Risk assessment in a federal regulatory agency: an assessment of risk associated with the human consumption of some species of fish contaminated with polychlorinated biphenyls (PCBs)

Property of cytochrome P450 1A inducibility by polychlorinated/brominated biphenyls (Co-PXBs) detected in Japanese breast milk

Coplanar polychlorinated/brominated biphenyls (Co-PXBs) belong to a class of structurally similar chemicals known as polyhalogenated aromatic hydrocarbons. We found that the milk of Japanese primiparous and multiparous mothers was similarly contaminated with Co-PXB congeners. Co-PXBs time- and dose-dependently increased ethoxyresorufin-O-deethoxylase (EROD activity) in HepG2 cells. The EROD activity of liver microsomes collected from C57BL/6 mice exposed to these congeners substituted with one or two, and with three or five bromine atoms time-dependently decreased and increased, respectively. These results indicate that introducing bromine into the chemical frame of a polychlorinated biphenyl tends to increase CYP1A activity in vitro and in vivo and that the number substituted bromine atoms alters the metabolism profiles. If Co-PXBs are more toxic than Co-PCBs, our findings suggest that the TEQ of Co-PXBs is important for human health risk.

Individual characteristics associated with PBDE levels in U.S. human milk samples

BACKGROUND

Reported polybrominated diphenyl ether (PBDE) concentrations in human samples in the United States have been higher than in Europe and Asia. Little is known about factors that contribute to individual variability in body burden.

OBJECTIVE

In this large study we measured PBDE concentrations in human milk from the United States during 2004-2006. We assessed characteristics associated with concentrations in milk and change in milk concentration between 3 and 12 months postpartum.

METHODS

We analyzed 303 milk samples obtained 3 months postpartum for PBDEs. A second sample was analyzed for 83 women still lactating 12 months postpartum. PBDE concentrations in milk and variability by individual characteristics such as age, parity, and prepregnancy body mass index (BMI) were evaluated using generalized linear models.

RESULTS

PBDE congeners BDEs 28, 47, 99, 100, and 153 were detected in > 70% of samples. BDE-47 concentrations were the highest, ranging from below the limit of detection to 1,430 ng/g lipid, with a median of 28 ng/g lipid. Concentrations of most individual PBDE congeners and the sum of BDEs 28, 47, 99, 100, and 153 (SigmaPBDE) were lower among mothers > 34 years of age compared with those 25-29 years of age and higher among mothers with high compared with normal BMI, after adjustment for other covariates. Parity was not associated with PBDE concentration. The change in SigmaPBDE concentration in milk between 3 and 12 months postpartum was highly variable (median increase, 14%; interquartile range, -26% to 50%).

CONCLUSIONS

PBDEs were detected in nearly all human milk samples, varying by maternal weight and age and over the course of breast-feeding.

Generic Assessment Criteria for human health risk assessment of potentially contaminated land in China

Generic Assessment Criteria (GAC) are derived using widely applicable assumptions about the characteristics and behaviour of contaminant sources, pathways and receptors. GAC provide nationally consistent guidance, thereby saving money and time. Currently, there are no human health based Generic Assessment Criteria (GAC) for contaminated sites in China. Protection of human health is therefore difficult to ensure and demonstrate; and the lack of GAC makes it difficult to tell if there is potential significant risk to human health unless site-specific criteria are derived. This paper derived Chinese GAC (GAC) for five inorganic and eight organic substances for three regions in China for three land uses: urban residential without plant uptake, Chinese cultivated land, and commercial/industrial using the SNIFFER model. The SNIFFER model has been further implemented with a dermal absorption algorithm and the model default input values have been changed to reflect the Chinese exposure scenarios. It is envisaged that the modified SNIFFER model could be used to derive GAC for more contaminants, more Regions, and more land uses. Further research to enhance the reliability and acceptability of the GAC is needed in regional/national surveys in diet and working patterns.

Global contamination of coplanar polybrominated/chlorinated biphenyls (Co-PXBs) in the market fishes from Japan

Polybrominated chlorinated biphenyls (PXBs, X=Br, Cl) are a group of environmental contaminants that have not been studied previously. The introduction of the second halogen to the biphenyl backbone increases the number of possible congeners to more than 9000. Only a limited number of PXBs are commercially available. In order to determine the occurrence of these compounds in environmental matrices, an isotope dilution HRGC/HRMS method for determination of five co-planar polybrominated/chlorinated biphenyls (Co-PXBs) in biota was developed. The method detection limit for these compounds ranged between 0.05 and 0.5 pg/g for 4'-monobromo-3,3',4,5-tetrachlorobiphenyl and 3',4',5'-tribromo-3,4-dichlorobiphenyl, respectively. Concentrations of five co-planar polybrominated and chlorinated biphenyls in eighteen different fish fillets from Japanese markets ranged between 4 and 46 pg/g wet weight for mink whale and young yellow-tail fish. These values are substantially lower than those reported for Co-PCBs; however, it should be noted that due to the unavailability of standards, identification and quantification of all the isomers was not possible.

