Polychlorinated Biphenyls In Blood Research Articles

Environmental exposure to dioxins and polychlorinated biphenyls reduce levels of gonadal hormones in newborns: Results from the Duisburg cohort study

Background Endocrine dysfunction related to the hypothalamic–pituitary–thyroid (HPT) and/or the hypothalamic–pituitary–gonadal axis (HPG) is being discussed as underlying developmental adversity of polychlorinated dibenzo- p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs). This study was done to evaluate effects related to the HPG axis. Methods A birth-cohort study was initiated in the year 2000. Healthy mother–infant pairs were recruited in the industrialized city of Duisburg, Germany. Dioxins, dioxin-like PCBs and six indicator PCBs were measured in maternal blood during pregnancy and in maternal milk. Testosterone and estradiol levels were measured in maternal and cord serum of 104 mother–infant pairs representing a subsample with a complete data set of the total basic sample of 232 participants. Linear regression analysis was used to describe the association of PCDD/Fs or PCB in maternal blood or milk with sex steroid concentrations after adjustment for confounding. Results Median concentrations for PCDD/Fs in maternal blood fat and milk fat in terms of WHO-TEq were 15.3 and 13.1 pg WHO-TEq/g, respectively, and for the sum of the indicator PCBs (#28, #52, #101, #138, #153, #180) 149 and 177 ng/g. The adjusted ratio of geometric means when doubling the concentration of PCDD/Fs in maternal blood fat was 0.86, 95% confidence interval (95% CI): 0.72–1.03 for testosterone and 0.73 (0.61–0.87) for estradiol in cord serum. Typically, testosterone reduction was more pronounced in cord serum of female and estradiol reduction in that of male babies. Reduction of hormone levels was generally more pronounced for dioxins than for indicator PCBs. Conclusions The hypothalamic–pituitary–gonadal axis of newborn babies is influenced by prenatal exposure to PCDD/Fs and PCBs in a manner suggestive of AhR-mediation. The clinical relevance of this finding remains to be established, however.

Polychlorinated Biphenyl Levels in Peripheral Blood and Non-Hodgkin's Lymphoma: A Report from Three Cohorts

The incidence of non-Hodgkin's lymphoma (NHL) unrelated to HIV infection has steadily increased over the past several decades and remains substantially unexplained. Limited evidence suggests that increased concentrations of polychlorinated biphenyls (PCB) measured in blood or fat tissue are associated with increased risk of NHL. Although PCB congeners vary in their biological activity, the relation between individual congeners and NHL risk has not been examined previously using prospectively collected biospecimens. We examined congener-specific associations in three prospective cohorts. Prediagnostic serum or plasma concentrations of selected PCB congeners were measured among NHL cases and controls from these cohorts: Janus (190 cases and 190 controls) in Norway and CLUE I (74 cases and 147 controls) and the Nurses' Health Study (30 cases and 78 controls) in the United States. All blood samples were collected in the 1970s or 1980s. We used logistic regression to calculate odds ratios (OR) and 95% confidence intervals (95% CI) for the relations between risk of NHL and lipid-corrected plasma or serum concentrations. Several congeners (i.e., 118, 138, and 153) that were present at higher levels and were moderately to highly correlated with each other showed exposure-response trends with risk of NHL in all three cohorts. These associations were observed primarily among subjects diagnosed closer to the date of blood collection in the two cohorts with sufficient cases to permit stratification by time. Among cases diagnosed within the median years of follow-up (16 years in Janus and 12 years in CLUE I), ORs and 95% CIs for increasing fourths of concentration of congener 118 relative to the lowest fourth were as follows: 2.4 (0.9-6.5), 4.9 (1.6-15.3), and 5.3 (1.5-18.8; P(trend) < 0.005) in Janus and 8.1 (1.0-68.9), 6.6 (0.7-59.0), and 13.0 (1.6-106.8; P(trend) < 0.05) in CLUE I. Similar patterns were seen for congeners 138 and 153 and for total PCBs. Limited evidence of exposure-response trends was also observed for several other congeners. The primary 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane metabolite, p,p'-DDE, was not significantly associated with NHL in most analyses but slightly to moderately confounded the PCB associations. The results from these three cohorts suggest that concentrations of certain PCBs in blood are associated with increased risk of NHL.

