Risk assessment of great horned owls (Bubo virginianus) exposed to polychlorinated biphenyls and DDT along the Kalamazoo River, Michigan, USA

The great horned owl (GHO; Bubo virginianus) was used in a multiple lines of evidence study of polychlorinated biphenyls (PCBs) and p,p'-dichlorodiphenyltrichloroethane (DDT) exposures at the Kalamazoo River Superfund Site (KRSS), Kalamazoo, Michigan, USA. The study examined risks from total PCBs, including 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQWorld Health Organization [WHO]-Avian Toxicity Equivalency Factor [TEF]), and total DDTs (sum of DDT, dichlorodiphenyldichloroethylene [DDE], and dichlorodiphenyldichloroethane [DDD]; sigmaDDT) by measuring concentrations in eggs and nestling blood plasma in two regions of the KRSS (upper, lower) and an upstream reference area (RA). An ecological risk assessment compared concentrations of the contaminants of concern (COCs) in eggs or plasma to toxicity reference values. Productivity and relative abundance measures for KRSS GHOs were compared with other GHO populations. Egg shell thickness was measured to assess effects of p,p'-DDE. The concentrations of PCBs in eggs were as great as 4.7 x 10(2) and 4.0 x 10(4) ng PCB/g, wet weight at the RA and combined KRSS sites, respectively. Egg TEQ(WHO-Avian) calculated from aryl hydrocarbon receptor-active PCB congeners and WHO TEFs ranged to 8.0 and 1.9 x 10(2) pg TEQ(WHO-Avian)/g, (wet wt) at the RA and combined KRSS, respectively. Egg sigmaDDT concentrations were as great as 4.2 x 10(2) and 5.0 x 10(3) ng sigmaDDT/g (wet wt) at the RA and combined KRSS, respectively. Hazard quotients (HQs) for the upper 95% confidence interval (UCI) (geometric mean) and least observable adverse effect concentration (LOAEC) for COCs in eggs were < or = 1.0 for all sites. Hazard quotient values based on the no observable adverse effect concentration (NOAEC) 95% UCI in eggs were < or = 1.0, except at the LKRSS (PCB HQ = 3.1; TEQ(WHO-Avian) HQ = 1.3). Productivity and relative abundance measures indicated no population level effects in the UKRSS.     

In utero polychlorinated biphenyl exposures in relation to fetal and early childhood growth

BACKGROUND: Polychlorinated biphenyls (PCBs) are industrial chemicals that were used widely for approximately 50 years. Now banned, they are still ubiquitous because of their persistence in the environment, the food chain, and human fatty tissue. High in utero exposures cause developmental deficits accompanied by growth retardation. Studies examining intrauterine growth at lower exposures have been inconsistent, with most such investigations having relied on surrogate exposure indicators such as consumption of fish from contaminated bodies of water. METHODS: In the 1960s, serum specimens were collected from pregnant women participating in the Child Health and Development Study in the San Francisco Bay Area. The women were interviewed and their serum samples stored at -20 degrees C. At 5 years of age, detailed anthropometric measurements were made on children born in the years 1964-1967. We measured PCBs in specimens from 399 mothers using gas chromatography/electron capture detection. We conducted multiple linear regression to examine the relationship between these organochlorine concentrations and both intrauterine and 5-year growth, with adjustment for medical, lifestyle, sociodemographic, and specimen characteristics. RESULTS: In male infants, higher total in utero PCB exposure was associated with reduced birth weight, head circumference, and weight-for-gestational age. An increase from the 10th to 90th percentile in total PCBs was related to 290 g lower birth weight, a 0.7-cm decrease in head circumference, and for weight for gestational age, a reduction in z-score of 0.6. In girls, smaller head circumference and shorter gestations were observed. In contrast, prenatal PCBs were associated with greater growth in 5-year-old girls, with no apparent effect in 5-year-old boys. CONCLUSIONS: Maternally mediated exposure to PCBs may be detrimental to fetal growth, particularly in boys. These effects apparently are not persistent. Interpretation of greater childhood growth of girls is unclear.     

