983.  Mean hepatic mirex concentrations were generally lower in the 1990s than in earlier decades, and declined at all sites except at Saginaw Bay , where mean concentrations were 0.14, 0.06, and 0.12 µg/g in 1982, 1985, and 1991, respectively.  The lowest mean concentration of mirex (0.01 µg/g) occurred at Kent Island in 1991 and the highest (4.09 µg/g) at Scotch Bonnet Island in 1974. 

10.

Four post-fledgling herring gulls were collected in 1977 at Lake Superior's Knife Island (Niemi et al., 1986). Mean (range) concentrations of PCBs were 3.1 (0.5-6.9) mg/g fresh weight in pectoral muscle, and mean concentrations of HCB, DDE, and DDT were < 0.8 mg/g.

11.

In 1978, herring gull samples (29 eggs, 24 chicks, 20 fledglings and 1 year-old juveniles, and 26 adults) were collected in the archipelago of southwestern Finland (Lemmetyinen et al., 1982). Concentrations of DDT and PCBs were similar among chicks aged 2-4 weeks through 14 months of age, with means ranging from 0.8-2.2 mg/g fresh weight. In adults, mean DDT concentrations were 6.7 mg/g for females and 6.9 mg/g for males, and means for PCB were 22.1 mg/g for females and 18.7 mg/g for males. No significant sex differences were found for juveniles or adults.

12.

In 1979 and 1980, eight adult herring gulls collected from a colony at Græsholmen, Christiansø ( Denmark ) had a mean DDE concentration of 1.90 mg/g wet weight in brain (Møller, 1982).

13.

Organochlorine concentrations were measured in liver, ovary, and body fat of 21-23 female herring gulls from the island of Mellum , Germany , and compared to concentrations in eggs, of which laying sequence was known (Becker et al., 1989). PCBs and DDT and its metabolites were found in the highest concentrations, with highest values found in the ovary. Mean concentrations (mg/g fat) for fat, ovary, and liver, respectively, were: HCB (0.67, 1.56, 0.48), g-HCH (0.18, 0.65, 0.52), heptachlor (0.10, 0.56, 0.06), heptachlor epoxide (0.36, 2.94, 0.27), aldrin (0.30, 0.83, 0.18), DDE (5.22, 7.81, 3.49), DDT (3.19, 4.04, 2.07), DDD (19.94, 25.03, 12.88), dieldrin (7.62, 13.89, 1.90) and PCBs (34.35, 23.30, 13.12). Females with higher concentrations in tissue tended to produce eggs with high concentrations, though tissues were general more contaminated than eggs.

14.

In 1980-1981, radio-labeled 14C-DDE was used to determine the clearance of DDE in free-living herring gulls at the breeding colony at Chantry Island , Lake Huron (Norstrom et al., 1986). Adults (24 females and 28 males) were captured and dosed with the labeled material and subsequently recaptured 7 days and one year later. Mean background DDE values were remarkedly similar in each tissue among males and females. In 1980 and 1981, respectively, mean DDE concentrations in whole body samples were 12.5 and 11.0 mg/g wet weight for males and 7.0 and 6.2 mg/g in females. Concentrations were similar in males and females, and among years, in muscle (3.4 to 6.6 mg/g), liver (1.2-4.3 mg/g), and brain (<1.1 mg/g). Mean 14C-DDE values were much lower in both males and females, respectively for 1980 (52.9 and 51.5 ng/g in whole body, 26.9 and 31.6 ng/g in muscle, 12.4 and 9.6 ng/g in liver, 3.4 and 3.3 ng/g in brain, and 1.5 and 1.7 ng/g in plasma) and 1981 (21.2 and 20.7 ng/g in whole body, 13.4 and 16.0 ng/g in muscle, 10.2 and 11.5 ng/g in liver, 2.4 and 2.0 ng/g in brain, and 1.4 and 1.2 ng/g in plasma).

15.

Liver samples were collected from 153 adult herring gulls from thirteen Great Lakes colonies in 1980-1985, 35 gulls from two Atlantic coast colonies in 1980-1984, and from adults and chicks archived in 1974 from colonies on the eastern shores of Lake Ontario and Lake Erie (Fox et al., 1988). DDE concentrations from the Great Lakes sites ranged from 1.7-5.6 mg/g wet weight. Concentrations of mirex, dieldrin, photomirex, heptachlor epoxide, oxychlordane, and DDT were <1.1 mg/g. Polyhalogenated aromatic hydrocarbons (PHAH) values, including those of TeCB, pentachlorobenzene, HCB and OCS, with one exception, were <0.2 mg/g. Concentrations of other PHAHs, including TCDD and Arochlors were 10-236 pg/g.

16.

In 1985, ten adult herring gulls were collected from the Snake Island colony in eastern Lake Ontario (Braune and Norstrom, 1989). Mean concentrations in whole body and liver were 47 and 12 mg/g wet weight, respectively, for total PCBs, 14 and 3.5 mg/g for DDE, 4.6 and 1.4 mg/g for mirex, 127 and 72 pg/g for PCDDs and PCDFs (primarily as TCDD), and 1.7 and 0.44 mg/g for photomirex. Concentrations of HCB, b-HCH, OCS, oxychlordane, trans-nonachlor, cis-nonachlor, DDT, heptachlor epoxide, and dieldrin were generally <0.3 mg/g in whole body and <1 mg/g in liver.

17.

From 1991-1993, breeding adult (N=160) herring gulls were collected from several colonies in the Great Lakes Region, and Lake Winnipeg and the Bay of Fundy (reference sites) (Grasman et al., 2000).  Total PCBs ranged from 1.8-23.8 µg/g in pooled adult liver samples, with concentrations exceeding 20 µg/g at Middle Island and Saginaw Bay .  DDE in pooled liver samples were 0.6-7.40 µg/g.

18.

Forty-seven adult herring gulls were collected from 11 Great Lakes and 2 reference sites ( Bay of Fundy , New Brunswick and Lake Winnepeg , Manitoba ) in May of 1992 (Kennedy et al., 1998).  Highly carboxylated porphyrins (HCP) concentrations in adult herring gulls were lower in New Brunswick (7-9 pmol/g, N=5) than Lake Winnepeg (11-56 pmol/g, N=6).  One additional gull from Lake Winnepeg had a HCP concentration of 327 pmol/g.  The Great Lakes adult herring gulls (N=34) had HCP concentrations that ranged from 18 to 355 pmol/g.  There was a linear correlation between HCP and total PCB concentrations.

19.

Gulls were collected from the Selenga delta, Lake Baikal , Russia in September 1996 (autumn) and May-June 1997 (spring) by shooting (Kunisue et al., 2002). Seasonal variation was examined by comparing persistent organochlorine levels in breast muscle tissue from differing seasons. Data is presented in ng/g lipid weight.

Autumn (N=3) PCBs 47,000 (17,000-73,000), DDTs 13,000 (4,000-20,000) HCHs 200 (110-280), chlordanes 680 (210-1,300).

Spring (N=3) PCBs 78,000 (34,000-140,000), DDTs 17,000 (10,000-26,000), HCHs 1,700 (780-3,400), chlordanes 460 (310-650). 

20.

In 1998, herring gulls (n=15) were collected in the outer Oslofjord in southeastern Norway (Ruus et al. 2002). Livers were analyzed for PCBs, DDT, CHL, HCH, HCB, and Mirex.  Mean concentrations were (in ng/g) ΣPCB: 6285; ΣDDT: 951; ΣCHL: 152; ΣHCH: 8; HCB: 109; Mirex: 5.

21.

Livers from 121 seabirds killed in mortality incidents were analyzed and for 16 PCB congeners from 1991 to 1996 (Malcolm et al. 2003).  Two herring gulls in Brighton were included in this group and concentrations were as follows (in mg/kg wet weight): PCB-118: 0.025; PCB-138: 0.048; PCB-153: 0.195; PCB-170: 0.021; PCB-180: 0.058; Total PCBs: 1.356.

B.

Concentrations in Eggs, Embryos, Chicks and Nestlings

1.

Ten herring gull eggs were collected from each of seven colonies in Alberta and Saskatchewan (Vermeer and Reynolds, 1970). Mean DDE concentrations in six colonies ranged from 11.9-17.2 mg/g wet weight, but were lower (2.67 mg/g) in the Namur Lake colony. Dieldrin means were 0.318-0.514 mg/g at the same six colonies and 0.012 at Namur Lake . Heptachlor epoxide was measured in five of the colonies and ranged from 0.043-0.167 mg/g. BHC was detected in only one of five colonies evaluated at 0.035 mg/g.

2.

Ten herring gull eggs were collected in 1969 from each of eight localities in Norway (Bjerk and Holt, 1971). Mean DDE concentrations for the colonies ranged from 0.89-2.19 mg/g wet weight, and PCB means ranged from 0.58-1.58 mg/g. DDT was found in only 4 of the 80 eggs at concentrations ranging from 0.15-0.30 mg/g.

3.

Herring gull eggs were collected from various locations in Canada (Gilbertson and Reynolds, 1974). The following geometric means, expressed as dry weights, were determined for DDE and PCB, respectively for each region: 68.4 and 33.7 mg/g in Manitoba; 110 and 368 mg/g in Lake Huron; 158 and 520 mg/g in the Detroit River; 48.0 and 300 mg/g in Lake Erie; 131 and 565 mg/g in Lake Ontario; 32.1 and 62.5 mg/g in Quebec; and 14.1 and 25.4 mg/g in New Brunswick.

4.

Herring gull eggs were collected in 1971 from two colonies (10 from Fatpot Island and 3 from Hospital Island ) in the Bay of Fundy, Maine (Zitko et al., 1972a; 1972b; Zitko and Choi, 1972; Zitko and Hutzinger, 1972). Mean concentrations of PCB (Aroclor 1254) in the colonies were 12.6 and 5.54 mg/g wet weight, respectively. Mean concentrations of DDE were 5.67 and 2.83 mg/g. Polychlorinated terphenyls (Aroclor 5460) were detected in the fatty tissue at a mean concentration of 0.1 mg/g.

5.

Herring gull eggs collected from 1971-1982, from Scotch Bonnet Island (1971, 1972, 1974, 1976-79, 1982), Lake Ontario, and Big Sister Island (1971-74, 1976, 1977, 1980, 1982), on Green Bay, Lake Michigan (Hebert et al., 1999) were examined for 97 PCB congeners from a composite sample of 10-15 eggs per site per year.  The mean ½ life of PCBs in herring gull eggs was 5.6 ± 1.4 yrs in Green Bay , and 4.6 ± 2.0 yrs in Lake Ontario .  The ½ lives of congeners 77, 81, 126, and 169 for Big Sister Island and Scotch Bonnet Island were greater than the mean for the homologue group, they were: 6.6 and 3.8, 9.2 and 2.6, 6.6 and 3.7, and, 7.7 and 5.6, respectively.  Less chlorinated congeners were more abundant in 1971, while more chlorinated congeners were present in 1982 at both sites.  In samples from Green Bay, proportions of Aroclor 1242 congeners declined by 50% (max.), Aroclor 1254 remained approximately the same, Aroclor 1260 increased by 20% (max.).  In Lake Ontario samples, proportions of Aroclor 1242 declined by 600% (max.), Aroclor 1254 declined by 50% (max.), and Aroclor 1260 increased by 40% (max.).  After 1976, Aroclor 1242 in samples declined at similar rates between sites. 

6.

A total of 25 herring gull eggs were collected between 1971-73 from three colonies scattered across Denmark (Jørgensen and Kraul, 1974). Mean concentrations in Jordsand and Egholm, both from 1971 samples, were relatively low at 0.17 and 0.37 mg/g fresh weight, respectively, for DDE, and 2.1 and 4.0 mg/g for PCB. Græsholm, located on the Baltic Sea , was sampled in two consecutive years. DDE and PCB levels both fell from 1972 to 1973, DDE from 57 to 18 mg/g and PCB from 93 to 32 mg/g.

7.

Eggs collected from Crete and Cyprus between 1971-1975, contained 2.58-29.0 µg/g wet weight DDE and 1.2-5.32 µg/g PCBs (Bourne and Bogan 1976).  

8.

Total PCBs and PCBs as Aroclor 1254/1260 were determined in archived herring gulls eggs originally collected between 1971 and 1983 from the Great Lakes in order to compute conversion factors between the two parameters (Turle et al., 1991). Total PCB concentrations ranged from 8.8-143.9 mg/g and corresponding Aroclor 1254/1260 1:1 mixture levels ranged from 17.7-290.1 mg/g. Conversion factors from Aroclor 1254/1260 to total PCB were calculated as 0.450 for Lake Superior, 0.484 for Lake Huron, 0.444 for Lake Erie, and 0.461 for Lake Ontario. Herring gull eggs from 1986-1988 in which both parameters had been analyzed were used to test the conversion factors and it was found that the calculated values were generally within 0.5 mg/g of the measured values and not significantly different.

9.

In 1972, geometric mean PCB concentrations were 580 mg/g dry weight from ten gull eggs collected from Lake Ontario and 300 mg/g from six eggs from Lake Erie (Gilbertson et al., 1976).

10.

Dead chicks associated with a breeding colony of herring gulls on Brothers Island, Lake Ontario were collected in 1973 (Teeple, 1977). Geometric mean brain concentrations for seven chicks weighing <56 g were 147 mg/g dry weight DDE and 651 mg/g PCB. Five larger chicks, weighing 140-724 g, had means of 27.7 mg/g DDE, and 135 mg/g PCB. Dieldrin, DDT, heptachlor epoxide, and hexachlorobenzene were also detected in the brains of all chicks at cocnentrations <7 mg/g in the smaller chicks and <2 mg/g in the larger chicks.

11.

Herring gull eggs collected in 1973 from the Bay of Fundy and Passamaquoddy Bay contained a pentachlorophenol concentration of 0.51 ng/g wet weight (Zitko et al., 1974).

12.

Eggs no longer being incubated by a breeding colony of herring gulls on Brothers Island, Lake Ontario were collected in 1973 (Teeple, 1977). Geometric mean contaminant concentrations were 134 mg/g dry weight DDE and 420 mg/g PCB. Concentrations of dieldrin, DDD, DDT, heptachlor epoxide, b-benzene hexachloride, and HCB were <6 mg/g in each egg.

13.

Artificially incubated eggs were collected in 1974 from colonies on Lake Ontario and Lake Erie, and northern Alberta and New Brunswick ("controls") (Gilbertson and Fox, 1977). Median (range) DDE concentrations were 16.9 (7.3-34.2) mg/g dry weight at control areas, 87.5 (47.7-143.0) mg/g at Lake Erie, and 211.0 (47.0-501.1) mg/g at Lake Ontario. Dieldrin ranged from 0.05-0.30 mg/g at control areas, 0.57-7.71 mg/g at Lake Erie, and 0.78-4.99 mg/g at Lake Ontario . HCB values ranged from 0.001-0.85 mg/g in controls, 0.69-3.79 mg/g at Lake Erie, and 0.86-15.97 mg/g at Lake Ontario . Heptachlor epoxide concentrations were 0.015 (0.001-0.03 mg/g) in controls, 0.38 (0.12-1.13) mg/g at Lake Erie, and 0.485 (0.03-1.13) mg/g at Lake Ontario . PCB values were low in the control eggs, 29.5 (12-100) mg/g, compared to 578 (345-2410) mg/g at Lake Erie, and 923.5 (247-2003) mg/g at Lake Ontario .

14.

In 1974 and 1975, about 40 herring gull eggs were collected from each of Lakes Ontario, Erie , Huron, and Superior , and 10 from Lake Michigan (Gilman et al., 1977). As no temporal trends were observed, data are reported as combined two-year means. DDE occurred at means ranging from 7.04 mg/g wet weight (Lake Erie) to 31.8 mg/g ( Lake Michigan ). Mean dieldrin concentrations were similar between colonies, and ranged from 0.30-0.48 mg/g. Mirex was detected at a mean of 5.06 mg/g in Lake Ontario , at trace levels in Lake Michigan , and between 0.31-0.66 mg/g at the remaining colonies. PCB means ranged from 51.5 mg/g (Lake Huron) to 142 mg/g ( Lake Ontario ). Concentrations of DDD, DDT, heptachlor epoxide, and HCB, similar among colonies, were <0.20 mg/g.

15.

Between 1974 and 1996 herring gull eggs were colected from five Great Lakes colonies: Granite Island , Agawa Rocks, Gull Island , Big Sister Island , and Double Island (Hebert, 1998).  Mean PCB concentrations in herring gull eggs for this period at Granite Island , Agawa Rocks, Gull Island , Big Sister Island , and Double Island were, respectively:  22.73, 19.44, 39.23, 36.78, and 16.38 μg/g wet weight.  Mean mirex concentrations in herring gull eggs for this period at Granite Island , Agawa Rocks, Gull Island , Big Sister Island , and Double Island were, respectively:  0.105, 0.155, 0.090, 0.087, and 0.142 μg/g.  PCB concentrations declined through time from 75.43 to 12.19 μg/g at Granite Island , 37.88 to 12.63 μg/g at Agawa Rocks, 91.49 to 22.74 μg/g at Gull Island , 118.4 to 16.83 at Big Sister Island, and 56.34 to 12.80 μg/g at Double Island .  Mirex concentrations declined through time from 1.347 to 0.083 μg/g at Granite Island , 0.274 to 0.079 μg/g at Agawa Rocks, 0.157 to 0.079 μg/g at Gull Island , 0.357 to 0.035 at Big Sister Island, and 0.519 to 0.173 μg/g at Double Island .