Association between biomarkers of exposure to persistent organochlorine compounds (POCs)

Serum concentrations of CB-153 and p,p'-DDE were assessed for 354 men and women from the Swedish Fishermen's Families Cohort, and were found to correlate very well (Pearson's r=0.72). In this particular cohort the main source of exposure to persistent organochlorine compounds are consumption of contaminated fatty fish. High correlations between total PCB/CB-153 and p,p'-DDE have also been found in other population with similar exposure, but not in populations whose major source of exposure to persistent organochlorine compounds is not necessarily through the consumption of contaminated sea food. The authors suggest that when investigating a possible relation between exposure to persistent organochlorine compounds and different health outcomes in populations with exposure similar to the Swedish Fishermen's Families Cohort, there may be no need to analyze more than either CB-153 or p,p'-DDE.

Maternal exposure to Great Lakes sport-caught fish and dichlorodiphenyl dichloroethylene, but not polychlorinated biphenyls, is associated with reduced birth weight

Fish consumption may be beneficial for a developing human fetus, but fish may also contain contaminants that could be detrimental. Great Lakes sport-caught fish (GLSCF) are contaminated with polychlorinated biphenyls (PCBs) and dichlorodiphenyl dichloroethylene (DDE), but the effects of these contaminants on birth outcome are not clear. To distinguish potential contaminant effects, we examined (1) whether the decrease over time in contaminant levels in GLSCF is paralleled by an increase in birth weight of children of GLSCF-consuming mothers and (2) the relation between maternal serum concentrations of these contaminants and birth weight. Mothers (n=511) were interviewed from 1993 to 1995, and maternal serum was collected from 1994 to 1995 (n=143). Potential confounders considered were child gender, maternal age at delivery, maternal prepregnancy body mass index, maternal cigarette and alcohol use during pregnancy, maternal education level, maternal parity, and maternal breastfeeding. Children born during 1970-1977, 1978-1984, and 1985-1993 to mothers who ate more than 116 meals of GLSCF before pregnancy were, on average, 164 g lighter, 46 g heavier, and 134 g heavier, respectively, than children of mothers who ate no GLSCF before pregnancy (P trend=0.05). GLSCF-consuming mothers had higher serum PCB and DDE concentrations, but only increased DDE was associated with lower birth weight. The data suggest that fetal DDE exposure (as indicated by maternal serum DDE concentration) may decrease birth weight and that decreased birth weight effects associated with GLSCF consumption have decreased over time.

Backward estimation of exposure to organochlorines using repeated measurements

Great Lakes sport-caught fish are contaminated with various organochlorines (OCs) such as polychlorinated biphenyls (PCBs). Through consumption of these fish, humans are subject to continuing levels of OC contamination. To assess potential adverse effects of past exposure, we compared three different backward extrapolation models. The data originated from OC determinations in a cohort of anglers and their families. Repeated PCB measurements collected in the 1970s, 1980s, and 1990s were used when testing the backward extrapolations. We applied a simple and a complex decay model based on assumptions used in previous studies; a third was a regression model incorporating markers of OC intake and loss. These techniques provided past exposure estimates. Intraclass correlation coefficients (ICCs) were calculated comparing measured and estimated PCB values. ICC values for the regression model equations were 0.77 and 0.89; ICC values for the simple and complex decay models were significantly lower, with ranges of 0.07-0.45 and -0.14-0.69, respectively. Plots showing trends of OC concentrations in fish and humans indicate comparable increases and decreases of PCB in fish and humans, with fish concentrations peaking approximately 10 years before that in humans. Our findings suggest that one should be cautious when using simple backward extrapolation techniques to estimate OC exposure in situations involving changing environmental exposures. Whenever repeated measurements are available, regression analyses seem to produce more accurate backward estimations of exposure.

Decreased sex ratio following maternal exposure to polychlorinated biphenyls from contaminated Great Lakes sport-caught fish: a retrospective cohort study

BACKGROUND

Fish from the Great Lakes are contaminated with polychlorinated biphenyls, which have been found to have several adverse reproductive effects. Several environmental contaminants have been found to alter the sex ratio of offspring at birth, but the evidence of such an effect of polychlorinated biphenyls has been inconsistent.