Associations between regional differences in polychlorinated biphenyls and dichlorodiphenyldichloroethylene in blood of nestling bald eagles and reproductive productivity

The relationship between regional reproduction rates of bald eagles (Haliaeetus leucocephalus) and concentrations of p.p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and total polychlorinated biphenyls (PCBs) in blood plasma from nestling bald eagles was assessed. Blood was analyzed from 309 nestlings from 10 subpopulations of eagles across the Great Lakes region. Geometric mean concentrations of p,p'-DDE and total PCBs were inversely correlated to the productivity and success rates of nesting bald eagles within nine subpopulations. Nestlings eight weeks of age and older had significantly greater geometric mean concentrations of total PCBs and p,p'-DDE than nestlings less than eight weeks of age. The ability to use measurements of p,p'-DDE and total PCBs in nestling blood to determine the potential impact of these contaminants on adult nesting on a regional scale was demonstrated.     

Herring gulls and great black-backed gulls as indicators of contaminants in bald eagles in Lake Ontario,Canada

In 2000, a pair of bald eagles (Haliaeetus leucocephalus) nested successfully along the shorelines of Lake Ontario in North America for the first time since 1957. However, it is a continuing question whether bald eagles will be able to reproduce successfully as they return to nest on Lake Ontario. Great black-backed gulls (Larus marinus) and herring gulls (L. argentatus) were selected as surrogate species to predict contaminant levels in eggs of bald eagles nesting on Lake Ontario. Because of the suspected overlap in the diets of great black-backed gulls and bald eagles (i.e., fish, gull chicks, and waterfowl), the two species probably occupy a similar trophic level in the Lake Ontario food web and, thus, may have similar contaminant levels. Fresh great black-backed gull and herring gull eggs were collected from three study sites in eastern Lake Ontario in 1993 and 1994 and analyzed for contaminants. Average contaminant levels of dichlorodiphenyldichloroethane (p,p'-DDE), total polychlorinated biphenyls (PCBs), and dieldrin in great black-backed gull eggs were 12.85, 26.27, and 0.27 microg/g, respectively. The mean ratio of contaminant levels in great black-backed gull eggs to contaminant levels in herring gull eggs for these three contaminants was 2.09 (range of means, 1.73-2.38). Predicted levels of contaminants in bald eagle eggs in Lake Ontario would be expected to be similar to the mean levels reported for great black-backed gull eggs. As a comparison, contaminant levels in bald eagle eggs collected from other Great Lakes nesting sites were compared to mean levels reported for herring gull eggs collected from nearby sites in 1986 to 1995. The mean ratio of contaminant levels in bald eagle eggs to contaminant levels in herring gull eggs from these sites for DDE, total PCBs, and dieldrin was 2.40 (range of means, 1.73-3.28). These ratios are very similar to those reported using great black-backed gull eggs, illustrating the apparent similarity in trophic status shared by the two top predator species at these Great Lakes sites. Predicted levels of contaminants in bald eagle eggs at Lake Ontario are similar to levels reported for bald eagles breeding at other Great Lakes sites, suggesting that bald eagles may be able to breed on the shores of Lake Ontario. However, it is unclear at this time what level of breeding success should be expected, given that productivity at other similarly contaminated Great Lakes sites may be below that required to sustain a successful breeding population. The absence of an inland bald eagle population from which bald eagles may begin to colonize the shorelines of Lake Ontario may be delaying initiation of nesting site selection; other factors such as habitat and prey availability would likely not limit reproductive success.     

