High PCB Levels Research Articles

Congener-specific accumulation and patterns of chlorinated and brominated contaminants in adult male walruses from Svalbard, Norway: Indications for individual-specific prey selection

Blubber samples from 17 adult, male walruses were sampled in eastern Svalbard and analyzed for chlorinated and brominated contaminants. A wide range of contaminants were detected, including PCBs (mean 2000; 95% range 1165–4005 ng/g lipid), DDE (mean 100: 95% range 50–310) ng/g lipid), chlordanes (mean 2500; 95% range 1347–5009) ng/g lipid, toxaphenes (mean 80; 95% range 51–132 ng/g lipid) and polybrominated diphenyl ethers (PBDEs) (mean15 ng/g; 95% range 9–27 ng/g lipid). PCB and DDE levels were substantially lower than those of animals sampled 10 year earlier in this area, confirming a decreasing trend for these compounds in the Arctic. However, compared to other recently sampled marine mammals from Svalbard, walruses showed relatively high PCB and chlordane levels although they had lower levels of DDE, toxaphenes, and PBDEs, possibly due to species- and location-specific differences in exposure and metabolism.The range in contaminant levels found within the sample group was vast, despite the fact that the animals investigated were all adult males from the same location. The PCB pattern in highly contaminated animals was different from that in animals with low levels of contamination, with relatively more persistent PCBs in the highly contaminated group. This suggests that the more contaminated animals were feeding at higher trophic levels; possibly targeting seals in addition to mollusks as their prey. This suggestion was reinforced by the fatty acid profiles of the inner blubber layer of walruses with low versus high contaminant levels, which suggested different diets for the two groups.

Hydroxylated PCB Metabolites in Nonhatched Fulmar Eggs from the Faroe Islands

Thirty-six polychlorinated biphenylols (OH-PCBs) congeners were characterized in Fulmar (Fulmarus glacialis) eggs collected from the Faroe Islands. The seven most abundant congeners were quantified in 19 samples, and the sigmaOH-PCB concentrations ranged between 0.92 and 4.0 ng g(-1) fresh weight (f.w.). These eggs constitute a part of the traditional diet for at least a part of the population on the Faroe Islands and may contribute to the high levels of these contaminants found in the blood of pregnant Faroese women. Because the metabolites are present in the nonhatched fulmar egg, it is concluded that the OH-PCBs are transferred to the egg before laying. High levels, 3300-18,000 ng g(-1) l.w., of sigmapolychlorinated biphenyls (PCB) were determined in the fulmar eggs, which are a considerable source for human exposure. The high PCB levels are a source for metabolic formation of hydroxylated PCBs.

Biomonitoring of heavy metals and trace organics using the intertidal mussel Perna viridis in Hong Kong coastal waters

This paper presents the results of a 6-year (1998–2003) survey of trace toxics in the intertidal mussel Perna viridis conducted by the Hong Kong Environmental Protection Department. Concentrations of heavy metals and trace organics were measured in the soft bodies of P. viridis collected from five sites in Hong Kong waters, i.e. Wu Kai Sha (Tolo Harbour), Ma Wan (Northwest), Tsim Sha Tsui (Victoria Harbour), Tai Tam (Hong Kong South) and Lamma Island (Southern Waters) in order to establish the spatial patterns of contaminants in mussels. Among the metals analysed, Cd showed a significant concentration gradient in Hong Kong waters. The levels of Cd in P. viridis were significantly higher at Ma Wan as compared to the other sites studied. Ma Wan also had relatively higher concentrations of Pb. Mn concentrations were particularly prominent at Wu Kai Sha. Significantly higher concentrations of Hg and Cu were recorded at Tai Tam and Tsim Sha Tsui. Tai Tam and Wu Kai Sha had higher levels of V; whereas higher Ni concentrations were recorded at Lamma Island and Tai Tam. No clear spatial patterns for Al, As, Cr, Fe and Zn were observed. Higher concentrations of PAHs in P. viridis were observed around urban centres impacted by sewage discharges (e.g. Tsim Sha Tsui); whereas higher PCB levels were found not only in Tsim Sha Tsui but also in less urbanised areas such as Lamma Island and Tai Tam, suggesting that these may be due to non-sewage related inputs. The study also shows that Northwest and Southern waters are subject to a higher degree of DDT pollution compared with other sites. Of the 17 dioxin compounds analysed, positive data were mostly recorded for two compounds which are of low toxicity (i.e. OCDD and 1,2,3,4,6,7,8-HpCDD) whereas the most toxic congeners (i.e. 2,3,7,8-TCDD and 1,2,3,7,8-PeCDD) were not detected in the 6 years of monitoring. In general, the levels of OCDD in P. viridis were found to be higher in Tai Tam and Lamma Island in Southern Waters of Hong Kong. This study found that the levels of some highly toxic heavy metals (i.e. Cd, Hg and Pb) in the mussel P. viridis did not exceed the recommended limits for shellfish as food in Hong Kong (i.e. Cd: 2.0 ppm; Hg: 0.5 ppm; Pb: 6.0 ppm wet weight). The levels of As and Ni in P. viridis were also well below the action limits set by the US FDA (i.e. As: 86 ppm; Ni: 80 ppm wet weight). DDT and PCB contaminations in P. viridis were below the concentrations of concern. Compared with data obtained in the 1980s, the current levels of DDTs in P. viridis were 4–16 times lower; whereas Pb concentrations recorded in Tsim Sha Tsui have also been lowered significantly. This is mainly related to reduction in local and regional pollution sources in the past 20 years.