METHODS

We examined parental serum polychlorinated biphenyl concentration in relation to the sex ratio of 173 children of mothers and 208 children of fathers from the Great Lakes region of the United States between 1970 and 1995. We calculated odds ratios for a male child using logistic regression and generalized estimating equations with adjustment for the year of birth of the child, maternal and paternal age, the mother's parity at the child's birth, and whether the child had an older brother.

RESULTS

The adjusted odds ratio for having a male child among mothers in the highest quintile of serum polychlorinated biphenyl concentration was 0.18 (95% CI: 0.06-0.59) compared to mothers in the lowest quintile. Treating exposure as a continuous variable, the adjusted odds ratio for having a male child was 0.54 per unit increase in the natural log of maternal serum polychlorinated biphenyl concentration (95% CI: 0.33-0.89). There was little evidence of an association with paternal exposure. We found no association between either maternal or paternal serum dichlorodiphenyl-dichloroethene concentration and the sex ratio.

CONCLUSIONS

These findings suggest that maternal exposure to polychlorinated biphenyls may decrease the sex ratio of offspring. These data add to the growing body of evidence that exposure to particular chemicals can alter the sex ratio at birth.

Characterizing Latino anglers' environmental risk perceptions, sport fish consumption, and advisory awareness

Sport fish advisories for the Great Lakes states suggest limiting consumption of fish taken from the lakes and their tributaries because of chemical contamination. It appears, however, that minority anglers are less aware of the advisories and also consume greater amounts of sport fish than white anglers. We conducted focus groups in western New York with Latino anglers and partners of anglers to explore these patterns. Analysis revealed that older anglers believed local waters were of good quality and that it was safe to consume fish taken from them. They based their evaluation of both water and fish primarily on visual inspection. In contrast, younger Latinos believed that area waters were highly polluted because of dumping of waste from local industries. They fished away from urban areas in an effort to find cleaner, more swiftly moving waters. They considered consuming sport fish from urban areas highly risky, given their occasional illness experiences following meals of what they thought were polluted fish. For all Latino anglers, however, state-sponsored advisories were minimally effective because of their limited distribution and complex wording. Results point to differences in lay and scientific models of pollution and a need to bridge this gap in future risk-communication strategies.

Identification of sport fish consumption patterns in families of recreational anglers through factor analysis

This paper reports on the identification of sport fish consumption patterns in angler families through the factor analysis technique. New York State recreational anglers and their spouses or partners were surveyed in 1991 about their consumption of Lake Ontario and Lake Erie sport fish. Respondents were surveyed again in 1997 to report the number of sport fish consumed by their children aged 5-10 years. Parental report revealed that 60% of children had consumed at least one sport fish meal over their lifetime. Anglers', partners', and children's variables were entered into three separate factor analysis models to assess consumption patterns. Factors for anglers and partners accounted for 65 and 59% of variance in consumption scores, respectively. Factors dealing with trout and salmon consumption accounted for the most variance. Children's factors accounted for 82% of variance in consumption scores, showing separation in relation to type of fish, body of water, and age at consumption. Children's factors were then used as dependent measures of separate multiple regression runs in which parental factors were entered stepwise as predictors. Significant associations between parental and children's factors were noted, suggesting that sport fish consumption patterns in parents are predictive of similar consumption patterns in children. Results suggest that sport fish consumption advisories do not fully prevent consumption of contaminated sport fish during childhood. Therefore, risk communicators may need to modify the current strategy of informing anglers and their families about sport fish consumption recommendations.

Biomarkers and bioassays for detecting dioxin-like compounds in the marine environment

