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Biological Characteristics
|
Species |
Ardea
herodias (GBH) is 97-137 cm in length, with a mean
wingspan of 179 cm. Males tend to have a greater average mass (2.6 kg)
than females (2.2 kg) (Dunning, 1993). Both sexes have a blue-gray back,
blackish sides and a gray and white striped belly. The crown, cheeks,
and throat are white, and a black stripe on the side of its crown merges
into a long occipital crest. The bill is yellow and the legs
greenish-brown. In breeding condition, grey plumes cover the back and
lower neck. An all-white form ("great white heron") occurs in
Florida (Hancock and Kushlan, 1984; McVey et al., 1993). |
|
Status
in Estuaries |
This
species can be found along inland freshwater lakes and rivers, brackish
marshes, lagoons, mangrove areas, and coastal wetlands. Nesting occurs
either in single-species or mixed colonies (Spendelow and Patton, 1988).
Nests are usually formed in trees, but ground, rock, cliff edges, reeds
or rushes may also be used. Typical clutch size is 3-7 eggs (Hancock and
Elliott, 1978). Young are altricial (Ehrlich et al., 1988). The maximum
age of a GBH recorded in nature 20 years (Bayer, 1981). |
|
Abundance
and Range |
The
GBH breeds throughout the U.S. and winters as far north as New England
and southern Alaska. (Bull and Farrand, 1977). The nationwide population
is estimated at 83,000 individuals (NACWCP, 2001). |
|
Site
Fidelity |
Great
blue herons are inclined to renest in the same area year after year. Old
nests may be enlarged and reused (Eckert, 1981). |
|
Ease
of Census |
Simple |
|
Feeding
Habits |
Generalist.
The GBH forages by walking slowly or standing motionless in water and
striking at prey. This species rarely forages more than 15 to 20 km from
its nesting grounds. Fishing requires shallow waters (up to 0.5 m) with
a firm substrate. Main prey items are fish and amphibians, but the GBH
will also take small mammals, reptiles, crustaceans, insects, and birds
(McVey et al., 1993). |
|
Great
Blue Heron Contaminant Exposure Data |
|
|
I. |
Organochlorine Contaminants |
|
A. |
Concentrations
in Adults |
|
1. |
From
1966-78, adult GBHs were collected from Maryland, Virginia, Florida,
North Carolina, Illinois, Michigan, Minnesota, and Wisconsin (Ohlendorf
et al., 1981). The following ranges of contaminant concentrations were
determined (µg/g wet weight): DDE:
0.63-130.0 in carcass (excludes head, skin, feet, wing tips, liver,
kidneys and gastrointestinal tract) and 0.15-82.0 in brain, TDE:
ND-78.0 in carcass and ND-22.0
in brain, dieldrin:
ND-7.9 in carcass and ND-14.0 in brain, heptachlor
epoxide: <1.0 in carcass and ND-1.9 in brain, cis-chlordane:
ND-1.8 in carcass and ND-2.5 in brain, trans-nonachlor: ND-2.5 in carcass and
ND-2.7 in brain, and mirex:
ND-4.5 in carcass and ND-2.9 in brain. DDT,
oxychlordane,
cis-nonachlor, endrin,
toxaphene, and HCB were
detected at concentrations 1.0 µg/g. PCB
concentrations ranged from ND-130 µg/g in carcass and ND-220 µg/g in
brain. |
|
2. |
A
GBH found dead in Sacramento County in 1968 contained 4.0 µg/g PCBs
in brain tissue (Bischoff et al., 1970). |
|
3. |
Two
GBHs, one dead and one alive and tremoring, were collected from Marshall
and Day Counties of northeastern South Dakota in the spring of 1975
(Call et al., 1976, Call et al., 1977). Residues detected from the bird
brought in alive were 246.33 µg/g wet weight brain and 569.74 µg/g
liver DDE, 0.98 µg/g brain
and 1.63 µg/g liver DDD,
0.60 µg/g brain and 0.64 µg/g liver DDT,
0.47 µg/g brain and 1.06 µg/g liver dieldrin,
less than 0.05 µg/g brain and liver lindane,
0.35 µg/g brain and 0.51 µg/g liver heptachlor
epoxide, and 1.00 µg/g brain and 2.50 µg/g liver PCBs.
For the bird found dead, only liver concentrations were measured, at
1.21 µg/g DDE, 0.98 µg/g
0.37 DDD, 0.26 µg/g DDT, 0.20 µg/g dieldrin,
less than 0.05 µg/g heptachlor
epoxide, and 0.42 µg/g PCBs. |
|
4. |
Organochlorine
residues were measured from the brains of GBHs from Maine, Maryland,
Virginia, Florida, North Carolina, Illinois, Minnesota, and Wisconsin (Ohlendorf
et al., 1979a). Dieldrin
was thought to be the cause of death of most of the herons, with levels
ranging from 5.1 µg/g wet weight to 14.0 µg/g. The highest levels were
found in Minnesota birds. Endrin
was detected at concentrations of 0.86 µg/g and 0.60 µg/g from
Minnesota and Wisconsin birds, respectively. A North Carolina bird
showed high levels of DDE
(62 µg/g), DDD (21 µg/g), and DDT
(20 µg/g) and a Wisconsin heron had PCBs
at 220 µg/g. |
|
5. |
Three
GBHs collected from the Sheboygan River area of Wisconsin between 1976
and 1980 were analyzed for organochlorines and PCBs
(Heinz et al., 1984). PCB
concentrations were highest in the brain, reaching levels of 220 µg/g
wet weight and 50 µg/g. DDE
was reached a high of 16 µg/g in the brain and 7.8 µg/g in the
carcass. Dieldrin was
detected in two of the birds, reaching levels of 2.8 µg/g in the brain
and 0.92 µg/g in the carcass. |
|
6. |
Adult
GBHs found dead in Umatilla, Oregon, and Wenatchee, Washington, from
1977 to 1981 were analyzed for organochlorine brain residues (Fitzner et
al., 1988). DDE
concentrations for the two birds found in Washington were 25.0 and 0.10
µg/g wet weight. The two birds recovered in Oregon contained levels of
14.0 and 15.0 µg/g. PCBs were measured at 2.50 and 0.10 µg/g in Washington and
7.40 and 12.0 µg/g in Oregon. Dieldrin
and oxychlordane were found
in one Oregon heron at levels of 0.31 µg/g and 0.23 µg/g,
respectively. HCB was
detected in both Oregon birds at levels of 0.23 and 0.87 µg/g. |
|
7. |
A
GBH sickened from the parasitic roundworm, Eustrongylides
ignotus, shot in Oneida County, Wisconsin, was analyzed for
organochlorine residues in the brain (Windingstad and Swineford, 1981).
