Biomonitoring of mercury and persistent organic pollutants in Michigan urban anglers and association with fish consumption

The 32-mile Detroit River and surrounding tributaries have been designated as a Great Lakes Area of Concern due to pollution from decades of municipal and industrial discharges, sewer overflows and urban development. Key pollutants in fish samples from the Detroit River include mercury, polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (DDE), dioxins and furans. A biomonitoring study was conducted to assess exposures to these persistent toxic substances in Detroit urban shoreline anglers who may be at high exposure risk due to consumption of locally caught fish. Using a modified venue-based sampling approach, 287 adult shoreline anglers along the Detroit River were recruited and participated in the program. Study participants provided blood and urine specimens and completed a questionnaire following informed consent. We examined percentile estimates for total blood mercury, PCBs, DDE, and dioxin-like total toxic equivalency (TEQ) concentrations among study participants. Multiple linear regression was used to identify important predictors of contaminant concentrations. Participants consumed a median of 64 Detroit River caught fish meals in the past year. The Detroit urban anglers’ median total blood mercury concentrations was 3.2 times higher than that for the general adult U.S. population. PCB concentrations among the Detroit anglers aged 18–39 years were higher than the U.S. population of the same race/ethnicity. Elevated levels of DDE and total TEQ concentrations were not observed in the cohort. Eating more locally caught fish was associated with higher total blood mercury and serum PCB concentrations. The biomonitoring data served to inform public health officials and help guide environmental public health actions to reduce harmful exposures.     

Exposure assessment and initial intervention regarding fish consumption of tribal members of the Upper Great Lakes Region in the United States

The Ojibwe Health Study (OHS) has concluded 10 years of data collection and exposure assessment. Eight hundred and twenty-two participants from tribes in the states of Wisconsin, Michigan, and Minnesota (USA) completed fish consumption and environmental risk perception questionnaires. Many participants provided hair and blood samples for mercury and polychlorinated biphenyl (PCB) residue analyses as body burden indicators of these persistent environmental pollutants. Fish were collected by the tribal organizations and contaminants were analyzed for numerous tribal reports and professional environmental journal articles, these data were used by the Great Lakes Indian Fish and Wildlife Commission to produce tribal-specific geographic information systems maps as part of a public health intervention strategy. These maps are currently available at for six Wisconsin tribes that regularly harvest walleye. To determine the health impacts (if any) of pollutants on cancer, diabetes, and reproduction, it was necessary to know the recent trends in key indicators such as cancer mortality ratios and birth gender ratios. The Great Lakes Inter-Tribal Council provided the OHS and each participating tribe in Wisconsin and Michigan with a health profile. Total fish consumption (estimated by recall) for 720 tribal participants was self-reported as 60 g/day, but the highest actual consumption was measured as 11.2 g/day in one of the tribal groups. The highest blood concentrations in tribal participants were 18.6 ppb total serum PCBs and 11.8 ppb total blood mercury. Ninety percent of the participants had less than 3.8 ppb total serum PCBs and 2.6 ppb total blood mercury. Compared to other studies of subsistence fishing populations, these exposures were only moderately elevated and not high enough to warrant widespread restrictions on diets. Furthermore, the benefits of eating a fish diet must be continually emphasized. However, sport fishermen and their families who consume larger and more contaminated fish should abide by their state fish consumption advisories to minimize their health risks.     

Biomarkers of oxidatively induced DNA damage in dreissenid mussels: A genotoxicity assessment tool for the Laurentian Great Lakes

Activities of fast growing human population are altering freshwater ecosystems, endangering their inhabitants and public health. Organic and trace compounds have a high potential for adverse impacts on aquatic organisms in some Great Lakes tributaries. Toxic compounds in tissues of organisms living in contaminated environments change their metabolism and alter cellular components. We measured oxidatively induced DNA damage in the soft tissues of dreissenid mussels to check on the possible contaminant‐induced impact on their DNA. The animals were obtained from archived samples of the National Oceanic and Atmospheric Administration (NOAA) Mussel Watch Program. Mussels were collected from the harbor of Ashtabula River in Ohio, and a reference area located at the Lake Erie shore. Using gas chromatography‐tandem mass spectrometry with isotope dilution, we identified and quantified numerous oxidatively modified DNA bases and 8,5′‐cyclopurine‐2′‐deoxynucleosides. We found significant differences in the concentrations of these potentially mutagenic and/or lethal lesions in the DNA of mussels from the harbor as compared to the animals collected at the reference site. These results align NOAA's data showing that elevated concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and heavy metals were found in mussels within the harbor as compared to mussels collected in the reference site. The measured DNA lesions can be used as biomarkers for identifying DNA damage in mussels from polluted and reference sites. Such biomarkers are needed to identify the bioeffects of contaminants in affected organisms, as well as whether remedial actions have proven successful in reducing observed toxic effects.     