The presence of toxic chemical contaminants in some marine organisms, including those consumed by humans, is well known. Monitoring the levels of such contaminants and their geographic and temporal variability is important for assessing and maintaining the safety of seafood and the health of the marine environment. Chemical analyses are sensitive and specific, but can be expensive and provide little information on the actual or potential biological activity of the contaminants. Biologically-based assays can be used to indicate the presence and potential effects of contaminants in marine animals, and therefore, have potential for routine monitoring of the marine environment. Halogenated aromatic hydrocarbons (HAHs) such as chlorinated dioxins, dibenzofurans, and biphenyls comprise a major group of marine contaminants. The most toxic HAHs (dioxin-like compounds) act through an intracellular receptor protein, the aryl hydrocarbon receptor, which is present in humans and many, but not all, marine animals. A toxic equivalency approach based on an understanding of this mechanism provides an integrated measure of the biological potency or activity of HAH mixtures. Biomarkers measured in marine animals indicate their exposure to these chemicals in vivo. Similarly, in vitro biomarker responses measured in cell culture bioassays can be used to assess the concentration of 'dioxin equivalents' in extracts of environmental matrices. Here, I have reviewed the types and relative sensitivities of mechanistically-based, in vitro bioassays for dioxin-like compounds, including assays of receptor-binding, DNA-binding and transcriptional activation of native (CYP1A) or reporter (luciferase) genes. Examples of their use in environmental monitoring are provided. Cell culture bioassays are rapid and inexpensive, and thus have great potential for routine monitoring of marine resources, including seafood. Several such assays exist, or are being developed, for a variety of marine contaminants in addition to the dioxin-like chemicals. A battery of cell culture bioassays might be used to rapidly and sensitively screen seafood for the presence of contaminants of concern, including dioxin-like compounds as well as other contaminants such as natural toxins, hormonally active agents, and heavy metals. Such a battery of mechanism-based, in vitro bioassays could be incorporated into monitoring efforts under recently adopted hazard analysis and critical control point (HACCP) programs.

Paternal Lake Ontario fish consumption and risk of conception delay, New York State Angler Cohort

The aquatic ecosystems of the Great Lakes are contaminated with a variety of compounds, some of which are considered reproductive toxicants. Few studies of paternal fish consumption and reproductive endpoints have been undertaken and serve as the impetus for study. Standardized telephone interviews were conducted with 2445 female members of the New York State Angler Cohort (82% response) to update reproductive profiles and to ascertain specific information on time-to-pregnancy (TTP). The study sample includes women with a known TTP and paternal fish consumption data (n=785). Conception delay was defined as more than 12 cycles of unprotected intercourse to achieve pregnancy. Paternal fish consumption was assessed by three measures: frequency of Lake Ontario sport fish meals in 1991, numbers of years eating fish, and estimated PCB exposure from fish consumption. Adjusted ORs for number of fish meals, based on logistic regression, ranged from 0.69 to 0.80; from 0.61 to 0.82 for number of years eating fish; and from 0.44 to 1.14 for quartiles of estimated PCB exposure from fish consumption. All confidence intervals included one. These findings suggest that, based on paternal self-reports, Lake Ontario fish consumption does not increase the risk of conception delay.

Dioxin-like and non-dioxin-like toxic effects of polychlorinated biphenyls (PCBs): implications for risk assessment

Polychlorinated biphenyls (PCBs) are persistent, bioaccumulative, and toxic contaminants in the environment. Individual PCB congeners exhibit different physicochemical properties and biological activities that result in different environmental distributions and toxicity profiles. The variable composition of PCB residues in environmental matrices and their different mechanisms of toxicity complicate the development of scientifically based regulations for the risk assessment. In this article various approaches for the assessment of risks of PCBs have been critically examined. Recent developments in the toxic equivalency factor (TEF) approach for the assessment of toxic effects due to dioxin-like PCBs have been examined. PCB exposure studies that describe non-dioxin-like toxic effects, particularly neurobehavioral effects and their effective doses in animals were compiled. A comparative assessment of effective doses for dioxin-like and non-dioxin-like effects by PCBs has been made to evaluate the relative significance of non-ortho-and ortho-substituted PCBs in risk assessment. Using mink as an example, relative merits and implications of using TEF and total PCB approaches for assessing the potential for toxic effects in wildlife was examined. There are several advantages and limitations associated with each method used for PCB risk assessment. Toxic effects due to coplanar PCBs occur at relatively smaller concentrations than those due to non-dioxin-like PCBs and therefore the TEF approach derives the risk assessment of PCBs, in the environment. The need for the refinement of TEF approach for more accurate assessment of risks is discussed.

The toxicological effects following the ingestion of chinook salmon from the Great Lakes by Sprague-Dawley rats during a two-generation feeding-reproduction study

