Double-Crested Cormorant Contaminant Exposure Data

I.

Organochlorine Contaminants

A.

Concentrations in Adults, Juveniles, and Nestlings

1.

DCCs were collected from Muscongus Bay, Maine in 1966-67 (Kury, 1969). In 1966, 25 adults contained the following mean concentrations of DDE: 1.5 mg/g brain, 6.5 mg/g gonads, and 3.0 mg/g heart. In 1967, 18 adults contained a mean DDE concentration of 0.34 mg/g in brain and of 23 pooled samples of nestlings (representing 89 birds), only 5 had measurable concentrations of DDE, ranging from a trace to 0.29 mg/g.  Analysis of the habitat and distribution of contaminants in the birds indicated that exposure to the pesticides occurred in some other area, possibly its wintering grounds in Florida.

2.

DCCs were collected from the Bay of Fundy in the Gulf of Maine area (Zitko et al., 1972; Zitko and Hutzinger, 1972). Mean concentrations of PCB (Aroclor 1254) were 3.38 mg/g wet weight muscle, 2.13 mg/g liver, 38 mg/g subcutaneous fat, and 52 mg/g abdominal fat. Mean concentrations of DDE were 8.40 mg/g muscle, 4.16 mg/g liver, 164 mg/g subcutaneous fat, and 162 mg/g abdominal fat.

3.

One DCC collected between 1969 and 1972 from Alberta contained geometric mean liver concentrations of 0.12 mg/g dry weight DDE and 0.004 mg/g PCB (Gilbertson and Reynolds, 1974).

4.

Adult DCCs were collected from rookeries on Dry Lake and South Waubay Lake, South Dakota, for analysis of chlorinated hydrocarbons and Hg (Greichus et al., 1973). Average total concentrations of organochlorine pesticides in "body", muscle, and liver were 10.7, 6.7, and 3.6 mg/g wet weight, respectively. Concentrations of individual pesticides were predominately in the DDT family. Mean concentrations of these compounds were 107.84 mg/g DDE, 2.11 mg/g DDD, and 2.16 mg/g parent DDT in fat, and 2.70 mg/g DDE, 0.44 mg/g DDD and 0.31 mg/g parent DDT in liver. Dieldrin concentrations were 1.38 mg/g in fat, 0.13 mg/g in liver, and 0.12 mg/g in brain. Heptachlor epoxide and lindane were detected at concentrations of 0.25 mg/g and 0.26 mg/g in fat, and <0.05 mg/g in liver and brain. PCB residues in fat, liver, brain and bodies were 22.4, 2.0, 1.3, and 4.6 mg/g, respectively.

5.

Organochlorines were measured in two DCCs collected from Florida in 1974 (Johnston, 1976). Concentrations detected in adipose tissue were 0.70 and 2.21 mg/g wet weight DDE, and 0.79 and 3.01 mg/g total DDT. In uropygial glands, values were 0.73 and 1.38 mg/g DDE, and 1.23 and 1.68 mg/g total DDT. Dieldrin was detected in the uropygial gland only of one bird at 0.34 mg/g. PCB was not detected.

6.

Adult DCCs were collected in November, 1982, in the Houston Ship Channel, Texas, shortly after completion of the fall migration (N=10), and in late February, 1983, after overwintering (N=10) (King et al., 1987). Carcasses were analyzed after removal of skin, bills, feet, and gastrointestinal tract. DDE was detected in all samples, at a geometric mean (range) of 0.66 (0.21-2.5) mg/g wet weight in the November samples and 0.93 (0.4-2.3) mg/g in the February samples. DDD, dieldrin, chlordane, HCB, and heptachlor epoxide were not detected in November samples, but were detected in some of the February samples (maximum concentrations were 0.25 mg/g for dieldrin and 0.28 mg/g for HCB). PCBs were found in 9 of 10 samples in November, 1.54 (0.8-6.0) mg/g, and in all samples collected in February, 1.58 (1.1-3.3). Mean and range of PCS were 0.13 (0.17-0.4) mg/g in 6 of 10 November samples and 0.34 (0.18-0.68) mg/g in all 10 February samples.

7.

Nestling DCC (N=3) were collected in 1983 from Spider Island and Gravelly Island in Lake Michigan for analysis of organochlorine contaminants (Stalling et al., 1985). Mean concentrations of contaminants detected were 4 ng/kg TCDD, 25 ng/kg total PCDDs, 2 ng/kg 2,3,7,8-TCDF, 10 ng/kg total PCDFs, and 1.0 DDE mg/kg non-ortho PCB.

8.

As part of a more extensive 1984 evaluation of nesting success and analysis of eggs, residues of chlorinated hydrocarbons were determined in breast muscle of 3 adult DCCs found dead near Williamson Rocks in Washington (Henny et al., 1989). Concentrations ranged from 0.14 to 0.35 mg/g wet weight DDE and from 0.49 to 0.73 mg/g PCB.

9.

Eggs (N=127) and juvenile (N=84) DCCs were collected in 1984 and 1985 from ten aquatic systems in Alberta and one in Saskatchewan (Somers et al., 1993). The geometric means of DDE and PCB residues in young were 0.95 and 0.94 mg/g wet weight lipid, respectively. HCB, BHC, oxychlordane, heptachlor epoxide, dieldrin, mirex, endrin were not detected in young.

10.

Adult DCC (N=20) were collected from the Caimanero Lagoon in northwest Mexico in 1986 (Mora and Anderson, 1991). Residues were determined in carcass samples after removing feathers, wings, head, feet and stomach contents. DDE was found in all birds at a geometric mean (range) concentration of 5.05 (0.77-13.46) mg/g wet weight. Parent DDT was found in 19 birds with values ranging from 0.007-0.041 mg/g. Dieldrin was detected in 14 specimens with concentrations ranging from 0.004-0.079 mg/g. PCBs were found in less than 50% (7/20) of the birds with a mean value of 0.116 mg/g. Values of HCH, detected in 19 birds, were low, ranging from 0.008-0.071 mg/g. Concentrations of HCB, DDD, oxychlordane, heptachlor epoxide, endosulfan, and endrin were <0.1 mg/g.