The following organochlorines were detected: DDE
(86.00 µg/g wet weight), DDD
(3.10 µg/g), DDT (0.71 µg/g),
dieldrin (0.82 µg/g), heptachlor
epoxide (0.23 µg/g), cis-chlordane
(1.30 µg/g), cis-nonachlor
(0.16 µg/g), toxaphene
(0.99 µg/g) and PCB (4.60
µg/g). |
|
B. |
Concentrations
in Nestlings |
|
1. |
From
1966-78, chicks and fledglings were collected from Maryland, Virginia,
Florida, North Carolina, Illinois, Michigan, Minnesota, and Wisconsin (Ohlendorf
et al., 1981). DDE residues
ranged from ND-20.0 µg/g wet weight in the carcass (excludes head,
skin, feet, wing tips, liver, kidneys and gastrointestinal tract) and
ND-9.7 µg/g in the brain. TDE ranged
from ND-5.5 µg/g in the carcass and ND-2.0 in the brain. Dieldrin
ranged from ND-6.5 µg/g in the carcass and from ND-3.9 µg/g in the
brain. Cis-chlordane ranged from ND-1.7 µg/g
in the carcass and ND-0.75 µg/g in the brain. Trans-nonachlor concentrations ranged
from ND-3.0 µg/g in the carcass and ND-1.0 µg/g in the brain. Heptachlor
epoxide, oxychlordane, cis-nonachlor,
endrin, toxaphene,
HCB, and mirex
were detected at concentration <1.0 µg/g. PCB
concentrations ranged from ND-6.4 µg/g in the carcass and ND-36 µg/g
in the brain. |
|
2. |
Three
GBH nestlings collected in 1969 and 1970 from Bolinas Lagoon, near San
Francisco, were analyzed for organochlorine residues (Faber et al.,
1972). Individual
contaminant concentrations in the nestlings were 0.49, 1.18, and 0.16 µg/g
wet weight DDE, 0.56, 1.33,
and 0.18 µg/g total DDT,
and 1.35, 1.82, and 0.49 µg/g PCB. |
|
3. |
GBH
chicks were collected in 1976 from four sites along the Upper
Mississippi River in Minnesota (Royalton, South St. Paul, and Wabasha)
and Wisconsin (La Crosse) (Ohlendorf et al., 1979). DDE,
total DDT, and PCBs
were detected in all chicks and mean concentrations were significantly
greater in South St. Paul when compared to all other colonies. Means at
each locality ranged from 0.37-1.31 DDE,
0.38-1.90 total DDT, and 0.22-6.43 PCB
µg/g wet weight. Concentrations of DDT,
detected in all chicks from La Crosse and South St. Paul, 1 of 10 chicks
from Royalton, and 5 of 12 chicks from Wabasha, were 0.1 µg/g.
Concentrations of TDE,
detected in all chicks from South St. Paul and La Crosse, 8 of 12 from
Wabasha, and 1 of 10 from Royalton, were 0.72 µg/g. In general, residue
concentrations tended to decrease as birds increased in weight. |
|
4. |
Livers
collected from GBH nestlings found dead at Lake Okeechobee, Florida, and
great white heron nestlings found dead in Florida Bay, between
1987-1991, were pooled for pesticides analysis (Spalding et al., 1997).
In GBH, mean concentrations of HCB,
oxychlordane, heptachlor epoxide, trans-nonachlor,
and DDE
were 0.01, 0.03, 0.03, 0.05, and 0.38 µg/g wet weight,
respectively. Only DDE
was detected in great white herons, at a mean concentration
of 0.02 µg/g. |
|
5. |
Between
1991 and 1994, nestlings were collected from 4 sites in Tennessee: 2
colonies on Oak Ridge Reservation (n=38), K25 and Melton Hill, and 2
reference colonies (n=35), Long Island and Looney Island (Halbrook et
al. 1999).
Mean (range) concentrations of Arochlor
1260 for the 4 sites, respectively, were 0.77 (0.10-3.90),
0.25 (0.05-0.15), 0.23 (0.09-0.53), and 0.20 (0.08-0.46) µg/g wet
weight in liver, 1.05 (0.13-4.00), 0.16 (0.07-0.30), 0.41 (0.04-1.60),
and 0.23 (0.09-0.71) µg/g in muscle, and 48.63 (5.70-180.00), 10.78
(2.50-28.00), 14.49 (3.90-74.00), and 19.04 (4.00-48.00) µg/g
in fat. |
|
6. |
In
1993, at Clear Lake, California, one GBH nestling was found to have 2.54
mg/g
wet weight DDE in liver
(Wolfe and Norman, 1998). Six young GBH were found to have TDE
residues >0.3 mg/g.
Mean (standard deviation) organochlorine residues found in liver (N=19)
were 0.079 (0.116) mg/g. |
|
C. |
Concentrations
in Eggs, Embryos, and Eggshells |
|
1. |
GBH
eggs collected in various locations in Alberta, Saskatchewan, and
Manitoba in 1968 to 1969 contained mean levels of DDE
ranging from 5.71 to 37.01 µg/g wet weight (Vermeer and Reynolds,
1970). Mean dieldrin levels
ranged from 0.056 to 0.344 µg/g. Mean heptachlor
epoxide and ß-BHC
levels were less than 0.071 and 0.082 µg/g, respectively. |
|
2. |
GBH
eggs and an embryo collected in 1969 and 1970 from Bolinas Lagoon, near
San Francisco, were analyzed for organochlorine residues (Faber et al.,
1972). The two eggs contained 108 and 287 µg/g lipid weight DDE
in the egg yolk. Total DDT
levels in the egg yolk lipid were 122 and 320 µg/g, respectively. PCB
was detected at a concentration of 50.6 in the first egg and not
detected in the second egg. The embryo, which was probably a heron,
contained 1.2 µg/g wet weight DDE,
1.4 µg/g total DDT, and
1.2 µg/g PCB. |
|
3. |
Forty
GBH eggs collected from 1969 to 1972 from Alberta contained a geometric
mean concentration of 33.9 µg/g dry weight DDE
and 1.48 µg/g PCBs
(Gilbertson and Reynolds, 1974). |
|
4. |
In
1970, two GBH eggs from Western Oregon contained DDE residues of 3.3 and 4.5 µg/g wet weight (Henny and
Bethers, 1971). A dead chick from the same colony had a whole body DDE
concentration of 10.1 µg/g. |
|
5. |
Twenty
GBH eggs collected in 1970 from sites along the Texas coast were
analyzed for organochlorine residues (King et al., 1971). DDE and PCBs
were found in all samples at similar mean levels: 5.55 and 5.54 µg/g
wet weight. Dieldrin was
detected in three eggs at a mean concentration of 0.14 µg/g |
|
6. |
A
total of five GBH eggs were collected from the Great Lakes area in
Wisconsin in 1970 to determine contaminant concentrations (Faber and
Hickey, 1973). Mean values of organochlorines were as follows: 472.1 µg/g
lipid weight DDE, 175.3 µg/g
PCBs, 10.10 µg/g dieldrin,
44.27 µg/g DDT + TDE, and
0.79 µg/g BHC. |
|
7. |
A
GBH egg collected in 1972 along the west coast of Florida contained
concentrations of 20.0 µg/g dry weight DDE,
29.1 µg/g PCB, and 2.18 µg/g
dieldrin (Lincer and
Salkind, 1973). |
|
8. |
In
1972 and 1973, a total of 58 GBH eggs were collected from various sites
in the eastern United States (Ohlendorf et al., 1979b). Mean DDE
concentrations were 6.76 µg/g wet weight in the Great Lakes region,
3.90 µg/g inland, 2.13 µg/g in the Southern Atlantic, and 1.39 µg/g
in the Gulf Coast. PCBs
were also greatest in the Great Lakes at 13.65 µg/g, followed by the
inland region at 2.95 µg/g, the Southern Atlantic at 2.42 µg/g, and
the Gulf Coast at 0.07 µg/g. |
|
9. |
Between
1975 and 1978, fifteen GBH eggs were collected from a colony near
Fountain City Bay, Wisconsin in the Upper Mississippi River for
organochlorine analysis (Nosek and Faber, 1984). PCB
levels ranged from 0.44-37.2 µg/g wet weight, with a mean of 14.1 µg/g.