Using heating degree days to determine winter severity, colder years were correlated with higher PCB concentrations in herring gull eggs from Granite, Gull, and Double Islands and with higher mirex concentrations in eggs from Double and Granite Islands .

16.

Ten unincubated herring gull eggs were collected from each of seven colonies in Lake Ontario in 1975 and examined for mirex and its degradation products (Norstrom et al., 1980). In addition to mirex and photomirex (8-monohydromirex), five minor mirex-related compounds were identified and mean concentrations were determined at the following concentrations: 0.016 mg/g wet weight 2,8-dihydromirex; 0.011 mg/g C10Cl10H2 (II), possibly 3,8-dihydromirex; 0.95 mg/g 8-monohydromirex; 0.077 mg/g C10Cl11H (III), possibly 9-monohydromirex; 0.199 mg/g 10-monohydromirex; 2.58 mg/g mirex; and 0.039 mg/g C10Cl12 (II), consistent with an isomer of mirex.

17.

In 1975, low herring gull reproductive success on Lake Ontario was examined via contaminant analysis of one egg from each of 10 nests in two gull colonies located on the Great Lakes (Lake Michigan excluded) (Fox et al., 1975). Total DDT concentrations were highest in Lake Ontario eggs at 21.3 and 22.3 (9.1-38.9) mg/g wet weight. Lake Erie means were lowest at 6.8 and 7.4 (3.8-14.6) mg/g with mean values from the other two lakes between 12.7 and 21.5 mg/g. Mean values of mirex were highest in Lake Ontario eggs at 4.18 and 6.18 (1.95-18.6) mg/g, and means values from the other three lakes ranged from 0.29-0.82 (0.14-6.82) mg/g. Mean concentrations of PCBs at Lake Ontario, 134.3 and 144.8 (73.8-261.0) mg/g, were also markedly higher compared to means of 59.0-69.4 (15.4-148.0) mg/g in eggs from the other 3 lakes. Mean concentrations of dieldrin, heptachlor epoxide, and HCB were <1 mg/g.

18.

In 1976, 58 herring gull eggs were collected from four colonies in eastern Lake Ontario (Norstrom et al., 1978). Mean concentrations were 138 mg/g wet weight PCBs, 17.4 mg/g DDE, 4.4 mg/g mirex, 1.6 mg/g photomirex, 0.52 mg/g HCB, 0.078 mg/g b-HCH, 0.20 mg/g oxychlordane, 0.12 mg/g heptachlor epoxide, 0.32 mg/g dieldrin, and 0.16 mg/g DDD. Comparing residue levels to those of Coho salmon in the Great Lakes , PCBs with more than five chlorines, DDE, mirex, and photomirex were found to have the highest bioconcentration factor (50±10) of the contaminants in this study.

19.

Ten eggs from each of seven herring gull colonies were collected from Lakes Michigan, Superior , and Huron in 1976 (Hildebrandt and Fay, 1977). Mean concentrations were found for the seven colonies in the following ranges: <0.18 mg/g wet weight PBB; 64-158 mg/g PCB; 18-49 mg/g DDE; 5-17 mg/g DDT, and 0.31-0.82 mg/g dieldrin.

20.

Eggs and nestlings were collected in 1977 from Lake Superior's Knife Island (Niemi et al., 1986). Mean (range) values detected in eggs were 11.3 (3.9-17.6) mg/g fresh weight PCB, 0.05 (0.03-0.07) mg/g HCB, 7.6 (3.4-12.4) mg/g DDE, and 2.8 (1.2-4.9) mg/g DDT. In pre-fledgling pectoral muscle, means were 1.9 (0.2-3.3) mg/g PCB, 0.01 (ND-0.02) mg/g HCB, 0.04 (0.1-1.1) mg/g DDE, and 0.2 (ND-0.6) mg/g DDT. In nestling blood, mean PCB values were 0.4 (0.2-1.1) mg/g and mean values of other contaminants were <0.06 mg/g.

21.

Herring gull eggs (30 from Appledore Island , Maine , and 28 from Fisherman Island , Virginia ) were collected in the spring of 1977 (Szaro et al., 1979). DDE and PCBs were the only chemicals found in all eggs from both locations. Mean (range) DDE concentrations were 1.94 (0.34-7.50) mg/g wet weight in eggs from Maine and 1.93 (0.70-4.50) mg/g in Virginia . Mean PCB values were 7.76 (0.00-32.0) mg/g in Maine and 9.06 (0.13-16.70) mg/g in Virginia . Other contaminants detected in some eggs included DDT, trans-nonachlor, and toxaphene. DDT had a mean concentration of 0.19 mg/g, with a single high value of 5.10 mg/g, while means of the other contaminants were generally <0.05 mg/g.

22.

Ten freshly laid herring gull eggs were collected from each of seven colonies on Lake Ontario in 1977 (Norstrom et al., 1981). Eggs consisted of about 84% PCB by weight of residues and 12% mirex, and had the following mean residue levels (fresh weight): 0.47 mg/g HCB, 13.2 mg/g DDE, 96 mg/g PCB, 2.58 mg/g mirex, 0.95 mg/g 8-MonoH-mirex, 0.11 mg/g ß-HCH, 0.25 mg/g oxychlordane, 0.02 mg/g a-chlordane, 0.28 mg/g DDD, 0.07 mg/g DDT, 0.13 mg/g heptachlor epoxide, and 0.44 mg/g dieldrin. Indications were that PCBs, DDE, mirex, and photomirex accounted for most organically-bound chlorine.

23.

Ten herring gull eggs were collected from each of two Lake Huron sites ( Black River Island and Saginaw Bay ) and contained mean (range) concentrations of 27.38 (15.20-43.75) mg/g wet weight DDE, 5.42 (2.77-9.37) mg/g DDD, 12.98 (7.20-24.00) mg/g DDT, 204.49 (110.60-333.20) mg/g PCB, and 0.76 (0.20-3.01) mg/g dieldrin (Stuht and Fay, 1978).

24.

In 1978, herring gull samples (29 eggs, 24 chicks, 20 fledglings and 1 year-old juveniles, and 26 adults) were collected in the archipelago of southwestern Finland (Lemmetyinen et al., 1982). Mean concentrations in eggs were 7.0 mg/g fresh weight DDT and 17.1 mg/g PCB. Concentrations in pectoral muscle of newly hatched chicks were 17.2 mg/g DDT and 33.0 mg/g PCB. Concentrations were similar among chicks aged 2-4 weeks through 14 months of age, with means ranging from 0.8-2.2 mg/g.

25.

In 1978 and 1979, herring gull eggs, ten from each of nine colonies, were collected from the St. Clair River, Lake St. Clair, the Detroit River , Lake Erie, and the Niagra River (Weseloh et al., 1990). Mean contaminant concentrations per colony ranged from 3.0-9.4 mg/g wet weight DDE, 0.03-0.09 mg/g DDT, 0.13-0.32 mg/g dieldrin, 0.09-0.33 mg/g HCB, 0.02-0.49 mg/g mirex, and 35-140 mg/g PCBs. The greatest concentrations were generally found in eggs from colonies near the Niagra or Detroit Rivers .

26.

Herring gull eggs, ten per colony, were collected between 1978 and 1982 from sites in Saginaw Bay , the Detroit River , and the Niagra River (Struger et al., 1985). Concentrations of 1,2,3,4-TeCB, pentachlorobenzene, 1,2,3,5/1,2,4,5-TeCB, and DDD were significantly higher in Saginaw Bay than other colonies, reaching means of 1.75, 0.18, 0.45, and 0.22 mg/g wet weight, respectively. HCB and PCBs were significantly higher in the Detroit River colony, with means reaching 0.37 and 130 mg/g in 1979. All other compounds were similar between colonies with the following ranges of mean yearly values: 3.7-9.4 mg/g DDE, 0.15-0.24 mg/g dieldrin, 0.02-0.28 mg/g a-chlordane, 0.12-0.24 mg/g oxychlordane, 0.01-0.13 mg/g g-chlordane, 0.08-0.13 mg/g heptachlor epoxide, 0.06-0.98 mg/g mirex, 0.02-0.18 mg/g photomirex, and <0.1 mg/g DDT, 1,2,4-TCB, 1,2,3-TCB, endrin, methoxychlor, trans-nonachlor, a-HCH, and b-HCH. Significant temporal differences in contaminant concentrations at all three sites occurred between 1981 and 1982, with evidence of both increasing and decreasing concentrations. When compared with data from over 25 Great Lakes colonies, eggs from Fighting Island on the Detroit River had the greatest levels of PCBs and HCB.

27.

Organochlorine residues were measured in the liver, ovary, and body fat of 21-23 female herring gulls from the island of Mellum , Germany , and compared to residues found in their eggs, of which laying sequence was known (Becker et al., 1989). HCB, DDE, DDT, and dieldrin concentrations were generally more concentrated in the third egg than the first. Mean concentrations in fat are given for first, second, and third eggs laid, respectively: 0.25, 0.25, 0.29 mg/g HCB; 0.07, 0.08, 0.07 mg/g g-HCH; 0.05, 0.05, 0.05 mg/g heptachlor; 0.26, 0.26, 0.24 mg/g heptachlor epoxide; 0.12, 0.12, 0.13 mg/g aldrin; 1.93, 2.03, 2.21 mg/g DDE; 1.24, 1.29,1.40 mg/g DDT; 5.70, 5.91, 6.94 mg/g DDD; 2.20, 2.30, 2.58 mg/g dieldrin; and 10.02, 9.93, 11.13 mg/g PCBs. Significant correlation occurred between residue concentrations of eggs in the same clutches, thus each egg reflected the contamination of the entire clutch.

28.

The ratio of DDE to PCB concentrations was examined in herring gull eggs collected from 13 colonies in the Great Lakes from 1979 to 1996 (Hughes et al., 1988).  Eggs from the upper Great Lakes and Lake Ontario showed a significant increase in this ratio, implying PCB levels are decreasing faster than DDE levels.  A significant increase in the ratio was also detected in eggs collected from Lake Erie sites, but at a rate 56% or less than that of other sites, signifying high and equal decreases of DDE and PCB concentrations.

29.

An analysis of PCB concentrations in herring gull eggs collected between 1979 and 1998 showed that PCB concentration decline was slower during the 1989 to 1998 period than during the 1979-1988 period for Great Lakes herring gull colonies with the exception of the Lake Erie colonies (Hebert et al., 2000). PCB concentrations declined 20% faster during the 1989-1998 period than the earlier years at Lake Erie .

30.

Pooled samples of ten herring gull eggs collected in 1980 from 12 Great Lakes colonies were analyzed for TCDD (Norstrom et al., 1982). Mean concentrations were 11 pg/g at Lake Superior; 9 pg/g at Lake Michigan; 9 pg/g at Lake Huron, 43 pg/g at Saginaw Bay North; 86 pg/g at Saginaw Bay South; 11 pg/g at Lake Erie; and 59 pg/g at Lake Ontario .

31.

Ten herring gull eggs from each of 9 colonies in Lake Huron and the Georgian Bay were collected in 1980 for analysis of spatial patterns of organochlorine concentrations (Ewins et al., 1992). Mean contaminant concentrations were computed for each colony and fell within the following ranges (mg/g wet weight): 2.1-8.9 DDE, 16.2-69.6 PCBs, 0.06-0.20 mirex, 6-88 pentachlorobenzene, and 55-194 HCB. Median values of 1,2,3,4-TeCB and 1,2,3,5/1,2,4,5-TeCB were 573 and 201 ng/g, respectively, at Channel/Shelter Island and 77 and 44 ng/g at Little Charity Island. Medians at all other colonies were <5 ng/g for both compounds. Heptachlor epoxide, DDD, DDT, b-HCH, oxychlordane, and a-chlordane were measured at only two sites (Chantry Island and Double Island) and mean values per site were all <0.11 mg/g. Dieldrin, analyzed for the same two sites, contained 0.23 and 0.24 mg/g respectively. Eggs from Saginaw Bay (Channel/Shelter Island) had the highest concentration of most organochlorines tested.

32.

Eighteen herring gull eggs collected in 1980 from the colony at Græsholmen, Christiansø (Denmark) contained a mean DDE concentration of 1.40 mg/g wet weight compared to 56.5 mg/g in 1972 and 18.3 mg/g in 1973 (Møller, 1982).

33.

Dioxin concentrations were determined in eggs collected in 1980 and 1983 from herring gull colonies in the vicinity of Lakes Ontario, Michigan, Superior , and New Brunswick (Spear et al., 1986). TCDD concentrations in Lake Ontario eggs ranged from 43-90 pg/g whereas values in eggs from other colonies ranged from 3-13 pg/g.

34.

Mean DDE concentrations in 6 herring gull eggs collected in 1981 were 2.6 mg/g (Norstrom et al., 1986). One year after dosing with 14C-DDE, the mean value of 14C-DDE in eggs was 10.4 ng/g.

35.

Unincubated herring gull eggs, 15 from each of six Great Lakes colonies, were collected in 1981 (Ellenton and McPherson, 1983). Mean TeCB concentrations were at a maximum of 1779 ng/g wet weight in Channel-Shelter Island , Saginaw Bay , and not detected in three other colonies. Pentachlorobenzene means were at a low of 2 ng/g at Kent Island , Bay of Fundy (considered the control), and ranged from 10-162 ng/g in the other five colonies. Mean HCB concentrations at Kent Island were 23 ng/g and ranged from 120-321 ng/g elsewhere. Concentrations of heptachlor epoxide, dieldrin, DDT, oxychlordane, and a-chlordane, similar in all colonies, were <0.56 mg/g. Concentrations of photomirex and mirex occurred at means of 0.96 and 2.23 mg/g, respectively, in Presqu'ile, Lake Ontario, and were <0.21 mg/g in other colonies. Mean DDE concentrations were 0.91 mg/g at Kent Island and ranged from 5.03-13.40 mg/g in other colonies. PCBs, 6.09 mg/g at Kent Island , occurred at mean concentrations of 34.9-94.4 mg/g elsewhere. Mean concentrations of TCDD were 3 pg/g at Kent Island , and 10-86 pg/g at other measured colonies. The same data is presented in Ellenton et al., 1985, with the exception of TeCB at Saginaw Bay , reported as above in 1983 and 779 ng/g in 1985, and pentachlorobenzene reported as 34 ng/g in 1983 and 19 ng/g in 1985.

36.

As in the companion paper above (Ellenton and McPherson, 1983), unincubated herring gull eggs, 25-30 from each of six Great Lakes colonies, were collected in the spring of 1981 (Ellenton et al., 1983). TeCB, not detected in three of the colonies reached a maximum of 610 ng/g wet weight in Channel-Shelter Island , Saginaw Bay . Pentachlorobenzene means were at a low of 1.6 ng/g at Kent Island , Bay of Fundy (considered the control), and ranged from 7.2-77.3 ng/g in the other five colonies. Mean HCB concentrations at Kent Island were 18 ng/g and ranged from 84-225 ng/g elsewhere. Concentrations of heptachlor epoxide, dieldrin, DDT, oxychlordane, and chlordane, similar among colonies, were <0.49 mg/g. Concentrations of photomirex and mirex, occurred at means of 0.77 and 1.75 mg/g, respectively, in Presqu'ile, Lake Ontario and were <0.25 mg/g in other colonies. Mean DDE concentrations were 1.4 mg/g at Kent Island and ranged from 3.4-11.0 mg/g in other colonies. PCBs were at a mean concentrations of 9.9 mg/g at Kent Island , and 26.0-104 mg/g elsewhere.

37.

Organochlorine concentrations were compared between herring gull eggs, 5 day-old chicks and 13-15 day old chicks collected from the same clutch in 1981 from the island of Mellum on the German North Sea coast (Becker and Sperveslage, 1989). All organochlorines analyzed except PCB were highest in 5-day old chicks and lowest in eggs. Mean values for eggs (mg/g whole egg), 5-day old chicks (mg/g whole body fat) and 13 to 15-day old chicks (mg/g liver-fat) are as follows: 5.500, 14.443, 8.120 DDT; 2.109, 3.983, 1.835 dieldrin; and <0.206, <0.519, <0.278 HCH, heptachlor, and HCB. PCB concentrations were 47.457, 26.838, and 69.450, respectively. Correlations between organochlorine concentrations in 5-day and 15-day old chicks in the same clutch were significant, but correlations between eggs and 5-day old chicks from the same clutch were not.

38.

Forty herring gull eggs collected from Telemark county, southeast Norway, in 1981-83 were compared with 21 eggs collected from the same location in 1969 to determine if a decrease in hydrocarbon egg content had accompanied the local decrease in emissions (Bergstrøm and Norheim, 1986). Mean HCB concentrations dropped from 0.61 mg/g wet weight to 0.21 mg/g, as did concentrations of OCS, from 0.32 to 0.16 mg/g. Decachlorobiphenyl showed an increase from the 1969 level of 0.11 mg/g to 0.24 mg/g in 1981-83. A decrease from 1.7 to 0.73 mg/g occurred for DDE and from 5.5 to 4.6 mg/g for PCB.

39.