11.

In 1989, DCC eggs and chicks were collected from 8 sites in the Great Lake region and assayed for total PCBs, and TCDD-equivalents using the in vitro H4IIE rat hepatoma bioassay (Jones et al., 1994). The TCDD-equivalents ranged from 141.7 to 382.3 pg/g wet weight in eggs and from 17.9 to 398.9 pg/g in chicks from the 7 sites. Concentrations of both PCBs and TCDD-equivalents decreased immediately upon hatching of the chicks. Rates of accumulation of both contaminants in growing chicks were directly correlated with concentrations in forage fish consumed by the chicks.

12.

Mean (standard deviation) organochlorine residues found in DCC livers (N=3) collected from Clear Lake, California, in 1993, were 0.204 (0.266) mg/g wet weight (Wolfe and Norman, 1998).

13.

In 1994 and 1995, DCC 10-day old chicks were collected from Wisconsin, Minnesota, and South Dakota (Custer et al., 2001). Geometric mean (range) total PCB concentrations (N=10/colony) at Marsh Lake & Piyas Lake, Spider Island, Hat Island, and Cat Island were, respectively: 0.13 (0.02-0.44), 1.64 (1.2-2.3), 1.89 (1.6-2.6), and 3.45 (2.6-5.0) mg/g wet weight. cis-Nonachlor concentrations were less than 1 mg/g in chicks at all test sites and were not detected in samples from the reference sites (Marsh and Piyas Lakes).

Geometric mean dieldrin concentrations (N=5/colony/year) in 1994 were 0.012, 0.118, 0.083, and 0.067 mg/g at Piyas Lake, Spider Island, Hat Island, and Cat Island, respectively, and in 1995 were 0.0006, 0.061, 0.077, and 0.051 mg/g at Marsh Lake, Spider Island, Hat Island, and Cat Island, respectively. Geometric mean heptachlor epoxide concentrations (N=5/colony/year) in 1994 were 0.006, 0.035, 0.025, and 0.018 mg/g at Piyas Lake, Spider Island, Hat Island, and Cat Island, respectively and in 1995 were ND, 0.020, 0.020, and 0.012 mg/g at Marsh Lake, Spider Island, Hat Island, and Cat Island, respectively. Geometric mean oxychlordane concentrations (N=5/colony/year) in 1994 were 0.006, 0.020, 0.017, and 0.015 mg/g at Piyas Lake, Spider Island, Hat Island, and Cat Island, respectively and in 1995 were ND, 0.011, 0.012, and 0.011 mg/g at Marsh Lake, Spider Island, Hat Island, and Cat Island, respectively. Geometric mean DDE concentrations (N=5/colony/year) in 1994 were 0.177, 0.549, 0.652, and 0.530 mg/g at Piyas Lake, Spider Island, Hat Island, and Cat Island, respectively and in 1995 were 0.126, 0.379, 0.463, and 0.547 mg/g at Marsh Lake, Spider Island, Hat Island, and Cat Island, respectively. Geometric mean Van den Berg TEQs in 1994 were 1, 30, 46, and 48 pg/g at Piyas Lake, Spider Island, Hat Island, and Cat Island, respectively and in 1995 were 1, 9, 17, and 24 pg/g at Marsh Lake, Spider Island, Hat Island, and Cat Island, respectively.

14.

In 1995, 20 DCC hatchlings, ages 0 – 11 days, were collected from Doré Lake, Saskatchewan, Canada and raised at the Animal Care Unit, University of Saskatchewan (Kuiken et al., 1999).  These birds were euthenized at ages 5 to 27 weeks.  In 1992, ten four-week-old DCC with normal bills were collected from each of the following places, and euthanized: Churchill Lake, Saskatchewan, Canada; Pigeon Island, eastern Lake Ontario, Canada; Little Gull Island, upper Green Bay, Lake Michigan, USA.  Total PCBs in livers of captive cormorants with a normal bill (n = 1) were 0.085 mg/g wet weight; DDE was 0.011 mg/g.  Total PCBs in livers of captive cormorants with crossed-bills were 0.118 ± 0.013 mg/g, and DDE was 0.013 ± 0.001 mg/g.  Total PCBs in livers of free-living cormorants collected at Churchill Lake, Lake Ontario, and Lake Michigan, respectively, were: 0.027, 0.658, and 0.656 mg/g (each number represents an average from 10 birds).  DDE in livers of free-living cormorants collected at Churchill Lake, Lake Ontario, and Lake Michigan, respectively, were:  0.018, 0.162, and 0.131 (each number represents an average from 10 birds). 

B.

Concentrations in Eggs and Embryos

1.

DCC eggs (N=89) were collected from several colonies in the Prairie states and Canadian provinces in the vicinity of the Great Lakes (Anderson et al., 1969). Mean concentrations detected in 35 egg pools were 10.4 mg/g wet weight DDE and 8 mg/g PCBs. DDD and DDT were only rarely detected.

2.

DCC nestlings and eggs were collected from Muscongus Bay, Maine in 1966-67 (Kury, 1969). In 1966, 24 eggs contained a mean of 1.5 mg/g DDT, 0.7 mg/g DDD, and 6.2 mg/g DDE. In 1967, 11 eggs averaged 4.5 mg/g DDT, 1.5 mg/g DDD, and 7.6 mg/g DDE. In the same year, of 23 samples (representing 89 nestlings), only 5 had measurable concentrations of DDE, ranging from a trace to 0.29 mg/g.

3.