DDT was detected at a mean
of 0.094 µg/g, with all values <0.74 µg/g. Mean DDD
levels were 0.12 µg/g, with all levels <0.51 µg/g. DDE
concentrations were at a mean of 1.41 µg/g, with all levels <5.72 µg/g.
HCB ranged from 0.0008 to
0.074 µg/g, with a mean of 0.011 µg/g. Mirex
residues, detected in ten of the eggs were less than 0.34 µg/g,
with a mean of 0.058 µg/g. Heptachlor
epoxide values ranged from 0.031-0.339 µg/g, with a mean of
0.028 µg/g. Dieldrin
levels ranged from 0.125-1.43 µg/g, with a mean of 0.400 µg/g. Endrin
was detected in six eggs at levels <0.068 µg/g and a mean of 0.019
µg/g. trans-Nonachlor, detected in thirteen eggs,
was at levels <0.221 µg/g and a mean of 0.101 µg/g. |
|
10. |
From
1977 to 1982, GBH eggs were collected from colonies in Washington,
Oregon, and Nevada (Fitzner et al., 1988). DDE
means for each colony ranged from 0.44 µg/g wet weight in Stillwater
National Wildlife Refuge in Nevada, to 4.7 µg/g on Foundation Island in
the Columbia River. Stillwater also contained the lowest mean
concentration of PCBs at
0.36 µg/g, and the Fort Lewis colony in the Puget Sound contained the
highest at 3.35 µg/g. Other organochlorines
detected sporadically in the eggs, (excluding those at the
Fort Lewis colony), were generally at <1 µg/g and included DDD,
dieldrin, heptachlor epoxide,
oxychlordane, and cis-nonachlor.
cis-Chlordane
was detected in its highest concentrations of up to 1.36 µg/g in the
Umatilla National Wildlife Refuge in the Columbia River System.
trans-Nonachlor also reached its peak at
Umatilla at 2.25 µg/g. Maximum pre-fledgling liver residues of DDE
and PCBs were 0.45 and 1.20
µg/g, respectively. Hatchlings found dead and collected from the Lake
Chatcolet colony in Idaho had maximum residue levels of 21 µg/g DDE
and 11 µg/g PCBs. |
|
11. |
In
the Columbia River Basin of Washington and Oregon in 1978,
organochlorine residues from the eggs of 21 nesting GBHs from the
Umatilla National Wildlife Refuge and the McNary Recreation Area were
analyzed (Blus et al., 1980). DDE
residues were detected in all eggs and had the highest concentrations
with a geometric mean of 3.30 µg/g wet weight in Umatilla and 4.71 µg/g
in McNary. PCBs were next
with 1.93 and 2.24 µg/g, respectively, followed by trans-nonachlor
with 0.44 and 0.30 µg/g. Other organochlorines detected in various
numbers of the eggs tested were DDD
(less than 0.49 and 1.00 µg/g for the two sites, respectively), dieldrin
(less than 0.29 and 1.16 µg/g), heptachlor
epoxide (less than 0.40 and 0.25 µg/g), oxychlordane
(less than 0.44 and 0.19 µg/g), cis-nonachlor (less than 0.69 and 0.20 µg/g), and cis-chlordane
(less than 1.36 and 0.63 µg/g). |
|
12. |
Eggs
of GBHs nesting at Nueces Bay, Corpus Christi, Texas in 1978 and 1979
contained DDE levels up to
49.00 µg/g wet weight, with median levels of 3.67 µg/g and 3.00 µg/g
for the two years, respectively (Mitchell et al., 1981). PCBs
reached 41.00 µg/g, with medians of 7.80 µg/g and 6.15 µg/g. Other
compounds detected included dieldrin
at <1.80 µg/g, and chlordane
at <2.38 µg/g. HCB was
detected in 1978 alone with a median concentration of 0.15 µg/g. |
|
13. |
GBH
eggs collected from five heronries along the St. Lawrence River in
Quebec in 1979 all contained organochlorine residues (Laporte, 1982). PCBs
concentrations were highest at a mean of 7.78 µg/g wet weight, followed
by DDE (2.42 µg/g), DDD
(0.15 µg/g), and dieldrin
(0.14 µg/g). Concentrations of DDT,
heptachlor epoxide, and oxychlordane
ranged from 0.01 to 1.26 µg/g. HCB
was detected at a range of 7 to 1093 ng/g, and pentachlorobenzene
levels were <33 ng/g. ß-BHC
and tri- and tetrachlorobenzene
were generally at or below detection level |
|
14. |
In
1980, a total of 40 GBH eggs were collected from four rookeries in the
Tennessee Valley: Armstrong Bend, Bellefonte, Duck River, and Sinking
Pond (Fleming et al., 1984). Throughout the colonies, DDE, dieldrin, cis-chlordane,
trans-nonachlor,
and PCBs were all found in
at least 70% of the eggs and concentrations did not differ significantly
between colonies. The greatest mean levels of the four colonies of each
compound were 5.2 µg/g wet weight, 0.22 µg/g, 0.20 µg/g, 0.54 µg/g,
and 9.2 µg/g, respectively. Cis-nonachlor
occurred in 50 to 80% of eggs with a high mean of 0.13 µg/g. Heptachlor
epoxide and oxychlordane
had means of 0.14 µg/g and 0.11 µg/g, respectively, at Sinking Pond,
and <0.1 µg/g at all other sites. Mean toxaphene
levels were 0.14 at Duck River, and <0.1 µg/g at all other sites. DDD
levels were significantly higher in Duck River (0.53 µg/g) and Sinking
Pond (0.20 µg/g) eggs than other sites (<0.1 µg/g). Other
organochlorines detected were DDT,
endrin, HCB,
and mirex, all at levels
<0.1 µg/g for all colonies. |
|
15. |
From
1983 to 1987, GBH eggs collected from five sites along the Strait of
Georgia in Vancouver were tested for organochlorine residues (Elliott et
al., 1988). 123678-HxCDD
was found in the greatest concentrations in all colonies, ranging from
6-1052 ng/kg wet weight. 12378-PnCDD
levels were second greatest with a range of 9-1018 ng/kg. 2378-TCDD
ranged from 3-444 ng/kg. Other organochlorines detected, at
concentrations <104 ng/kg were 123789-HxCDD,
1234678-HpCDD, OCDD,
2378-TCDF, and 23478-PnCDF.