A two-generation reproduction-feeding study was undertaken with Sprague-Dawley rats to ascertain the effects of ingesting chinook salmon fillets caught in the Credit River, which empties into Lake Ontario (LO), or in the Owen Sound region of Lake Huron (LH). Rats (30/sex/group) were randomly assigned to groups whose dietary protein consisted of casein and/or lyophilized salmon [Group 1: 20% casein (controls); Group 2: 15% casein + 5% LO salmon (LO-5%); Group 3: 20% LO salmon (LO-20%); Group 4: 15% casein + 5% LH salmon (LH-5%); Group 5: 20% LH salmon (LH-20%)]. After 70 days on test, the males and females were mated on a 1:1 basis within diet groups. Approximately 70 days postweaning, one F1 male and one F1 female from 24 litters were mated within diet groups, avoiding sibling matings. At weaning, the F0 and F1 adults and the F1 and F2 neonates not randomly selected for further testing were necropsied. Evaluated parameters included growth, feed consumption, organ weights, reproduction indices, serum chemistry, hematology, and coagulation times. The only statistically significant effects which were present in both generations were increased relative liver and kidney weights of both sexes in the LO-20% and LH-20% groups; the LH-20% females had lower alanine transaminase activity than the controls; the controls had lower creatinine levels than the fish groups and the LO-20% females; the LH-20% and LO-20% males had a lower blood urea nitrogen than the controls; and the LH-20% females had a heavier terminal body weight than the controls and a lower number of red blood cells, hematocrit, hemoglobin values, and mean platelet volume. There was a tendency for the fish-fed groups to grow faster, eat more feed, and have larger litters with heavier pups. Overall, there was little to suggest that the myriad of contaminants in chinook salmon from the Great Lakes presented an appreciable toxicological risk to Sprague-Dawley growth and reproduction.

Fishing in a polluted estuary: fishing behavior, fish consumption, and potential risk

People make subjective judgments about hazards relying on what they know and feel. These risk perceptions may be based on accurate or inaccurate information and are often optimistically biased. The existence of uncertainties in the evaluation of many environmental hazards effects how risks are perceived. This paper examines fish consumption and risk perception of urban fishermen in the New York/New Jersey estuary, in areas where there were consumption advisories. We interviewed 318 fishermen and crabbers in the Arthur Kill, Raritan Bay, and New Jersey shore. Fish were eaten an average of at least four times per month in all regions, but fishermen in the Arthur Kill fished most frequently, averaging over eight times per month. Although 60% of fishermen and crabbers in the Arthur Kill reported hearing warnings about consuming fish caught in these waters, 70% of fishermen and 76% of crabbers said they are their catch. Significantly fewer fishermen in the Bay and Shore regions had heard warnings (28% and 30%, respectively), and more reported consuming their catch (88% and 82%, respectively). In all regions, most people thought that the fish were safe to eat, many believing they were "fresher" than store bought fish. Thus, most people ignored the consumption advisories in effect for these waters. Some of these people are consuming high quantities of fish and crabs, and thus are exposed to potentially deleterious levels of contaminants. In general, people failed to consider the possibility of chronic effects and did not perceive that this enjoyable, familiar pastime could be hazardous. Further, fishermen generally had great confidence in their own knowledge, which proved to be inaccurate in many cases, and often expressed distrust in the information source (government). Clearly, simply issuing consumption advisories is insufficient to promote risk-reducing behavior.

The New York Angler Cohort Study: exposure characterization and reproductive and developmental health

The New York State Angler Study will evaluate the association between past and current consumption of contaminated fish from Lake Ontario and both short- and long-term health effects in a population-based cohort. It will measure fish consumption and reproductive and developmental health among 10,518 male anglers and 6,651 of their wives or partners, as well as among 913 female anglers. To characterize exposure among subgroups of the cohort, further analytical methods were developed and implemented to measure specific polychlorinated biphenyls (PCB) congeners, methylmercury, and other substances in biological samples. Exposure assessment has been completed for a stratified random sample of 321 anglers. In addition, analyses for 79 congeners of PCBs are complete for 177 anglers. A special study of duck and turtle consumers currently is underway. Telephone interviews have been completed with 2,454 of the 2,999 women who planned a pregnancy between 1991 and 1994. The entire cohort of male anglers, partners of male anglers, and female anglers has been submitted for matching with the New York State live birth and fetal death registries to obtain lifetime reproductive histories. A medical record abstraction study will assess perinatal and developmental outcomes among the 3,442 births that occurred between 1986 and 1991. Finally, a study of breast milk from currently lactating women is underway, and 215 breast milk samples have been collected from the planned pregnancy subcohort. Progress on each of the study components is discussed herein.

Immunotoxicity of PCBs (Aroclors) in relation to Great Lakes

Polychlorinated biphenyls (PCBs) are among the most widespread environmental pollutants and a prominent contaminant of the Great Lakes basin. Due to their resistance to biodegradation and lipophilic properties, PCBs bioaccumulate in fish tissues and in fish-eating humans. PCBs are also known to cross the placenta and to be excreted into the mother's milk, thus predisposing the infant to potentially adverse health effects. For example, a higher incidence of bacterial infections was reported for breast-fed infants born to mothers who consumed large amounts of Great Lakes fish compared to the incidence in control infants whose mothers ingested low amounts of fish. While data regarding the PCB-induced immunotoxic effects in humans are scarce, data derived from the use of experimental animals, including nonhuman primates, indicate that the immune system is a potential target for the immunotoxic effects of PCBs. Such studies have used the commercially available PCB mixtures alone. However, PCBs have the potential of partially antagonizing the effects of other structurally related compounds including the highly toxic dioxins, which are also present in small amounts in the Great Lakes. Thus, to fully evaluate the magnitude of the immunotoxic risk PCBs pose to humans, consideration should be given to investigations in which the interactive effects of PCBs are combined with other contaminants present in the Great Lakes.