Maternal Pregnancy Levels of Polychlorinated Biphenyls and Risk of Hypospadias and Cryptorchidism in Male Offspring

Background

The etiologies of the male urogenital anomalies cryptorchidism and hypospadias are poorly understood. It has been suggested, however, that in utero hormone levels may be related to risk. Endocrine-disrupting chemicals, including polychlorinated biphenyl (PCB) compounds, may alter hormone levels and thereby affect the fetus.

Objectives

To examine whether in utero PCB exposure is related to cryptorchidism and hypospadias, we examined PCB levels among pregnant women enrolled in the Collaborative Perinatal Project (CPP).

Methods

The CPP enrolled pregnant women at 12 U.S. medical centers between 1959 and 1965. For the present research, we analyzed third-trimester serum samples from the mothers of 230 sons with cryptorchidism, 201 sons with hypospadias, and 593 sons with neither condition. We estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) using logistic regression and examined the associations of each anomaly with individual PCB congener levels, sum of PCBs, and several functional groupings of PCBs.

Results

In general, the ORs for cryptorchidism or hypospadias showed no notable associations with individual PCB congener levels or functional groupings of PCBs. However, the ORs and 95% CIs for the sum of PCBs associated with hypospadias were as follows: 0–1.9 μg/L, reference group; 2–2.9 μg/L, OR = 1.57, 95% CI, 1.05–2.34; 3–3.9 μg/L, OR = 1.45, 95% CI, 0.90–2.34; and ≥ 4.0 μg/L, OR = 1.69, 95% CI, 1.06–2.68; p-value for trend = 0.08.

Conclusions

Given the large number of associations examined, these findings do not strongly support the hypothesis that PCBs are associated with cryptorchidism or hypospadias. Because population serum PCB levels at the time of sample collection were considerably higher than levels at present, it is unlikely that current PCB exposure is related to the development of either anomaly.     

Predictors of Serum Dioxins and PCBs among Peripubertal Russian Boys

Background

Although sources and routes of exposure to dioxins and polychlorinated biphenyls (PCBs) have been studied, information regarding exposure among children is limited. Breast-feeding and diet are two important contributors to early life exposure. To further understand other significant contributors to childhood exposure, we studied a cohort of children from a city with high environmental dioxin levels.

Objectives

We investigated predictors of serum concentrations of polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs)/co-planar PCBs (C-PCBs), toxic equivalents (TEQs), and PCBs among 8- to 9-year-old boys in Chapaevsk, Russia.

Methods

We used general linear regression models to explore associations of log₁₀-transformed serum concentrations of PCDDs/PCDFs/C-PCBs, TEQs, and PCBs at study entry with anthropometric, demographic, geographic, and dietary factors in 482 boys in Chapaevsk, Russia.

Results

The median (25th, 75th percentile) concentration for total 2005 TEQs was 21.1 pg/g lipid (14.4, 33.2). Boys who were older, consumed local foods, were breast-fed longer, and whose mothers were employed at the Khimprom chemical plant (where chlorinated chemicals were produced) or gardened locally had significantly higher serum dioxins and PCBs, whereas boys with higher body mass index or more educated parents had significantly lower serum dioxins and PCBs. Boys who lived < 2 km from Khimprom had higher total TEQs (picograms per gram lipid) [adjusted mean = 30.6; 95% confidence interval (CI), 26.8–35.0] than boys who lived > 5 km away (adjusted mean = 18.8; 95% CI, 17.2–20.6).

Conclusions

Our findings suggest that there are specific local sources of dioxin and PCB exposure among children in Chapaevsk including maternal gardening, consumption of locally grown food, and residential proximity to the Khimprom plant.     

Infecundity and Consumption of Polychlorinated Biphenyl-Contaminated Fish

Biologic capacity for reproduction, or fecundity, may be threatened by environmental contaminants, especially compounds capable of disrupting endocrine pathways. Telephone interviews that focused on reproductive events were conducted with female members of the New York State Angler Cohort Study who became pregnant between 1991 and 1993 and who reported known time to pregnancy (N = 895; 73%). Consumption of polychlorinated biphenyl-contaminated Lake Ontario sportfish and other factors were ascertained in 1991. The authors classified the women as follows: (a) fecund (time to pregnancy < 12 cycles; n = 723); (b) having resolved infecundity (time to pregnancy > 12 cycles; n = 81); or (c) having unresolved infecundity (time to pregnancy > 12 cycles without pregnancy; n = 94). Adjusted odds ratios for duration of fish consumption for both resolved and unresolved infecundity were elevated (1.46 and 1.19, respectively), although confidence intervals included unity. Frequency of recent fish consumption was associated with an increased risk for select categories, although confidence intervals included one.     