Distribution of organochlorine pesticides, polychlorinated biphenyls and α-HCH enantiomers in pork tissues

The distribution of HCH isomers, DDT analogues and selected PCB congeners in pork organs collected from the same individuals raised in Romanian farms was investigated. Organochlorine pesticides (HCHs and DDTs) were the principal contaminants in all samples, while PCB concentrations were low, in accordance with previously reported concentrations from Romanian animal farms. The most part of the pollutant load in the body is retained in the adipose tissue, with HCHs ranging between 16 and 27.7 ng/g lipid and with higher concentrations of DDTs ranging between 65.9 and 334.5 ng/g lipid. The highest PCB levels (up to 32 ng/g lipid) were measured in lung and liver. The lipid-normalized concentrations in the brain were lower than in all other tissues due to the presence of the blood-brain barrier or due to a lower proportion of the neutral lipids such as triglycerides. The highest concentrations of DDTs were measured in muscle and fat, with p, p ′-DDE being the principal contributor and with a variable contribution of p, p ′-DDD and p, p ′-DDT. In liver, p, p ′-DDD has a higher contribution to the sum DDTs, while in all analyzed livers, the concentration of p, p ′-DDT was very low. β-HCH was the most persistent HCH isomer in all tissues, accounting for 40–97% of sum HCHs. For all animals, the highest concentrations of β-HCH and HCHs were found in liver, while the lowest HCH concentrations were measured in brain and spinal marrow. Additionally, the distribution of α-HCH enantiomers in the tissues was discussed. In all samples (except 2 brain samples), (+) α-HCH was depleted and (−) α-HCH was enantioenriched. Enantiomeric ratios in brain were the highest measured values between all organs. For all studied animals, ERs increased in the order fat < muscle < liver < brain.

Exposure of Taiwan residents to polychlorinated biphenyl congeners from farmed, ocean-caught, and imported fish.

This study is to assess PCB levels in five frequently consumed fish species in Taiwan, tilapia, milkfish, white pomfret, hairtail, and cod. Seventeen congeners were measured in fillet samples purchased from major markets in northern, central, and southern Taiwan. All 136 samples had traces of PCBs. The median concentrations were 0.18, 0.46, 0.62, 0.69, and 7.34 ng/g wet wt and 1.01, 0.28, 1.14, 5.06, and 19.3 pg-WHO-TEQ/g lipid in tilapia, milkfish, white pomfret, hairtail, and cod samples, respectively. Cod (the imported fish) had the highest wet weight PCB concentrations. The fish caught off-shore (white pomfret and hairtail) had higher levels than the farmed fish (tilapia and milkfish). The congener profiles varied among species. PCB 105/153 and 126 accounted for more than 28% and 53% of the 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (WHO-TEQs) in hairtail and cod, respectively; while PCB 156 was the major TEQ contributor in the other species. The estimated median PCB intake of the general public from consumption of the five species ranged from 0.000023 to 0.048 pg-WHO-TEQ/kg/day. It was also found that samples farmed or caught along the southern coast had higher PCB levels than those from other parts of Taiwan, indicating possible elevated PCB contamination around that area.