Eggs collected at Crofton and University of British Columbia contained
significantly higher concentrations of TCDD
than eggs collected from Sidney Island and Nicomekl. From 1983 to 1987, TCDD
values increased in all colonies that were sampled in multiple years. |
|
16. |
GBH
eggs collected from the Puget Sound, Washington area in 1984 were tested
for PCB and DDT
residues (Speich et al., 1992). Concentrations ranged from 1.39 to 15.58
µg/g wet weight PCB and
0.35 to 2.22 µg/g DDT. The
Seattle area eggs contained the highest amounts of both compounds. |
|
17. |
GBH
eggs were collected from 1986-1987 from four colonies in the Strait of
Georgia, British Columbia: Crofton (pulp and paper mill), Vancouver
(industrial), Nicomekl (agricultural), and Sidney Island (control)
(Elliott et al., 1989). Crofton, in 1987, contained the greatest mean
concentrations for all years and all colonies of 2378-TCDD
(210 pg/g (ppt) wet weight), 12378-PnCDD
(257 pg/g), 123678-HxCDD
(402 pg/g), 123789-HpCDD
(27 pg/g), 23478-PnCDF (37
pg/g), and total TCDD
equivalents (230 pg/g).
Vancouver contained the greatest mean of 2378-TCDF
at 17 pg/g. Means of 1234678-HpCDD
and OCDD were less than 7
pg/g for all colonies. Nicomekl contained the highest mean DDE
level at 0.549 µg/g. Oxychlordane,
trans-nonachlor,
heptachlor epoxide, dieldrin,
and HCB were detected at low mean levels in all eggs (<0.062
µg/g) and DDT, mirex,
and ß-HCH in most eggs (<0.021 µg/g). Total mean PCB
concentrations, detectable in all eggs, ranged from 0.418 µg/g in
Sidney to 1.22 µg/g at Vancouver, 1987. Only trace levels of PCDD
residues were found in nestling regurgitations. |
|
18. |
In
1988, GBH eggs were collected and hatched from three sites of increasing
contamination levels in British Columbia: Nicomekl (control), Vancouver,
and Crofton (Bellward et al., 1990). TCDD
levels detected in Vancouver and Crofton eggs were significantly greater
than controls with means of 135 pg/g wet weight and 211 pg/g,
respectively. 1,2,3,7,8-PnCDD
and 1,2,3,6,7,8- and 1,2,3,7,8,9-HxCDD
levels showed a significant increase in Crofton eggs at 263, 430, and 48
pg/g, respectively. Also detected were 2,3,7,8-TCDF
and 2,3,4,7,8-PnCDF at
levels of 11 and 33 pg/g for Vancouver, and 8 and 33 pg/g for Crofton.
Means of PCBs detected were
0.636, 1.650, and 0.808 µg/g, respectively. Dieldrin
and DDE were highest at
Nicomekl with levels of 0.0417 and 0.712 µg/g, respectively. trans-Nonachlor
levels were highest at Vancouver, at 0.0392 µg/g. HCB, DDT, oxychlordane,
and heptachlor epoxide each had concentrations of <0.0244 µg/g for all
sites. |
|
19. |
In
1988, 1990, 1991, and 1992, GBH heron eggs were collected and hatched
from two contaminated sites (University of British Columbia Endowment
Lands and Crofton) and three reference sites (Nicomekl, Chilliwack, and
Tillicum) in British Columbia (Henshel et al., 1995). Mean
concentrations of TCDD
ranged from 0.00-0.46 pg/g at reference sites and 0.46-8.81 at
contaminated sites. Means of TCDD-TEQs
ranged from 0.00-0.77 at reference sites and 0.99-14.63 at contaminated
sites. |
|
20. |
GBH
eggs collected from two sites on the west coast of Canada were analyzed
for organochlorine residues (Kennedy et al., 1992). Concentrations of PCB
77, 126, and 169
were <0.18 ng/g for all eggs. PCB
105 was detected at
concentrations of 31 and 17 ng/g and PCB
118 at 116 and 63 ng/g. TCDD
was detected at 319 ng/g at the Crofton, British Columbia site. |
|
21. |
In
1988, GBH eggs were collected with salvaged eggshells from the colony
floor for organochlorine analysis from three sites in the Puget Sound
area: Dumas Bay, Samish Island, and Nisqually (Cobb et al., 1994). Mean
organochlorine concentrations in heron tissue and eggs from Samish
Island were 1.15 ng/g pentachlorobenzene,
18 ng/g HCB, and 380 ng/g DDE.