Polychlorinated Biphenyls and Non-Hodgkin Lymphoma

Several epidemiologic studies suggest that polychlorinated biphenyl (PCB) levels measured in peripheral blood or adipose tissue are related to increased risk of non-Hodgkin lymphoma (NHL) and, therefore, may be at least partially responsible for the rising incidence of NHL unrelated to HIV infection in recent decades. Case-control studies that measured PCBs in blood, adipose tissue, or household carpet dust, at the time of diagnosis, have observed elevated NHL risk associated with concentrations of either total PCBs or of specific congeners. Similar associations have been found in a number of prospective cohorts. These associations do not seem to be due to confounding by other organochlorines or by other known NHL risk factors. These results support evidence of PCB carcinogenicity from animal studies. However, interpretation of the epidemiologic evidence is limited by the wide range in measurement precision across congeners and by the moderate to high correlation among many congeners. Occupational cohort studies provide very limited support for a relationship between PCBs and NHL. In conclusion, there is mounting evidence of a relationship between certain PCBs and risk of NHL, but important questions remain, especially regarding the magnitude, timing, and causality of that relationship.

PCDD/F and dioxin-like PCB in human blood and milk from German mothers

Blood samples of pregnant women aged between 19 and 42 years at the time they gave birth and milk samples from the same women following delivery were collected between September 2000 and January 2003 from 169 participants living in an industrialized area of Germany (Duisburg birth cohort study). All samples were analyzed for their content of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) as well as dioxin-like and indicator polychlorinated biphenyls (PCB). Levels of WHO-TEq were in the range of 4.34-97.3 pg/g(lipid base) (median: 26.37, arithmetic mean: 28.36) for blood, or 3.01-78.7 pg/g(lipid base) (median: 26.40, arithmetic mean: 27.27) for milk, respectively. The four congeners 12378-PeCDD, 23478-PeCDF, 33'44'5-PeCB (# 126) and 233'44'5-HxCB (# 156) contribute the main share to total WHO-TEq. The contribution of PCDD/F in relation to PCB to total WHO-TEq was 60:40% in blood and 52:48% in milk. Good correlations of the contaminant levels in lipid base between both matrices were found. The distribution between blood and milk depends on the molecular weight of the substances. Higher chlorinated PCDD/F- and PCB-congeners were found in 2-4-fold higher concentrations in blood in relation to milk and the concentrations of lower chlorinated PCB-congeners were up to 2-fold higher in milk in relation to blood. The body burden of PCDD/F and PCB increases with age and decreases over the total nursing period. Women who had lived outside highly industrialized countries showed lower concentrations of PCDD/F and PCB. In some cases, elevated levels of PCB were observed when the women had previously lived in Eastern Europe for a long time. In comparison with recent data, the decline in human PCDD/F and PCB levels observed during the nineties seems to have stopped. The individual exposures of the infants due to breastfeeding within the first 18 months were calculated to be from 4.4 to 318 ng WHO-TEq (median: 106, arithmetic mean: 118). The actual mean daily exposure of a breastfed infant can be estimated to 131 pg WHO-TEq/kg(body weight).