Composite samples of 10 DCC eggs collected from sixteen colonies in Alberta and Saskatchewan in 1968 and 1969 were analyzed for organochlorine residues (Vermeer and Reynolds, 1970). Mean concentrations for each colony ranged from 3.43-9.00 mg/g wet weight DDE and from 0.112-0.681 mg/g dieldrin. Heptachlor epoxide was measured in ten of the colonies and means ranged from 0.015-0.075 mg/g. b-BHC was detected in eight of ten colonies evaluated, and means ranged from 0.065-0.280 mg/g. Variation in DDE was calculated in one of colonies, Lake Therien, which had a mean level of 3.57 mg/g, a range 1.5-6.4 mg/g, and a coefficient of variation of 41.65.

4.

Crushed and intact eggs were collected in 1969 in southern California and northwest Baja California from the west inlet of Anacopa Island, South Los Coronados Island, and San Martin Island (Gress et al., 1973). Yolk of intact eggs was analyzed for chlorinated hydrocarbon residues. Mean (range) DDE residues in yolk lipids were 754 (510-1000) mg/g in the eggs from Anacapa Island, 574 (180-1300) mg/g from Los Coronados Island and 41.4 (24-63) mg/g in eggs from the San Martin colony. PCB was detected at concentrations of 87 (55-130), 422 (66-1100), and 17.6 (12-25) mg/g, respectively. DDD was present in eggs from the Anacapa Island (2.1, 0.66-6.8 mg/g) and Los Coronados Island (13.8, 3.6-36 mg/g) but not detected in samples from San Martin. Parent DDT was found at each of the sites: 7.0 (0.0-11) mg/g at Anacapa Island, 5.5 (0.0-12) mg/g at Los Coronados Island, and 0.28 (0.14-0.41) mg/g at San Martin.

5.

DCC eggs collected from various locations in Canada were analyzed for DDE and PCBs (Gilbertson and Reynolds, 1974). The following geometric means were determined for DDE and PCB respectively for each region (mg/g dry weight): British Columbia (N=1), 21.9 and 75.3; Alberta (N=2), 20.9 and 13.2; Saskatchewan (N=1), 22.2 and 4.29; Manitoba (N=2), 46.9 and 8.34; and Lake Nipigon (N=52), 56.8 and 77.5.

6.

Mean DDE concentrations in 90 DCC eggs collected during 1970-1976 from 11 colonies in eastern Canadian coastal waters ranged from 1.49-8.57 mg/g wet weight (Pearce et al, 1979). The highest mean and individual concentrations were generally found in 1972 and 1973, declining markedly by 1976. PCB means ranged from 5.66-19.3 mg/g and dieldrin from 0.07-0.21 mg/g.

7.

Eggs (N=17) from DCC rookeries on Dry Lake and South Waubay Lake, South Dakota, were collected for analysis in the early 1970s and analyzed for organochlorine residues (Greichus et al., 1973). Average DDE and PCB concentrations were 10.38 mg/g weight and 5.9 mg/g, respectively. Heptachlor epoxide, lindane, and dieldrin were found at levels of 0.05, 0.05, and 0.13 mg/g, respectively. Hepatic concentrations of PCBs in nestlings averaged 0.60 mg/g.

8.

One egg per 4-egg clutch was collected from Lake Ontario, Lake Erie, Georgian Bay in Lake Huron, the North Channel of Lake Huron, Lake Superior, Lake Nipigon, and Lake-of-the-Woods in 1970-72, 1975, 1979, 1981, 1983, 1984, 1989, 1990, and 1995 and analyzed for organochlorine pesticides, PCBs, dioxins, and dibenzofurans (Ryckman et al., 1998).  Mean DDE concentrations were greatest at Georgian Bay compared to other sites in 1972-73 at 18.56 µg/g wet weight but declined at all sites until the means ranged from 2.26-2.83 µg/g in 1995.  Mean dieldren was highest at Lake Huron in 1972-73 at 0.47 µg/g, but declined at all sites until the means ranged from 0.05-0.09 µg/g in 1995.  Mean mirex was highest at Lake Ontario in 1981 at 0.87 µg/g, but declined at all sites until the means ranged from 0.03-0.29 µg/g in 1995.  Mean photomirex was highest at Lake Ontario in 1984 at 0.28 µg/g, but declined at all sites until the means ranged from 0.01-0.03 µg/g in 1995. Mean oxychlordane was highest at Lake Superior in 1984 at 0.13 µg/g, but declined at all sites until the means ranged from 0.03-0.04 µg/g in 1995.  Mean heptachlor epoxide was 0.26 and 0.18 µg/g at Georgian Bay and Lake Nipigon, respectively in 1972-73 and 0.15 µg/g at Lake Superior in 1984, but <0.1 µg/g at all other sites in all collection periods.  Mean HCB was 0.18 µg/g at Georgian Bay in 1970-72 and <0.1 µg/g at all other sites in all collection periods. Mean concentrations of trans-nonachlor, and cis-nonachlor were <0.1 µg/g at all sites in all collection periods.  Mean total PCBs were greatest at Lake Erie in each collection period, with a peak in 1979 at 35.5 µg/g, but declined at all sites until the means ranged from 2.52-15.46 µg/g in 1995.  For eggs collected between 1989-91, mean concentrations of TCDD, 1,2,3,7,8-PnCDD, 1,2,3,6,7,8-HxCDD, 1,2,3,4,6,7,8-HpCDD, OCDD, 1,2,3,4,7,8-HxCDD, and 1,2,3,7,8,9-HxCDD ranged from 9-20, 14-27, 11-25, 8-21, 4-22, 1-3, and 3-8 pg/g, respectively.  For eggs collected between 1989-91, mean concentrations of 2,3,7,8-TCDF, 2,3,4,7,8-PCDF, 1,2,3,4,7,8/1,2,3,4,6,7-HxCDF, 1,2,3,6,7,8-HxCDF, and 2,3,4,6,7,8-HxCDF ranged from ND-2, 8-21, 2-7, 1-4, and 1-4 ng/g.