Accumulation patterns of polychlorinated biphenyl congeners and organochlorine pesticides in Steller's sea eagles and white-tailed sea eagles, threatened species, in Hokkaido, Japan

Polychlorinated biphenyls (PCBs), including coplanar congeners, hexachlorocyclohexane isomers, chlordane-related compounds, and hexachlorobenzene, were found in the breast muscle of Steller's sea eagles (SSE) and white-tailed sea eagles (WSE) threatened species, collected in Hokkaido, Japan, during the two years from 1998 to 1999. Both PCBs and DDTs were the most notable compounds, with concentrations one to two orders of magnitude higher than the other compounds, that is, from 120 to 39,000 and from 68 to 15,000 ng/g wet weight, respectively. Non-ortho (International Union of Pure and Applied Chemistry [IUPAC] 77, 126, and 169) and mono-ortho (IUPAC 105, 118, and 156)-substituted coplanar PCB congeners amounted to 9.2 to 740 pg/g of 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents derived from the World Health Organization, Paris, France (WHO), toxic equivalent factors. The atmospheric PCBs and DDTs in eastern Siberian cities, such as Khabarovsk and Magadan, have been reported to be much higher than Hokkaido and the North Pacific. Thus, we speculated that the eagles might have been contaminated in these areas, where they spend most of the year except winter, which they spend in eastern Siberia. Adult eagles accumulated more PCBs and DDTs than younger ones. The patterns of PCB congeners were also found to change, depending on the age of the eagle examined; adult eagles showed relatively higher proportions of highly chlorinated PCBs thanjuvenile eagles did. This difference would be related to the efficiency of the excretion and the metabolism of each PCB congener in the eagles.     

Contaminants in fishes from great lakes-influenced sections and above dams of three Michigan Rivers: III. Implications for health of bald eagles

Recently, there have been discussions of the relative merits of passage of fishes around hydroelectric dams on three rivers (Au Sable, Manistee, and Muskegon) in Michigan. A hazard assessment was conducted to determine the potential for adverse effects on bald eagles that could consume such fishes from above and below dams on the three primary rivers. The hazard assessments were verified by comparing the reproductive productivities of eagles nesting in areas where they ate primarily fish from either above or below dams on the three primary rivers, as well as on two additional rivers in Michigan, the Menominee and Thunder Bay. Concentrations of organochlorine insecticides (OCI), polychlorinated biphenyls (total PCBs), 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TCDD-EQ), and total mercury (Hg) were measured in composite samples of fishes from above and below hydroelectric dams on the Manistee and Muskegon Rivers, which flow into Lake Michigan, and the Au Sable River, which flows into Lake Huron. Mean concentrations of OCI, total PCBs, and TCDD-EQ were all greater in fishes from below the dams than in those from above. The hazard assessment indicated that current concentrations of Hg and OCI other than DDT (DDT + DDE + DDD) in fish from neither above nor below dams would present a significant hazard to bald eagles (Haliaeetus leucocephalus). Both total PCBs and TCDD-EQ in fishes from below the dams currently present a significant hazard to bald eagles, since their mean hazard quotients (HQ) were all greater than one.     

Association of a polychlorinated dibenzo-p-dioxin, a polychlorinated biphenyl, and DDT with diabetes in the 1999-2002 National Health and Nutrition Examination Survey