Women’s Health: Endometriosis and PCB Exposure

Vol. 114, No. 7 EnvironewsOpen AccessWomen’s Health: Endometriosis and PCB Exposure Carol Potera Carol Potera Search for more papers by this author Published:1 July 2006https://doi.org/10.1289/ehp.114-a404aCited by:2AboutSectionsPDF ToolsDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InReddit Endometriosis may be related to exposure to persistent pollutants such as polychlorinated biphenyls (PCBs), according to research published in the May 2006 issue of Chemosphere. This gynecological disorder linked to infertility afflicts 10% of U.S. women of reproductive age. Researchers measured blood PCB levels in women undergoing laparoscopy for suspected endometriosis or other gynecological conditions. Higher levels of PCBs were detected in women with histologically confirmed endometriosis compared with controls.Toxicologist Elena De Felip of the Istituto Superiore di Sanità in Rome and her colleagues measured 11 PCB congeners that are most abundant in human tissue. In 80 women aged 20 to 40, the sum of all congeners was 1.6 times higher in the 40 women diagnosed with endometriosis than in controls. Three congeners, PCBs 138, 153, and 180, were particularly higher in women with endometriosis. These three congeners have been reported to have estrogenic activity and to interfere with hormone-regulated processes.PCBs have been used since the 1930s, mainly in electrical equipment. Although no longer manufactured, these persistent chemicals accumulate in the food chain; today meat, fish, eggs, and milk are chief sources of PCBs. But diet seems unable to explain the difference in PCB levels detected in the two groups of women, since “the dietary habits of the women were basically the same,” says De Felip.De Felip suspects that differences in how women detoxify and eliminate PCBs from the body may explain the disparity. These processes are mediated by polymorphic enzymes; therefore, she says, differences in toxicokinetic activity may represent the basis for the higher concentrations detected in women with endometriosis and may also be related to higher or lower susceptibility to that condition.Studies of PCBs and endometriosis face several limitations. Researchers typically measure only a few widespread congeners that are selected because of their toxicological activities, including an association with cancer shown in animal models. “So we’re only getting part of the picture,” says Germaine Buck Louis, chief of the Epidemiology Branch at the National Institute of Child Health and Human Development.In a study described in the January 2005 issue of Human Reproduction, Buck’s team measured 62 congeners in 84 women undergoing laparoscopy. Levels of 4 antiestrogenic congeners were 3.77 times higher in women diagnosed with endometriosis than in controls. “We don’t fully understand the role of estrogenic and antiestrogenic PCBs,” she says, but complex interactions of many PCBs as well as other chemicals may be involved in developing endometriosis.Recent advances in PCB detection methods allow more congeners to be measured at lower concentrations. “Women with endometriosis may have low levels of a particular congener not found in [other women],” says Louis. Moreover, breastfeeding reduces PCB levels in women, so women without endometriosis may have lower blood levels because they become pregnant and breastfeed more often. “There’s no ideal comparison group for endometriosis studies,” says Louis, and “there are no easy answers.”FiguresReferencesRelatedDetailsCited By Wang J, Hülck K, Hong S, Atkinson S and Li Q (2011) Accumulation and maternal transfer of polychlorinated biphenyls in Steller Sea Lions ( Eumetopias jubatus ) from Prince William Sound and the Bering Sea, Alaska, Environmental Pollution, 10.1016/j.envpol.2010.09.022, 159:1, (71-77), Online publication date: 1-Jan-2011. Trenck K, Schilling F and Schmidt D (2007) Bioindikation mit WanderfalkenBioindication with peregrine falcons: New results from Baden-Wuerttemberg, Umweltwissenschaften und Schadstoff-Forschung, 10.1065/uwsf2007.03.187, 19:2, (75-82), Online publication date: 1-Apr-2007. Vol. 114, No. 7 July 2006Metrics About Article Metrics Publication History Originally published1 July 2006Published in print1 July 2006 Financial disclosuresPDF download License information EHP is an open-access journal published with support from the National Institute of Environmental Health Sciences, National Institutes of Health. All content is public domain unless otherwise noted. Note to readers with disabilities EHP strives to ensure that all journal content is accessible to all readers. However, some figures and Supplemental Material published in EHP articles may not conform to 508 standards due to the complexity of the information being presented. If you need assistance accessing journal content, please contact [email protected]. Our staff will work with you to assess and meet your accessibility needs within 3 working days.

High plasma concentrations of polychlorinated biphenyls and phthalate esters in women with endometriosis: a prospective case control study

The objective of this study was to detect the probable association between polychlorinated biphenyls (PCBs) and phthalate esters (PEs), and the occurrence of endometriosis in a prospective case control study. We found that PCBs and PEs may be instrumental in the etiology of endometriosis.