9.

The mean (standard deviation) concentration of DDE in 11 eggs collected in 1971 from Fatpot Island, Bay of Fundy, Maine, was 29.4 (8.5) mg/g wet weight (Zitko et al., 1972; Zitko and Choi, 1972; Zitko and Hutzinger, 1972) Four eggs collected at the same time from Hospital Island, Passamaquoddy Bay in New Brunswick, Canada had a mean DDE concentration of 8.63 (1.25) mg/g. PCB (Aroclor 1254) residues in eggs from these sites were 43.5 (2.6) and 17.2 (0.79) mg/g, respectively. Trace quantities of hexachlorobenzene, DDT, heptachlor epoxide, and dieldrin were present in most samples. Chlorinated dibenzodioxins and dibenzofurans were not detected.

10.

Eggs (9-10/year, 1 egg/nest) were collected in early May 1971 through 1975 from the DCC colony on Whitehorse Island, Bay of Fundy, for determination of chlorinated hydrocarbons in yolk (Zitko, 1976). Annual arithmetic means (standard deviation) of DDE residues from 1971-1975 were 9.70 (0.86), 6.72 (3.59), 2.89 (1.54), 1.92 (0.45), and 2.01 (5.21) mg/g wet weight, respectively. Mean DDD and DDT concentrations were <0.2 mg/g during the sampling period. PCB concentrations were 14.3 (0.86), 9.06 (3.42), 5.57 (2.46), 5.25 (1.90), and 5.23 (3.67) in samples from 1971-1975, respectively. Dieldrin was present in the 1972 samples at a concentration of 0.297 mg/g but generally lower (<0.20 mg/g) thereafter. HCB and mirex were found but at very low levels (generally <0.1 mg/g).

11.

Fresh and intact eggs (N=10), and dented and cracked eggs (N=8), were collected in 1972 from 5 colonies in the Lake Huron area and analyzed for contaminants (Weseloh et al., 1983). The overall mean (standard deviation) for DDE concentration was 14.5 (6.2) mg/g wet weight, with colony means ranging from 5.12-16.4 mg/g. Mean concentrations of parent DDT and DDD were 0.22 (0.20) and 0.17 (0.15) mg/g, respectively. Mean PCB concentration was 23.8 (9.6) mg/g, ranging from 10.3- 25.6 mg/g in the 5 colonies. Mean dieldrin concentration was 0.33 (0.33) mg/g, and heptachlorobenzene and heptachlor epoxide were found, and averaged mean levels < 0.05 mg/g.

12.

DCC eggs collected in 1973 from the Bay of Fundy and Passamaquoddy Bay contained pentachlorophenol at a concentration of 0.36 ng/g wet weight (Zitko et al., 1974).

13.

From 1973-1976, DCC eggs (N=4) were collected from Ugaiusyak Island, Gulf of Alaska (N=4) and from Shaiak Island, Bristol Bay, Alaska (N=3) (Ohlendorf et al., 1982). Concentrations of DDE and PCB were <1 mg/g wet weight in all samples. In eggs from Ugaiusyak Island, heptachlor epoxide, oxychlordane, and HCB were detected at concentrations <1 mg/g. In eggs from Shaiak Island, DDD, dieldrin, heptachlor epoxide, oxychlordane, cis-nonachlor and HCBs were found at <1 mg/g.

14.

Eggs collected from 1977-1980 in rookeries around Green Bay, Wisconsin and Lake Michigan were analyzed for organochlorine contaminants (Heinz et al., 1985). Mean contaminant concentrations ranged from 0.40 to 5.3 mg/g wet weight DDE and from 2.0 to 16.5 mg/g PCB. TDE, heptachlor epoxide, oxychlordane, cis-chlordane, trans-nonachlor, cis-nonachlor, endrin, toxaphene, HCB, mirex, PCS, and PBB were detected at concentrations <1 mg/g.

15.

Organochlorine contaminants were quantified in eggs (N=10) collected in 1979 from the Oregon coast (Henny et al., 1982). Geometric mean (standard deviation) concentrations of DDE and PCBs were 1.6 (0.77-5.2) and 1.3 (0.45-10) mg/g fresh wet weight, respectively. Dieldrin was detected in 2 eggs at 0.09 and 0.19 mg/g, oxychlordane in 2 eggs at 0.12 and 0.16 mg/g; and cis-nonachlor in 1 egg at 0.09 mg/g.

16.

Twenty 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; PCB congener #52 31, #97 5.89, #101 132, #118 1,066, #153 2,216, #105 165, #138 2,445, #180 1,756, #203 280, #77 0.08, #126 2.60, #169 0.45, Aroclor1254-1260 33,044.

1992 Lake Erie; PCB congener #52 15, #97 1.67, #101 61, #118 601, #153 1,804, #105 106, #138 1,758, #180 1,626, #203 246, #77 0.04, #126 2.08, #169 0.39, Aroclor1254-1260 23,754.

1981 Lake Ontario; PCB congener #52 24, #97 3.09, #101 76, #118 647, #153 1,070, #105 108, #138 994, #180 691, #203 136, #77 0.15, #126 2.14, #169 0.16, Aroclor1254-1260 13,573.

1992 Lake Ontario; PCB congener #52 12, #97 0.04, #101 35, #118 653, #153 528, #105 104, #138 981, #180 913, #203 146, #77 0.09, #126 2.54, #169 0.36, Aroclor1254-1260 13,381.

17.

Eggs collected in 1984 from Protection Island National Wildlife Refuge (N=11) and Colville Island (N=36), Washington, were analyzed for organochlorine contaminants and heavy metals (Henny et al., 1989). Geometric mean concentrations of DDE were 0.59 mg/g wet weight at Protection Island National Wildlife Refuge and 0.58 mg/g at Colville. The highest concentrations detected were 3.2 mg/g at Colville Island and 1.7 mg/g at Protection Island. Mean PCB levels were 2.19 mg/g at Colville Island and 1.37 mg/g at Protection Island, with highest values of 25 and 12 mg/g at each site, respectively.