Birth defects risk associated with maternal sport fish consumption: potential effect modification by sex of offspring

Contaminated sport fish consumption may result in exposure to various reproductive and developmental toxicants, including pesticides and other suspected endocrine disruptors. We investigated the relation between maternal sport fish meals and risk of major birth defects among infants born to members of the New York State (NYS) Angler Cohort between 1986 and 1991 (n=2237 births). Birth defects (n=125 cases) were ascertained from both newborn medical records and the NYS Congenital Malformations Registry. For sport fish meals eaten during pregnancy, the odds ratio (OR) for all major malformations combined was slightly elevated for < or =1 meal/month (OR=1.26, 95% confidence interval (CI): 0.84, 1.89) and > or =2 meals/month (OR=1.51, CI=0.74, 3.09), with no meals during pregnancy as the reference category. Higher ORs were consistently observed among male offspring compared with females. For > or =2 meals/month, the risk for males was significantly elevated (males: OR=3.01, CI: 1.2, 7.5; females: OR=0.73, CI: 0.2, 2.4). Exposure during pregnancy and effect modification by infants sex could be important considerations for future studies of birth outcomes associated with endocrine disruptors.     

Breastfeeding and concentrations of HCB and p,p'-DDE at the age of 1 year

Exposure to organochlorine compounds (OCs) occurs both in utero and through breastfeeding. Levels of hexachlorobenzene (HCB) in the cord serum of newborns from a population located in the vicinity of an electrochemical factory in Spain are among the highest ever reported. We aimed to assess the degree of breast milk contamination in this population and the subsequent exposure of children to these chemicals through breastfeeding. A birth cohort including 92 mother-infant pairs (84% of all births in the study area) was recruited between 1997 and 1999 in five neighboring villages. OCs were measured in cord serum, colostrum, breast milk, and children's serum at 13 months of age. Concentrations of OCs were detected and quantified in all colostrum and milk samples. The concentrations in mature milk were lower than those encountered in colostrum. At 13 months of age the highest concentration of OC was found for dichlorodiphenyl dichloroethane (p,p'-DDE), in contrast to what these children presented at birth, where HCB was the highest compound. Those infants who were breastfed had higher concentrations at the age of 1 than those who were formula fed (2.13 ng/mL of HCB among formula feeders vs 4.26 among breast feeders, and 1.95 of p,p'-DDE vs 6.00 (P<0.05)). Long-term breastfeeding leads to a dose-response increase of the concentrations in children's serum during the first year of life.     

Effects of polychlorinated biphenyls on liver ultrastructure, hepatic monooxygenases, and reproductive success in the barbel

Polychlorinated biphenyls (PCBs) are organochlorinated micropollutants ubiquitously distributed in the environment. They are known to be strong inducers of hepatic monooxygenases in fish. This can adversely affect reproduction by increasing steroid metabolism. In this work, adult barbels were contaminated with food containing Aroclor 1260, a commercial PCB mixture from Monsanto, at environmentally relevant concentrations. A significant increase in cytochrome P450 was observed, and two particularly sensitive enzymes, ethoxyresorufin o-deethylase (EROD) and ethoxycoumarin o-deethylase (ECOD), were strongly induced. Electron microscopy revealed alterations in liver ultrastructure in contaminated fish, principally an increase in the number of cisternae of the rough endoplasmic reticulum, drastic glycogen depletion, dissolution of mitochondrial contents, and appearance of myelin figures. Contamination was also studied in relation to reproductive success in a hatchery. Contaminated males displayed no alteration in milt quality, but PCBs did alter female reproductive parameters. Total mortality of eggs and larvae increased significantly with the level of PCBs in the eggs. The most highly contaminated fish did not even spawn. All the adverse effects recorded here tended to be reversible when the intoxication ended, sometimes after only a 1-year detoxication period.     

Associations between intrauterine exposure to polychlorinated biphenyls on neonatal ano-genital distance

Polychlorinated Biphenyls (PCBs) are widespread environmental contaminants. PCBs have endocrine disrupting properties which raises concerns regarding their effect on the developing fetus.This study aimed to examine the association between prenatal exposure to PCBs and anogenital distance (AGD) in newborns.Serum concentrations of PCB congeners -118, -138, -153 and -180 were measured in 175 pregnant women presenting to the delivery room. AGD was measured in their newborns. Regression models were used to estimate associations between maternal PCB exposure and infant anogenital measurements, controlling for possible confounding variables.Mean maternal serum concentrations were 2.95 ± 2.18 ng/g, 4.62 ± 3.54 ng/g, 7.67 ± 6.42 ng/g and 5.10 ± 3.91 ng/g for congeners -118, -138, -153 and -180, respectively. Higher maternal concentrations of PCBs were associated with reduced AGD measures in male infants. Higher maternal concentrations of PCB-138 and PCB-153 were associated with reduced ano-scrotal distances and higher maternal concentrations of all four PCB congeners were associated with reduced ano-penile distances. No significant associations were found between any PCB congener and any AGD measure in female newborns.This study demonstrates that intrauterine exposure to PCBs may be associated with reduced AGD in male newborns. More research is needed to reveal the implications for adult reproductive health.