Herring gull eggs collected from 13 Great Lakes colonies between 1981 and 1991 were analyzed for temporal and geographic patterns of PCDD and PCDF (Hebert et al., 1994). Between 1981-1984, several colonies exhibited a decrease in the concentration of various congeners. Since no significant temporal changes were detected after that time, geometric means were calculated for the period 1984-1991 for each colony. Significant differences were found between colonies, with Saginaw Bay eggs having the highest concentrations of every compound. Contaminant residues had the following ranges of means between colonies (wet weight): 14.09-86.50 pg/g TCDD; 6.65-23.17 pg/g 1,2,3,7,8-PnCDD; 8.65-32.51 pg/g 1,2,3,6,7,8-HxCDD; and 5.71-23.28 pg/g 2,3,4,7,8-PnCDF. Concentrations of 1,2,3,4,6,7,8-HpCDD, 2,3,7,8-TCDF, 1,2,3,4,7,8-HxCDF, and 1,2,3,6,7,8-HxCDF were all <10 pg/g. OCDD was <10 pg/g in all colonies but Saginaw Bay, which had a level of 18.62 pg/g. Patterns of PCDD accumulation were compared to a variety of organisms and found to be similar to the lake trout and walleye, indicating the utility of these species as regional indicators.

40.

Ten eggs from each of from 9 colonies were collected in 1982 from the Great Lakes region (Boersma et al., 1986). Eggs from the Kent Island (KI) colony, a relatively uncontaminated site, were considered controls. The following ranges of mean concentrations were found at 8 Great Lakes colonies and compared to Kent Island values: pentachlorobenzene: 9-120 ng/g wet weight, not detected at KI; HCB: 88-172 ng/g, 14 ng/g at KI; heptachlor epoxide: 0.10-0.39 mg/g for all nine colonies; dieldrin: 0.15-0.83 mg/g, 0.03 mg/g at KI; DDE: 3-13 mg/g, 0.47 mg/g at KI; oxychlordane: 0.15-0.68 mg/g, 0.02 mg/g at KI; PCBs: 22-66 mg/g, 2 mg/g at KI; and mirex: 0.11-2.8 mg/g, 0.01 mg/g at KI; 20-214 pg/g, 7 pg/g TCDD.

41.

Twenty-one day-old nestlings were collected in 1982 from Great Island , Newfoundland (Peakall et al., 1986). Mean (range) concentrations of contaminants in liver were 9.3 (6.1-16.0) ng/g wet weight HCB, 33 (10-75) ng/g DDE, 250 (74-670) ng/g PCBs, 5.7 (2.0-13.0) ng/g oxychlordane, 1.6 (0.9-2.6) ng/g heptachlor epoxide, and 5.0 (3.0-8.4) ng/g dieldrin. Concentrations were also determined in liver from 25-day-old embryos and 14-day-old chicks and concentrations in muscle from 21-day-old embryos through 21-day-old chicks. Liver concentrations of all organochlorines were highest in embryos at 135 ng/g HCB, 2000 ng/g DDE, 10,100 ng/g PCBs, 110 ng/g oxychlordane, 22 ng/g heptachlor epoxide, and 66 ng/g dieldrin. HCB, oxychlordane, heptachlor epoxide and dieldrin all reached high concentrations in muscle of 25-day-old embryos (71, 140, 34, and 92 ng/g, respectively) then gradually fell to minimums for the 21-day-old chicks (6, 3.9, 1.1, and 4.4 ng/g, respectively). Concentration in muscle for DDE and PCB were greatest in the 10-day-old chicks at 1700 and 8400 ng/g, respectively, then fell to 30 and 160 ng/g at the 21-day-old nestling phase.

42.

Herring gull eggs were obtained in 1983 from eight colonies in the Great Lakes and found to contain the following mean concentrations: 90.0 pg/g TCDD, 9.7 pg/g 1,2,3,7,8-PCDD, 17.0 pg/g 1,2,3,6,7,8-HCDD, and 24.3 pg/g OCDD (Stalling et al., 1985). The highest concentrations of TCDD were found in eggs from Lake Huron (141 pg/g) and Lake Ontario (90 pg/g)

43.

In 1985, eggs were collected from Snake Island in eastern Lake Ontario (Braune and Norstrom, 1989). Eggs contained mean concentrations of 16 mg/g wet weight total PCBs, 5.4 mg/g DDE, 1.4 mg/g mirex, and 0.58 mg/g photo-mirex. Concentrations of PCDD and PCDF , primarily as TCDD, were about 83 pg/g. Concentrations of other contaminants were generally <0.1 mg/g.

44.

To validate the use of pooled samples as a technique for monitoring wildlife, herring gull eggs from 2-3 colonies in each of the five Great Lakes collected between 1986 and 1990 were analyzed for several organochlorines on both an individual basis and pooled (Turle and Collins, 1992). For most chemicals, in most colonies, differences were not significant, and concentrations reported are ranges of colony means of individual eggs (wet weight): 1.12-5.03 mg/g DDE; 0.09-0.60 mg/g dieldrin; 0.08-0.21 mg/g heptachlor epoxide; 0.03-1.21 mg/g mirex; 0.01-0.45 mg/g photomirex; 0.10-0.21 mg/g oxychlordane; and 0.03-0.10 mg/g trans-nonachlor. DDT, cis-nonachlor, HCB, and octachlorostyrene means were <0.1 mg/g; DDD, a-chlordane, 1234-TCB, pentachlorobenzene, 1245-TCB, and b-HCH were <0.05 mg/g; and g-chlordane, g-HCH, and a-HCH were <0.01 mg/g. Values of mirex from the pooled analyses were higher than the individual means 13 out of 13 times, and pooled values of trans-nonachlor were higher 12 out of 13 times.

45.

Ten herring gull eggs collected in 1987 from 5 breeding sites at the Jade, German Wadden Sea contained a mean concentration of 1.45 mg/g PCB (Denker et al., 1994). The mean Degree of "Metabolism", defined as the difference between the degree of chlorination of the environmental samples and a standard PCB-mixture, was 0.40.

46.

Ten eggs collected in 1987 from the Jade, German Wadden Sea had mean DDT and PCB concentrations of <0.1 and approximately 3.0 mg/g wet weight, respectively (Becker, 1991).

47.

Three infertile herring gull eggs were collected in 1988 from a nesting colony on Chafarinas Island in the Mediterranean Sea (Gonzalez et al., 1991). Mean (range) concentrations were 2.45 (0.77-7.05) mg/g DDE, and 2.00 (1.10-3.63) mg/g PCB. PCB congeners detected most frequently were 153, 138, and 180.

48.

Herring gulls eggs were collected from two islands (Trischen and Alte Mellum) on the German North Sea coast from 1988-90 (Oxynos et al., 1993). Mean concentrations (ng/g wet weight) were determined for the following contaminants on Trischen in 1988, 1989, and 1990, respectively: 23, 29, 24 HCB; 0.5, 1.2, 11 g-HCH; 6.5, 12, 25 b-HCH; 12, 35, 43 dieldrin; 89, 280, 185 DDE; and 500, 1425, 1285 PCB. a-HCH was detected in 6 of 15 eggs on Trischen in 1989, (<1.2 ng/g), and in all samples in 1990 (0.2-42.0 ng/g). Chloroheptane was not detected in any 1989 samples and in 3 of the 1990 samples (2, 3, and 55 ng/g). Heptachloroepoxide was detected in all 1990 samples (1.9-57.0 ng/g), and none of the 1989 samples. Aldrin was detected in 9 of the 1989 samples (4-15 ng/g) and 3 of the 1990 samples (2, 2, and 50 ng/g). At Alte Mellum, data was reported for 1989 alone and the following means (range) were found (ng/g wet weight): 12 (8.0-26) HCB; 1.3 (0.1-5) a-HCH; 1 (0.4-2.0) g-HCH; 4.6 (3-8) b-HCH; 27 (10-50) dieldrin; 84 (42-300) DDE; and 1280 (730-2640) PCB. Chloroheptane, heptachloroepoxide, and aldrin were not detected in any of the Alte Mellum samples.

49.

Concentrations of TEQs in herring gulls eggs at Trischen and Mellum, Germany decreased from approximately 10.5 and 8 pg/g wet weight, respectively, in 1988 to approximately 5 and 2.5 pg/g in 1993 (Schramm et al., 1997).

50.

Fourteen herring gull eggs collected in the spring of 1990 from breeding sites in the Southern Karelia, Russia, contained mean (range) concentrations of 0.201 (0.042-0.393) mg/g wet weight DDE and 0.019 (0.003-0.046) mg/g lindane (Medvedev and Markova, 1994). Concentrations of DDE were considered lower than the threshold needed to influence reproduction.

51.

From 1991-1993, 4-week old (N=101) herring gulls were collected from several colonies in the Great Lakes Region, and Lake Winnipeg and the Bay of Fundy (reference sites) (Grasman et al., 2000).  In chicks, PCBs were <1 µg/g at all sites except Saginaw Bay (1.19 µg/g) and upper Green Bay (5.05 µg/g). DDE in pooled liver samples were <0.6 µg/g in chicks from all sites except upper Green Bay (2.41 µg/g). 

52.

Herring gull eggs were collected in both 1981 and 1992, from Lakes Ontario and Erie by the Canadian Wildlife Service (Haffner et al., 1997). Concentrations were recorded in mg/g wet weight.

1981 Lake Erie (N=10); PCB congener #52 181, #97 58, #101 356, #118 1,048, #153 2,739, #105 219, #138 3,079, #180 2,105, #203 291, #77 1.09, #126 6.11, #169 0.53, Aroclor1254-1260 41,602.

1992 Lake Erie (N=10); PCB congener #52 82, #97 41, #101 234, #118 589, #153 1,914, #105 118, #138 1,964, #180 1,657, #203 261, #77 0.96, #126 4.13, #169 0.18, Aroclor1254-1260 28,757.

1981 Lake Ontario (N=9); PCB congener #52 194, #97 81, #101 550, #118 1,880, #153 3,636, #105 471, #138 3,904, #180 2,169, #203 319, #77 0.94, #126 6.60, #169 0.69, Aroclor1254-1260 52,729.

1992 Lake Ontario (N=10); PCB congener #52 58, #97 31, #101 159, #118 536, #153 890, #105 1114, #138 1,022, #180 635, #203 103, #77 0.58, #126 3.45, #169 0.20, Aroclor1254-1260 17,129.

53.

One herring gull egg was collected in 1993 from each of six nests on Gull Island , near Presquile Provincial Park in Lake Ontario as part of a study examining PCB concentrations in several trophic levels of a food web (Metcalfe and Metcalfe, 1997). Total PCB concentrations in eggs were approximately 2.5 mg/g wet weight. Concentrations of non-ortho PCB congeners were approximately 54 ng/g lipid weight for congener number 126, 40 ng/g for 77, 15 ng/g for 169, and 14 ng/g for 81. TEQs were approximately 5.5 ng/g lipid weight for total non-ortho PCBs and 6.5 ng/g for total mono-ortho PCBs. PCB congeners in greatest abundance were numbers 153 (comprising approximately 17% of total PCBs), 138 (16%), 118 (10%), and 180 (9%). Herring gulls represented the highest trophic level in this study and contained the highest concentrations of PCBs, giving evidence to the occurrence of biomagnification of this compound.

54.

Five herring gull eggs collected from each of 4 sites in northern Norway in 1992-1993 were compared to eggs obtained at the same sites in 1983 (Barrett et al., 1996). In 1992-1993 samples, mean DDE concentrations ranged from 0.22 to 1.0 mg/g wet weight and mean total PCBs from 0.83 to 2.67 mg/g. Other organochlorines detected included DDT isomers, HCB, chlordane, and HCH isomers. Mirex and dieldrin were detected at very low concentrations in some samples. Increases of PCB and DDE were found in eggs from one site but significant decreases were documented for the other organochlorines.

55.

Herring gull chicks were sampled from 1992-94 from five colonies, four of which were located in the Great Lakes (Grasman et al., 1996). Colony sites were Saginaw Bay and North Channel, Lake Huron; Monroe, Lake Erie; Hamilton Harbor, Lake Ontario; and Pony Island, Lake Winnipeg (control), and contained the following mean contamination ranges: 4.17-27.45 mg/g wet weight PCB, 2.60-17.53 ng/g chicken bioassay derived-TEQs, 71-421 pg/g herring gull-specific-TEQs, 5.3-35.6 pg/g TCDD, 1.00-7.78 mg/g DDE, 0.07-0.31 mg/g dieldrin, 0.03-0.60 mg/g mirex, 0.03-0.05 mg/g HCB, and 0.04-0.12 mg/g heptachlor epoxide.

56.

During 1992–1994, 7 herring gulls were collected from the Nakdong River Estuary, Korea (Choi et al., 2001). Fat was collected and tested for persistent organochlorines. Mean concentrations  and ranges in ng/g, lipid weight (n=7) were: total HCHs 231 (81-517), CHLs 386 (154-948), total DDTs 2,675 (1,136-5,100), HCB 149 (93-176), PCBs 7,818 (1,800-24,000). Concentrations of 2,3,7,8-substituted PCDD/Fs (pg/g, lipid weight) were: 2378-TeCDD ND-193.8, 12378-PeCDD ND-59.0, 123478-HxCDD ND-4.3, 123678-HxCDD ND-14.5, 123789-HxCDD ND-1.1, 1234678-HpCDD ND-8.6, 2378-TeCDF ND-35.0, 12378-PeCDF ND-24.5, 23478-PeCDF 19.1-118.6, 123478HxCDF ND-79.1, 123678-HxCDF ND-175, 234678-HxCDF ND-43.9, 1234678-HpCDF ND-12.1, 1234789-HpCDF ND-10.4, OCDF ND, PCDDs 123.3 (ND-511.5), PCDFs 138.0 (41.3-364.7),  PCDD/Fs 261 (66.9-876.2), WHO TEQs 134.5 (56.9-293.0).

57.

Herring gull eggs (N=46) were collected from several sites on Lake Ontario in 1993 and 1994 (Weseloh et al., 2002). Contaminant levels in pooled eggs are presented in mg/g wet weight for means and ranges. DDE 6.36 (5.54-6.97), mirex 0.99 (0.76-1.15), heptachlor epoxide 0.07 (0.06-0.11), dieldrin 0.15 (0.11-0.19), oxychlordane 0.12 (0.10-0.16), HCB 0.05 (0.04-0.06), total PCBs 11.73 (10.11-13.49).

58.

In 1997, unincubated fertile herring gull eggs were collected from five locations--Kent Island, New Brunswick, Canada (control site); Middle Island, Lake Erie; Snake Island, Lake Ontario; Hamilton Harbor, Lake Ontario; and Papoose Island, Lake Superior (Lorenzen et al., 1999).  In yolk sacs, mean chlorinated hydrocarbon concentrations (>75% DDE) were <1 µg/g wet weight at the control site and ranged from approximately 5-10 µg/g at Great Lakes sites.  Total PCB concentrations, <4 µg/g at the control sites, ranged from approximately 18 µg/g ( Papoose Island ) to 42 µg/g ( Middle Island ) in the Great Lakes .  Non-ortho PCBs (>75% PCB 126), <4 ng/g at the control site, ranged from approximately 17 ng/g ( Hamilton Harbor ) to 42 ng/g ( Middle Island ) in the Great Lakes .  PCDDs/PCDFs, and TEQ concentrations were <1 ng/g at all locations.

59.

Freshly laid herring gull eggs were collected from Lake Huron and Lake Superior , Michigan , sites in May 1998 (Kannan et al., 2001). Mean (range) concentrations (N=2) from Little Charity Island, Lake Huron, were (in pg/g wet weight), respectively: 2,000,000 (1,000,000-3,010,000) total PCBs, 575 (430-720) total PCNs, 37 (20-55) 2,3,7,8-PCDDs, and 7.7 (3.4-12) 2,3,7,8-PCDFs. Mean (range) concentrations (N=2) from Scarecrow Island, Lake Huron, were (in pg/g), respectively: 3,770,000 (3,600,000-3,950,000) total PCBs, 430 (390-470) total PCNs, 20 (12-27) 2,3,7,8-PCDDs, and 17 (8.7-26) 2,3,7,8-PCDFs. Mean (range) concentrations (N=2) from Taquamenon, Lake Superior, were (in pg/g), respectively: 4,150,000 (380,000-7,930,000) total PCBs, 690 (83-1300) total PCNs, 64 (N=1) 2,3,7,8-PCDDs, and 35 (N=1) 2,3,7,8-PCDFs. No significant differences between sites were found. Concentrations of 2,3,7,8-substituted PCDDs and PCDFs are reported.

Mean TCDD equivalents, totaling 53 pg/g, for Little Charity Island were (in pg/g): 32 PCBs, 1.3 PCNs, 19 PCDDs, and 0.92 PCDFs. Mean TCDD equivalents, totaling 36 pg/g, for Scarecrow Island were (in pg/g): 21 PCBs, 0.85 PCNs, 11 PCDDs, and 3.4 PCDFs. Mean TCDD equivalents, totaling 70, for Taquamenon were (in pg/g): 51 PCBs, 1.5 PCNs, 15 PCDDs, and 2.4 PCDFs. PCNs only contribute 2% of the total TEQs while PCBs contribute 58-73%.

60.