Long-term effects of Aroclor 1254 (PCBs) on plasma lipid and carnitine concentrations in rhesus monkey

Sixty-seven female rhesus monkeys (Macaca mulatta) were orally dosed daily for 152 weeks with 0, 5, 20, 40, and 80 micrograms Aroclor 1254 (PCB)/kg body wt. Blood polychlorinated biphenyl (PCB) concentrations were highly positively correlated (r = 0.92, P < 0.001) with doses of PCB administered. A comprehensive analysis of plasma lipids/lipoproteins revealed a PCB-associated increase in plasma triglycerides and decreases in plasma total cholesterol, high-density lipoprotein cholesterol (HDL-chol), very-low plus low-density lipoprotein cholesterol (VLDL+LDL-chol), and total carnitine (which is involved in fatty acid metabolism). All of the lipid/lipoprotein changes were significantly (P < or = 0.05) correlated with blood PCB concentration. These data, obtained after 152 weeks of continuous daily exposure of a primate model to PCB support a causal relationship between plasma lipid changes and PCB intake. Previously, causality has been refuted on the premise that the commonly observed elevation of triglycerides with increasing concentration of blood PCB is a reflection, not of PCB dose, but of the partitioning of PCB between tissues (adipose) and blood in proportion to the blood lipid present. The mechanism of the plasma lipid changes was not investigated in this study but the altered lipid/lipoprotein pattern is discussed with respect to known cardiovascular risk profiles.

PCBs and other organochlorines in human tissue samples from the Welsh population: II--Milk

Polychlorinated biphenyl (PCB) and SigmaDDT (i.e. p,p'-DDT + p,p'-DDE = p,p'-DDD) concentrations were determined from the analysis of 115 Welsh breast milk samples collected in 1990 and 1991. Fifty PCB congeners were screened, of which 24 were identified in most samples. The PCB congener pattern was consistent between individual milk samples, with IUPAC congeners 28, 138, 153 and 180 being the most abundant and accounting for an average of 50% of the SigmaPCB concentrations determined. PCB concentrations varied between 2 and 70 ng g(-1) whole milk, were positively correlated with age, and negatively correlated with the total lactation period and with the percent lipid content of the milk. PCB pattern distributions differed between milk and adipose tissue samples. Human milk had a higher proportion of tri- (18 and 28), tetra- (44, 52 and 66) and pentachlorinated biphenyls (101) compared to human adipose tissue. SigmaDDT concentrations ranged from 0.3 to 71 ng g(-1) of whole milk, with p,p'-DDE contributing towards an average of 92% of the SigmaDDT concentrations. SigmaDDT levels were also positively correlated with age and negatively associated with the lactation period, though these correlations were rather weak. No significant differences in the SigmaPCB and SigmaDDT concentrations were noted between milk samples from donors living in rural and urban locations, or between the subjects' body weight, smoking habits or diet.

Ecological assessment of a region with PCB emissions using samples of soil, vegetation and breast milk: a case study

An ecological assessment is performed by using a data bank of air, soil, vegetation and biology data from the area of a capacitor plant in Serpukhov, Russia. Over a number of years the use of PCBs for filling capacitors has brought about environmental contamination beyond the plant's sanitary zone, in particular along a stream where vegetables and berries are grown commercially. A correlation has been found between abnormally high concentrations of PCBs in breast milk of women living in the proximity of the plant and the occurrence of diathesis in babies. A number of remedial measures have been developed in conjunction with the city's sanitary service.