18.

In 1984, DCC eggs (N=127) were collected from 12 sites in southern Alberta, Canada for analysis of organochlorine contaminants (Somers et al., 1993). Major contaminants were DDE and PCBs. The overall geometric mean DDE concentration was 3.90 mg/g wet weight, with means from the 12 sites ranging from 2.59-6.16 mg/g. The overall mean PCB concentration was 2.22 mg/g with the 12 sites ranging from 1.16-5.58 mg/g. The mean dieldrin concentration, based on analysis of eggs from 3 sites, was 0.068 mg/g. Cis-chlordane was not detected in any of the eggs, and DDD and parent DDT were detected in only 7 eggs. Other chlorinated chemicals found at concentrations <0.01 mg/g included HCB, BHC, oxychlordane, heptachlor epoxide, mirex and endrin.

19.

Between 1986-1988, DCC eggs were collected from 11 colonies in 5 locations around the Great Lakes and a distant reference site outside the lake region (Tillitt et al., 1992). Samples were analyzed for total PCBs and for TCDD-equivalents via an in vitro H4IIE rat hepatoma bioassay. Reproductive success was also monitored at these sites. Mean total PCB concentrations ranged from 0.1 to 14.8 mg/g wet weight from the sites in the Great Lakes compared to 0.08 mg/g in eggs from the reference location. Concentrations of H4IIE bioassay-derived TCDD-equivalents ranged from 85 to 344 pg/g in eggs from the Great Lakes sample regions compared to 35 pg/g from the reference eggs.

20.

DDE, PCB, TEQs and other organochlorine contaminants were determined in DCC eggs collected in 1988 from the upper areas of the Great Lakes for correlations with toxicological endpoints (Yamashita et al., 1993). PCB concentrations in the DCC eggs ranged from 3600 to 7300 pg/g wet weight and DDE levels ranged from 2200-6300 pg/g. Other organochlorines were present at concentrations <60 pg/g.

21.

In 1989, DCC eggs and chicks were collected from 8 sites in the Great Lake region and assayed for total PCBs, and TCDD-equivalents using the in vitro H4IIE rat hepatoma bioassay (Jones et al., 1994). The TCDD-equivalents ranged from 141.7 to 382.3 pg/g wet weight in eggs and from 17.9 to 398.9 pg/g in chicks from the 7 sites. Concentrations of both PCBs and TCDD-equivalents decreased immediately upon hatching of the chicks. Rates of accumulation of both contaminants in growing chicks were directly correlated with concentrations in forage fish consumed by the chicks.

22.

In 1989, one DCC egg was collected from each of 1000 nests on Spider Island, near Green Bay, Wisconsin (Williams et al., 1995). Nine pools of three eggs each were randomly selected for contaminant analysis. Mean (range) concentration of total PCBs was 15.5 (9.71-38.4) mg/g wet weight. Mean concentrations were determined for non-ortho-substituted PCB congeners 77 (2.03 ng/g), 81 (2.23 ng/g), 126 (6.12 ng/g), 169 (1.27 ng/g), and mono-ortho-substituted congeners 105 (224 ng/g), 118 (595 ng/g), 138 (924 ng/g) and 153 with co-eluting congener 132 (1530 ng/g). Mean TEQs and TCDD-EQ were determined to be 150 and 350 pg/g, respectively. PCB congeners contributed <50% of the total TCDD-EQs in these samples.

23.

In 1990 and 1991, DCC eggs were collected from one highly contaminated colony (Pigeon Island, Lake Ontario, N=4), three moderately contaminated colonies (two near the Straight of Georgia, British Columbia--near Crofton, N=6, and on Christy Island, N=12,--and one from an ecological reserve on the southern tip of Vancouver Island, N=15), and one reference colony (Lost Mountain Lake, Saskatchewan, N=12) (Henshel et al., 1997).  Mean TCDD concentrations were 5.6 pg/g wet weight at the reference site, 20.8-33.4 pg/g at intermediate sites, and 37.3 at Lake Ontario.  Concentrations of individiual PCB congeners, respectively, were 83, 41-76, and 342 pg/g PCB-77; 520, 256-784, and 3731 pg/g PCB-126; 89, 49-104, and 430 pg/g PCB-169, 133,000, 26,000-62,000, and 173,000 pg/g PCB-188; 18,300, 26,000-62,000, and 173,000 pg/g PCB-105.  TEQs values are reported for several methods of calculation; mean values as calculated by Safe were 241.44 pg/g at the reference site, 253.37-611.88 pg/g at intermediate sites, and 1276.58 pg/g at Lake Ontario.

24.

About 1000 DCC eggs were collected from Big Sister Island, Green Bay, Lake Michigan and combined to form one 41,293 gram sample (Meadows et al., 1996). Total PCB concentration for the sample was 5849 ng/g. Individual PCB congeners analyzed included non-ortho-substituted: 81 (883 pg/g), 77 (570 pg/g), 126 (3667 pg/g), and mono-ortho-substituted: 105 (301 ng/g), 114 (19 ng/g), 118 (704 ng/g), 123 (7.4 ng/g), 156 (59 ng/g), 157 (20 ng/g), 167 (49 ng/g), and 189 (7.8 ng/g). Concentrations of dieldrin and DDE were quantified as .0257 and 1.155 mg/g, respectively. Concentrations of HCB, a-BHC, b-BHC, oxychlordane, heptachlor epoxide, trans-nonachlor, cis-chlordane, o,p=-DDD, endrin, cis-nonachlor, DDD, DDT , and mirex were <0.1 mg/g.

25.

