Polychlorinated biphenyls in human adipose tissue

Bulletin of Environmental Contamination and Toxicology - Among the chlorinated hydrocarbon synthetic pollutants in the environment, polychlorinated biphenyls represent a class of compounds...     

Polychlorinated biphenyls and human health

Polychlorinated biphenyls (PCBs) were manufactured and used widely for many years. Because they are very persistent in both the environment and biological systems, there has been significant global contamination. This review presents a summary of known or suspected health effects of various PCB congeners, documented on the basis of both human and animal studies. As our knowledge increases several important points become apparent. PCBs interfere with many biological functions, including the immune system, the nervous system, and several endocrine system, and the fetus appears to be particularly vulnerable to these actions. PCBs cause certain cancers in animals. PCBs are mixtures of multiple congeners, differing on the basis of the numbers and positions of chlorines around the biphenyl ring, and it is becoming increasingly apparent that different congeners may have very different actions. These observations suggest that the potential human health hazards from PCB exposure have been underappreciated.     

Metabolites of polychlorinated biphenyls in human liver and adipose tissue

A method for analysis of hydroxylated metabolites of polychlorinated biphenyls (OH-PCBs) was developed and adopted to the previously described method for determination of PCBs and methylsulfonyl-PCBs (MeSO2-PCBs) in human liver and adipose tissue. The concentrations of OH-PCBs (14 congeners), MeSO2-PCBs (24 congeners), and PCBs (17 congeners) in five paired samples of human liver and adipose tissue are reported. The sum of OH-PCB congeners was higher in liver (7-175 ng/g lipids) than in adipose tissue (0.3-9 ng/g lipids). In both liver and adipose tissue, 2,2',3,4,4',5'-hexachloro-3'-biphenylol (3'-OH-CB138) and 2,2',3,3',4,5'-hexachloro-4'-biphenylol (4'-OH-CB130) were the predominant hydroxylated PCB metabolites. The sum of OH-PCB congeners were of the same order of magnitude as those of methylsulfonyl metabolites of PCB in the same samples, 12 to 358 ng/g lipids and 2 to 9 ng/g lipids in liver and adipose tissue, respectively. The levels of PCBs were similar in liver and adipose tissue, 459 to 2,085 ng/g lipids and 561 to 2,343 ng/g lipids, respectively. The sum of OH-PCBs and the sum of MeSO2-PCBs correlated to the sum of PCBs. The determined PCB metabolites constituted 3 to 26% of total PCB concentration in the liver and 0.3 to 0.8% of total PCBs in the adipose tissue samples.     

Polychlorinated biphenyls and organochlorine insecticides in human milk in Israel

Individual samples of human milk collected in Jerusalem at 2 to 12 weeks post partum were analyzed for polychlorinated biphenyls (PCBs) and chlorinated insecticides. PCBs were found in 95% of the samples and the mean value was 0.54 mg/kg fat. The mean values of DDE, the major metabolite of DDT, was 2.44 mg/kg fat and DDT 0.29 mg/kg fat. All samples were contaminated with HCH (hexachlorocyclohexane); the mean value was 0.35 mg/kg fat and with hexachlorobenzene, mean value 0.08 mg/kg fat. HCH was not detected, and in less than 50% of the samples small residues of HCH (lindane) were found. The results provide further data on the general trend of a decrease in the levels of organochlorine insectides in human milk and proves the effectiveness of the steps taken by the health authorities to restrict or ban the use of these compounds. The omnipresence of PCBs require further monitoring and epidemiological studies to clarify possible detrimental health effects in breast-fed infants.     

Polychlorinated biphenyls and menstrual cycle characteristics

BACKGROUND: Experimental studies in nonhuman primates provide evidence that low-level exposure to persistent organochlorine pollutants such as polychlorinated biphenyls (PCBs) may affect aspects of their menstrual cycle, including cycle length, regularity, and bleeding duration. Few studies have examined these associations in humans. METHODS: We used data from 2314 pregnant women who participated in the Collaborative Perinatal Project, a cohort study that enrolled pregnant women in the 1960s in 12 centers in the United States. Information about usual (prepregnancy) menstrual cycle length, regularity, bleeding duration, and dysmenorrhea was collected at enrollment, and 11 PCBs and p,p'-DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) were measured in stored blood samples collected during the third trimester of pregnancy. We used multivariate linear and logistic regression to examine the association between organochlorine levels and menstrual cycles, adjusting for demographic factors, cholesterol, and triglycerides. RESULTS: Total PCBs were positively associated with increasing menstrual cycle length (adjusted difference across 5 categories of PCB exposure = 0.7 days, trend-test P value = 0.02). Irregular cycles were slightly more frequent among those in the 2 highest categories of PCB exposure (odds ratio for highest category = 1.5; 95% confidence interval = 0.70-3.3), and there also was some evidence of an association with DDE. The strengths of these associations increased with various exclusions made to decrease potential misclassification of the outcome and the exposures. There was little evidence for associations between DDE or PCBs and bleeding duration, heavy bleeding, or dysmenorrhea. CONCLUSIONS: This study supports experimental studies in monkeys showing an effect of low-dose PCB exposure on menstrual function.     

Polychlorinated biphenyls in serum and time to pregnancy

Polychlorinated biphenyls (PCBs) may affect the female reproductive system in both animals and humans. In Sweden, a main exposure source to PCBs is consumption of fatty fish from the Baltic Sea. From 165 female consumers of such fish (fishermen's sisters), information on time to pregnancy (TTP) and miscarriages was collected, blood was drawn, and serum was analyzed for 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153), a biomarker for total PCB exposure. TTP and miscarriage data, as well as plasma CB-153 concentrations, for 121 fishermen's wives were available from previous studies. Thus, information on 286 women was available for investigation of whether a high exposure to PCB affects fertility negatively by increasing the TTP. The concentrations of CB-153 at the time of conception were estimated and trichotomized into low, medium, and high exposure groups. When we analyzed the joint data set of fishermen's wives and fishermen's sisters, a decrease rather than an increase in TTP was indicated for women in the medium (fecundability ratio 1.27 [95% confidence interval 0.89-1.82]) and high (fecundability ratio 1.42 [0.99-2.03]) exposure groups compared to those in the low exposure group. Similar results were found when we stratified on the original data set (fishermen's wives and fishermen's sisters) or childhood exposure. Women with miscarriages had lower estimated past CB-153 concentrations than women with live births. Our data provide no evidence of a hazardous effect associated with CB-153 concentration in the exposure range assessed. The exposure levels found in the fishermen's families, although high compared to that in the general Swedish population, may not be high enough to negatively affect fertility.