Ecological risk assessment of persistent organic pollutants in the arctic

Ecological risk assessment of persistent organic chemicals in marine mammals in the Arctic would comprise assessments of both exposure and effect and risk characterization. Results from a comprehensive collaborative study between Norwegian and Canadian researchers, comprising epizoological (ecological) studies (reproductive rate, offspring survival), experimental studies on the immune system function, monitoring studies (e.g. physiological assays of thyroid hormones, retinol, IgG and testosterone) and registration of biological data (e.g. sex, age, reproductive status, nutritional status) were coupled with PCB exposure data. Assessment of the results indicates that population status and health of polar bears with very high PCB levels may be at risk.

Persistent chlorinated pesticides and polychlorinated biphenyls in selected fish species from Lake Tanganyika, Burundi, Africa

Concentrations of selected organochlorine pesticides and PCBs in seven fish species (cichlids) from the north end of the Lake Tanganyika, Burundi, Africa were determined. Results were compared to previous work on the Lake Tanganyika and other water bodies and to the European Community maximum residue levels (MRLs) in edible fat. The analytical method included a hot Soxhlet extraction with a mixture of acetone: hexane (1:3, v/v), gravimetrically lipid determination, and a single step clean-up. For PCBs and stable pesticides, the clean-up was done on activated silica gel impregnated with concentrated sulfuric acid, while for non acid-stable pesticides superposed layers of alumina, silica and florisil impregnated with 15% methanolic solution of KOH were successively used. Recoveries of organochlorine pesticides from certified reference material (CRM 430) were ranging from 86% for p,p′-DDT to 107% for endrin, while recoveries from blank fat spiked fortified at three different levels were between 65% for alachlor at the lowest fortification level and 107% for mirex at the highest fortification level. The limits of detection for each analyte were ranging from 0.1 ng/g to 0.5 ng/g fat. All chlorinated pesticides were found in the analyzed species but at low concentrations. Boulengerochromis microlepis contained the highest concentrations of HCHs (288.2±15.5 ng/g fat) and DDTs (909.1±42.5 ng/g fat), while the highest PCB levels (166.7±37.4 ng/g fat for the sum of 12 congeners) were found in Oreochromis niloticus. However, there is no evidence that Lake Tanganyika is more contaminated with pesticides than other African water bodies.

Concentration and toxic potential of polychlorinated biphenyl congeners in migratory oceanic birds from the North Pacific and the Southern Ocean

Concentrations of PCBs and their toxic potential were examined in subcutaneous fat of eight albatross and one petrel species collected from the North Pacific and the Southern Oceans. Among all the species analyzed, high PCB levels were found in adult male black-footed albatross from the North Pacific with the mean value of 92 μg/g wet weight. No significant gender difference in PCB accumulation was observed ( P>0.1). The mean PCB levels in Southern Oceanic birds were 1 or 2 orders of magnitude lower than those from the North Pacific albatrosses. A regional-specific accumulation of non-ortho coplanar congeners were observed, most birds from the Southern Ocean had higher IUPAC 169 levels while IUPAC 126 concentrations were higher in those from the North Pacific. The estimated toxic equivalents for black-footed and Laysan albatrosses from the North Pacific were in the same range of some fish-eating birds, which were highly contaminated by PCBs. The correlation between ratio of IUPAC 169/126 concentration and total PCBs concentration indicated the possibility of induction in cytochrome P450 activities in North Pacific albatrosses ( P<0.01). The calculated hazard indices indicated that black-footed and Laysan albatrosses inhabiting in the North Pacific had similar threshold levels which were known to cause toxic effects in some populations of fish-eating birds.