Fish consumption and reproductive outcomes in Green Bay, Wisconsin

Prenatal exposure to polychlorinated biphenyls (PCBs) and reproductive outcome was determined in a population of 1112 women during 1987-1989. The women studied were from the Green Bay, Wisconsin area, thereby providing a population with potential PCB exposure from Lake Michigan sport fish consumption. All women with positive pregnancy tests from two Green Bay prenatal clinics were asked to complete a self-administered questionnaire on fish consumption, health and reproductive history, and other relevant issues and to provide blood samples for PCB analysis. A positive correlation was found between the amount of Lake Michigan fish mothers claimed to consume and their PCB serum levels. After the pregnancy period, reproductive outcome measures (fetal wastage; stillbirths; and birth weight, birth length, head circumference, ponderal index, and birth weight percentiles for live births) were abstracted from hospital labor reports. Typical negative associations between birth size measures and consumption of caffeine, smoking, and alcohol were found. Birth size was positively associated with gestational age, birth order, weight gain during pregnancy, male babies, and rural residence. Birth size was also associated with PCB exposure; however contrary to expectations, a positive association was found (P < 0.044) for most mothers (the exception being those mothers who gained more than 34 lb during their pregnancy). PCB exposures were lower than the other studies that found that birth size was negatively associated with PCB exposure.

Carcinogenicity of polyhalogenated biphenyls: PCBs and PBBs

Polychlorinated biphenyls (PCBs) and polybrominated biphenyls (PBBs) are compounds whose physical/chemical properties led to their widespread commercial use. Although their production has been banned or severely limited in most countries since the 1970s, the persistence and stability of these compounds have resulted in a worldwide distribution, especially of PCBs. PBB contamination is limited principally to the state of Michigan, where a series of tragic errors eventually resulted in the accumulation of residues in livestock and the general human population. Long-term exposure to PCBs and PBBs in animals has been associated with the induction of neoplastic nodules in the liver and in some cases hepatocellular carcinoma. This review discusses the role of PCBs and PBBs in the process of carcinogenesis. The mutagenicity/genotoxicity of these compounds, as well as their initiation/promotion potential is discussed. The epidemiology of PCB and PBB exposure is reported along with an estimation of the risk of cancer to humans. Finally, possible molecular mechanisms of action are suggested for polyhalogenated biphenyls in cancer development.

Toxic effects in C57B1/6 and DBA/2 mice following consumption of halogenated aromatic hydrocarbon-contaminated Great Lakes coho salmon (Oncorhynchus kisutch Walbaum)

Diets containing coho salmon (Oncorhynchus kisutch Walbaum) from the Pacific Ocean or from Lakes Erie, Michigan, and Ontario [containing a gradation from low to high of halogenated aromatic hydrocarbons, (HAHs)] were fed to C57B1/6 and DBA/2 mice. Following a 4-month dietary exposure to Lake Ontario salmon, both strains of mice demonstrated hepatomegaly. The ethoxyresorufin-O-deethylase (ERR) enzyme levels were elevated in livers of C57B1/6 mice fed diets of salmon from all of the Great Lakes studied, with exceptionally high levels detected in C57B1/6 mice fed Lake Ontario salmon. Induction of ERR enzyme levels was detected in DBA/2 mice only following dietary exposure to Lake Ontario salmon. Serum levels of L-thyroxine (T4) and triiodo-L-thryonine (T3) were suppressed in C57B1/6 mice following consumption of Lake Ontario coho salmon, but T3 and T4 levels remained unchanged in DBA/2 mice. In general, pathobiological effects correlated with both dietary HAH exposure level and Ah receptor status.

The use of epidemiology and clinical toxicology to assess environmental health problems

Historically, epidemiology has played an important role in the changes that have taken place over time as epidemics of important infectious diseases have been replaced with modern epidemics of chronic, degenerative diseases such as elevated blood pressure, various types of cancers, diabetes, and stroke, among others. Two illustrations of the early uses of epidemiologic methods in investigations of disease outbreaks are described in the work of John Snow, who described outbreaks of cholera in the 1800s (1936, Snow on Cholera, Commonwealth Fund, New York), and J. Goldberger, who investigated the incidence of pellagra in the early 1900s (1964, Goldberger on Pellagra, M. Terris, ed., Louisiana State Univ. Press, Baton Rouge). The more contemporary use of epidemiology and clinical toxicology to assess the outcome of human exposure to environmental contaminants in the food supply are described for exposure to the polychlorinated biphenyls (PCBs) and to the polybrominated biphenyls (PBBs). Exposure to the PCBs has occurred in a variety of locations worldwide, with the greatest exposure taking place in individuals of many countries who consume fish and in Japan and Taiwan through contaminated cooking oil. Exposure to PBBs has essentially been limited to the State of Michigan where widespread contamination of cattle, dairy products, and poultry has taken place.