Oral mucosa and dental findings in Yusho

Summary Background: Yusho is a disease caused by the ingestion of rice bran oil contaminated with polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs) and related compounds. Oral lesions such as oral pigmentation, anomalies of the dental root shape and deficiency of tooth germs have been observed in Yusho patients. Objective: The purpose of this study was to determine the prevalence of oral lesions, especially oral pigmentation, in Yusho patients, and also to describe the relationship between oral lesions and PCBs or PCDFs. Methods: Visual and radiographic examinations were performed on Yusho patients who visited the dentist during the annual health examination in Fukuoka prefecture. The data obtained from 1968 to 2003 were analyzed. Results: Gingival pigmentation was the most common of all types of oral pigmentation seen in Yusho patients. Of all the examined Yusho patients, the proportion who had gingival pigmentation was more than 60% during the early phase after the Yusho incident, but this value had decreased to below 30% in 1993. However, it subsequently increased again to about 50% in 2003. Yusho patients with a blood PCB pattern typical of Yusho showed the highest incidence of oral pigmentation 5 years after PCB poisoning. As time passed, however, there was no specific difference in the prevalence of oral pigmentation between any type of PCB pattern, either specific to Yusho or commonly observed in the general population. Analysis of data by three-way analysis of variance (ANOVA) in 2001 and 2002 showed that there was a close relationship between the presence of upper gingival pigmentation and blood PCDF levels. Conclusions: The prevalence of oral pigmentation still remains high even after 35 years, and PCDFs may be responsible for the presence of oral pigmentation.

Complete blood cell counts and blood chemistry in Yusho

Because of their lipophilic nature, polychlorinated biphenyls (PCBs) bioaccumulate in the food chain and their residues have been detected in foods. Consequently, they accumulate readily in the human body. Reports suggest that PCB blood levels remain constant or increase. Little, however, is known about the long-term hazardous effects of PCBs and dioxins on human health. Yusho is a type of food poisoning caused by PCBs and dioxins that contaminated rice bran oil. We analyzed blood samples of the Yusho patients from 1986 to 2002, and studied changes in blood cell counts, blood chemistry and tumor markers. A population of 1041 patients was divided into patient and control groups based on the diagnostic criteria established for Yusho and participant's blood polychlorinated quarterphenyl (PCQ) levels. In total, 1666 blood and 1652 urine samples from 374 patients in the patient group (PCQ levels = 0.1 ppb), and 373 blood and 302 urine samples from 151 people in the control group (PCQ levels < 0.02 ppb) were analyzed. Blood levels of PCBs, PCQs, polychlorinated dibenzo- p -dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined, and we analyzed their correlation with the data of complete blood cell counts, blood chemistry and urinalysis . Blood analyses, blood chemistry and urine values in Yusho patients were not significantly different from those in the control group 34 years after the Yusho incident. PCBs, PCQs or PCDFs may, however, affect hematogenesis, serum potassium, serum phosphorus, protein metabolism and creatine kinase metabolism because these parameters had slight but significant correlations with the levels of PCBs, PCQs or PCDFs. Exposure to PCBs and the related organochlorine compounds should be avoided.

Great Lakes Resource at Risk

For centuries the Great Lakes have been treated callously These five magnificent lakes—Superior, Michigan, Huron, Erie, and Ontario—located along the eastern half of the Canadian–U.S. border have served as a virtual sewer catching waste from industry, agriculture, commercial shipping, and households. Their natural barriers to other water systems have been breached, exposing indigenous ecosystems to aggressive invaders. They’ve been used as a highway for colossal ships that require deepened and broadened channels to crisscross the lakes, and that import exotic species along with their intended cargo. At times it could seem that this long-suffering water system will see no end of indignities. But recent renewed focus on the unique and tremendous value of this resource by governments and communities surrounding the lakes may turn the tide of neglect and abuse. According to the U.S. Environmental Protection Agency (EPA), the Great Lakes contain 21% of the Earth’s and about 84% of United States’ surface freshwater. That’s about 22,000 cubic kilometers of water spread over 94,250 square miles. Each year the lakes provide more than 6.7 million cubic meters of water to municipalities and quadruple that to industry. They support a commercial fishery worth about $13 million as of 2002, according to the U.S. Geological Survey (USGS), and a sport-fishing industry of nearly $1.3 billion as of 2001, according to the U.S. Fish and Wildlife Service. Today about 25% of Canadians and 10% of Americans—a total of more than 33 million people—live in the Great Lakes watershed. “The whole industrial expansion that took place during the ‘robber baron’ era [of the late nineteenth century] expanded along the shores of the Great Lakes,” says Deborah Swackhamer, a University of Minnesota professor of environmental chemistry. Soon ships were carrying iron ore, coal, and limestone from mines and quarries to steel mills and later steel to factories and products to markets. In addition to serving as a transportation system, the lakes provided a place to discharge manufacturing by-products. Unlike a sewer, however, whatever enters this lake system stays awhile. On average, less than 1% of the five lakes’ water turns over each year, which means that many pollutants stay in place. They settle in sediments, adhere to other surfaces, become suspended in water, and bioaccumulate in organisms. Similarly, with the exception of migratory birds, most wildlife in the basin spend their entire life cycle in or near the lakes. As a result of all these stressors, the lakes now house fish that are dangerous to eat, water that can be unsafe to drink, anoxic “dead zones”—areas in which virtually no plants or animals can survive—that appear each summer like clockwork, and an ever-growing population of unwanted species from other parts of the world.