The greatest mean PCB
levels detected in tissue and eggs from the same location were Arochlor
1254 (2470 ng/g), 1260
(656 ng/g), and 1242 (458
ng/g). Chlorio-allantoic membrane analysis revealed mean organochlorine
concentrations of 1.44 ng/g pentachlorobenzene,
7.98 ng/g HCB, and 336 ng/g
DDE, and mean Arochlor levels of 1530 ng/g (1254), 496 ng/g (1260),
and 56 ng/g (1242). Dumas
Bay had higher mean tissue and egg concentrations with 4.37 ng/g pentachlorobenzene,
110 ng/g HCB, and 1670 ng/g
DDE; mean arochlor concentration was 16,600 ng/g (1254),
3428 ng/g (1260), and 2140
ng/g (1242). |
|
22. |
Organochlorine
levels of GBHs nesting on Whidbey Island, WA in 1989 were determined by
chorio-allantoic membrane analysis (Cobb et al., 1995). Mean combined DDT,
DDE, and DDD concentrations were 0.171 µg/g dry weight and mean PCB
concentrations were 0.247 µg/g. Low correlations among DDT
and its metabolites in CAM’s suggested inconsistent exposure to these
compounds. |
|
23. |
In
1991 in Crofton and 1990 and 1992 in Vancouver, GBH eggs were collected
from colonies in the Strait of Georgia, British Columbia and determined
to have lower concentrations of contaminants than those found in 1988
(Sanderson et al., 1994). TCDD
was detected at mean levels of 16, 42, and 10 pg/g wet weight,
respectively. Mean 1,2,3,7,8-PnCDD
levels were 37, 45, and 10 pg/g, respectively, and those of 1,2,3,6,7,8-HxCDD
measured 46, 57, and 11 pg/g, respectively. Other mean PCDD
concentrations were <5 pg/g. PCDFs
in greatest abundance were 2,3,7,8-TCDF
and 2,3,4,7,8-PnCDF with
means of 15 and 16 pg/g, respectively, in Vancouver, 1990. Mean PCB residues detected were 101, 293, and 327 pg/g (PCB-126);
20, 43, and 47 pg/g (PCB-169);
5, 22, and 30 ng/g (PCB-105);
and 40, 144, and 170 ng/g (PCB-118).
Mean TEQ levels were greatest at Vancouver, 1990 (278 pg/g),
followed by Vancouver, 1992 (253 pg/g), and Crofton (100 pg/g). |
|
24. |
In
1991, 65 GBH eggs were collected from nine heronries (seven along the
St. Lawrence River and two reference sites) (Boily et al., 1994).
Freshwater and estuarine eggs contained similar concentrations of mirex and photomirex,
reaching values of 0.145 and 0.038 µg/g, respectively. For other
organochlorines tested, estuarine sites consistently had higher
concentrations than freshwater sites, with means reaching 0.0089 µg/g OCS,
7.818 µg/g total PCBs, 175
ng/g PCB 105, 917 ng/g PCB
188, and 63.9 pg/g TCDD-EQs.
|
|
25. |
Between
1991 and 1994, eggs were collected from 4 sites in Tennessee; 2 colonies
on Oak Ridge Reservation (n=33), K25 and Melton Hill, and 2 reference
colonies (n=34), Long Island and Looney Island (Halbrook et al., 1999).
Mean (range) concentrations of Arochlor
1260 in the eggs were 2.01 (0.10-8.80), 0.86 (0.07-2.40),
0.53 (0.07-2.20), and 0.34 (0.09-1.10) µg/g wet weight for the 4
colonies, respectively. |
|
26. |
In
1993, GBH eggs were collected from 10 colonies on the Upper Mississippi
River and incubated until pipping (Custer et al., 1997). Dieldrin, heptachlor
epoxide, and HCB
had overall mean embryo liver concentrations of 0.10, 0.05 and 0.003 µg/g
wet weight, respectively. Means for these compounds for the southernmost
colonies were significantly higher than those of colonies furthest
north. Mean levels of other organochlorines did not differ between
colonies: 1.31 µg/g DDE,
3.04 µg/g PCBs, 0.0031 µg/g BHC,
0.0304 µg/g oxychlordane,
0.0321 µg/g cis-nonachlor,
0.0829 µg/g trans-nonachlor,
0.0046 µg/g mirex, 0.0149
µg/g DDD, and 0.0066 µg/g
DDT. Endrin
and
|
|
27. |
Organochlorine
contaminants were measured in 10 GBH eggs collected from the Indiana
Dunes National Lakeshore in 1993 (Custer et al., 1998). Mean concentrations were 0.19 µg/g wet weight trans-nonachlor,
0.26 µg/g dieldrin, 0.3 µg/g
toxaphene, 1.58 µg/g DDE,
4.9 µg/g total PCBs, 0.0871 µg/g PCB
105, 0.0057 µg/g PCB 114,
0.2647 µg/g PCB 118/106,
and 0.0005 µg/g PCB 156.
One egg had elevated concentrations of DDE
(13.0 µg/g) and PCBs (56
µg/g). Concentrations of BHC,
cis-chlordane,
oxychlordane, cis-nonachlor,
endrin, HCB,
heptachlor epoxide, mirex,
DDD, and DDT
were <0.08 µg/g. TEQs
were 465 pg/g, as calculated by Safe (1990), and 929 pg/g, as calculated
by Kennedy (1996). |
|
28. |
In
1993, GBH eggs were collected from the National Audubon Sanctuary
Islands of the Lower Laguna Madre, Texas (Mora, 1996a). Total PCB concentrations averaged 0.246 µg/g wet weight. PCB
congeners detected at the highest concentration were 138,
153, 180,
and 110. |
|
29. |
In
1993-94, ten GBH eggs were collected from the National Audubon Sanctuary
Islands of the Lower Laguna Madre, Texas (Mora, 1996b). Median (range)
contaminant concentrations were 0.735 (0.092-2.59) µg/g wet weight DDE
and 0.396 (0.058-0.199) µg/g PCBs. |
|
30. |
Eggs
were collected from sites near paper or pulp mills and a reference site
in the Columbia and Willamette Rivers and Puget Sound in Washington and
Oregon in 1994-1995 (Thomas and Anthony 1999). In 1994 and 1995,
respectively, mean DDE
ranged from 263-1,616 and 183-1,489 ng/g wet weight at study sites and
was 101 and 150 ng/g at the reference site.
Mean DDT ranged from 26-34 and 4.5-22 ng/g at study sites and was
<16 and 5.0 ng/g at the reference site.
Mean trans-nonachlor
ranged from 18-199 and 8.4-88 ng/g at study sites, and was 14 ng/g at
the reference site in 1995. Mean total
PCBs ranged from 382-3,454 and 423-2,426 ng/g at study sites
and was 223 and 369 ng/g at the reference site.
PCB congeners were
below detection limits in 1994. A
different lab was used in 1995. Mean
PCB 77 ranged from 0.03-0.23 pg/g at study sites and was 0.05
pg/g at the reference site in 1995.