Dead herring gulls chicks (N=37) were collected from a colony at Söderskär Game Research Station, in the central Gulf of Finland in 1991 and necropsied (Hario et al., 2000).  Liver and leg muscle tissue was analyzed for 23 PCB congeners. PCB congeners 28, 52, 118, 138, 153, made up >70% of total PCBs.  Arithmetic mean (range) concentrations of the combined 6 congeners was 41.3 (8.2-81.0) µg/g wet weight in liver and 21.0 (6.3-65.4) µg/g in muscle.  Congeners 118, 138, 153, 167, 170, and 180 were 2.7 times higher in liver than muscle.  One outlying chick that died at hatching had 99 mg/g in liver and 9.8 mg/g in leg muscle; this data was not used in further analysis. 

II.

Cholinesterase-Inhibiting Pesticides

1.

Gizzard contents of a specimen found dead in a wheat field in New York State in 1975 contained 1.71 µg/g carbofuran (Stone 1979).

III.

Trace Elements, Metals, and Metalloids

A.

Concentrations in Adults and Juveniles

1.

A fledgling herring gull captured on Clay Lake , Western Ontario in 1971 had a hepatic Hg concentration of 10 mg/g wet weight (Vermeer et al., 1973).

 

From 1974 to 1976, 2 herring gulls were collected and analyzed from Brunswick , Georgia (Gardner et al. 1978). A mean Hg concentration of 0.86 mg/g dry weight was found in the muscle (of which 89% was methyl Hg) and 2.4 mg/g in the liver (of which 62% was methyl Hg).

2.

In 1975 and 1976, 119 adult herring gulls were collected from three sites in Denmark (Hirsholmene, Saltholm, and Christianos) (Karlog and Clausen, 1983). Mean Hg concentrations in liver were 0.63 mg/g wet weight for females and 0.68 mg/g for males. For both sexes, Hg values were highest in Hirsholmene (0.87 mg/g), followed by Saltholm (0.67 mg/g), and Christianos (0.36 mg/g). Eleven birds with high Hg content from each colony (1.07 mg/g mean for females and 1.02 mg/g for males) were selected for MeHg analysis. Females in this group contained 0.37 mg/g MeHg in liver and males contained 0.53 mg/g. The mean concentration for all 33 birds tested was 0.44 mg/g.

3.

Herring gull tissue samples consisting of kidney, liver, brain, muscle, bone, and gastrointestinal tract contents were collected in the spring of 1976 from the Isle of May, Fife, United Kingdom (Hutton, 1981). Mean (range) Cd concentrations were 13.0 (9.2-20.0) mg/g dry weight in kidney, 2.01 (0.78-3.34) mg/g in liver, 0.44 (0.08-0.64) mg/g in brain, and 0.67 (0.18-0.95) mg/g in muscle. Zinc concentrations were 97.6 (78.7-148.2) mg/g in kidney, 91.6 (55.8-135.5) mg/g in liver, 83.2 (73.6-93.4) mg/g in brain, 70.0 (47.3-127.8) mg/g in muscle, and 146.8 (119.6-165.4) mg/g in bone. Mean Hg values were lower: 3.87 (1.58-8.63) mg/g in kidney, 4.08 (0.52-11.1) mg/g in liver, 1.42 (0.70-2.25) mg/g in brain, and 1.29 (0.66-2.60) mg/g in muscle. Mean Se values were 14.1 (8.57-19.4) mg/g in kidney and 7.86 (6.90-9.31) mg/g in liver. The mean concentration of Pb in bone was 37.7 (14.2-78.0) mg/g. In the intestinal tract contents, mean concentrations of Hg, Cd and Pb were relatively low but generally similar, 0.76-3.2 mg/g, in contrast to the mean value of Zn, 124.8 mg/g.

4.

Eleven adult herring gulls were collected in 1977 from a breeding colony on the Isle of May off the east coast of Scotland (Nicholson, 1981). Zinc concentrations were generally similar to values reported in the previous year (see Hutton, 1981, above) and, excluding levels in pancreas (with a mean of 7.6 mg/g), were consistent between tissues. Mean Zn values ranged from 58.7 mg/g dry weight in the heart and pectoral muscles to 140 mg/g in the foregut, with intermediate values in liver and kidneys. Cadmium was detected only in liver (1.86 mg/g in birds with detectable concentrations) and kidneys (13.7 mg/g mean, 6.68-23.3 mg/g range). Mercury was detected in all 11 liver samples at 2.22 (0.321-7.85) mg/g, and in 9 of 10 kidney samples at 2.01 (ND-4.40 mg/g). Mercury was detected in only some samples of other tissues, generally at concentrations <1-2 mg/g.

5.

Four adult herring gulls collected from the Quoddy region, New Brunswick, Canada, during the period of 1978 to 1984 contained mean Hg concentrations of 0.101 mg/g in muscle, 0.482 mg/g in liver, 0.350 mg/g in kidney, and 0.056 mg/g in brain (Braune, 1987).

6.

Hepatic metal concentrations in 12-24 female herring gulls from the island of Mellum , Germany , were compared to concentrations found in their eggs, of which laying sequence was known (Becker et al., 1989). Mean hepatic concentrations were determined for Hg (0.18 mg/g fresh weight), Pb (0.48 mg/g), and Cd (0.57 mg/g). Lead and Cd values were higher in the liver than the egg, while Hg values were higher in the egg.

7.

Adult herring gulls collected from Lakes Ontario, Erie , Huron, and Superior in 1983 were analyzed for metals in the liver, kidney, feathers, and bone (Struger et al., 1987). Combined mean concentrations of Pb for all colonies were 0.163 mg/g wet weight in liver, 2.15 mg/g in kidney, 4.61 mg/g in feather, and 16.1 mg/g in bone. Lake Erie contained the lowest Pb concentrations. Concentrations of Cd were less varied between colonies than Pb, and means were 0.429 mg/g in liver, 1.69 mg/g in kidney, 0.094 mg/g in feather, and 0.008 mg/g in bone. Mean Hg concentrations, also similar between colonies, were 0.701 mg/g in liver, 0.675 in mg/g kidney, 4.06 in mg/g feather, and 0.118 mg/g in bone. Concentrations of these metals were higher in adults than in prefledglings, except Hg and Cd in bone, where values were similar.

8.

Adult herring gulls were collected in 1984-1985 from two coastal and two inland dump sites (Leonzio et al., 1986). Concentrations of all metals were highest in kidney and liver, and ranged from 6.73-13.30 mg/g dry weight for Hg, 9.97-26.8 mg/g for Se, and 0.73-8.26 mg/g for Cd. In the other tissues (subcutaneous fat, uropygial gland, muscle, and brain) means were 0.5-4.95 mg/g for Hg, 2.63 to 13.26 for mg/g Se, and were <0.43 mg/g for Cd. The highest mean Pb concentrations were 13.25 mg/g in kidney at an inland dump site, and <3.40 mg/g at other sites. Lead values were next highest in the liver, but generally <2.0 mg/g.

9.

Seven herring gulls of at least one year of age collected from Raritan Bay , New Jersey had a mean (range) hepatic Cd concentration of 1017 (653-1470) ng/g wet weight (Gochfeld and Burger, 1982). Stomach contents of the gulls, mostly crabs and small fish, had a mean Cd concentration of 118 ng/g, yielding a Concentration Factor (liver:food) of 8.6

10.

Herring gulls were collected during the 1988 breeding season from adults in 7 colonies on the Canadian Atlantic (Elliott et al., 1992). Not all metals could be analyzed in all tissues. Mean Cd concentrations of 6 birds from each of 3 sites ranged from 1.7-5.4 mg/g dry weight in liver and from 13- 40 mg/g in kidney. Mean Pb values at 3 sites ranged from 0.24-1.3 mg/g in liver and from 32-63 mg/g in bone. Mean Hg concentrations were lower at 0.69-1.7 mg/g in liver and 1.11-1.95 mg/g in kidney. Other trace elements measured in liver included Se, (3.20-3.36 mg/g); Zn, (84.7-129 mg/g); Cu, (12.2-30.6 mg/g); Mn, (12.4-14.9 mg/g); Cr, (ND-1.23 mg/g); Mg, (66.5-636 mg/g); and Fe, (895-1690 mg/g).

11.

Tissues were collected from 37 herring gulls (27 females and 10 males) in 1990 at an expanding colony on the German Wadden Sea coast (Lewis, et al., 1993). Mean (range) Hg values in the liver were 4.37 (1.44-9.29) mg/g dry weight in females, and 4.72 (1.31-12.08) mg/g in males. In pectoral muscle, mean concentrations were 2.00 (1.04-4.17) mg/g in females and 2.56 (1.41-5.32) mg/g in males. Concentrations in ovaries of females were 1.87 (0.96-3.27) mg/g.

12.

Blood was collected from fledgling and adult herring gulls at Captree, Long Island , New York (Burger and Gochfeld, 1997).  Young gulls sampled in 1993 (N=16) had the following mean levels of heavy metals and selenium in their blood: 55.6±7.7 mg/dl As, 0.9±0.1 mg/dl Ca, 35.3±1.2 mg/dl Cr, 9.4±0.5 mg/dl Pb, 49.1±5.7 mg/dl Mn, 9.5±2.2 mg/dl Hg, and 77.3±4.5 mg/dl Se. In 1994, 26 young gulls were sampled and had the following mean concentration of heavy metals and selenium in their blood: 16.6±1.3 mg/dl As, 4.7±1.2 mg/dl Ca, 20.7±0.2 mg/dl Cr, 17.6±5.4 mg/dl Pb, 7.3±0.6 mg/dl Mn, 7.1±0.6 mg/dl Hg, and 47.3±2.2 mg/dl Se.  Eleven adult gulls sampled in 1994 had these mean concentrations of heavy metals and selenium in their blood: 2.8±0.4 mg/dl As, 1.6±0.7 mg/dl Ca, 19.7±1.1 mg/dl Cr, 23.3±6.1 mg/dl Pb, 10.3±1.4 mg/dl Mn, 9.3±2.1 mg/dl Hg, and 35.5±9.1 mg/dl Se. 

13.

Herring gulls (N=8) were collected from John F. Kennedy Airport , Long Island , New York (Burger et al., 2000).  The liver, kidney, heart muscle, breast muscle, and salt glands were analyzed for Pb, Hg, As, Cd, Se, Cr, Mn, and Sn.  The geometric mean concentrations (ng/g wet weight) are as follows:  Pb: heart 174, kidney 899, liver 804, breast muscle 89.8, and salt gland 849.  Hg: heart 374, kidney 347, liver 811, breast muscle 346, and salt gland 755.  As: heart 212, kidney 291, liver 282, breast muscle 312, and salt gland 423.  Cd: heart 224, kidney 245, liver 557, breast muscle 105, and salt gland 246.  Se:  heart 361, kidney 1143, liver 2218, breast muscle 481, and salt gland 1431.  Cr:  heart 349, kidney 721, liver 572, breast muscle 232, and salt gland 799.  Mn: heart 2092, kidney 5402, liver 5051, breast muscle 1068, and salt gland 6765.  Sn: heart 142, kidney 509, liver 295, breast muscle 95.5, and salt gland 424.  Concentrations of most metals in the salt gland were as high as those in the kidney and liver, suggesting that the salt gland may be a route of excretion for heavy metals.

B.

Concentrations in Eggs, Eggshells, Embryos, Chicks and Nestlings

1.

The first egg laid of 18 herring gull clutches was collected from Clay Lake, Western Ontario in 1971 (Vermeer et al., 1973). Concentrations of Hg, determined in combined albumen and yolk samples from 14 eggs, were 2.3-15.8 mg/g wet weight. The remaining 4 eggs, in which yolk and albumen were analyzed independently, concentrations of Hg ranged from 3.5-22.7 mg/g in albumen and 0.9-3.5 mg/g in yolk.

2.

Metal concentrations were compared between eggs, 5-day old chicks, and 13 to 15-day old chicks from the same clutch collected in 1981 from Mellum Island on the North German Sea coast (Becker and Sperveslage, 1989). Lead and Cd concentrations were highest in 15-day old chicks and lowest in eggs. Mean concentrations for eggs, 5-day old chicks (whole body), and 15-day old chicks (liver) were: 0.030, 0.055, 0.234 mg/g wet weight Pb and 0.005, 0.018, 0.026 mg/g Cd. Mercury, not analyzed in older chicks, had a mean concentrations of 0.327 mg/g in eggs and 0.356 mg/g in 5-day old chicks. The correlation between Hg in eggs and 5-day old chicks in the same clutch was significant, though no significant correlations were found for Pb or Cd.

3.

Herring gull eggs were collected from 21 sites in the Great Lakes from 1972-76, 1981-83, 1985, and 1992 (Koster et al., 1996). For each of the Great Lakes, mean Hg concentrations were at a maximum in 1982, and ranged from 0.24 mg/g wet weight in Lake Erie to 0.73 mg/g in Lake Ontario . By 1992, means dropped to 0.15-0.20 mg/g. Lake Erie generally had the lowest concentrations and Lake Ontario the highest. A significant decline in Hg concentrations occurred in five sites from 1972-92, and in three sites from 1981-92.

4.

Eggs no longer being incubated by a breeding colony of herring gulls on Brothers Island, Lake Ontario were collected in 1973 and found to contain <6 mg/g dry weight Hg (Teeple, 1977).

5.

About 40 herring gull eggs were collected from each of four colonies in the Great Lakes in 1974 and 1975 (Gilman et al, 1977). Temporal differences were not observed and the following means were determined for the two-year period: 0.51 mg/g wet weight at Lake Ontario, 0.22 mg/g at Lake Erie, 0.23 mg/g at Lake Huron, and 0.39 mg/g at Lake Superior.

6.

In 1974-1975, low reproductive success prompted a comparison of Hg concentrations in herring gull eggs collected from Lake Ontario with those from Lakes Superior, Huron, and Erie (Fox et al., 1975). Mean (range) Hg concentrations in eggs from Lake Ontario were 0.46 (0.29-0.89) mg/g wet weight in 1974 and 0.66 (0.38-1.47) mg/g in 1975. Mean values in eggs from the other 3 lakes ranged from 0.20 to 0.39 mg/g for both years, with an overall range of 0.11-0.63 mg/g. The mean value in the 1975 Lake Ontario eggs was significantly different from means of other colonies.

7.

Mercury concentration in herring gull eggs was found to decrease with laying sequence in a clutch collected on Mellum, Wadden Sea , in 1979-1980 (Becker, 1992). Mean (range) concentrations were 0.43 (0.20-0.82) mg/g wet weight in first-laid eggs, 0.37 (0.13-0.63) mg/g in second-laid eggs and 0.31 (0.13-0.51) mg/g in third-laid eggs.

8.

Herring gull eggs, ten per colony, were collected in 1981 and 1982 from Saginaw Bay , the Detroit River , and the Niagra River in the Great Lakes region (Struger et al., 1985). Eggs from all colonies showed a slight, but statistically significant increase in Hg concentrations from 1981 (0.16-0.24 mg/g wet weight) to 1982 (0.22-0.35 mg/g), though values between the colonies were similar.

9.

Metal concentrations were determined in the liver, kidney, feather, and bone of pooled samples of 9-13 prefledgling herring gulls collected from colonies on Lakes Ontario, Erie, Huron, and Superior in 1983 (Struger et al., 1987). Mean concentrations of Pb for all colonies were 0.085 mg/g wet weight in liver, 0.145 mg/g in kidney, and 0.913 mg/g in bone with the lowest values occurring in Lake Erie . Mean Cd values, more uniform among colonies, were 0.052 mg/g in liver, 0.069 mg/g in kidney, and 0.013 mg/g in bone. Mean Hg concentrations, also similar between colonies, were 0.195 mg/g in liver, 0.160 in mg/g kidney, and 0.053 in mg/g bone. Concentrations of all three metals were lower in prefledgling gulls than adults for all tissues except the bone, where Cd and Hg levels were similar.

10.

Lead and Cd were determined in tissues of 45 day-old herring gull chicks following injection of Pb (0.1 or 0.2 mg Pb/g body weight) at 2-days of age (Burger and Gochfeld, 1990). Seven birds constituted the high dose group whereas there were 8 birds each in the control (saline-injected) and low-dose groups. Bone contained the highest mean Pb values at 785 ng/g dry weight, 53,602 ng/g, and 130,552 ng/g in the controls, low-dose and high-dose groups, respectively. Means for other tissues were 51.8 ng/g, 7,009 ng/g, and 21,504 ng/g in liver; 101 ng/g, 7194 ng/g, and 41,074 ng/g in kidney; and 12.2 ng/g, 334 ng/g, and 1615 ng/g in brain tissue. Mean Pb values in muscle and blood were low, all groups <165 and 197 ng/g, respectively, but showed dose dependency. In the salt gland, means of Pb were low and variable and did not show dose dependency. Mean Cd values were generally low and did not show dose dependency. The highest mean Cd values were found in the kidney at 1586 ng/g, 1143 ng/g, and 1106 ng/g.

11.

Metal residues were measured in the liver, ovary, and body fat of 21-23 female herring gulls from the island of Mellum , Germany , and compared to residues found in their eggs, of which laying sequence was known (Becker et al., 1989). Mean concentrations are given in mg/g fresh weight for first, second, and third eggs laid, respectively: Hg (0.43, 0.37, 0.31), Pb (0.06, 0.04, 0.04), and Cd (0.01, 0.02, 0.01). Mercury concentrations were higher in eggs than in the liver, while Pb and Cd had higher concentrations in the liver. Intraclutch variation was smaller than interclutch, except in the case of Hg.