The association of a polychlorinated dibenzo-p-dioxin, a polychlorinated biphenyl, and p,p'-DDT with diabetes was evaluated using the 1999-2002 National Health and Nutrition Examination Survey. Persons 20 years old and older were included. Relationships with diagnosed diabetes, undiagnosed diabetes (glycohemoglobin (HbA1c) >6.1%), and total diabetes (diagnosed plus undiagnosed) were tested. When all three chemicals were evaluated together for total diabetes, the unweighted number of participants was 1830. All three compounds were significantly associated with diagnosed diabetes. PCB 126 and p,p'-DDT were significantly associated with undiagnosed diabetes. 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin (HxCDD) was not associated with undiagnosed diabetes. When the three chemicals were included in a combined model for total diabetes, PCB 126>83.8pg/g lipid adjusted had an odds ratio of 2.57 (95% CI 1.33-4.95) compared to PCB 126 < or = 31.2pg/g lipid adjusted. Also significant in a combined model for total diabetes was p,p'-DDT 20.8-26.6ng/g lipid adjusted with an odds ratio of 2.52 (95% CI 1.26-5.02) and p,p'-DDT >26.6ng/g lipid adjusted with an odds ratio of 2.74 (95% CI 1.44-5.23) both compared to p,p'-DDT < or = 20.7ng/g lipid adjusted. HxCDD was not associated with total diabetes in a combined model. When participants with poor liver function and poor kidney function were removed from the analysis, the combined model for total diabetes produced similar results with PCB 126 and p,p'-DDT having been significantly associated, and HxCDD not having been associated. These findings add to the list of chemicals found to be associated with diabetes in the 1999-2002 National Health and Nutrition Examination Survey.     

Maternal DDT exposures in relation to fetal and 5-year growth

BACKGROUND: Dichlorodiphenyltrichloroethane (DDT) is an organochlorine pesticide still used in areas of the world where malaria vector control is needed. Few studies have examined in utero exposures to DDT in relation to fetal and early childhood growth in populations with substantial exposure to DDT. Furthermore, only a portion of these studies have investigated in utero exposures and growth during childhood. METHODS: To assess the role of in utero exposures to DDT on fetal and early childhood growth, we analyzed data from mothers and children who participated in the Child Health and Development Study (CHDS), a cohort study of 20,754 women and their pregnancies conducted in the San Francisco Bay area during the 1960s. We measured p,p'-DDE, o,p'-DDT, and p,p'-DDT concentrations from the stored sera of 399 women collected during pregnancy. Outcomes were measured at the child's birth and at 5 years of age. RESULTS: Maternal p,p'-DDE concentrations were considerable in this study, averaging 6.9 micrograms per gram lipid. After covariate adjustment, a small increase in gestational age was observed with increases in p,p'-DDT and o,p'-DDT, but there was no association with p,p'-DDE. At 5 years of age, an increase from the 25th to the 75th percentile in p,p'-DDE was related to a 2-mm increase in head circumference (95% confidence interval = 0 to 4). Overall effect sizes were small and imprecise. Furthermore, there was little evidence of specificity for a given outcome or exposure at either age. CONCLUSIONS: At the concentrations studied in this sample, DDT compounds did not appear to impair fetal or 5-year growth.     

Toxicity and bioaccumulation of DDT in freshwater amphipods in exposures to spiked sediments

The amphipods Hyalella azteca and Diporeia spp. were exposed to sediments dosed with dichlorodiphenyltrichloroethane (DDT), and the toxicity and toxicokinetics were determined. The toxicity was evaluated with the equilibrium partitioning (EqP) and critical body residue approaches. The DDT in the sediments degraded during the equilibration period prior to organism exposure. Thus, the toxicity using EqP pore-water toxic units (TUs) was evaluated for DDT and its degradation product, dichlorodiphenyldichloroethane (DDD), as the ratio of the predicted interstitial water concentration divided by the water-only LC50 values. The sum of TUs (sum(TU)) was assumed to best represent the toxicity of the mixture. For H. azteca, the 10-d LC50 was 0.98 and 0.33 sum(TU) for two experiments. For Diporeia spp., no toxicity was found in the first experiment with up to 3 sum(TU) predicted in the interstitial water. However, in the second experiment, the 28-d LC50 was 0.67 sum(TU). These data suggest that the EqP approach approximately predicts the toxicity for the combination of DDT and DDD in sediment, provided a toxic unit approach is employed. The critical body residue approach also used TUs because DDT is biotransformed by H. azteca and because of the dual exposure to DDT and DDD. Because biotransformation was only determined in the second experiment, the critical body residue approach could only be evaluated for that case. The TUs were calculated as the ratio of the concentration in the live amphipods divided by the respective LR50 (residue concentration required to produce 50% mortality) values. The LR50 was 1.1 sum(TU) for H. azteca for the 10-d exposure and 0.53 for Diporeia spp. after a 28-d exposure. Thus, this approach was also quite successful in predicting the toxicity. The accumulation and loss rates for H. azteca were much greater than for Diporeia spp. Thus, 10-d exposures represent steady-state conditions for H. azteca, while even at 28-d, the Diporeia spp. are not at steady state.     