Mean PCB 126 ranged
from 0.12-0.65 pg/g at study sites and was 0.21 pg/g at the reference
site in 1995. Mean PCB 169 ranged from 0.02-0.06 pg/g at study sites and was
0.03 pg/g at the reference site in 1995.
In 1994 and 1995, respectively, mean TCDD
ranged from 1.7-8.3 and 2.5-6.4 pg/g at study sites and was 3.7 pg/g at
the reference site in 1995. In
1994 and 1995, respectively, mean OCDD
ranged from ND-33 and 10-40 pg/g at study sites and was 34 pg/g at the
reference site in 1995. Levels
of 2,3,7,8-TCDF were below
detection limits in 1994. In
1995, mean 2,3,7,8-TCDF
ranged from 0.5-1.3 pg/g at study sites and was 1.3 pg/g at the
reference site. In 1994 and 1995, respectively, calculated total TEQs
based on Safe ranged from 27-206 and 21-97 pg/g at study sites and was
26 and 33 pg/g at the reference site.
In 1994 and 1995, TEQs
measured by H4IIE bioassay ranged from 1.5-30 and <0.6-<1.7 pg/g
at study sites and was 1.5 and 2.5 pg/g at the reference site.
|
|
31. |
Over
the period of 1977-2000, great blue heron eggs were collected from 23
colonies along the Strait of Georgia, British Columbia, Canada (Harris
et al., 2003). The sites were divided into three categories; urban, pulp
and paper mill, and rural reference. Concentrations of organochlorine
pesticides and PCBs (µg/g
wet weight) in eggs from reference colonies around the Strait of Georgia
from 1978-200 were all <0.11 for trans-Nonachlor,
cis-Nonachlor,
oxy-Chlordane,
cis-Chlordane,
heptachlor epoxide, dieldrin,
DDD, mirex, HCB
and HCH. DDE
levels were <0.995 and sum PCBs
<5.41. Concentrations from contaminated sites near the Fraser River
delta between 1977-2000 were <0.154 for trans-Nonachlor,
cis-Nonachlor,
oxy-Chlordane,
cis-Chlordane,
heptachlor epoxide, dieldrin,
DDD, mirex, HCB
and HCH. DDE
levels were <2.97 and sum PCBs
<9.57. The
most common pesticides detected in eggs, regardless of amount detected,
were DDE (100% of samples),
HCB (100%), trans-Nonachlor
and cis-Nonachlor
(>99%), dieldrin (99%),
heptachlor epoxide (95%),
DDT (93%), cis-chlordane (92%), HCH (85%),
DDD (82%) and mirex (66%). |
|
II. |
Cholinesterase-Inhibiting Pesticides |
|
1. |
In
1993 and 1994, GBH nestlings were collected from Clear Lake, California,
near the Sulphur Bank Mercury Mine (Wolfe and Norman, 1998). Brain ChE
activities at Quercus Point and Slater Island were, respectively, 12.9
and 11.4 mmoles
acetylthiocholine hydrolyzed/g brain weight. Plasma ChE activities at
Quercus Point and Slater Island, were, respectively, 0.25 and 0.27 mmoles
acetylthiocholine hydrolyzed/ml plasma. Brain and plasma
ChE activity measurements were not depressed for either
site. |
|
III. |
Trace Elements, Metals, and Metalloids |
|
A. |
Concentrations
in Adults |
|
1. |
The
concentration of Pb in the
liver of an east coast GBH either captured or shot was 0.7 µg/g wet
weight (Bagley and Locke, 1967). |
|
2. |
In
1978, excrement cast from GBHs was collected from cheesecloth strips
placed on the ground beneath nests in four colonies in Washington and
Idaho (Fitzner et al., 1982). Cheesecloth strips placed under nearby
trees without nests served as controls. Significant differences in mean
metal concentrations between treatments and controls were found in only
one site, Lake Chatcolet, Idaho, where values in excrement were 46 (5.7
control) µg/g Pb, 1.8
(0.22) µg/g Cd, and 0.28
(0.085) µg/g Hg.
Concentrations at other nesting sites (Tacoma, Richland, and Potholes
Resevoir, Washington) were similar to control values and are presumed to
be associated with airborne deposition and foliage drip. |
|
3. |
Heavy
metal concentrations residing in fecal matter were assessed from GBHs
nesting in various locations in eastern and western Washington in 1982
and 1983 (Fitzner et al, 1995). Lead,
Cd, Cr,
and Co were detected in all
samples from eastern Washington. Cadmium
was found in the greatest concentration in Hanford (0.53 µg/g). Highest
Pb values were found at
Hanford (6.01 µg/g wet weight) and Foundation Island (5.28 µg/g).
Foundation Island also contained the highest concentrations of Cr
(3.34 µg/g) and Co (1.67
µg/g), each at values more than twice that of any other area. In
western Washington, metal concentrations were similar or higher than
eastern levels. Cadmium was
found at similar concentrations, reaching a maximum of 0.57 µg/g in
Samish Island. Concentrations of Pb
were highest in Auburn (10.45 µg/g) and Dumas Bay (8.53 µg/g). Dumas
Bay (4.25 µg/g) and Deception Pass (4.21 µg/g) had the highest levels
of Cr, and Oyster Bay
contained the greatest level of Co
(1.87 µg/g). Metal concentrations detected tended to increase with
increased proximity to industrial and developed areas, indicating fecal
matter concentrations as a potentially reliable biomarker of heavy metal
exposure. |
|
4. |
Between
1987 and 1989, 64 nestling and 23 adult great white herons (A.
herodias occidentalis) in Florida were radio-tagged,
monitored and collected upon death to test for Hg
concentrations in the liver, which ranged from 0.6 to 59.4 µg/g wet
weight (Spalding et al., 1994). |
|
5. |
Concentration
of Hg was determined in
herons found dead in southern Florida between 1987 and 1990 (Beyer et
al., 1997). One adult GBH contained 4.5 µg/g wet weight in the liver
and 6.9 µg/g dry weight in feathers. Adult great white herons were
found to have a mean concentration of 8.2 (4.1-14) µg/g dry weight in
feathers. One great white heron contained 2.9 µg/g wet weight in liver
and 6.2 µg/g dry weight in feathers. |
|
6. |
Adult
GBH found dead were collected from four areas in south Florida between
1987-1991 and analyzed for hepatic Hg (Sundlof
et al., 1994). Mean Hg
concentrations were 0.60, 0.80, 4.25, and 7.62 µg/g wet
weight at Lake Okeechobee, the Everglades, eastern Florida Bay, and Big
Cypress National Preserve, respectively.
|
|
7. |
A
great blue heron collected in 1989 from Old Woman Creek Estuary, Ohio,
had a concentration of 1.62 µg/g wet weight
Hg in muscle (Francis et al., 1998). |
|
8. |
Elemental
profiles were determined in flight feathers collected from 19 adult
great blue herons at a mercury contaminated site, Clear Lake, California
(Cahill et al., 1998). Mean
concentrations were 32,772 µg/g S,
3283 µg/g Ca, 10.9 µg/g Ti, 252 ug.g Fe,
281 µg/g Zn, 2.51 µg/g Se,
10.3 µg/g Br, 19.3 µg/g Sr,
6.11 µg/g Hg, and 1.07 µg/g
Pb.