12.

Ten eggs collected in 1987 from the Jade, German Wadden Sea , had a mean Hg concentration of approximately 0.4 mg/g wet weight (Becker, 1991).

13.

Lead and Cd were determined in eggs collected (one per clutch) in 1989 from four sites at the New York Bight (N=6-15 nests) (Burger and Gochfeld, 1993). Mean Pb concentrations were 3,613; 1,720; 6,743; and 5,857 ng/g dry weight at the 4 sites. Mean Cd values were 22, 4, 7 and 13 ng/g, respectively.

14.

Mean (range) Hg concentrations in 26 eggs collected in 1990 on the German Wadden Sea coast were 1.43 (0.58-3.01) mg/g (Lewis et al., 1993). Ovary concentrations in the adults from this study were 1.87 (0.96-3.27) mg/g.

15.

In 1990, herring gull eggs were collected from a total of six colonies in four locations: Long Island Sound and Jamaica Bay , New York , and Newark Bay and Barnegat Bay , New Jersey (Gochfeld, 1997). Mean metal concentrations for each colony ranged from 0.180-0.568 mg/g wet weight Hg, 0.934-4.150 mg/g Pb, 0.123-0.400 mg/g Cd, 1.635-2.447 mg/g Se, 2.594-4.627 mg/g Mn, and 0.327-6.85 mg/g Cr. Significant differences were detected between localities, though patterns were not the same for all metals. Shooter's Island, in Newark Bay , ranked first or second in concentration in all metals except for Hg, for which it had the lowest mean value.

16.

Mercury was determined in eggs and in liver tissue of nestlings (5-19 found dead per site) collected in 1991 from 3 breeding sites on the German North Sea and the river Elbe (Becker et al., 1993). Results were not tabulated but presented graphically and used to calculate site differences as well as species differences with other gulls. Mean values in eggs from the 3 sites varied from about 0.3-2.0 mg/g fresh weight, with individual values from about 0.2-3.0 g/g. In chicks, mean hepatic concentrations ranged from about 0.6-3.5 mg/g, and individual values from 0.3-4.0 mg/g.

17.

Fluoride was measured in eggshells and femurs collected in 1991-1993 from two sites exposed to direct drift or emissions from primary aluminum smelters (Karmoy and Sunndial, Norway), and three reference sites (Vikoren and Stuve, 1996). Mean (range) fluoride concentrations in eggshells were significantly higher at sites in proximity to smelters [153 (54-545) mg/g] than at reference sites [109 (20-306) mg/g]. Within each of the groups, shells from third-laid eggs, had significantly higher concentrations of fluoride those of the first- and second-laid eggs. Concentrations were higher in females than males from areas near smelters, and there was a positive correlation between fluoride concentration in bone of individual laying hens and concentration in eggshells. There were no effects on other egg parameters, including bone morphology.

18.

Herring gull eggs were collected in 1992 from a colony at Captree, Long Island , New York (Burger, 1994). Mean concentrations (mg/g dry weight), of metals in the contents of 12 eggs were: 2.5 Pb, 0.01 Cd, 0.23 Hg, 2.9 Se, 5.5 Mn, and 2.7 Cr. Mean values in 13 eggshells were: 0.3 Pb, 0.05 Cd, 0.01 Hg, 0.4 Se, 8.2 Mn, and 1.6 Cr.

19.

Five herring gull eggs collected from each of 4 sites in northern Norway in 1992-1993 were compared to data obtained at the same sites in 1983 (Barrett, et al. 1996). Mean Hg concentrations at the 4 sites were low (0.06 to 0.10 mg/g wet weight) and similar to values found in 1983.

20.

Temporal changes were determined in the concentrations of 5 heavy metals and Se in herring gull eggs collected from Captree, Long Island, NY, during the period of 1989 to 1994 (Burger and Gochfeld, 1995a). Samples (20/year), were collected in the middle of each egg-laying period (1 egg/nest). Geometric mean concentrations of Pb declined from 2540 ng/g dry weight in 1989 to 380 ng/g in 1994. Mean Cd concentrations were variable, ranging from 37.1 ng/g in 1989 to 62.2 ng/g in 1993, then down to 8.5 ng/g in 1994. Mercury concentrations increased from 172 ng/g in 1989 to 458 ng/g in 1994. Concentrations of Se were 1920 ng/g in 1989 and decreased to 1010 ng/g in 1994. Chromium values were variable ranging from 2319 ng/g in 1989 to 909 ng/g in 1993. Concentrations of Mn also were variable, ranging from 2990 ng/g in 1994 to 3810 ng/g in 1993.

21.

One-day old herring gull chicks were collected from Captree, Long Island (Burger et al., 1992). Half of the 22 chicks collected were dosed on day 2 with 0.1 or 02 mg/g of a 50 mg/ml Pb nitrate solution and sacrificed on day 30. The dosed birds had significantly higher Pb concentrations than did the control birds. There were some differences between and within bones in the dosed and control chicks. The dosed birds had more correlations in Pb concentrations among and within ulna and radius parts than did control birds. 

Two-day old chicks and 15- to 20-day old chicks were collected from Captree, Long Island . Mean Pb concentrations in the 2-day (N=11) and 15- to 20-day old chicks (N=13) were, respectively: 0.70±0.92 and 0.27±0.10 mg/g dry weight in liver, 6.32±5.74 and 0.81±0.31 in feathers, 13.48±7.20 (N=10) and 19.85±8.35 in tibiotarsus, 38.90±19.14 (N=9) and 13.82±7.65 in radius/ulna. Mean Pb concentration in the 15 to 20-day old chicks was 18.66±10.70 mg/g in skull. The 2-day old chicks had significantly higher Pb concentrations than the 15- to 20-day old chicks. There were no significant differences Pb concentrations between tissue samples of the 2-day old chicks. No correlations were found between bone and liver samples in the 2-day old chicks. The Pb concentrations between bones were not different in the older chicks, but the liver and feather concentrations were different from the bone concentrations. The Pb concentrations in the older chicks various bone samples were correlated with each other but not with liver values or weight. Lead concentrations were higher in the ribs of 15- to 20-day old chicks.  These Pb concentrations in front and back ribs (N=13) were, respectively: 60.9±77.2 front and 49.7±44.2 mg/g for rib 1, 58.8±127.8 and 54.7±75.1 mg/g for rib 2, and 57.7±64.4 and 41.5±43.4 mg/g for rib 3. These data suggest that Pb is not deposited evenly among bones but is homogenous within a bone.

22.

In 1993, 2-day old herring gull chicks from 20 different nests at Captree, Long Island, New York, were injected intraperitoneally with 100 mg/kg Pb acetate in sterile saline while siblings from the same nest were administered an equal amount of saline (Burger and Gochfeld 1994). After 40 days, blood Pb concentrations averaged 25.8±4.7 mg/dl in the 20 Pb-injected chicks while the 28 saline-injected siblings blood Pb concentrations averaged 10.0±0.5 mg/dl. Chicks from 12 other nests (N=30) were not injected and had average blood Pb concentrations of 8.1±0.6 mg/dl. Lead-injected chicks had Pb feather concentrations of 4790±1693 ng/g, saline-injected siblings had concentrations of 1205±334 ng/g, and chicks from other nests had concentrations of 853±342 ng/g.

23.

Between May 20 and August 1, 1993, 20 experimental and 12 control herring gull nests were observed in Captree State Park , Long Island (Burger and Gochfeld, 1996).  One chick per nest was injected with Pb acetate (100 mg/kg) and one sibling injected with an equal amount of saline solution.  Blood lead levels were significantly different between experimental chicks (N=20, 25.8±4.7 mg/dl) and control chicks (N=28, 10.0±0.5 mg/dl).

24.

At Captree, Long Island , 36 one-day old first hatched herring gull chicks were collected (Burger and Gochfeld, 1995c).  The chicks were given an injection of Cr nitrate (50 mg/kg), Mn acetate (25 mg/kg), or normal saline (0.9%) on the second day.  The chicks were sacrificed at an age of 50 days.  The blood levels of Cr averaged 38.5±1.6 mg/dl in the Cr injected chicks and averaged 35.2±1.1 mg/dl in the control saline injected chicks.  The blood levels of Mn averaged 15.1±3.7 mg/dl in the Mn injected chicks and averaged 5.5±0.2 mg/dl in the control saline injected chicks.

25.

First hatched one-day old chicks were collected from colonies in Captree, Long Island, and Barnegat Bay , New Jersey (Dey et al., 2000).  Chicks were injected with 100 mg/kg Pb in sterile water or an isotonic saline solution on day 2 post-hatching.  There were 12 control birds, and 12 Pb dosed birds, 4 birds from each group were sacrificed at 34, 44, and 55 days old.  For control birds at 34, 44, and 55 day old, respectively, means for blood Pb were 1.4, 2.4, 1.3, mean 2.2.  For Pb dosed birds at 34, 44, and 55 day old, respectively, blood Pb was 27.4, 20.8, 19.5, mean 22.3.  Blood Pb was significantly higher in the Pb treated chicks than in the control chicks (p<0.01).  

C.

Concentrations in Feathers

1.

Mean (range) Hg and Zn concentrations in herring gull primary feathers collected in 1976 from the Isle of May, Fife, United Kingdom, were 2.84 (0.63-5.44) and 79.6 (60.0-99.5) mg/g dry weight, respectively (Hutton, 1981).

2.

Mercury values obtained from a single bird collected between 1982-1984 in the Quoddy region of New Brunswick , Canada decreased from approximately 2.2 mg/g in primary feather # 1 to about 0.5 mg/g in primary feather #4 and above (Braune, 1987).

3.

Metal concentrations were determined in the feathers of pooled samples of 9-13 prefledgling herring gulls collected from colonies on Lakes Ontario, Erie, Huron, and Superior in 1983 (Struger et al., 1987). Mean colony concentrations of Pb ranged from 1.93-7.90 mg/g wet weight for adults and 0.540-1.210 mg/g for prefledglings, and were lowest in Lake Erie gulls. Means for other metals were uniform between colonies with Cd ranging from 0.055-0.156 mg/g and 0.062-0.105 mg/g, and Hg from 2.95-6.11 mg/g and 0.670-1.71 mg/g in adults and prefledglings, respectively.

4.

Lead and Cd were determined in feathers of 45 day-old chicks following injection of Pb (0.1 or 0.2 mg Pb/g body weight as Pb nitrate solution) at 2-days of age (Burger and Gochfeld, 1990). Mean Pb concentrations in the control, low- and high-dose groups were 172, 4838, and 9203 ng/g dry weight, respectively. Means Cd values were 195, 116, and 187 ng/g.

5.

Lead and Cd were determined in breast feathers from 38-42 day-old birds collected in 1989 from 2 sites (8 samples from Captree, Suffolk County , New York , and 10 samples from N.W. Lavalette, Ocean County , New Jersey ) on the New York Bight (Burger and Gochfeld, 1993). Mean concentrations of Pb at the 2 sites were 1,797 and 2,101 ng/g dry weight, respectively, and Cd means were 220 and 187 ng/g.

6.

Concentrations of Hg in adult and juvenile herring gull feathers collected from the German North Sea coast in 1989 and 1990 were compared with values in feathers dating back to 1884 obtained from museum specimens (Thompson et al., 1993). Concentrations did not vary seasonally or geographically when analyzed by age or time period. Analysis of long-term trends revealed about a two-fold increase in Hg concentrations between the periods of pre-1941 and post-1941. Mean Hg concentrations were 7.91 mg/g fresh weight in post-1941 adults, and 4.56 mg/g in pre-1941 adults. For juveniles, median values were 4.25 mg/g for post-1941 gulls and 2.02 mg/g for pre-1941 gulls. Adult Hg concentrations per decade showed significant increases in the 1940's, 1960's and 1970's, with the increase in the 1940's the most pronounced.

7.

Mean (range) Hg concentrations were measured in Primary #1 feathers of females [5.84 (3.28-10.03) mg/g dry weight] and males [9.59 (4.19-13.35) mg/g] collected in 1990 from a colony on the Wadden Sea coast of Germany (Lewis et al., 1993). In body feathers, mean concentrations were 4.87 (2.15-9.40) mg/g in females and 6.41 (3.65-10.94) mg/g in males.

8.

Feathers of fledglings were collected from Long Island, New York, New York Harbor, coastal New Jersey, and Chincoteague, Virginia in 1990 (Burger 1997).  Mean concentrations of metals ranged from 1.56-3.52 µg/g dry weight Pb, 0.81-2.83 µg/g Hg, 0.08-0.39 µg/g Cd, 0.97-1.99 µg/g Se, 0.31-0.98 µg/g Cr, and 1.22-4.46 µg/g Mn.

9.

Mean Hg concentrations ranged from 2.01-2.79 mg/g dry weight in samples of 9-15 herring gull Primaries 6-10 collected in Germany (Hahn et al., 1993). Mercury concentration was found to distribute evenly throughout the feather.

10.

In 1991, feathers were collected from herring gull chicks in 3 breeding colonies on the German North Sea and the river Elbe (Becker et al., 1993). Individual and mean concentrations of Hg were presented graphically but not tabulated. From the graphically presented data, mean (range) values appeared to be about 8 (5-10), 7 (6-8) and 35 (7-52) mg/g fresh weight for the 3 colonies analyzed. Mercury values in feathers of nestling birds showed interspecies as well as intersite differences, suggesting that feathers can be as useful as eggs to assess variability, therefore decreasing the need to collect eggs which decreases productivity and hatchling numbers.

11.

In 1991 and 1992, down and feathers were collected from embryos and newly-hatched chicks from the German North Sea coast and Elbe River (Becker et al., 1994). Mean (range) Hg values were 1.42 (0.38-2.87) mg/g wet weight in down at 17 days of age, 1.31 (0.49-2.89) mg/g in shoulder feathers at 27 days of age, and 1.27 (0.47-2.98) mg/g in back feathers at 29 days of age. Mercury reduction from down to back feathers was 26%. Further comparisons of the data indicated that more Hg was transferred to feathers in more highly contaminated chicks, and that the first hatched herring gull chicks had 20% higher Hg concentration than later hatched siblings.

12.

In 1993 and 1994, Pb acetate (0.0, 0.1, 0.05, or 0.025 mg/g) was injected in nesting herring gulls at Captree State Park, Long Island, New York, for comparison of Pb concentrations in tissues of herring gulls given identical injections in the lab (Burger et al., 1997). Concentrations of Pb in blood were significantly lower in field-treated than lab-treated gulls under the same dosing regime, despite the fact that Pb concentrations in controls were higher in gulls raised in the field. Lead concentrations in feather showed no difference between the field and the lab.

IV.

Petroleum

1.

At least 105 herring gulls were observed oiled, but alive and in-flight, after the grounded tanker Panther released oil directly into waters near the coast of Kent , United Kingdom (Dixon and Dixon, 1971).

2.

As part of an investigation of high avian mortalities, including over 200 gull and tern deaths, in the North Irish Sea and Firth of Clyde in 1974, 106 herring gulls (103 alive and 3 dead) in Ayshire were found to be oiled (Lloyd et al., 1974).

3.

Sixteen PAHs were measured in herring gull eggs (5 per site) collected from breeding colonies on Caldey and Skomer Islands, Wales, and Isle of May, Scotland (Shore et al., 1999).  For all 15 samples, the sum of PAHs was 29.0 ng/g lipid weight.  Concentrations of individual PAHs were 12.7 ng/g naphthalene, 19.1 ng/g fluorene, 1.45 ng/g phenanthrene, 2.23 ng/g benzo[b]fluoranthrene, and 1.17 ng/g benzo[k]fluoranthrene.  Acenaphthalene, acenaphthylene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, chrysene, benzo[a]pyrene, dibenz[a,h]anthracene, benzo[g,h,i]perylene, and ideno[1,2,3-cd] pyrene were detected in less than half the samples.

V.

Other

1.

Dead and dying herring gulls were collected between 1976-78 at locations up to 5 km from sites where 4-Aminopyridine had been applied to repel birds (Frank et al., 1981). Samples of baited grains, collected 1-3 days after application of the chemical, contained an average of 18 mg/g 4-Aminopyridine. Mean concentrations in the gulls were highest in the crop and gut contents, 17 mg/g, and similar in other organs, ranging from 2.8-4.8 mg/g in the liver, heart, muscle, kidney, brain, and lungs. One gull appeared to have selectively consumed more treated than untreated grain, and had a concentration of 92 mg/g 4-Aminopyridine in the crop and gut contents.


Herring Gull Contaminant Response Data

I.

Organochlorine Contaminants

A.

Eggshell Thinning and Reproduction

1.

Mean shell thickness of herring gull eggs collected from five colonies ( Black Island , Rhode Island ; Green Island , Maine ; Rogers City, Michigan; Knife River , Minnesota ; Sisters Island , Wisconsin ) in 1967 showed no significant differences from pre-1947 values (Hickey and Anderson, 1968). DDE values were inversely related to shell thickness. Reproductive success was normal at all sites except Sister Islands , where egg breakage and shell flaking was observed.

2.