Changes in Serum PBB and PCB Levels over Time among Women of Varying Ages at Exposure

The identification of host factors that are predictors of changes in serum polyhalogenated biphenyl contaminants over time has been a difficult challenge in epidemiologic studies of exposed individuals. Of particular concern are age at exposure, reproductive and lactational histories, and changes in body mass index. Using both cross-sectional and longitudinal approaches, this study examined factors related to high initial serum PBB and PCB levels and changes in these levels over time among women of varying ages at exposure (n=1772; age range<1 to 45 years). In 1973, PBB exposure occurred through consumption of farm products contaminated with PBB added to cattle feed. Exposures to PCBs began in 1941 through PCB-contaminated silo sealant deteriorating into animal feed. The Michigan Department of Public Health began enrolling participants in 1977 and has continued to follow them through annual updates. At enrollment, questionnaires were administered to obtain demographic, lifestyle, and anthropometric measurements, medical/reproductive and occupational histories, and contaminated food consumption patterns. Blood samples were collected for PBB and PCB analysis at enrollment for all participants; additional serum tests were done on a subset of the population during follow-up. Median serum levels at enrollment were 2.0 ppb PBB and 5.0 ppb PCB. A decline in serum PBB level over an interval that ranged from 1 to 146 months (median=31) was observed for 44.6% of the women (median=1.0 ppb), while 12.2% showed an increase (median=1.0 ppb). PCB levels declined in 50.3% of the women (median=3.0 ppb) while 12.2% increased (median=2.0 ppb). Relative to women whose contaminant levels were stable, higher initial serum level was a predictor of decline for both PBB and PCB (OR=1.66, 95% CI 1.52–1.82; OR=3.26, 95% CI 2.58–4.12, respectively); a yearly increase in interval between tests was related to declining PCBs (OR=1.65, 95% CI 1.46–1.87). In addition, age≤10 years at exposure (OR=1.72, 95% CI 1.03–2.86) and residence on a quarantined farm (OR=1.40, 95− CI 1.03–1.90) were predictors of a decrease in PBBs. Factors related to an increase in PBB levels were age≤10 years at exposure (OR=0.30, 95% CI 0.10–0.96) and initial PBB level (OR=1.24, 95% CI 1.15–1.33); and for PCBs, high initial level (OR=1.34, 95% CI 1.17–1.53) and body mass index (OR=1.07, 95% CI 1.01–1.13). One or more live births during the interval between tests were not related to changing levels of either contaminant; breastfeeding data were not available for examination. Early age at exposure appears to be an important predictor of changes in serum PBB levels OVER TIME.

Chemical contamination of bottom sediments of Pechenga Bay, Barents Sea

The results of a 1977 survey of contamination levels in bottom sediments from the Pechenega Bay, Barents Sea, are presented. Aliphatic and aromatic hydrocarbons, chlorinated hydrocarbons (11 PCB congeners, DDT with metabolites, HCB, alpha‐HCH, lindane), and trace elements were analyzed in samples from five sites. Levels of trace elements and of polycyclic aromatic hydrocarbons (PAH) were found to be low. High levels of PCB and some pesticides found in the bottom sediments indicate anthropogenic contamination sources. Translated by Edward Torrey, Alexandria, VA from: Izvestiya Rossiyskoy Akademii Nauk, seriya geograficheskaya 2000, No. 1, pp. 79–87.

Geographical differences and time trends of persistent organic pollutants in the Arctic

Geographical and temporal trends of total PCBs (Σ PCBs) and hexachlorocyclohexanes (Σ HCHs) have been examined in polar bear ( Ursus maritimus) adipose tissue and ringed seal ( Phoca hispida) blubber along a transect from Alaska to Svalbard and northern Norway/western Russia. PCB concentrations in polar bear show a strong west to east trend with higher levels in east Greenland, Svalbard. In ringed seal, highest PCB levels were found at two sites near the Russian coast. Σ HCHs levels in ringed seals and polar bear show the reverse trend coinciding with much higher levels of Σ HCHs in seawater in the North American Arctic. Some of these geographical differences may reflect dietary differences especially in the case of PCBs. Levels of Σ PCBs in polar bears in the eastern Canadian Arctic appear to have increased from the 1970s to the 1980s but are now on the decline. Σ PCBs and Σ HCHs levels showed no significant change from the mid-1980s to 1990s in ringed seal blubber from three locations in the eastern Canadian Arctic.

A Source of PCB Contamination in Modified High-Volume Air Samplers

Modified Anderson High Volume (Hi-Vol) air samplers are widely used for the collection of semi-volatile organic compounds (such as PCBs) from air. The foam gasket near the main air flow path in these samplers can become contaminated with PCBs if the sampler or the gasket is stored at a location with high indoor air PCB levels. Once the gasket is contaminated, it releases PCBs back into the air stream during sampling, and as a result, incorrectly high air PCB concentrations are measured. This paper presents data demonstrating this contamination problem using measurements from two Integrated Atmospheric Deposition Network sites: one at Sleeping Bear Dunes on Lake Michigan and the other at Point Petre on Lake Ontario. The authors recommend that these gaskets be replaced by Teflon tape and that the storage history of each sampler be carefully tracked.