Pesticides and polychlorinated biphenyl residues in human breast lipids and their relation to breast cancer.

The etiology of human breast cancer is unknown; accepted risk factors, e.g., menstrual, reproductive, and family histories, are implicated in less than half of all cases. Various halogenated hydrocarbons--acting as either co-carcinogens or promoting agents--which are derived from the environment and are concentrated in human fatty stores, may also play a role in breast cancer risk. A pilot study was undertaken to measure and compare levels of chemical residues in mammary adipose tissue from women with malignant and nonmalignant breast disease. Elevated levels of polychlorinated biphenyls, bis (4-chlorophenyl)-1,1 dichloroethene, and bis(4-chlorophenyl)-1,1,1 trichloroethane were found in fat samples from women with cancer, compared with those who had benign breast disease. These results, although preliminary, suggest a role for environmentally derived suspect carcinogens in the genesis of mammary carcinoma.     

Critical evaluation of polychlorinated biphenyl toxicity in terrestrial and marine mammals: Increasing impact of non-ortho and mono-ortho coplanar polychlorinated biphenyls from land to ocean

Residues of potentially toxic non-ortho chlorine substituted coplanar 3,3,4,4-tetra-,3,3,4,4,5-penta-, 3,3,4,4,5,5-hexachlorobiphenyl and their mono- and di-ortho analogs (2,3,4,4,5-penta-, 2,3,3,4,4-penta-, 2,3,3,4,4,5-hexa-and 2,2,3,3,4,4-hexa-, 2,2,3,4,4,5-hexa-chlorobiphenyl) were determined in humans, dogs, cats (terrestrial), a finless porpoise (Neophocoena phocoenoides-coastal), Dall's porpoises (Phocoenoides dalli,dalli), Baird's beaked whales (Berardius bairdii) and killer whales (Orcinus orca-open ocean). Among the coplanar polychlorinated biphenyl (PCB) congeners, the concentration of the di-ortho congeners was the highest and the non-ortho congeners was the lowest. However, all three coplanar PCBs occurred at significantly higher levels than toxic polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The relative bioconcentration and metabolic capacity of terrestrial and marine mammals to these chemicals, suggest that the toxic threat of coplanar PCBs increases from land to ocean, but the reverse is true for PCDDs and PCDFs. The toxic threat of coplanar PCBs to higher aquatic predators such as cetaceans was principally assessed by 2,3,7,8-T₄CDD Toxic Equivalent Analysis which is based on the induction of arylhydrocarbon hydroxylase (AHH) and ethoxyresorufinO-deethylase (EROD). Analysis indicates, in particular, that the bioaccumulation of toxic 3,3,4,4,5-penta- and 2,3,3,4,4-pentachlorobiphenyls in carnivorous marine mammals is a cause for considerable concern.     

A mass spectroscopic method for analysis of AHH-inducing and other polychlorinated biphenyl congeners and selected pesticides in fish