Mean eggshell thickness in 294 herring gull eggs collected in 1969 from eight colonies throughout Norway ranged from .270-.307 mm (Bjerk and Holt, 1971). PCB concentrations were more highly correlated with thickness than DDE concentrations.

3.

Mean eggshell thickness in samples of approximately 45 herring gull eggs collected from four colonies scattered across Denmark from 1971-73 ranged from 0.332 to 0.364 mm (Jørgensen and Kraul, 1974). Eggs from the Baltic Sea tended to be thinner, lighter, and more contaminated than those from other colonies. Correlations of PCB and DDE residues with shell thickness were highly significant in the Baltic Sea colony in 1973, but not in 1972. The thinning of shells was found to be located in the spongy layer, and a portion of the eggs showed minor defects in the mammillary layer and a rippled structure on the shell surface.

4.

Reproductive success was measured in a herring gull colony on Brothers Island , Lake Ontario , in 1973 (Teeple, 1977). Of 124 eggs, laid to 34 pairs of gulls, 77% failed to hatch and only 2-5% produced chicks that fledged, representing a rate of 0.06-0.18 per pair. Of seven newly hatched chicks that were found dead, all weighing <56 g, the geometric mean concentrations in brain were 147 mg/g dry weight DDE and 651 mg/g PCB. The remaining five dead chicks, weighing 140-724 g, had lower concentrations of both DDE (27.7 mg/g) and PCB (135 mg/g). Other compounds found at low concentrations were dieldrin, DDT, heptachlor epoxide, and HCB. Mean thickness of 13 eggshells was 0.339 mm, with a range of 0.327-0.351 mm. There was a highly significant correlation between shell thickness and DDE concentration.

5.

Hatching success in eggs collected from herring gull colonies in 1974 was 53% in Lake Erie, 26% in Lake Ontario , and 69% in control sites in northern Alberta and New Brunswick (Gilbertson and Fox, 1977).

6.

Herring gulls in Lake Ontario showed abnormal nest defense and nest attentiveness accompanied with low air temperature levels in nests (Fox et al., 1978). Decreased nest defense was sufficient to account for increased egg losses and decreased air temperatures were sufficient to increase embryo mortality. These effects were thought to be the result of pollutant-induced endocrine dysfunction.

7.

Two colonies from each of Lakes Superior, Huron, Erie , and Ontario were observed during 1975-1976 to determine reproductive success (Gilman et al., 1977). In addition, ten eggs from each colony were collected for artificial incubation or contaminant analysis, including eggs from Lake Michigan . Gulls from Lake Ontario had a higher number of one-egg clutches and a significantly lower number of eggs hatched per nest than the other three colonies. Fledgling rate was just 0.15 per pair, compared to 1.38-1.48 in other colonies, and none survived more than 38 days. The low success of the Lake Ontario colony was attributed to disappearance of eggs and failure of the embryo to develop. Hatching success of artificially incubated eggs, conducted over three years, was about 25% for Lake Ontario and 64% for relatively uncontaminated eggs. Of all four lakes studied, Lake Ontario contained the greatest concentrations of PCB, Hg, and mirex, at nearly ten times the levels of the other sites. Median DDE concentrations at Lake Ontario were 22.6 mg/g, and ranged from 7.04 mg/g (Lake Erie)-31.8 mg/g ( Lake Michigan ) overall. Eggshell thinning ranged between 2% (Lake Erie) and 8% (Lakes Ontario and Superior ).

8.

Organochlorine contaminants extracted from herring gull eggs collected from Lake Ontario in 1976 were injected into relatively uncontaminated eggs on Kent Island and allowed to incubate naturally (Gilman et al., 1978). Contaminant uptake rates of treated eggs were compared with the rate of uptake of naturally deposited contaminants in a Lake Superior colony and were found to be almost identical for PCBs, DDE, dieldrin, and heptachlor epoxide. Surprisingly, no decrease in hatch rate was observed between organochlorine-injected and control eggs.

9.

In 1978 and 1979, eggshell thinning and productivity were examined in a total of nine herring gull colonies located in the St. Clair River, Lake St. Clair, the Detroit River , Lake Erie, and the Niagra River (Weseloh et al., 1990). Mean eggshell thickness per colony ranged from 0.332-0.368 mm, representing 11.5-1.9% thinning compared to pre-1947 values. DDE concentrations had a significant, yet weak, correlation with thickness values. Productivity in all colonies ranged from 1-1.7 young raised per pair of nesting adults, and was considered within normal limits.

10.

Ten herring gull eggs collected from each of nine colonies in Lake Huron and the Georgian Bay showed mean eggshell thinning per colony ranging from 0.334 mm to 0.360 mm, representing 10.9% to 4.0% thinning compared to pre-DDT data (Ewins et al., 1992). Only pentachlorobenzene concentrations were significantly correlated with eggshell thickness. The average number of fledglings per active nest ranged from 1.05 to 2.39. A significant positive relationship was found between reproductive output and pentachlorobenzene, and a significant negative relationship was found with DDE.

11.

Fifteen herring gull eggs injected with 150 mL TCB after five days of incubation showed no gross abnormalities and had embryonic mortality levels that were similar to non-treated controls (Brunström, 1988).

12.

In 1991, productivity was studied in a herring gull colony, Söderskär Game Research Station, in the central Gulf of Finland in 1991, characterized by high PCB concentrations in tissues and recent nestling mortality (Hario et al., 2000).  Productivity was calculated at 1.2 fledglings/pair. Mean clutch size was 2.83, with 5.2% of eggs addled and 0.7% dead at hatching.  Mean brood size was 2.54, with 26.3% of chicks disappeared, 5.9% preyed upon, and 8% found diseased at 0-4 days old.  Chicks found dead had elevated concentrations of PCBs. 

B.

Biochemical and Morphological Responses

1.

In 1967, seven adult herring gulls were captured from Bellow Island in Grand Traverse Bay, Lake Michigan , housed in a large outdoor cage, and fed only water (Ludwig and Ludwig, 1969). Six of the gulls developed violent uncontrollable tremors and died during starvation after fat supplies were exhausted and they had begun to metabolize muscle tissue. At the time of death, concentrations of DDT metabolites and dieldrin in the brain were 6.6 times higher than those found in 8 gulls that died en route from the colony as a result of heat prostration. Determination of these high pesticide concentrations in brain tissue led to the diagnosis of chlorinated hydrocarbon poisoning.

2.

Of approximately 850 herring gull chicks examined in 1972 and 1973 on Lake Ontario and Lake Erie , only one chick was observed to possess an abnormality, an inability to fly which persisted through 90 days of observation (Gilbertson et al., 1976). The geometric mean PCB concentration on Lake Erie , where the abnormality was observed, was 300 mg/g dry weight for six eggs from three colonies.

3.

Highly carboxylated porphyrins (HCPs), coproporphyrin, protoporphyrin, and total porphyrins were determined in 22 archived liver samples collected from herring gull chicks in Lakes Erie and Ontario in 1973 or 1974 (Kennedy and Fox, 1990). Values in samples from Lakes Erie (pmol/g) were <40 HCPs, 42-700 coproporphyrin, 330-870 protoporphyrin, and 470-1370 total porphyrins. In Lake Ontario , concentrations were generally higher at <850 HCPs, 100-560 coproporphyrin, 600-31,000 protoporphyrin, and 740-40,000 total porphyrins. Liver HCPs were elevated in about half the livers sampled. HCP was concluded to be a more accurate biomarker for polyhalogenated aromatic hydrocarbon exposure than total porphyrins in that samples with elevated total concentrations did not necessarily have elevated HCP concentrations, and those with elevated HCP concentrations did not always have elevated total concentrations.

4.

In embryos collected in 1974 from two Lake Ontario colonies, median (range) total hepatic porphyrin concentrations were 0.07 (0.04-0.29) ng/g in liver in controls from northern Alberta and New Brunswick , 0.17 (0.04-0.51, N=11) ng/g in eggs from Lake Erie, and 0.50 (0.05-36.30) ng/g in eggs from Lake Ontario (Gilbertson and Fox, 1977).

5.

Adult herring gulls were collected from 9 sites in the Bay of Fundy, the Great Lakes, and the Detroit River polluted with organochlorine contaminants, between 1974-1993 (Fox et al., 1998).  Median hepatic porphyrin levels were generally higher in the 1990's than in prior decades, and increased at all sites except Hamilton Harbor in Lake Ontario, where porphyrin decreased from 80 to 62 pmol/g between 1985-91, and at Scotch Bonnet Island in Lake Ontario, where porphyrin decreased from 190 to 46 pmol/g between 1974-1991.  The lowest median porphyrin concentration (<5 pmol/g) occurred at Kent Island in the Bay of Fundy in 1980 and the highest (190 pmol/g) at Scotch Bonnet Island in 1974.  Median levels of vitamin A in liver were generally higher in the 1990's than in prior decades, and increased at all sites except Saginaw Bay, where vitamin A decreased from 1,014 to 585 µg/g between 1985-91, and at Fighting Island in the Detroit River, where vitamin A decreased from 125 to 104 µg/g between 1985-1991.  Vitamin A levels in the Detroit River, Saginaw Bay, and Western Lake Erie were considered to be “very seriously depleted” in the 1990's.  The lowest detectable median vitamin A concentration (37 µg/g) occurred at Middle Island in Lake Erie in 1985, and the highest (4,576 µg/g) at Kent Island in 1991.  Median relative thyroid masses were generally lower in the 1990's than in prior decades, and decreased at all sites where multiple measurements were taken.  The lowest median thyroid mass (95 µg/g body weight) occurred at Kent Island in 1985 and 1991, and the highest (328 µg/g) at Middle Sister Island in Lake Erie in 1980.

6.

Qualitative and quantitative histological assessment of thyroid glands from 213 adults collected from nine colonies from the Great Lakes basin in 1974 to 1983 and from one colony in the Bay of Fundy in 1977 to 1982 revealed that a majority of the Great Lakes gulls suffered from goiter (Moccia et al., 1986). Thyroids of Great Lakes gulls had a greater mass than those from the Bay of Fundy and were microfollicular and frequently hyperplastic. Temporal and spatial differences in the severity of the thyroid dysfunction were considered consistent with the hypothesis that polyhalogenated hydrocarbons were responsible for the goiter development and observed thyrotoxic effects.

7.

In 1980 and 1983, eggs were collected from herring gull colonies in the vicinity of Lakes Ontario, Michigan, Superior , and New Brunswick (Spear et al., 1986). TCDD concentrations in eggs from Lake Ontario ranged from 43-90 pg/g whereas values in eggs from other colonies ranged from 3-13 pg/g. Mean hepatic concentrations of retinol and retinyl palmitate were lower in eggs from Lake Ontario, 131 and 231 mg/g, respectively, than in eggs from the other Great Lakes, 289-864 and 377-1737 mg/g. Retinoid values were inversely related to dioxin concentration. Results supported the hypothesis that hepatic retinoid metabolism in wildlife species is affected by chlorinated dibenzodioxins or other contaminants capable of inducing aryl hydrocarbon hydroxylase.

8.

Highly carboxylated porphyrins (HCPs) were determined in 153 liver samples collected in 1980 to 1985 from adults in thirteen colonies throughout the Great Lakes and compared to liver samples from at least 35 adults collected in two colonies from the Atlantic coast and from 18 1974 archival samples from the eastern basins of Lakes Erie and Ontario (Fox et al, 1988). the Median (range) HCP concentration in samples from the Atlantic Coast , considered controls, was 5 (<5-24) pmol/g. In samples collected in 1980-1985 from the Great Lakes , median concentration ranged from 10-138 pmol/g and the range of individual values was 5-680 pmol/g. In 1974, median concentrations in the Great Lakes were 56 and 190 pmol/g and the range of individual values was 19-570 pmol/g. Data suggest that several porphyrinogenic contaminants may contribute to porphyria and the authors speculated that elevated HCP values appear to serve as a specific and sensitive early warning of polyhalogenated aromatic hydrocarbon-induced toxicity.

9.

Sister Chromatid Exchange (SCE) rates were determined in 7-day old embryos collected in 1981 from 5 sites in the Great Lakes Basin and from a control site, Kent Island , Bay of Fundy (Ellenton and McPherson, 1983). Mean SCE rates in Great Lakes Basin colonies ranged from 0.069-0.101 SCE/Chromosome compared to 0.101 SCE/Chromosome in controls.

10.

Mutagenic activity was determined in egg extracts collected in 1981 from 5 colonies in the Great Lakes Basin and from a control site, Kent Island , Bay of Fundy (Ellenton et al., 1983). Egg extracts were analyzed in the Salmonella/mammalian microsome assay for induction of point mutations and in Chinese hamster ovary (CHO) cells for the induction of sister chromatid exchanges (SCEs) and chromosome aberrations. None of the extracts were mutagenic in Salmonella either with or without metabolic activation. All of the extracts, including controls, caused significant increases in both the SCE rates and in the number of chromosome aberrations in the CHO cells. Results suggested that the use of herring gull eggs as a monitor for mutagenic activity of bioaccumulated contaminants is of limited value.

11.

AHH values were determined in 20- and 25-day embryos collected from 5 colonies in the Great Lakes Basin in 1981 (Ellenton et al., 1985). In 20-day old embryos, mean AHH concentrations (pmol 3-OH/min/mg protein) ranged from 11.38 at Fighting Island , Detroit River , to 108.27 at Channel-Shelter Island , Saginaw Bay . In the 25-day embryos at Channel-Shelter Island , Saginaw Bay , values ranged 72.14 to 668.38. AHH activities closely paralleled TCDD concentrations. Results clearly demonstrated that AHH activity in 25-day old embryos may be used as a "bio-effects" monitor of exposure to certain environmental chemicals.

12.

In nine Great Lakes herring gull colonies, changes in hepatic EROD and rate of aminopyrene-N-demethylation (APDM) were small where organochlorine residues were determined but rates of aniline hydroxylation (AnH) were significantly depressed in 7 of the 8 colonies compared to the control colony (Boersma et al., 1986). AnH activities showed the greatest depression in the 3 colonies with highest mirex values. Significant negative correlations were found between rates of APDM and PCB and HCB concentrations and between AnH rates and mirex values. The calculated embryo LD50 value of HCB in injected eggs was 4.3 mg/g but mortality in the mirex-injected eggs was similar to the control at 20%.

13.

The whole body annual average clearance rate of DDE was calculated to be 0.95±0.51/year (half-life=264 days) based data from a study using 14C-DDE (Norstrom et al., 1986).

14.

A two-compartment open pharmacokinetic model using plasma and seasonally variable lipid compartments was developed and validated for ten organochlorine compounds in herring gulls (Clark et al., 1987). Plasma clearance rate constants, plasma:whole-body lipid partition coefficients, and compartment sizes for lipid and plasma were obtained for juvenile herring gulls intraperitoneal (i.p.)-injected with a mixture of ten compounds. Plasma clearance rate constants varied widely from 0.04 L/kg*d for slowly clearing chemicals such as DDE and mirex to 500 L/kg*d for rapidly clearing HCH and trans-chlordane. Simulations using these coefficients and lipid weight regimens for individual experimental birds successfully tracked observed plasma concentrations and total body burdens. Simulated whole-body half- lives of organochlorines in wild adult herring gulls were similar to those published for other species.

15.

Significant correlations existed between the molar ratio of retinoid and TCDD concentrations, toxic equivalents of PCDDs and PCDFs, and the sum of PCDD and PCDF concentrations in herring gull eggs (Spear et al., 1990). Results suggested that changes in yolk retinoid might prove to be an early indicator of such effects as embryo mortality and teratogenesis currently observed in Great Lakes birds.

16.

In 1992-94, herring gull chicks were sampled across a gradient of organochlorine contamination at five sites, four of which were within the Great Lakes ( Saginaw Bay , and North Channel, Lake Huron; Monroe , Lake Erie; Hamilton Harbor , Lake Ontario ; and Pony Island , Lake Winnipeg ), in order to study contamination effects on immunosuppression (Grasman et al., 1996). A phytohemagglutinin skin test revealed an inverse relationship between concentrations of PCB, C-TEQ's, HG-TEQs, and DDE with T-cell function. The most highly contaminated sites ( Saginaw Bay , Monroe , and Hamilton Harbor ) were suppressed 35 to 45% compared to the least contaminated sites. No suppression of total antibody (IgM + IgG) and IgG responses following SRBC immunization was observed, though there was some evidence of site and/or year influences. Moderate evidence of plasma retinol decrease in response to increases in PCBs, chicken bioassay derived-TEQs, herring gull-specific-TEQs, and DDE was observed in 1992-93. Neither plasma thyroxine concentration nor white blood cell concentration were found to be influenced by organochlorine exposure, either by site and/or year differences. Body mass and wing chord length were found to positively correlate with plasma thyroxine and retinol, and negatively correlate with the heterophil/lymphocyte ratio.

17.

Cytochrome P4501A induction in response to various halogenated aromatic hydrocarbons was measured in primary hepatocytes from several avian species to determine its usefulness as a tool to measure relative sensitivity (Kennedy et al., 1996).  In herring gull hepatocytes, the rank order of potency of tested substances was TCDD $ TCDF > PCB 126  > PCB 81 > PCB 169.  No induction occurred in response to PCBs 77, 105, or 118.  Among species, the rank order in sensitivity to EROD induction was chicken > pheasant > turkey $ mallard $ herring gulls.  Relative sensitivity rankings of species following administration of PCB 77 and TCDD were similar to those obtained by measuring lethality during in ovo dosing studies. 