Concentrations of Cr were
not detectable, and V, Ni,
As, and Rb
in trace amounts only. |
|
B. |
Concentrations
in Nestlings |
|
1. |
Nestling
GBHs found dead in southern Florida between 1987 and 1990 contained a
mean (range) Hg
concentration of 3.5 (1.8-7.7) µg/g dry weight in feather (Beyer et
al., 1997). A comparison to liver concentrations was performed in one
nestling, which contained 0.21 µg/g wet weight in the liver and 2.7 µg/g
dry weight in feathers, and one juvenile which contained 75 µg/g wet
weight in liver and 27 µg/g dry weight in feathers. Great white herons
were found to have a mean concentration of 6.7 (2.7-15) µg/g dry weight
in feathers of juveniles and 4.7 (1.0-9.1) µg/g dry weight in feathers
of nestlings. Four juveniles were found to have concentrations of
0.87-8.3 µg/g wet weight in liver and 6.2-8.1 µg/g in feathers. Two
nestlings were found to contain 7.3 and 1.9 µg/g wet weight in liver
and 9.1 and 3.9 µg/g dry weight in feathers. |
|
2. |
Livers
were collected between 1987-1991 from GBH nestlings found dead at Lake
Okeechobee, Florida and great white heron nestlings found dead in
Florida Bay (Spalding et al., 1997).
Mean concentrations of Pb, Cu, and
Cd were 0.28, 5.5, and 0.05
µg/g wet weight, respectively at Lake Okeechobee and 0.32, 20, and 0.10
µg/g ww at Florida Bay. |
|
3. |
Nestling
and fledgling GBHs found dead were collected from four areas in south
Florida (Lake Okeechobee, the Everglades, eastern Florida Bay, and Big
Cypress National Preserve) between 1987-1991 and analyzed for hepatic Hg
(Sundlof et al., 1994). Mean
Hg concentrations ranged
from 0.31-1.53 µg/g in
nestlings and were 6.65 µg/g in fledglings. |
|
4. |
Between
1991 and 1994, nestlings were collected from 4 sites in Tennessee:
2 colonies on Oak Ridge Reservation (n=38), K25 and Melton Hill,
and 2 reference colonies (n=35), Long Island and Looney Island (Halbrook
et al. 1999). Hg
concentrations in the feathers were 2.02 ± 0.28, 1.02 ± 0.13, 0.87 ±
0.08, and 1.02 ± 0.16 µg/g
dry weight, for the 4 colonies. Hg
concentrations in the liver were 0.29 ± 0.04, 0.15 ± 0.02, 0.12 ±
0.01, and 0.26 ± 0.04 µg/g. Hg
concentrations in muscle were 0.09 ± 0.01, 0.05 ± 0.01, 0.07 ± 0.01,
and 0.08 ± 0.01 µg/g. Cr
concentrations in the feathers were 1.00 ± 0.17, 0.87 ± 0.43, 1.29 ±
0.26, and 0.93 ± 0.18 µg/g. Cr
concentrations in the liver were 1.54 ± 0.65, 1.39 ± 0.62, 1.82 ±
0.71, and 0.15 ± 0.02 µg/g. Cr
concentrations in the muscle were 1.40 ± 0.63, 3.01 ± 1.18, 3.14 ±
1.14, and 2.26 ± 0.97 µg/g. As
concentrations in the liver were 0.65, 0.55, 0.49, and ND.
As concentrations in
the muscle were 1.16, 0.41, 0.05and 0.64, and 0.42
µg/g. |
|
5. |
From
1993 to 1994, GBH nestlings were collected at Clear Lake, California,
near the Sulphur Bank Mercury Mine (Wolfe and Norman, 1998).
Mean (range) Hg concentrations in tissues were 0.35 (0.3-0.4) mg/g
wet weight in brain and 1.46 (1.32-1.71) mg/g
in liver. In
1993, at Slater Island, mean (standard deviation) Hg
concentrations in tissues of young GBHs (in mg/g
wet weight) were as follows: 0.36 (0.15) in brain (N=8), 1.42 (0.67) in
liver (N=8), 2.23 (0.77) in feathers (N=7), 1.3 (0.23) in blood (N=4),
and 1.15 (0.10) in kidney (N=5). In
1994, at Slater Island, mean (standard deviation) Hg
concentrations in tissues of young GBHs (in mg/g)
were as follows: 0.30 (0.14) in brain (N=6), 1.39 (0.58) in liver
(N=11), and 1.97 (1.18) in feathers (N=11). In
1993, at Quercus Point, mean (standard deviation) Hg
concentrations in tissues of young GBHs (in mg/g)
were as follows: 0.35 (0.11) in brain (N=7), 1.71 (0.63) in liver (N=7),
2.43 (0.99) in feathers (N=6), 1.08 (0.32) in blood (N=4), and 1.00
(0.33) in kidney (N=3). In
1994, at Quercus Point, mean (standard deviation) Hg concentrations in tissues of young GBHs (in mg/g)
were as follows: 0.36 (0.15) in brain (N=6), 1.46 (0.57) in liver, and
2.01 (1.18) in feathers (N=11). In
1993, at Rodman Slough, mean (standard deviation) Hg concentrations in tissues of young GBHs (in mg/g)
were as follows: 0.4 (0.09) in brain (N=10), 1.32 (0.59) in liver
(N=10), 3.16 (0.82) in feathers (N=10), 1.16 (0.33) in blood (N=5), and
1.12 (0.26) in kidney (N=7). Mercury concentrations in GBH nestlings
were not correlated to distance from the Hg
mine. |
|
C. |
Concentrations
in Eggs and Embryos |
|
1. |
A
total of five great blue heron eggs collected from the Great Lakes area
in Wisconsin in 1970 contained a mean concentration of 0.29 µg/g wet
weight Hg (Faber and
Hickey, 1973). |
|
2. |
In
1980, a total of 40 GBH eggs were collected from four rookeries in the
Tennessee Valley: Armstrong Bend, Bellefonte, Duck River, and Sinking
Pond (Fleming et al., 1984). Mercury
was detected in all the eggs with mean levels for the colonies at 0.34
µg/g wet weight, 0.29 µg/g, 0.49 µg/g, and 0.50 µg/g, respectively. Chromium
was detected in all but one egg with means of 0.23 µg/g, 0.18 µg/g,
0.16 µg/g, and 0.18 µg/g, respectively. |
|
3. |
GBH
eggs and hatchlings from
colonies located near sources of heavy metal pollution by Puget Sound,
Washington and Lake Chatcolet, Idaho were collected in 1981 and 1982 and
tested for residues in tissues and eggs (Blus et al., 1985). Eggs
contained levels of Cu up
to 2.71 µg/g wet weight, Zn
up to 6.37 µg/g, and Hg up
to 0.37 µg/g. Arsenic was
not detected. Whole body analysis of hatchlings and advanced embryos
revealed concentrations not exceeding those of the eggs, except for Zn
which reached 11.0 µg/g. Lead
and Cd were detected in a
portion of the samples at levels up to 0.44 and 0.22 µg/g,
respectively. Young herons from Fort Lewis, Washington contained the
highest liver concentrations of Cu,
Zn, and Hg,
with levels reaching 90, 83, and 1.5 µg/g respectively.