Neuromotor functions in Inuit preschool children exposed to Pb, PCBs, and Hg

The aim of this study was to examine the effects of prenatal and postnatal chronic exposure to mercury (Hg), polychlorinated biphenyls (PCBs) and lead (Pb) on the neuromotor development of preschool children. The study population consisted of 110 preschool Inuit children from Nunavik (Canada). Blood Hg, PCBs and Pb concentrations were measured at birth (cord blood) and at the time of testing. Gross motor functions were evaluated and a neurological examination was performed. Fine neuromotor performance was assessed using quantitative measures of postural hand tremor, reaction time, sway oscillations, as well as alternating and pointing movements. Potential covariates were documented including demographic and familial characteristics, other prenatal neurotoxicants (alcohol, tobacco) and nutrients (selenium (Se), Omega-3 polyunsaturated fatty acids (n-3 PUFA)). Hierarchical multivariate regression analyses were performed, controlling for significant covariates. Gross motor development was not linked to prenatal exposures. However, significant associations were observed between blood Pb concentration at testing time and changes in reaction time, sway oscillations, alternating arm movements and action tremor. For some of these outcomes, neuromotor effects of Pb exposure are observed at blood concentrations below 10 μg/dl. Negative effects of PCBs on neuromotor development were not clearly observed, neither were the potential beneficial effects of n-3 PUFA and selenium. Tremor amplitude was related to blood Hg concentrations at testing time, which corroborate an effect already reported among adults.

Zehn Jahre PCB-Richtlinie - Versuch einer Bilanz aus hygienischer und umweltmedizinisch-toxikologischer Sicht

In 1995 a guideline was established in Germany, which requires the remediation of buildings with elevated indoor air concentrations of polychlorinated biphenyls (PCB). The action limit is 3000 ng/m(3). The tolerable PCB indoor air concentration is 300 ng/m(3). The aim of remediation actions is to reduce PCB in indoor air to levels < 300 ng/m(3) by removing the sources of PCB in buildings (mainly sealants, ceiling plates, wall colours). Based on this guideline a great number of school buildings, university buildings and administration buildings constructed in the 1960-ties and 1970-ties were renovated. In this paper, the toxicological basis of the aforementioned guide values are discussed. Furthermore, recent papers and proposals to establish lower guideline values for PCB in indoor air are discussed. The existing PCB guideline should be revised. When revising the guide values for PCB in indoor air it should be kept in mind that human PCB exposure is mainly via food, that PCB intake via food has been declining since more than 20 years, and that there is only a minor increase of PCB blood levels following inhalation of PCB in indoor air. In public discussions it should be clearly stated that remediation of PCB contaminated buildings is a preventive action. PCB concentrations in indoor air, which are associated with significant health risks, are presumably much higher than the current action value.

Impact of FEBRA (fermented brown rice with Aspergillus oryzae) intake and concentrations of PCDDs, PCDFs and PCBs in blood of humans from Japan