18.

In 1997, unincubated fertile herring gull eggs were collected from five locations--Kent Island, New Brunswick, Canada (control site); Middle Island , Lake Erie; Snake Island , Lake Ontario ; Hamilton Harbor , Lake Ontario ; and Papoose Island , Lake Superior --and analyzed for plasma corticosterone and intermediary metabolic enzyme activities (Lorenzen et al., 1999).  Eggs were artificially incubated and blood was collected from 24-day-old embryos.  Mean plasma corticosterone levels were similar between sites and ranged from approximately 4-8 ng/ml.  However, significant negative correlations were found between yolk sac concentrations of PCDDs/PCDFs, total PCBs, non-ortho PCBs, and TEQs and basal plasma corticosterone levels for the same individuals.  Activities of four intermediary metabolic enzymes were measured in liver and kidney--phosphoenolpyruvate carboxykinase (PEPCK), malic enzyme (ME), alanine aminotransferase (ALAT), and aspartate aminotransferase (ASPAT).  Hepatic and renal PEPCK and hepatic ME activities tended to be higher at Great Lakes sites than the control site.  A significant negative correlation was found between yolk sac PCDD/PCDF concentrations and ME activity.  A similar relationship approached significance for renal PEPCK activities.  

19.

From 1991-1993, breeding adult (N=160) and 4-week old (N=101) herring gulls were collected from several colonies in the Great Lakes Region, and Lake Winnipeg and the Bay of Fundy (reference sites), and organochlorine concentrations measured in liver (Grasman et al., 2000).  In adults, total leukocytes and total heterophils were negatively associated with liver EROD and concentrations of highly carboxylated porphyrins (HCPs), and positively associated with DDE concentrations. Total lymphocytes were positively associated with PCB and HCP concentrations.  Heterophil: lymphocyte ratio was negatively associated with liver EROD and HCPs.  Packed cell volume was negatively associated with DDE and positively associated with TEQs.  In chicks, a positive association existed between the heterophil: lymphocyte ratio and TEQs, as well as a positive association between packed cell volume and mean EROD activity.  EROD was highest at Hamilton Harbour . 

20.

Dead herring gulls chicks (N=37) were collected from a colony at Söderskär Game Research Station, in the central Gulf of Finland in 1991 (Hario et al., 2000).  All chicks found dead died of disease and showed signs such as inflammation of lungs and intestines, degeneration of the liver and cardial muscle, and kidney sepsis.  In total, 8% of chicks were found diseased at 0-4 days old.  Disease may be associated with high concentrations of PCBs found in liver and leg muscle of dead chicks.

II.

Cholinesterase-Inhibiting Pesticides

1.

Several specimens were found dead in a wheat field in New York State in 1975 (Stone 1979).  Analysis of the wheat seed detected 2,000 µg/g carbofuran, which had been intentionally spread in the field to kill birds.

2.

In 1986, herring gulls found in convulsions or dead at a Saskatchewan landfill were poisoned (as evidenced by residues found in the gullet) by the organophosphate fensulfothion (Leighton, 1988). Two herring gulls analyzed were found to have been in good physical condition until the poisoning.

III.

Trace Elements, Metals, and Metalloids

1.

Reproductive success of herring gulls on Clay Lake, Eastern Ontario in which Hg concentrations in albumen and yolk of eggs ranged from 2.3-15.8 mg/g wet weight, was determined to be normal (Vermeer et al., 1973). In 16 of 18 nests in which one egg was removed for Hg analysis, all eggs hatched and hatching success was not related to Hg concentration. The fledging rate was 0.7 fledged per pair, and all young appeared to be in good health.

2.

A study of herring gull reproduction was initiated in 1975 in an attempt to define overall effects of organochlorine contaminants and Hg on reproductive success in the four Canadian Great Lakes (Fox et al., 1975). Reproductive success in the Lake Ontario colony was just 1/15th the overall production of the best of the other colonies in the Great Lakes . In this colony, significantly more 1-egg clutches were observed, fewer eggs hatched, and fewer of the hatchlings survived to day 21 of life. The major problems in the Lake Ontario colony were disappearance of eggs and failure of the embryo to develop. Egg disappearance suggested an adult behavioral component (possible reduced site defense, egg breakage and/or nest abandonment) whereas high embryonic mortality implicated poor egg incubation or presence of an embryo-toxicant. It was concluded that the herring gull's high trophic level and higher toxicant burden makes it a good species for monitoring the health of the Great Lakes .

3.

From 1979-1981, 123 herring gulls were among about 2400 birds to die in the Mersey Estuary, UK, from alkyl Pb poisoning derived from industrial effluent from petrochemical works (Bull et al., 1983).

4.

Twenty-four one-day-old first chicks were collected in 1987 from salt-marsh colonies in Barnegat Bay, New Jersey, and assigned to 1 of 3 groups to receive single intraperitoneal (i.p.) injections on day 2 of Pb nitrate solutions at 0.1 or 0.2 mg/g (50 mg/ml in sterile water) or a similar volume of sterile saline as controls (Burger and Gochfeld, 1988). Significant dose-dependent differences in bill, tarsus, and wing bone lengths were found by day 8 which, except for bill length, persisted to the end of the study, 46-days of age. Mean body weights of both groups of Pb-treated birds were significantly lower than the controls by day 6 post-injection and persisted until day 40. Feed consumption and feeding behavior were similar in all three groups.

5.

In 1987, blood was collected from a total of 22 brooding herring gulls from two colonies in Ontario ( Hamilton Harbor and Chantry Island ) (Scheuhammer, 1989). No differences in red blood cell-ALAD activity ratios (reactivated ALAD:non-reactivated ALAD were detected between the two colonies, though Hamilton Harbor is known to have a higher level of contamination from industrial sources. Of the 22 gulls sampled, 6 had ratios between 1.4 and 2.0, indicating slightly elevated blood Pb concentrations. The mean ratio for all gulls was 1.30, considered to be within the normal range for the Pb concentrations present.

6.

In 1987, 24 one-day-old first hatched herring gulls were collected from Barnegat Bay , New Jersey and given an intraperitoneal (i.p.) injection of either 0.1 or 0.2 mg/g Pb, or sterile saline (Burger, 1990). Lead-injected birds weighed less than controls and had a slower bill growth-rate. Control gulls showed better performance in tests for begging intensity, balance, righting time, and depth perception on a greater number of days than experimental birds. Individual recognition development was slowed by the injection of Pb in a dose-dependent manner. Control birds also showed higher feeding ability and ability to walk an incline. Balance and righting ability were most adversely affected in the first days following injection.

7.

Herring gull tissues were collected during the 1988 breeding season from adults in 3 sites on the Canadian Atlantic (Elliott et al., 1992). Renal metallothionein means ranged from 73.2 to 248 mg/g wet weight, with an overall range of 33.9-377 mg/g. A positive correlation was found between Cd and renal metallothionein. Histological examination of liver and kidney failed to show any indications of tissue damage associated with elevated concentrations of heavy metals.

8.

In 1992, 60 one-day old herring gull chicks were collected from Captree, Long Island, and Barnegat Bay , New Jersey (Burger and Gochfeld 1993b). Chicks were given one of four doses injected peritoneally: 100 mg/kg Pb on day 2, day 6, divided between day 2, 4, and 6, or an isotonic saline solution.  Lead injected birds performed less well on behavioral response tests than did control birds.  Chicks injected with Pb on day 6 were more accurate than the other Pb-injected chicks but took longer to make a decision.

9.

In 1992, 72 one-day-old first chicks were collected from Captree, Long Island and Barnegat Bay, New Jersey, and given either an injection of 100 mg/g Pb in sterile water on day 2 or 6, three equal injections totaling 100 mg/g Pb solution over the course of days 2, 4, and 6, or saline injections to mimic the above conditions (Burger and Gochfeld, 1995b). The Pb-day 6 group stopped gaining weight after day 20 and was sacrificed on day 40. Lead-exposed gulls failed to develop balance skills at the rate of controls and Pb-day 6 birds actually showed a decrease in performance with time. Lead-day 6 birds also showed the greatest adverse effect in depth perception and thermoregulation tests, though the Pb-day 2,4,6 group also showed lower abilities in depth perception.

10.

In 1993, at Captree, Long Island , New York , 78 herring gull chicks were monitored until fledging (Burger and Gochfeld 1994). Lead acetate in saline (100 mg/kg) was injected intraperitoneally into one nestling while the other received an equal volume of saline solution. The 20 Pb-injected herring gull nestlings scored more behavioral deficits and more misses when stimulating regurgitation from their parents’ bills than the control chicks. Only 55% of the 20 chicks injected Pb survived to fledging compared to 89% of the 28 sibling chicks injected with saline.  Thirty chicks from other nests that were not injected survived to fledging 87% of the time.

11.

Between May 20 and August 1, 1993, 20 experimental and 12 control herring gull nests were observed in Captree State Park , Long Island (Burger and Gochfeld, 1996).  One chick per nest was injected with Pb acetate (100 mg/kg) and one sibling injected with an equal amount of saline solution.  The experimental (N=20) and control (N=28) chick weights were significantly different at 16 days (131.3±14.3 and 188.9±17.7 g, respectively) but not at fledging (825±62 and 890±21 g, respectively).  The fledging rate was significantly less for the experimental chicks (55%) than the control chicks (89%).  The Pb injected chicks performed less well than control chicks on behaviors such as walking, begging, and seeking cover during rain showers.

12.

At Captree, Long Island , 36 one-day old first hatched herring gull chicks were collected (Burger and Gochfeld, 1995c).  The chicks were given an injection of Cr nitrate (50 mg/kg), Mn acetate (25 mg/kg), or normal saline (0.9%) on the second day.  Control birds began pecking for food earlier during tests, took less time to right themselves overall, and thermoregulated faster than Mn or Cr injected birds.  Control chicks had an average final weight (at 40 days old) of 821±1 g, while Cr and Mn chicks were significantly less, an average of 528±30 and 546±31 g, respectively.

13.

First hatched 1- to 2-day old herring gull chicks were collected from Captree, Long Island , New York (Burger and Gochfeld, 1995d).  There were 4 groups of 16 chicks and each group received one of the following intraperitoneal injections: 100mg/g of Pb acetate on day 6, 100 mg/g of Pb acetate on day 12, 50 mg/g on Pb acetate on day 12, or normal saline solution.  Righting was disrupted in chicks following Pb exposure and time to choose the caretaker with food took longer following Pb injections.  Lead injected chicks with the full dose at age 12 days performed less well than the other groups on the balance beam test and the maximum angle incline test.  Day 6 Pb injected chicks took longer to reach shade in thermoregulation tests and spent less time in the shade.

14.

One-day old herring gull chicks were collected from Captree, Long Island and Barnegat Bay, New Jersey in 1997 (Burger and Gochfeld 1998). The chicks were given an intraperitoneal injection of either a Pb dose of 100 mg/kg or an isotonic saline solution on the second day. Sibling recognition improved with age in the saline-injected chicks but not the Pb-injected chicks. Lead-injected chicks also took longer to respond to calls from other chicks than did control chicks.

15.

First hatched one-day old chicks were collected from colonies in Captree, Long Island, and Barnegat Bay , New Jersey (Dey et al., 2000).  Chicks were injected with 100 mg/kg Pb in sterile water or an isotonic saline solution on day 2 post-hatching.  Half-brains were analyzed for golgi sialyltransferase and three cell adhesion molecules (CAMs) including N-cadherin, NCAM, and L1. There were 12 control birds, and 12 Pb dosed birds, 4 birds from each group were sacrificed at 34, 44, and 55 days old.  For control birds at 34, 44, and 55 day old, respectively, means for the measured variables were: golgi ST 221, 305, 224, mean 267; N-cadherin 598, 1144, 707, mean 816; L1 308, 821, 865, mean 664; and PSA-NCAM 421, 106, 62.5, mean 421.  For Pb dosed birds at 34, 44, and 55 day old, respectively, the variables were: golgi ST 302, 306, 209, mean 248; N-cadherin 313, 441, 640, mean 465; L1 287, 715, 862, mean 621; and PSA-NCAM 447, 115, 49.5, mean 204.   N-cadherin was significantly lower in Pb treated chicks (p<0.05).  

IV.

Petroleum

1.

Herring gull chicks, collected from Cutler, Maine, were given a single oral dose of 0.2-ml Kuwait crude (KC) oil containing 22% aromatics or South Louisiana crude (SLC) oil containing 17% aromatics, and maintained on 100% seawater for eight to nine days (Miller et al., 1978). Undosed birds gained weight at a normal rate (about 3% per day) during the maintenance period while treated birds, though consuming more food, gained no weight. Intestinal tissue examination from gulls given SLC revealed an accumulation of about 30% less cycloleucine than control gulls and major pathological changes in tissue morphology including proliferative edema with considerable cytoplasmic disruption. Plasma Na+ concentrations were elevated in gulls given either KC and SLC, indicating possible disruption of osmoregulatory function. Both groups of birds also experienced hypertrophy of nasal and hepatic tissue and induction of microsomal cytochrome P-450 activity, and SLC-dosed birds experienced adrenal gland hypertrophy.

2.

Herring gull chicks collected from Aberdeen , Scotland , and dosed with either 0.1 or 1.0 ml Forties Field crude oil per day for eight to ten days, or two doses of 10 ml crude oil failed to show any inhibition of growth or evidence of histological damage (Gorman and Simms, 1978). The authors suggest that in previous contradictory studies, birds may have stopped growing before they were treated with oil, falsely giving the appearance that the oil had inhibited growth.

3.

Herring gull chicks captured from Northeast Harbor , Maine were dosed with either 1 ml corn oil, 0.8 ml corn oil + 0.2 ml weathered South Louisiana crude oil (WSLC), or 0.5 ml corn oil + 0.5 ml WSLC, and then released (Butler and Lukasiewicz, 1979). Both sets of dosed birds exhibited a reduction in weight gain by days 7-9, with recovery by days 11-13 in the 0.2 ml group and by days 18-22 in the 0.5 ml group. Culmen growth rates were also reduced in both groups on days 7-9 and 11-13, though the rate of toe growth was not affected. Survival to 700 g or 20 days following dosing was lower in the 0.5 ml group (41%) than the controls (62%) or the 0.2 ml gulls (65%).

4.

Nestling herring gulls collected from Maine were either sham dosed, or given a single 1 ml dose of Prudhoe Bay crude oil (PBCO) or 9/1 PBCO:dispersant (Corexit) by intubation and then maintained on seawater but no food (Miller et al., 1980). Dosed birds lost weight at a rate nearly twice that of control birds, though there was no difference between PBCO or PBC0:dispersant groups.

5.

In laboratory and field studies, single oral doses (0.1-1.0 ml) of Prudhoe Bay (PBCO), South Louisiana crudes SLC-76 or SLC-78, weathered SLC-76, and aromatic and aliphatic fractions of SLC-76 were administered to nestling herring gulls to evaluate effects on plasma thyroxine and corticosterone levels (Peakall et al., 1981). Of the oils tested at 1.0 ml doses, SLC-76, SLC-76-AR, weathered SLC, PBCO, and PBC-Ar2 (aromatic fraction of PBCO) caused significant increases in both circulating plasma corticosterone and thyroxine. Corticosterone values were elevated within 1 day, reached maximum values after 5 days, and returned to normal after 2 weeks. Thyroxine values did not increase until 6 days after dosing and were still elevated after 2 weeks.

6.

Nestling herring gulls maintained on fresh herring and seawater were given a single dose by intubation of 1 ml Prudhoe Bay crude oil (PBCO), PBCO fraction, PBCO:Corexit 9527 (0.9 ml PBCO:0.1 ml Clorexit premixed), or an equal volume of corn oil (controls) (Peakall et al., 1982). Depression of weight gain occurred within one day in response to dosing with PBCO, PBCO:Clorexit, or the second PBCO aromatic fraction (PBCO-Ar-2). Reduction in weight gain also occurred to a lesser extent in gulls dosed with Clorexit alone. A significant increase in nasal gland and adrenal weight occurred in groups dosed with PBCO-Ar-2, PBCO, and PBCO + Corexit, and liver weight increased for PBCO-Ar-2 birds alone. Birds dosed with PBCO, PBCO-Ar-2, and PBCO:Clorexit all showed significant increases in plasma Na+ levels on day one, with PBCO:Clorexit producing the most prolonged effect. The activity of the cytochrome P-450 dependent enzyme benzphetamine N-demethylase was reduced only in birds exposed to oil + dispersant and those of benzo(a)pyrene hydroxylase were reduced in birds exposed to oil with or without the dispersant.

7.

Nestling herring gulls collected from an island off the coast of Maine were dosed with 0.2-1.0 ml South Louisiana crude-78 (SLC-78), Kuwait crude, Prudhoe Bay crude or weathered SLC-76 oil split into aliphatic and aromatic fractions by single oral dose intubation (Miller et al., 1982). Only aromatic fractions were shown to reduce weight gain, and of those, only aromatics with four or more rings.

8.

Kuwait crude or No. 2 fuel oil applied to the surface of 7-9 day-old naturally-incubating eggs resulted in a significant reduction in hatching success with as little as 20 ml of petroleum (Lewis and Malecki, 1983). In a second study, hatching success was again markedly reduced when the nesting female was captured and breast feathers treated with as little as 1 ml of crude oil. Embryo toxicities of the two oils were approximately the same.