Lead was detected irregularly among the young birds and Cd
was not detected. Other elements detected in a single young heron found
dead were Cr, Al,
Mg, and Mn. |
|
4. |
GBH
eggs were collected from 1986-1987 from four colonies in the Strait of
Georgia, British Columbia: Crofton (pulp and paper mill), Vancouver
(industrial), Nicomekl (agricultural), and Sidney Island (control)
(Elliott et al., 1989). Total Hg
concentrations were 0.042, 0.094, 0.098, and 0.059 µg/g wet weight,
respectively. Nestling regurgitation contained concentrations of
<0.05 µg/g Hg and
<0.1 µg/g Cd. Total Pb levels reached 1.8 µg/g in Vancouver regurgitation
samples. |
|
5. |
Between
1991 and 1994, eggs were collected from 2 colonies on Oak Ridge
Reservation (n=33), K25 and Melton Hill, and 2 reference colonies
(n=34), Long Island and Looney Island, all sites were in Tennessee (Halbrook
et al 1999). Hg
concentrations in the eggs were 0.17 ± 0.02, 0.13 ± 0.06,
0.14 ± 0.02, and 0.12 ±0.02. Hg
concentrations were significantly higher in K25 feathers than in
feathers from other sites. Hg
concentrations in liver from K25 and Looney Island were significantly
higher than the other 2 sites. Cr
concentrations in the eggs were 0.15 ± 0.02, 0.22 ± 0.08, 0.11 ±
0.01, and 0.11 ± 0.01µg/g As was below
the detection limit (0.4 ppm dry weight) in all eggs. |
|
6. |
In
1993, GBH eggs were collected from 10 colonies on the Upper Mississippi
River and incubated until pipping (Custer et al., 1997). Concentrations
of Hg from embryo livers
ranged from 0.24 to 2.82 µg/g dry weight, with a geometric mean of 0.82
µg/g. Mean Hg levels did
not differ between colonies. Values of Se
ranged from 1.76 to 4.17 µg/g, with a mean in Vogt Lake, Wisconsin
(3.56 µg/g) that was significantly higher than Mertes Slough, Wisconsin
(2.48 µg/g). |
|
7. |
Concentrations
of Hg and Se
were detected in all 10 GBH eggs collected from the Indiana Dunes
National Lakeshore in 1993 (Custer et al., 1998).
Mean concentrations were 0.908 µg/g dry weight Hg
and 3.976 µg/g Se. |
|
8. |
In
1993-94, ten GBH eggs were collected from the National Audubon Sanctuary
Islands of the Lower Laguna Madre, Texas (Mora, 1996b). Median (range)
metal concentrations were as follows (µg/g wet weight): 0.09
(0.02-0.15) Hg, 0.32
(0.17-0.44) Se, 0.63
(0.53-2.10) B, 0.29
(0.09-11) Cr, 1.70
(0.75-36) Cu, 22.0 (15-53) Fe,
110 (76-170) Mg, 0.48
(0.17-1.1) Mn, 1.90
(1.3-2.9) Sr, and 11.5
(7.2-21) Zn. |
|
9. |
Eggs
were collected from sites near paper or pulp mills and a reference site
in the Columbia and Willamette Rivers and Puget Sound in Washington and
Oregon in 1994 (Thomas and Anthony 1999).
Mean Hg
concentrations ranged from 0.35-0.66 µg/g dry weight at study sites and
was 0.53 µg/g at the reference site. |
|
IV. |
Petroleum |
|
|
No
residue data available |
|
V. |
Other Contaminants |
|
1. |
Rejecta
cast from GBH nests of birds feeding in the Columbia River contained
higher levels of the biologically active Cs-137,
K-40, Zn-65,
and Co-60 radionuclides than controls (Rickard et al., 1978).
Controls had higher concentrations of Ce-144,
Ru-164, Zr-95,
and Mn-54
radionuclides. One heron found dead contained detectable amounts of Zr-95,
and Mn-54 in the
liver. |
|
2. |
GBH
livers collected from St. Martinville, Louisiana, had the following
concentrations (in ng/g) of perfluorooctane
sulfonate: 59, 173, 188, 261, and 1061 (Minnesota Mining and
Manufacturing Company, 2000). |
|
Great
Blue Heron Contaminant Response Data |
|
|
I. |
Organochlorine Contaminants |
|
A. |
Eggshell
Thinning and Reproduction |
|
1. |
GBH
eggs were collected from various locations in Alberta from 1968 to 1969
(Vermeer and Reynolds, 1970). Eggshell thickness was inversely related
to DDE concentration (wet
weight basis). |
|
2. |
Expanding
on data from Vermeer and Reynolds (1970), DDE
residues were shown to be correlated with decreased eggshell thickness
in 40 GBHs from Alberta (Vermeer and Risebrough, 1972). This
relationship had a greater degree of significance if residue
concentrations were expressed on a lipid weight basis rather than on a
wet weight basis. Dieldrin
concentration was also correlated with eggshell thinning, though the
relationship was less significant. |
|
3. |
Eggshells collected in 1969 and 1970 from a GBH colony in Bolinas Lagoon near San Francisco showed signs of thinning (Faber et al., 1972). "Hatched" (N=42) and broken (N=17) eggs had a mean thickness of 0.355 mm, representing a 10.4% decrease from pre-1947 specimens. The shells of eggs that "hatched" had a mean thickness of 0.365 |