A review of the Food and Drug Administration risk analysis for polychlorinated biphenyls in fish

This paper reviews the Food and Drug Administration (FDA) analysis of the risk to humans from consuming fish contaminated with polychlorinated biphenyls (PCBs). In brief, the FDA methodology employed "high" dose experiments on animals and extrapolated the observed rates of certain types of cancer at these elevated doses to the low doses found in human diets. These extrapolations were then used to define a recommended tolerance level of 5 ppm, and proposed reduction to 2 ppm, for fish sold in interstate commerce. Unfortunately, as is shown here, such a procedure is extremely sensitive to the basis for extrapolation. Important elements of the FDA analysis include the following: (i) FDA assumed a particular form of the dose-response model: the one-hit model. Many other models have been proposed and, on balance, appear equally plausible. These models estimate lower risks than does the one-hit model. (ii) FDA calculated 99% upper confidence bounds on these risks and, moreover, emphasized cases of fish eaters who consume greater amounts of PCB-contaminated fish than do 98.5% of the U.S. population. (iii) FDA based PCB ingestion computations on consumption of raw fish, whereas most fish are cooked before eating, and it is known that PCB levels in cooked fish are lower than PCB levels in raw fish. (iv) FDA based estimates of cancer risk on the assumption that PCB levels in fish would be constant over the nominal 70-year human life span used in the FDA "lifetime risk" computation. Recent data suggest that PCB levels have been declining in fish (particularly in sport fish) and humans as well. Such trends imply significantly lower cumulative lifetime PCB doses than were assumed in the FDA analysis. (v) FDA assumed that humans and test animals are equally sensitive to PCB ingestion when measured on a parts per million in diet basis. Extrapolations on an equivalent consumption per unit of body weight, thought appropriate by most researchers, result in much lower health risks. In short, when confronted with methodological choices, the FDA consistently selected "worst case" or conservative assumptions over other alternatives of at least equal plausibility. This philosophy of choice was explicitly acknowledged by the FDA. What was omitted from the FDA analysis, however, was the possible degree of overstatement of these risks. The results of replicate risk computations using alternative assumptions to examine the possible magnitude of overstatement of health risk are summarized in Table 12. As can be seen, this overstatement could easily account for a discrepancy of several orders of magnitude between actual and calculated risks.(ABSTRACT TRUNCATED AT 400 WORDS)

Polychlorinated biphenyls (PCBs) in the marine environment, particularly in the Mediterranean

Polychlorinated biphenyls (PCBs) possess a low water solubility, a high n-octanol/water partition coefficient, and a high persistence, particularly those which are highly chlorinated. Because of these properties they are bioaccumulated in many organisms in the environment. PCBs are still manufactured industrially and used in the Mediterranean countries (e.g., Italy, Spain, and France). Production figures for these countries and for the FRG, the United Kingdom, and the United States between 1973 and 1979 are given. The concentrations of PCBs in marine air, water, sediments, microplankton , algae, mussels, fish, and other marine organisms including seabirds from the Mediterranean area are reviewed and compared with PCB concentrations in marine samples from non-Mediterranean regions. Levels of PCBs in seawater are highest in the western and central Mediterranean. The data for mussels and fish give a clear indication that the PCB levels are higher in the Northwest and the Tyrrhenian Sea than in the eastern Mediterranean. The FDA in June 1979 set 2 mg/kg as the temporary maximum concentration for PCBs in fish and shellfish. The PCB residues in some fish from the northwestern Mediterranean and Tyrrhenian Sea and in some mussels from the Adriatic Sea are higher than this limit. The amount of PCBs ingested via food by the Mediterranean population is unknown.

Use of epidemiology and clinical toxicology to determine human risk in regulating polychlorinated biphenyls in the food supply

Polychlorinated biphenyls (PCBs) became a national problem in 1971 when several accidental contaminations of foods were reported. Extensive efforts were successfully undertaken by FDA to reduce the residues of PCBs in food. However, the PCB levels in several species of freshwater fish have raised concern about PCB residues from environmental contamination. This concern prompted a reassessment of the human risk involved in consumption of such fish. The best evidence that a chemical may produce adverse health effects in humans is provided by adequate epidemiologic data confirmed or supplemented by data from valid animal tests. Traditionally, where the regulatory agencies have used results of animal toxicology experiments to evaluate hazard and predict hypothetical safety for humans, "safety factors" such as 1 to 10 or 1 to 100 have been used. The size of the safety factor and the potential exposure to a chemical are established by properly informed scientific judgment. More recent efforts have involved use of a combination of human and animal data and a variety of mathematical models to determine risk. The human epidemiology data and the animal toxicity data of PCB exposure are reviewed, as well as risk assessment in general. Specific examples of risk assessment are presented in which animal data are extrapolated to humans, based on several levels of human exposure to PCBs in fish.