RAPID MICROBIAL GROWTH ON POLYCHLORINATED BIPHENYL AND ITS FATE IN CELLS

Abstract Nine cultures were examined for growth at 37C in media with different levels of PCB and selected one culture to treat an industrial liquid waste containing high levels of PCB 1248. All the nine cultures grew well in the presence of 100 to 500 μg PCB 1254 mL−1 glucose basal salt broth (GBSB) as well as in tryptic soy broth (TSP) with no significant changes in generation time. The cultures grew well in basal salt agar containing PCB as sole source of carbon. Pseudomonas aeruginosa and Serratia liquefaciens strains survived for 75 to 120 min in the presence of 300 to 2000 μg PCB 1254 mL−1 sodium‐phosphate buffer (SPB) pH 7.0. The P. aeruginosa cells removed both PCB 1254 and 14C‐PCB from SPB and GBSB within 48 h and the percent uptakes were 26 and 39.7%, respectively. The results of the fate and distribution of PCB 1254, including 14C‐PCB, in cells of P. aeruginosa, S. liquefaciens, and two Bacillus strains grown in PCB‐media showed that more than 50% of the 14C‐PCB were in the alcohol and in alcohol‐ether soluble fractions (mostly lipids). This was also confirmed after rupturing the P. aeruginosa cells using French pressure and/or lysozyme and fractionation. Both the intrinsic flora and P. aeruginosa strain were used in a bioreactor system for the treatments of 27 and 33 gallons industrial liquid waste containing 150 and/or 800 mg PCB 12481 1−1, respectively, and complete oxidation was achieved, within approximately 150 days and the biological half‐life of the PCB was 30 and 15 days, respectively.

Short-term distribution, metabolism, and excretion of 2,2',5-tri-, 2, 2',4,4'-tetra-, and 3,3',4,4'-tetrachlorobiphenyls in prepubertal rats.

The excretion and tissue retention of three 14C-labeled lower chlorinated biphenyls were examined in prepubertal male and female Sprague-Dawley rats following IV administration. Urine and feces were collected individually at different time intervals up to 72 h for pharmacokinetic analyses. After 72 h, different organs were removed and extracted in acetone:hexane (1:1, v/v) to determine radioactivity. Within the first 10 h after dosing, 2,2', 5-trichlorobiphenyl (PCB 18) was rapidly excreted in urine (8-18% of the administered dose), whereas only 0.6-0.8% of 2,2',4, 4'-tetrachlorobiphenyl (PCB 47) and 0.3-0.8% 3,3',4, 4'-tetrachlorobiphenyl (PCB 77) were found in urine during this time period. The half-life of elimination was shortest for PCB 18 (37.5 to 49.2 h). The half-lives for PCB 47 and PCB 77 were 351 to 672 h and 152 to 186 h, respectively. The cumulative total excretion (urinary + fecal) of PCB 18 within 72 h was 51-62%, of PCB 77 was 22-25%, and of PCB 47 was 7-10%. No parent PCBs were detected in urine. PCB 47 accumulated preferentially in adipose tissues (subcutaneous fat > mesenteric fat); relatively high levels of PCB 47 were also found in adrenals, ovaries, lungs, liver, and skin. The highest concentration of PCB 77 was found in serum, followed by adipose tissues. Very low concentrations of PCB 18 were found in most tissues; the highest being found in serum, followed by ovaries and adrenal glands. This study suggests that prepubertal rats retain higher short-term serum levels and have lower excretion rates than adult rats.

Luteinized ovarian cysts in Mediterranean striped dolphins.