As part of a reproductive study, 75 DCC eggs were collected for contaminant analysis from nests on Cat Island, Green Bay, Wisconsin in 1994 and 1995 (Custer et al., 1999).  Mean concentrations for both years combined were 13.6 µg/g wet weight total PCBs, 3.9 µg/g DDE, 0.25 µg/g dieldrin, 0.08 µg/g heptachlor epoxide, 0.5 µg/g oxychlordane, 0.04 µg/g cis-nonachlor, 0.02 µg/g mirex, and 0.01 µg/g HCB.  trans-Nonachlor, cis-chlordane, endrin, toxaphene, DDD, and DDT were detected in less than half the samples.  HCH isomers, trans-chlordane, o,p’-DDE, o,p’-DDD, and o,p’-DDD were not detected in any samples.

26.

In 1994 and 1995, DCC pipping embryos were collected from Wisconsin (Spider Island, Hat Island, and Cat Island), Minnesota (Marsh Lake), and South Dakota (Piyas Lake) (Custer et al., 2001).  Geometric mean (range) total PCB concentrations (N=10/colony) at Marsh Lake & Piyas Lake, Spider Island, Hat Island, and Cat Island were, respectively: 0.9 (0.1-4.6), 9.6 (5.2-20.1), 10.0 (7.1-15.0), and 13.4 (9.0-22.8) mg/g wet weight. For all four sites, mean concentrations of cis-nonachlor, oxychlordane, HCB, mirex, and congeners 114, 128, 156, 157, 158, 167, and 189 were all below 1 mg/g. Concentrations of congener 126 were nine- to ten-fold higher at Spider, Hat, and Cat Islands than at the reference sites, Marsh and Piyas Lakes. Wisconsin sites had significantly higher concentrations of all organochlorines except mirex and HCB.

Geometric mean dieldrin concentrations (N=5/colony/year) in 1994 were 0.066, 0.391, 0.212, and 0.140 mg/g at Piyas Lake, Spider Island, Hat Island, and Cat Island, respectively and in 1995 were 0.029, 0.095, 0.114, and 0.088 mg/g at Marsh Lake, Spider Island, Hat Island, and Cat Island, respectively.  Geometric mean heptachlor epoxide concentrations (N=5/colony/year) in 1994 were 0.023, 0.113, 0.086, and 0.048 mg/g at Piyas Lake, Spider Island, Hat Island, and Cat Island, respectively and in 1995 were ND, 0.064, 0.042, and 0.044 mg/g at Marsh Lake, Spider Island, Hat Island, and Cat Island, respectively. Geometric mean DDE concentrations (N=5/colony/year) in 1994 were 1.15, 3.63, 4.14, and 1.94 mg/g at Piyas Lake, Spider Island, Hat Island, and Cat Island, respectively and in 1995 were 0.67, 1.74, 2.42, and 3.59 mg/g at Marsh Lake, Spider Island, Hat Island, and Cat Island, respectively.

Geometric mean congener 77 concentrations (N=5/colony/year) in 1994 were 0.0001, 0.0004, 0.0004, and 0.0003 mg/g at Piyas Lake, Spider Island, Hat Island, and Cat Island, respectively and in 1995 were ND, 0.0001, ND, and 0.0002 mg/g at Marsh Lake, Spider Island, Hat Island, and Cat Island, respectively. Geometric mean congener 105 concentrations (N=5/colony/year) in 1994 were 0.014, 0.102, 0.102, and 0.092 mg/g at Piyas Lake, Spider Island, Hat Island, and Cat Island, respectively and in 1995 were 0.011, 0.132, 0.176, and 0.373 mg/g at Marsh Lake, Spider Island, Hat Island, and Cat Island, respectively. Geometric mean congener 169 concentrations (N=5/colony/year) in 1994 were ND, 0.0002, 0.0001, and 0.0001 mg/g at Piyas Lake, Spider Island, Hat Island, and Cat Island, respectively and in 1995 were ND, 0.0001, 0.0001, and 0.0001 mg/g at Marsh Lake, Spider Island, Hat Island, and Cat Island, respectively. Geometric mean Van den Berg TEQs in 1994 were 13, 188, 128, 106 pg/g at Piyas Lake, Spider Island, Hat Island, and Cat Island, respectively and in 1995 were 6, 98, 120, and 227 pg/g at Marsh Lake, Spider Island, Hat Island, and Cat Island, respectively.

27.

Fresh eggs (N=5) were collected in 1995 from a colony of DCC on Cat Island, Green Bay, Wisconsin that was contaminated with PCBs (Custer et al., 1997). Samples consisting of egg contents (excluding shell and chorioallantoic membrane) and sibling embryos (head, yolk sac, liver, fecal sac and remaining carcass) were analyzed for organochlorine contaminants including PCB congeners. A total of 20 organochlorine compounds including 13 PCB congeners were detected in all eggs and sibling embryos. In eggs and embryos, DDE concentrations were 2.22 and 2.17 mg/g wet weight, respectively, and total PCBs were 12.9 and 14.0 mg/g, respectively. Dieldrin, concentrations were 0.147 and 0.157 mg/g in the eggs and embryos, respectively. Oxychlordane, cis-nonachlor, and heptachlor epoxide were detected at values <0.05 mg/g. The most common PCB congeners were 118/106 and 138.

28.

Freshly laid DCC eggs were collected from Lake Huron and Lake Superior, Michigan, sites in May 1998 (Kannan et al., 2001). Mean (range) concentrations (N=3) from Little Charity Island, Lake Huron, were (in pg/g wet weight), respectively: 1,650,000 (1,250,000-2,370,000) total PCBs, 1200 (620-2400) total PCNs, 62 (25-97) 2,3,7,8-PCDDs, and 48 (28-76) 2,3,7,8-PCDFs. Mean (range) concentrations (N=3) from Scarecrow Island, Lake Huron, were (in pg/g), respectively: 1,420,000 (1,220,000-1,680,000) total PCBs, 1100 (520-1900) total PCNs, 16 (7.4-26) 2,3,7,8-PCDDs, and 37 (22-57) 2,3,7,8-PCDFs. Mean (range) concentrations (N=3) from Taquamenon, Lake Superior, were (in pg/g), respectively: 1,790,000 (1,130,000-2,960,000) total PCBs, 1100 (380-2000) total PCNs, 26 (18-37) 2,3,7,8-PCDDs, and 27 (20-37) 2,3,7,8-PCDFs. No significant differences between sites were found. Low concentrations of 2,3,7,8-substituted PCDDs and PCDFs were reported.