Impact of FEBRA (fermented brown rice with Aspergillus oryzae, a rich dietary fiber) intake on the concentrations of polychlorinated-biphenyls (PCBs), -dioxin-like polychlorinated biphenyls (DLPCBs), -dibenzo- p-dioxins (PCDDs), and -dibenzofurans (PCDFs) in blood of nine married Japanese were studied for 2 years. Concentrations of total PCBs (average ± standard deviation) were greater 326 000 ± 263 000 and 207 000 ± 89 000 in FEBRA-intake and non-FEBRA-intake groups, respectively, on pg/g lipid (from now onwards data expressed on pg/g lipid). DLPCBs were second major contaminants 94 000 ± 77 000 and 60 000 ± 28 000, orderly in FEBRA-intake and non-FEBRA-intake groups. The concentrations of PCDD/DFs were several orders of magnitude lower than those of PCBs, whereas PCDDs were greater (433 ± 233 and 512 ± 511, in FEBRA-intake and non-FEBRA-intake groups, respectively) than PCDFs (56 ± 50 and 43 ± 35). Calculated toxic equivalency (TEQ) concentrations were 34 ± 24 and 23 ± 10 in FEBRA-intake and non-FEBRA-intake groups, respectively. In order to corroborate the impact of FEBRA, the changes of PCDD/DFs and PCB concentrations for 0.5-year, 1-year, 1.5-year, and 2-year samples were estimated from average concentration of 1-day before study commences and 1-week study samples. The results explicit FEBRA-intake group eliminated 7%, 33%, 45%, 36%, and 26% and non-FEBRA-intake group eliminated 8%, 28%, 36%, 31%, and 20% of DLPCBs, PCDDs, PCDFs, PCDD/DF TEQ and total TEQ, respectively. This study is the first of its kind showing the possible elimination of PCDDs, PCDFs and their TEQ in humans from Japan after the consumption of FEBRA.

Hydroxylated and methyl sulfone PCB metabolites in adipose and whole blood of polar bear ( Ursus maritimus) from East Greenland

Persistent methyl sulfone (MeSO 2–) and hydroxylated (HO–) polychlorinated biphenyl (PCB) metabolites have emerged as important classes of environmental contaminants in vertebrate, aquatic biota and humans. In the present study, PCB, MeSO 2–PCB and HO–PCB concentrations and congener patterns were determined in the whole blood and adipose tissue of male ( n=7) and female ( n=12) polar bears ( Ursus maritimus) of random age (3–25 years of age), and collected in 1999–2001 from the Ittoqqortoormiit/Scoresby Sound area in central East Greenland. There was no significant difference ( P<0.05) between males and females with respect to PCB or PCB metabolite concentrations in either tissue. The mean sum (Σ) PCB concentrations were 7020±3366 ng/g lipid weight (lw) (range 2708–18148 ng/g lw) and 46.1±44.6 ng/g wet weight (ww) (range 12.6–204.2 ng/g ww) in adipose and blood, respectively. The mean Σ-HO–PCB concentration in whole blood was 182.3±72.1 ng/g ww (range 93.8–382.1 ng/g ww). The mean Σ-HO–PCB to Σ-PCB concentration ratios in whole blood were 4.59±3.58 (range 1.03–11.88) and 8.30±5.56 (range 2.16–19.47) in females and males, respectively, which are the highest ratios reported so far for polar bears from any population, or for any free-ranging animal. Σ-HO–PCB concentrations were greater than all other major classes of organochlorines (i.e. Σ-PCBs, Σ-MeSO 2–PCBs, Σ-chlordanes (CHLs), Σ-hexachlorocyclohexanes (HCHs) and Σ-chlorobenzenes (CBzs). The mean Σ-MeSO 2–PCB concentrations were 699±836 ng/g lw (range 127–3920 ng/g lw) and 10.9±9.6 ng/g ww (range 4.3–52.1 ng/g ww) in the adipose and blood, respectively. Regardless of age and sex, in both adipose and whole blood the MeSO 2–PCB congener pattern was dominated by 3′- and 4′-MeSO 2–CB101 and -CB87, and 4-MeSO 2–CB149 (approx. 70% of the Σ-MeSO 2–PCBs). Minor differences in the MeSO 2–PCB congener pattern were observed between blood and adipose, which suggests the possible influence of metabolite structure on mobilization and/or deposition to the adipose tissue. Sixteen HO–PCB congeners and one di-HO–PCB congener were identified, and five HO–PCB isomers and one di-HO–PCB isomer were detected. However, congener patterns were dominated by 4′-OH–CB120, 4-HO–CB146/3-HO–CB153, 4-OH–CB187, 4′-HO–CB172, 4-HO–CB193 and 4,4′-di-HO–CB202 (>10 ng/g ww). HO–PCB congener patterns in whole blood were not significantly different ( P<0.05) between males and females. Other chlorinated phenolic contaminants, pentachlorophenol (0.3±0.3 ng/g ww) and 4-HO-heptachlorostyrene (7.5±2.9 ng/g ww) were also detected in blood. To our knowledge, this is to first report comparing PCBs, MeSO 2–PCBs and HO–PCBs in whole blood and adipose tissue in a free-ranging wildlife species. HO–PCBs and MeSO 2–PCBs are both important circulating contaminants in polar bears from this eastern Greenland population. Given the known toxicities of PCB metabolites, this population of polar bear may be experiencing health risks due to exposure to a complex loading of organohalogen contaminants that include HO–PCB and MeSO 2–PCB metabolites.