9.

Nestling herring gulls captured from an island off the coast of Maine were dosed orally, 0.2-1.0 ml, with single doses of two South Louisiana crude oils, SLC-76 and SLC-78, crude fractions, or a weathered fraction of SLC-76 (Peakall et al., 1983). At termination of the study nasal glands and intestinal mucosa were used for assays of Na+, K+-ATPase and transport experiments in slices of the jejunum. SLC-76 caused marked retardation of growth, hypertrophy of adrenal and nasal salt gland tissue, and some disruption of plasma osmoregulation.  SLC-78 had no detectable effects on the chicks. Weathering of SLC-76 for 36 hours did not reduce its toxicity and when fractionated, the aromatic fraction of SLC-76 was substantially more toxic than the aliphatic hydrocarbon fraction.

10.

Young herring gull chicks were dosed twice daily via gelatin capsule with a Prudhoe Bay crude oil for a total daily dose of 0,1,4,10, or 20 ml/kg (Leighton et al., 1983). In blood samples obtained 96 hrs after the first dose, hematological parameters consisting of hematocrit (%) and hemoglobin (g/dl) were markedly and significantly reduced at the 10 and 20 ml/kg dose levels. hematocrit values were about 16% in the two treated groups compared to 30% in controls, and hemoglobin values were 5.0 and 6.0 g/dl compared to 9.2 g/dl in controls. In these birds, reticulocyte counts increased from about 7% to 26% and Heinz-body counts increased drastically from 0.3% to about 90%. At 4 ml/kg, hematocrit (%) was slightly but significantly reduced, and reticulocyte and Heinz-body counts were not affected. The 1.0 ml/kg/day level appeared to be a no-effect-level.

11.

Reproductive success was measured in herring gull eggs treated externally with fresh or weathered No. 2 fuel oil in doses of 10, 20, 50, or 100 ml of oil per egg on day 4, 8, 16, or 24 days of incubation (Lewis and Malecki, 1984). Oiled eggs hatched at rates inversely proportional to the amount of applied oil, yet dose responses were dependent on the age of the embryo. Eggs which were 4 days old at treatment were sensitive to levels of 10 ml, those which were 8 days old required 10-20 ml to elicit adverse effects, and eggs 16 days or older were tolerant of levels up to 100 ml. At doses of 20 and 50 ml, a similar decrease in hatching success occurred with oil weathered up to about one month, after which point the oil composition was altered enough that eggs treated with 20 ml began to hatch at levels comparable with controls. Productivity was reduced to less than or equal to 0.3 chick per pair only when eggs received large doses (greater than or equal to 50 ml) by day 8, or smaller doses (10-20 ml) by day 4.

12.

Nestling herring gulls treated with Prudhoe Bay Crude Oil (PBCO) internally or externally were examined for morphological and biochemical effects (Peakall et al., 1985). In the first experiment, gulls were intubated with either a single dose of 1 ml PBCO, 1 ml dispersant (Corexit 9527), a 10:1 (by volume) PBCO:dispersant emulsion, or were sham dosed, and then deprived of food. Weight loss in gulls given oil with or without dispersant was significantly greater than controls, plasma triglyceride concentrations were increased, and plasma sodium levels were elevated from days 2-4, but returned to normal by day 5. Alpha-amino-n-butyric acid levels were greater in the emulsion group alone. In a second experiment, breast feathers of nestling herring gulls were painted with 4 g PBCO, 4 g of 10/1 PBCO/Corexit, or sham dosed with water, and maintained on herring and seawater. Only those treated with the oil emulsion were affected and saw a loss in body weight, and an increase in triiodothyronine (T3) and thyroxine (T4) levels.

13.

Nestling herring gulls collected in 1982 and 1983 were given daily oral doses of 0, 1, 4, 5, 10 or 20 ml Prudhoe Bay crude oil/kg body weight/day by intubation (Leighton, 1985). Red blood cell lesions were observed in birds receiving greater than or equal to 10 ml oil/kg/day. Affected gulls tended to have red cells with irregular shapes and contours, and increased incidence of anisocytosis, poikilocytosis, polychromasia, and Heinz bodies. In addition, nuclear membranes were often severely disrupted, degenerate mitochondria and membrane bound vesicles were present, circumferential microtubules were absent, and cytoplasmic density was either increased or reduced to abnormal levels.

14.

The effects of Prudhoe Bay crude oil (PBCO)-83 on nestling herring gulls collected near St. John's , Newfoundland , were compared to those of PBCO-80, and then studied under varying durations of treatment (Leighton et al., 1985). Gulls given either 10 ml PBCO-80/kg body weight or 10 ml PBCO-83/kg by intubation twice daily for 5 days (Experiment A) did not differ in their responses to the oil and results were pooled. A second set of gull groups were treated with 10 ml PBCO-83/ kg but treatment duration was varied from 0 to 5 days (Experiment B). All treated birds in both experiments defecated substantial amounts of oil after administration and all gulls developed Heinz body hemolytic anemia. Oil treatment in Experiment A resulted in red blood cells with elevated reduced glutathione (GSH), peroxidation of membrane lipids, an increase of membrane permeability, and a decrease in the oxygen-carrying capacity of cyanomethemoglobin-convertible hemoglobin. In Experiment B, packed cell volume, total hemoglobin, and GSH/packed cell volume showed highly significant covariance with total dose and dependence on total dose. Red cell damage occurred in some birds after just two days of administration.

15.

Herring gull nestlings were collected from Great Island, south of St. John=s, Newfoundland and treated with oral doses of Hibernia crude oil (HCO) or Prudhoe Bay crude oil (PBCO) to study effects on hepatic and renal MFOs (Lee et al., 1985). Effects on Heinz-body formation in red blood cells were reported earlier in a companion study (see above, Leighton et al., 1983). Hepatic cytochrome P-450 contents were increased approximately fourfold following oral dosing of PBCO at 4 and 10 ml/kg and HCO at 10 ml/kg. Other MFOs and Phase II enzyme activities were also increased: 7-ethoxyresorufin-O-deethylase (19-fold), benzo(a)pyrene 3-hydroxylase (sixfold), aniline hydroxylase (threefold), aminopyrine N-demethylase (twofold, uridine diphosphate glucuronyl transferase (twofold). Hepatic reduced glutathione S-transferase activity was unchanged after treatment with the oils. Renal MFO activities were also increased. Hepatic activities of DT-diaphorase, although present at only very low levels, were induced three to fivefold following administration of the oils. Feed consumption and body weight gains were reduced in birds dosed with PBCO at 10 ml/kg.

16.

Nestling herring gulls were treated with doses of 0, 1, 4, 10, or 20 ml Prudhoe Bay crude oil by esophageal intubation twice daily for 5 to 7 consecutive days (Leighton, 1986). Substantial oil was defecated by birds after each dosage. Gulls receiving greater than or equal to 10 ml/kg oil were lethargic, exhibited pallor and discoloration of the oral mucosa, greatly reduced subcutaneous fat masses, decreased food consumption followed by decreased body weight, decreased size of the thymus and bursa of Fabricius, and showed dark brown discoloration of the liver, spleen, skeletal muscle, and blood. Histological lesions, including those secondary to primary toxic hemolytic diseases and those considered nonspecific reactions to stress, occurred in the liver, spleen, bone marrow, kidney, bursa of Fabricius, thymus, and adrenal glands. Findings indicated that the peripheral red blood cell was the primary target of oil toxicity, but other significant stress-related lesions are also associated with ingestion.

17.

Herring gull chicks were collected from the Little Bell Island, Conception Bay , Newfoundland , for two separate crude oil toxicity studies (Peakall et al., 1989). In the first study, gulls were dosed orally with 0.1, 0.5, or 1.0 ml Prudhoe Bay crude oil (PBCO) and liver and blood samples obtained after 24 hours for MFO assays in liver and select hematological parameters in blood. A second 1.0 ml group was dosed and samples collected after 3 days. In the second study, birds were dosed orally for 5 days with capsules containing PBCO (10 ml/kg), or aliphatic or aromatic fractions equivalent to 10 ml/kg. Hepatic MFO activities of aminopyrine N-demethylase, benzo(a)pyrene 3-hydroxylase, 7-ethoxyresorufin O-demethylase and aldrin epoxidase were induced 24-hours after a single oral dose of PBCO; activities had decreased significantly after 72 hours. Induction was due largely to the aromatic fraction. 

18.

In 1979 and 1980, adult herring gulls and chicks from Chantry Island, Lake Huron, were exposed to No. 2 fuel oil to determine the effect on chicks that swim in a slick after hatching and the minimum quantity of oil on fresh water which, when swam in by a nesting adult, produces a risk to the embryo (Harfenist et al., 1990). Hatching success in young of adults oiled early in the hatching stage was reduced at 321 ml oil/m2 and survival of young to 7 days post-hatch was reduced at 107 and 321 ml/m2. Since 107 ml/m2 is more than 20 times the maximum thickness of No. 2 oil ever measured on the Great Lakes, a single exposure of adults or chicks to an oil slick of this magnitude should not cause a significant reduction in hatching success or survival of newly hatched chicks. The effects of repeated exposures to a fresh oil slick are not known.

19.

All herring gull nests on Lake Ontario sprayed 4, 5, or 6 times with 100% pure, white mineral oil failed to produce any eggs that hatched (Christens and Blokpoel, 1991).

20.

Herring gulls from Hamilton Harbor, an industrial area contaminated with PAHs and heavy metals, had a significantly higher rate of DNA sequence mutations than gulls from references sites at Chantry Island on Lake Huron, Presqu=ile Provincial Park on Lake Ontario, and Kent Island in the Bay of Fundy (Yauk and Quinn, 1996). Mean mutation rates, as determined by multilocus DNA fingerprinting, were 0.017 for Hamilton Harbor, 0.006 for Kent Island, 0.002 for Chantry Island, and 0.004 for Presqu=ile Provincial Park.

V.

Other Contaminants

1.

Dead and dying herring gulls were collected between 1976-78 at locations up to 5 km from sites where 4-Aminopyridine had been applied to repell birds (Frank et al., 1981). The lethal dose for the gulls was calculated as 4.0 mg/g of body weight.

2.

Herring gulls nesting less than one mile from Kennedy Airport at Jamaica Bay , New York were observed for behavioral effects as a result of noise pollution (Burger, 1981). When supersonic transport planes (SSTs) passed over the colony, significantly more birds were observed flying over the colony (mean=137.0), indicating disturbance, than when non-SST planes flew overhead (11.0) or conditions were normal (11.7). In addition, the total number of bird fights increased 60-fold over normal conditions in the minute after an SST flight, and were significantly greater in number and longer in duration than the fights produced by a human walking through the colony. Egg loss in one colony was 10 out of 60 eggs, and of 100 nests sampled, mean clutch size dropped from 2.76 during the first week of incubation to 2.06 at the end of the incubation period compared to a final mean clutch size of 2.67 for solitary breeders. Only 60% of the eggs in the colony hatched. Loafing birds followed similar patterns to breeding birds, with more birds flying after SSTs than non-SSTs.

3.

Herring gulls exposed to the fertilizer manufacturing waste product calcium nitrite were found dead within 24 hours and diagnosed with nitrite poisoning (Ley, 1986). Necropsies of thirteen gulls revealed small quantities of a grayish-white material in the proventriculus and gizzard of each bird.

4.

White phosphorus (P4) has been identified as one cause of mortality in dabbling ducks and swans in an estuarine salt marsh in Alaska that may in turn present a potential hazard to predatory birds including herring gulls (Roebuck et al., 1994). P4 was found in one herring gull egg at a concentration of 0.003 mg/g wet weight. 
 

5.

In 2000, herring gull eggs (n = 13 egg pools) were collected from 15 specific sites in the Great Lakes regions, pooled, and analyzed for polybrominated diphenyl ethers (PBDE) (Norstrom et al. 2002).  A total of 25 di- to hepta-BDE congeners were identified in herring gull eggs.  Seven congeners, BDE-28, 47, 99, 100, 153, 154, and 183, constituted about 97.5% of ΣBDEs in the herring gull colonies that were collection sites.  The mean concentrations found in eggs pooled are as follows (data shown for each location in μg/kg wet wt): BDEs-28, 47, 100, 99, 154, 153, 183 (in order), Σ7BDEs, and ΣBDEs total.  Granite Island in Lake Superior: 3.8, 253, 83.6, 202, 25.4, 71.6, 646, 664; Agawa Rock in Lake Superior: 3.1, 323, 113, 284, 28.8, 106, 8.0, 866, 887; Big Sister Island in Green Bay: 5.1, 522, 167, 459, 59.5, 143, 7.1, 1362, 1400; Gull Island in Lake Michigan: 8.2, 602, 203, 323, 55.6, 118, 22.0, 1332, 1366; Double Island in Lake Huron: 2.5, 146, 45.2, 74.6, 15.0, 22.8, 2.6, 309, 320; Chantry Island in Lake Huron: 2.5, 127, 37.3, 77.7, 11.7, 36.4, 7.0, 299, 308; Channel-Shelter Island in Saginaw Bay: 6.9, 291, 89.5, 161, 29.1, 50.6, 7.9, 635, 652; Fighting Island in the Detroit River: 6.3, 322, 92.6, 130, 17.6, 53.5, 4.5, 627, 639; Middle Island in Lake Erie: 4.8, 163, 51.8, 52.0, 10.3, 37.5, 10.2, 329, 340; Port Colbourne in Lake Erie: 1.0, 70.0, 24.6, 55.9, 7.2, 25.6, 3.3, 188, 192; Niagara River (above the falls): 1.7, 168, 53.0, 111, 17.9, 57.6, 13.8, 423, 432; Hamilton Harbor in Lake Ontario: 7.0, 361, 102, 167, 28.8, 67.0, 5.1, 738, 755; Toronto Harbor in Lake Ontario: 2.7, 4.1, 108, 322, 38.9, 89.9, 12.5, 975, 1003; Snake Island in Lake Ontario: 3.9, 220, 66.5, 113.0, 31.8, 65.2, 15.1, 515, 530; Strachen Island in the St. Lawrence River: 2.8, 220, 56.6, 89.8, 20.0, 47.7, 7.3, 444, 453.

Eggs collected by the Canadian Wildlife Service were also analyzed for BDEs.  The eggs represented the years 1981-2000, and were from Snake Island in Lake Ontario; Gull Island in Lake Michigan; and Channel-Shelter Island in Saginaw Bay, Lake Huron.   The  ΣBDEs (1981-2000) are as follows (in μg/kg wet wt): Snake Island in Lake Ontario: 9.4, 14, 209, 211, 155, 183, 216, 276, 297, 382, 557, 530; Gull Island in Lake Michigan: 18, 21, 116, 146, na, na, 243, 851, 679, 1544, 820, 1366; Channel-Shelter Island in Saginaw Bay, Lake Huron: 31, 141, 78, 119, na, 165, 230, 290, 402, 498, 650, 652.

References for Herring Gulls

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Barrett, R.T., J.U. Skaare, and G.W. Gabrielsen. 1996. Recent changes in levels of persistent organochlorines and mercury in eggs of seabirds from the Barents Sea . Environ. Pollut. 92:13-18.

Becker, P.H. 1991. Population and contamination studies in coastal birds: the common tern Sterna hirundo. In C.M. Perrins, J.-D. Lebreton, and G.J.M. Hirons, eds., Bird Population Studies. Oxford University Press, New York , pp. 433-460.

Becker, P.H. 1992. Egg mercury levels decline with the laying sequence in Charadriiformes. Bull. Environ. Contam. Toxicol. 48:762-767.

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Becker, P.H., B. Conrad, and H. Sperveslage. 1989. Organochlorines and heavy metals in female herring gulls (Larus argentatus) and in their eggs of known laying sequence. Vogelwarte 35:1-10.

Becker, P.H., R.W. Furness, and D. Henning. 1993. The value of chick feathers to assess spatial and interspecific variation in the mercury contamination of seabirds. Environ. Monit. Assess. 28:255-262.

Becker, P.H., D. Henning, and R.W. Furness. 1994. Differences in mercury contamination and elimination during feather development in gull and tern broods. Arch. Environ. Contam. Toxicol. 27:162-167.

Bergstrøm, R. and Norheim, G. 1986. Persistent chlorinated hydrocarbons in eggs of seabirds from the coast of Telemark in South-Eastern Norway. Fauna 39:53-57.

Bjerk, J.E. and G. Holt. 1971. Residues of DDE and PCB in eggs from herring gull (Larus argentatus) and common gull (Larus canus) in Norway . Acta. vet. scand. 12:429-441.

Boersma , D.C. , J.A. Ellenton, and A. Yagminas. 1986. Investigation of the hepatic mixed-function oxidase system in herring gull embryos in relation to environmental contaminants. Environ. Toxicol. Chem. 5:309-318.

Bourne, W.R.P and J.A. Bogan.  1976.  Seabirds and pollution. Appendix: Estimations of chlorinated hydrocarbons in marine birds.  In R. Johnson ed., Marine Pollution.  Academic Press, New York , pp. 482-493.

Braune, B.M. 1987. Comparison of total mercury levels in relation to diet and molt for nine species of marine birds. Arch. Environ. Contam. Toxicol. 16:217-224.

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