Mean TCDD equivalents, totaling 55 pg/g, for Little Charity Island were (in pg/g): 33 PCBs, 1.1 PCNs, 13 PCDDs, and 7.8 PCDFs. Mean TCDD equivalents, totaling 35 pg/g, for Scarecrow Island were (in pg/g): 25 PCBs, 1 PCNs, 3.2 PCDDs, and 6 PCDFs. Mean TCDD equivalents, totaling 38, for Taquamenon were (in pg/g): 28 PCBs, 0.89 PCNs, 6.3 PCDDs, and 3.1 PCDFs. PCNs only contributed 2-3% of the total TEQs while PCBs contributed 60-73%.

II.

Cholinesterase-Inhibiting Pesticides

No direct exposure data available.

III.

Trace Elements, Metals, and Metalloids

A.

Concentrations in Adults, Juveniles, and Nestlings

1.

Tissues from DCCs (N=10) were collected in the early 1970s from rookeries on Dry Lake and South Waybay Lake, South Dakota (Greichus et al., 1973). Mercury concentrations in adult body, muscle, kidney, and liver were 0.64, 0.78, 1.51, and 7.98 mg/g wet weight. Hepatic concentrations of Hg in nestlings averaged 0.28 mg/g.

2.

Adult DCC were collected in the early 1970s from 3 sites on the Cheyenne river system in South Dakota (N=6), and controls (N=3) were collected from Lewis and Clark Lake and the Missouri River, South Dakota (Hesse et al., 1975). Mean (SE) Hg concentrations in pectoris muscle, liver, and kidney from the Cheyenne River birds were 2.28 (0.74), 30.9 (15), and 7.49 mg/g wet weight, respectively, compared to 0.94 (0.29), 7.61 (3.66), and 3.02 (1.04) mg/g in birds from the control site.

3.

Concentrations of Hg in breast muscle and liver were determined in one adult DCC collected from the Savannah area of Georgia in 1978 and one collected from the same area in 1980 (Odom, 1981). Mercury concentrations in the muscle and liver were 1.70 and 13.69 mg/g wet weight, respectively, in the bird collected in 1978, and 0.64 and 2.13 mg/g in the bird collected in 1980.

4.

Concentrations of Hg were determined in tissues from adult DCC (N=3) collected from the Quoddy area of New Brunswick (Braune, 1987). One bird was field collected during the period of 1978-1984 and two were received from the New Brunswick Museum as obtained in 1978-1979. Mean tissue Hg concentrations in muscle, liver, kidney and brain were 0.606, 7.048, 5.345, and 0.360 mg/g wet weight, respectively.

5.

Concentrations of several elements were determined in liver of three adult DCCs found dead in 1984 near Williamson Rocks, Washington (Henny et al., 1989). Concentrations in the birds ranged from of 5.7-12.0 mg/g wet weight Hg, 3.4 to 4.2 mg/g Se, 3.6-5.2 mg/g Cu, 180-309 mg/g Fe, and 20.8-27.1 mg/g Zn.

6.

Concentrations of several elements were determined in nine adult DCC collected in 1986 from the Mexicali Valley in northeastern Baja, California (Mora and Anderson, 1995). Mean (range) Se liver concentrations were 5.1 (2.9-7.3) mg/g wet weight which were significantly higher than in tissues of 4 other species of birds collected at the same time. Levels of Zn, Cd, Cu, Cr, and B were similar in DCC and the other 4 species and considered to be well below thresholds for biological effects in birds.

7.

Adult DCC were collected during the 1988 breeding season from Heron and Manawagonish Islands, New Brunswick, and juveniles about 6 weeks of age were collected from Manawagonish Island and from Ile au Pommes, Quebec (Elliott et al., 1992). Tissues were analyzed for toxic metals (Cd, Hg, and Pb) plus 18 other trace elements. Mean (range) concentrations of Hg in adult liver samples from the 2 sites were 9.2 (3.1-29) and 21 (1.0-82) mg/g dry weight while values in the juvenile birds were lower, 1.68 (1.2-2.20) and 1.18 (0.70-2.10) mg/g. In kidneys, Hg values in adults from the 2 sites were 10.5 (2.45-42.6) and 12.9 (3.61-27.7) mg/g compared to 1.09 (0.83-1.55) and 0.77 (0.50-1.50) mg/g in the juveniles. Mean Pb levels in tissues of adult and juveniles were generally <0.5 mg/g except in bone of adults from one site where the mean was 0.84 (0.12-2.87) mg/g. Selenium levels varied greatly but were in the broad range normally expected. Histological examination of liver and kidney failed to reveal any indications of tissue damage associated with elevated levels of heavy metals. Levels of the essential trace elements were in close agreement with previously reported literature values.

8.

From 1993 to 1994, double-crested cormorant nestlings were collected near a Hg mine in Clear Lake, California (Wolfe and Norman, 1998).  Mean (range) Hg concentrations in tissues were 0.63 (0.54-0.72) mg/g wet weight in brain, and 2.42 (1.91-2.94) mg/g in liver. 

In 1993, at Quercus Point, mean (standard deviation) Hg concentrations in tissues of five young double-crested cormorants (in mg/g wet weight) were 0.72 (0.15) in brain, 2.94 (1.07) in liver, and 2.95 (0.31) in feathers.