The morbillivirus epizootic during 1990 to 1992 in Mediterranean striped dolphins (Stenella coeruleoalba) off the Mediterranean coast of Spain diminished these populations directly through mortalities, and indirectly through loss of normal fecundity. High levels of polychlorinated biphenyls (PCB's) also were detected in stranded animals. In addition to high numbers of abortions during the epidemic, unusual cystic structures were noted in the ovaries of several morbillivirus-infected dolphins with high PCB levels. These structures were identified as multiple luteinized cysts from their gross and histomorphologic characteristics. No morbillivirus antigens were detected in the lesions by immunohistochemistry. Because luteinized cysts occur when ovulation is impeded, either an effect of morbillivirus or PCB's on hypothalamic/pituitary function or an effect of PCB's on ovarian responsiveness are proposed as pathogenic mechanisms. These cysts may impede population recovery from the epidemic if similar cysts occurred on surviving dolphins.

Evidence That PCBs Are Approaching Stable Concentrations In Lake Michigan Fishes

We examined PCB concentration data for seven species of Lake Michigan fishes to determine what trends were apparent °20 yr after PCB restrictions became effective. Total PCB concentrations in all seven species, lake trout (Salvelinus namaycush), rainbow trout (Oncorhynchus mykiss), brown trout (Salmo trutta), chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), alewife (Alosa pseudoharengus), and bloater chub (Coregonus hoyi) declined and appeared to stabilize in the mid‐to‐late 1980s. Concentrations in two species, chinook and coho salmon, appear to have increased slightly since the late 1980s. All species are currently well below the high PCB levels that existed when PCB use was curtailed in the 1970s. We believe stabilizing concentrations are the result of large pools of PCBs that are being recycled in the environment. Atmospheric and sediment PCB inputs to the lake probably constitute current PCB sources. Increasing concentrations in chinook and coho salmon are likely the result of changing growth dynamics caused by alterations in the mid‐trophic levels of the food web. Median stable PCB concentrations estimated in this analysis are below the current FDA action level of 2 mg/kg, but not appreciably below this threshold. Improvements beyond these levels may result if management practices that maximize fish growth rates are implemented. Detection of future improvements in PCB levels may require samples in the range of 1000‐2000 fish because of the high variability in PCB concentrations among individuals.

Abnormally high polychlorinated biphenyl levels in striped dolphins ( Stenella coeruleoalba) affected by the 1990–1992 Mediterranean epizootic

PCB concentrations and total lipid content were determined in the blubber and liver of striped dolphins affected by the 1990 morbillivirus epizootic in the Mediterranean Sea, and in the blubber of striped dolphins from the same area sampled with a biopsy dart in 1987–1989 and 1991. PCB levels were found to be significantly higher in the individuals that succumbed to the epizootic than in the ‘healthy’ population sampled before or after the event. Although recent mobilization of lipid reserves was found to have occurred in some of the diseased dolphins, this had little effect on their PCB blubber concentrations and cannot explain the observed difference with the healthy individuals. Three hypotheses are put forward to explain the apparent link between high PCB levels and mortality caused by the epizootic: (i) depressed immunocompetence caused by PCBs leading to an increase in individual susceptibility to the morbillivirus infection, (ii) mobilization of fat reserves leading to increased PCB levels in blood which, in turn, may produce a liver lesion capable of increasing the individual's susceptibility to the morbillivirus infection, and (iii) previous existence of an unspecific hepatic lesion producing impairment of the liver function which, in turn, could lead to an increase both in tissue PCB concentrations and in individual susceptibility to the morbillivirus infection.

Environmental Contaminants in Bald Eagles in the Columbia River Estuary

Eggs, blood, and carcasses of bald eagles (Haliaeetus leucocephalus) and fish were collected and breeding success of eagles was monitored in the Columbia River estuary, 1980-87, to determine if contaminants were having an effect on productivity. High levels of dichloro diphenyl dichloroethylene (DDE), polychlorinated biphenyls (PCB's), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were found in eggs, blood from adults, and 2 eagle carcasses. Detectable levels of DDE and PCB's were found in blood of nestlings indicating they were exposed to these contaminants early in life. Increasing concentrations of DDE and PCB's with age also indicated accumulation of these contaminants. Adult eagles also had higher levels of mercury (Hg) in blood than subadults or young indicating accumulation with age. The high levels of DDE and PCB's were associated with eggshell thinning ([bar x] = 10%) and with productivity ([bar x] = 0.56 young/occupied site) that was lower than that of healthy populations (i.e., [ge]1.00 young/occupied site). DDE and PCB's had a deleterious effect on reproduction of bald eagles in the estuary. The role dioxins play in eagle reproduction remains unclear, but concentrations in eagle eggs were similar to those in laboratory studies on other species where dioxins adversely affected hatchability of eggs. Probable sourcemore » of these contaminants include dredged river sediments and hydroelectric dams, and the proper management of each may reduce the amount of contaminants released into the Columbia River estuary. 46 refs., 1 fig., 4 tabs.« less