The 209 polychlorinated biphenyl (PCB) congeners exhibit a wide range in toxicity to fish, birds, and mammals. This paper discusses the use of gas chromatography/mass spectrometry negative chemical ionization (GC/MS-NCI) to quantify congeners of highly suspected toxicity such as IUPAC #77 (3,3,4,4-tetrachlorobiphenyl) and #126 (3,3,4,4,5-pentachlorobiphenyl). GC/MS analysis time needed to produce the necessary resolution was reduced to 1 h per sample or standard, allowing an autosampler to inject 12 samples in 24 hours, plus 12 standards/QC samples. Identification and quantification of some 60+ congeners and several selected pesticides and estimation of total PCBs are also possible within the 1 h analysis. For congeners of high chlorination (penta through octa), the method exhibited excellent sensitivity, such that we could not locate a fish which exhibited PCB levels below our calibrated quantitation range. NCI was not as sensitive for mono through tri and for some tetrachlorinated PCB congeners, an exception being PCB #77, for which sensitivity was of the same order as for the more highly chlorinated biphenyls. Long term stability was excellent. Over a 6-mo period, results of replicate analyses for PCB congeners and pesticides in a composited sample of lake trout (Salvelinus namaycush) from Lake Michigan had a relative standard deviation of 12% of the mean. Over the same time period, mean recoveries for samples spiked at concentrations similar to those in Lake Michigan lake trout were 90–102%. Response was linear over a wide range of concentrations for each of the analyzed compounds. This method is now being used for routine analysis of PCB congeners and selected pesticides in our laboratory.Contribution 799 of the National Fisheries Research Center-Great Lakes, U.S. Fish and Wildlife Service, 1451 Green Road, Ann Arbor, MI 48105.     

A cohort study of <Emphasis Type="Italic">in utero</Emphasis> polychlorinated biphenyl (PCB) exposures in relation to secondary sex ratio

Background  

Polychlorinated biphenyls (PCBs) are ubiquitous industrial chemicals that persist in the environment and in human fatty tissue. PCBs are related to a class of compounds known as dioxins, specifically 2,3,7,8-TCDD (tetrachloro-dibenzodioxin), which has been implicated as a cause of altered sex ratio, especially in relation to paternal exposures.     

Association of transposition of the great arteries in infants with maternal exposures to herbicides and rodenticides

The Baltimore-Washington Infant Study, a case-control study of congenital heart defects in liveborn infants conducted in 1981--1989, interviewed parents about a wide range of environmental exposures that occurred during and before the pregnancy. In the period 1987--1989, the questionnaire was expanded to include a detailed inquiry about exposures to pesticides. An analysis of these latter data revealed an association of maternal exposure to any pesticides during the first trimester with transposition of the great arteries in their infants (TGA; n = 66 infants), relative to 771 control infants, with an odds ratio of 2.0 (95% confidence interval (CI): 1.2, 3.3). No other heart defects were associated with pesticides. When analyzed by type of pesticide and adjusted for covariates, there were associations of TGA with maternal exposures to herbicides (odds ratio (OR) = 2.8; 95% CI: 1.3, 7.2) and to rodenticidal chemicals (OR = 4.7; 95% CI: 1.4, 12.1) but not to insecticides (OR = 1.5; 95% CI: 0.9, 2.6). No data were collected on specific chemicals or brand names. These results raise new questions about the possible epidemiologic association of TGA with some classes of pesticides and warrant new, carefully targeted investigations.     

Exposure to the polychlorinated biphenyl mixture Aroclor 1254 alters melanocyte and tail muscle morphology in developing Xenopus laevis tadpoles

Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants that have damaging effects on both ecosystem and human health. Numerous studies have shown that exposure to PCBs can alter growth and development of aquatic organisms, including frogs. In this report, developing Xenopus laevis tadpoles were exposed to the PCB mixture Aroclor 1254. Tadpoles were exposed from 5 through 9 d postfertilization to either 0, 1, 10, 50, or 100 ppm Aroclor 1254. Exposure to an acute, high concentration of Aroclor 1254 (10, 50, and 100 ppm) caused statistically significant reductions in survival and body size. In addition, tadpoles exposed to these higher concentrations showed histological abnormalities, including aberrant tail tip, myotomal, and melanocyte morphologies. Described adverse health effects associated with PCB exposure of developing frogs will serve as useful health endpoints in ongoing and future molecular-based studies that correlate health effects with changes in gene expression.