In 1994, at Quercus Point, mean (standard deviation) Hg concentrations in tissues of 10 young double-crested cormorants (in mg/g) were 0.54 (0.09) in brain, 1.91 (0.39) in liver, and 4.05 (1.32) in feathers.

Mercury concentrations were not correlated to distance from the Hg mine.

9.

In 1994, adult DCC feathers were collected at Agassiz NWR in Minnesota (Burger and Gochfeld, 1996). Mean heavy metal concentrations in adult feathers were: 1930±310 ng/g dry weight Pb, 957±167 ng/g Cd, 4840±878 ng/g Hg, 1510±135 ng/g Se, 790±111 ng/g Cr, and 40,100±6764 ng/g Mn.

10.

In 1995, 20 DCC hatchlings, ages 0 – 11 days, were collected from Doré Lake, Saskatchewan, Canada and raised at the Animal Care Unit, University of Saskatchewan (Kuiken et al., 1999).  These birds were euthenized at ages 5 to 27 weeks.  In 1992, ten four-week-old DCC with normal bills were collected from each of the following places, and euthanized: Churchill Lake, Saskatchewan, Canada; Pigeon Island, eastern Lake Ontario, Canada; Little Gull Island, upper Green Bay, Lake Michigan, USA.  Pb concentration in the liver of a captive cormorant with a normal bill (n = 1) was 0.21mg/g dry weight; Cd was 1.12 mg/g, Hg was 1.10 mg/g, and Se was 5.06 mg/g.  Pb concentration in the kidenys of captive cormorants with crossed-bills were <0.08 mg/g, Cd was 2.44 ± 0.37 mg/g, Hg was 0.93 ± 0.26 mg/g, and Se was 4.23 ± 0.53 mg/g.  In kidneys of free-living cormorants collected at Churchill Lake, Lake Ontario, and Lake Michigan, respectively: Pb concentrations were <0.04, 0.07, and <0.04 mg/g; Cd concentrations were <0.16, 0.64, and 0.82 mg/g; Hg concentrations were 0.27, 1.26, and 0.78 mg/g; and Se concentrations were 3.4, 15.3, and 8.2 mg/g (each number represents an average from 10 birds). 

11.

Sick or injured birds were collected from southern Florida between 1994-97, and analyzed for Hg and Se (Sepulveda et al. 1998).  Mean Hg concentration in liver, kidney, and brain was 48, 12, and 1.5 µg/g wet weight, respectively in adults and 12, 4.8, and 1.6 µg/g in juveniles. Mean Se concentration in liver, kidney, and brain was 19, 9.9, and 1.2 µg/g in adults and 4.1, 3.5, and 0.45 µg/g in juveniles.

12.

In 1995, blood, liver, muscle, and feathers were collected from DCC nestlings at Caballo and Elephant Butte reservoirs in New Mexico (Caldwell et al., 1999).   The number of samples ranged from 3-18.  Blood was collected twice, at 7-10 days after hatching and again 10-12 days later.  Mean (range) blood Hg concentrations for Caballo and Elephant Butte, respectively, were 0.36 (0.20-0.70) and 0.36 (0.22-0.72) µg/g wet weight at the first collection, and 0.39 (0.39-0.40) and 0.34 (0.22-0.50) µg/g at the second collection.  Concentrations of Hg in other tissues for the two reservoirs were 0.40 (0.34-0.48) and 0.40 (0.30-0.51) µg/g in liver, 0.18 (0.16-0.21) and 0.17 (0.12-0.23) µg/g in muscle, 3.54 (2.20-4.60) and 2.42 (1.40-5.30) µg/g in primary feather, 4.89 (2.40-10.0) and 2.06 (1.40-3.20) µg/g in secondary feather, and 4.01 (2.40-7.60) and 2.34 (1.50-5.0) µg/g in tail feather.  Concentrations of Hg in feathers were not strongly correlated with concentrations in other tissues. 

B.

Concentrations in Eggs and Embryos

1.

Mean Hg concentration in DCC eggs (N=5) collected about 1970 from rookeries on Dry Lake and South Waubay Lake in South Dakota was 0.29 mg/g wet weight (Greichus et al., 1973). Hepatic concentrations of Hg in nestlings averaged 0.28 mg/g.

2.

Mean Hg concentrations in 90 DCC eggs collected during 1970-1976 from 11 colonies in eastern Canadian coastal waters ranged from 0.21-0.50 mg/g wet weight (Pearce et al, 1979).

3.

Mean (SD, where N>1) Hg values in DCC eggs (N=18) collected in 1972 from 3 sites in the North Channel of Lake Huron were 0.32, 0.34 (0.12), and 0.38 (0.11) mg/g wet weight, and 0.83 (0.09) and 0.53 (0.04) mg/g from 2 sites from the Georgian Bay area (Weseloh et al., 1983). The overall mean concentration of Hg in eggs from the 5 sites was 0.46 (0.20) mg/g.

4.

Mean Hg concentrations in DCC eggs (N=19) collected from 1977 to 1980 from sites around Green Bay and Lake Michigan were <0.32 mg/g wet weight (Heinz et al., 1985).

5.

DCC eggs were collected in 1984 from 2 nesting sites in northwest Washington (Henny et al., 1989). Mean Hg and Se concentrations were 0.26 and 0.28 mg/g wet weight in eggs (N=11) from Protection Island, respectively, and 0.27 and 0.31 mg/g in eggs (N=12) from Colville Island. Both elements were found in all eggs. Maximum concentrations at each site were 0.67 and 0.44 mg/g Hg and 0.41 and 0.47 mg/g Se.

6.

In 1994, DCC eggs were collected at Agassiz NWR in Minnesota (Burger and Gochfeld 1996). The mean heavy metal concentrations in the eggs were: 128±39 ng/g dry weight Pb, 390±46 ng/g Cd, 1610±128 ng/g Hg, 1960