PCBs and organochlorine pesticides in phytoplankton and zooplankton in the Indian sector of the Southern Ocean

Samples of phyto- and zooplankton were collected in the Indian sector of the Southern Ocean (38–67°S, 18–84°E) and analysed for organochlorine residues (PCBs and pesticides). The PCB concentration in particulate matter (mainly phytoplankton) appeared to be high and similar to that of temperate zones: 0.7 μg g−1 dry weight. Contamination levels were more constant expressed per water volume than per dry weight, and seven times lower (1.2 μg m−3) than in northern temperate zones (8.8 μm−3 in the North Sea). The Antarctic ecosystems are thus less contaminated than temperate ones — as expected — but the very low phytoplankton biomass present cause high PCB levels per unit of biomass. These results confirm the necessity of using different systems of units in order to correctly express the contamination levels and to identify the main mechanisms responsible for the accumulation of stable pollutants. PCB levels in netplankton samples (mainly zooplankton) were comparable with phytoplankton on a dry weight basis (0.7 μm−3), lower on a lipid weight basis (5.8 μg g−1 lw for netplankton, 16.3 for particulate matter) and were much higher per seawater volume (27.2 μg m−3 for netplankton, 1.2 for particulate matter). Netplankton contamination is comparable in the Antarctic (0.35 μg g−1 dw) and the North Sea (0.70) since zooplankton feeding on phytoplankton has similar levels of contamination in both ecosystems. Lindane, heptachlor epoxide, dieldrin, DDE and DDT were observed in various samples at trace levels. The high DDE/DDT ratio reflects the more recent origin of Antarctic organochlorines.

Great lakes embryo mortality, edema, and deformities syndrome (GLEMEDS) in colonial fish‐eating birds: Similarity to chick‐edema disease

Several species of colonial fish-eating birds nesting in the Great Lakes basin, including herring gulls, common terns and double-crested cormorants, have exhibited chronic impairment of reproduction. In addition to eggshell thinning caused by high levels of DDT and metabolites, the reproductive impairment is characterized by high embryonic and chick mortality, edema, growth retardation, and deformities, hence the name Great Lakes embryo mortality, edema, and deformities syndrome (GLEMEDS). The hypothesis has been advanced that GLEMEDS in colonial fish-eating birds resembles chick-edema disease of poultry and has been caused by exposure to chick-edema active compounds that have a common mode of action through the cytochrome P-448 system. Detailed evidence has been collected from the following three groups of studies on herring gulls in the lower Great Lakes during the early 1970s; Forster's terns in Green Bay, Wisconsin in 1983; and double-crested cormorants and Caspian terns in various locations in the upper Great Lakes from 1986 onwards. It has proved difficult to establish not only the onset of the disease in the various species at various locations but also the period in which chick-edema active compounds were released. Anecdotal evidence suggested that serious egg mortality in Lake Ontario herring gulls first occurred in 1966, through the signs of chick-edema disease were not looked for until 1974. Only indirect evidence is available on the date of the release of one of the presumed causal agents, 2,3,7,8-tetrachlorodibenzo-p-dioxin, but highest levels may have occurred in the early to mid 1960s. More reliable data show that the onset of the improvement of reproduction of Lake Ontario herring gulls coincided with the declines in organochlorine compounds and particularly 2,3,7,8-TCDD and PCB. Similarly, information on the onset of the disease and exposures in the Forster's tern and double-crested cormorants in Green Bay is uncertain but bird banders did not observe deformities until the 1970s, which corresponds with the onset of high levels of PCB. If the disappearance of the Caspian tern from Saginaw Bay in the mid 1960s corresponds with the onset of GLEMEDS at that location, then there is a close temporal relationship to the onset of high PCB levels. Chick-edema disease is difficult to diagnose because there is no specific lesion, but rather there is a suite of lesions.(ABSTRACT TRUNCATED AT 400 WORDS)