Associations between organochlorine contaminant concentrations and clinical health parameters in loggerhead sea turtles from North Carolina, USA.

Widespread and persistent organochlorine (OC) contaminants, such as polychlorinated biphenyls (PCBs) and pesticides, are known to have broad-ranging toxicities in wildlife. In this study we investigated, for the first time, their possible health effects on loggerhead sea turtles (Caretta caretta). Nonlethal fat biopsies and blood samples were collected from live turtles for OC contaminant analysis, and concentrations were compared with clinical health assessment data, including hematology, plasma chemistry, and body condition. Concentrations of total PCBs (∑PCBs), ∑DDTs, ∑chlordanes, dieldrin, and mirex were determined in 44 fat biopsies and 48 blood samples. Blood concentrations of ∑chlordanes were negatively correlated with red blood cell counts, hemoglobin, and hematocrit, indicative of anemia. Positive correlations were observed between most classes of OC contaminants and white blood cell counts and between mirex and ∑TCDD-like PCB concentrations and the heterophil:lymphocyte ratio, suggesting modulation of the immune system. All classes of OCs in the blood except dieldrin were correlated positively with aspartate aminotransferase (AST) activity, indicating possible hepatocellular damage. Mirex and ∑TCDD-like PCB blood concentrations were negatively correlated with alkaline phosphatase (ALP) activity. Significant correlations to levels of certain OC contaminant classes also suggested possible alteration of protein (↑blood urea nitrogen, ↓albumin:globulin ratio), carbohydrate (↓glucose), and ion (↑sodium, ↓magnesium) regulation. These correlations suggest that OC contaminants may be affecting the health of loggerhead sea turtles even though sea turtles accumulate lower concentrations of OCs compared with other wildlife.

Organochlorines in the free-ranging Hawaiian monk seal ( Monachus schauinslandi) from French Frigate Shoals, North Pacific Ocean

The Hawaiian monk seal ( Monachus schauinslandi) is an endangered species found only in the Hawaiian Island chain. The largest subpopulation, at French Frigate Shoals, has been in decline since 1989. In order to assess organochlorine (OC) levels in the Hawaiian monk seals, whole blood and blubber samples were collected in 1999 from 46 free-ranging Hawaiian monk seals at French Frigate Shoals, and were analyzed for eight dioxin-like polychlorinated biphenyls (PCBs) as well as six other PCB congeners, DDT and DDT metabolites. Average levels of the total PCBs in blood samples from adult male, juvenile and reproductive female groups were 4800, 4000 and 3000 ng/g lipid wt., respectively, whereas 3200, 1300 and 1200 ng/g, respectively, in blubber from the three corresponding groups. p, p′-DDE was the only DDT detected in blubber samples, and no DDTs were detected in blood samples. Concentrations of the total PCBs in adult males were significantly higher than the levels measured in either reproductive females or juveniles. There were significant correlations between age and blubber p, p′-DDE, estimated mass and total blood PCBs or blubber p, p′-DDE, and body condition and total blood PCBs. Although it is clear that the Hawaiian monk seal has been exposed to OCs, it is unclear what biological effects, if any, these xenobiotics may have on the animals.

Prenatal PCB exposure, the corpus callosum, and response inhibition.

The present study reports the association between prenatal exposure to polychlorinated biphenyls (PCBs), the corpus callosum, and response inhibition in children who are 4.5 years old. Children (n = 189) enrolled in the Oswego study were tested using a continuous performance test. We measured (square millimeters) the splenium of the corpus callosum, a pathway implicated in the regulation of response inhibition, using magnetic resonance imaging. Results indicated a dose-dependent association between cord blood PCBs and errors of commission. Splenium size but not other brain areas predicted errors of commission (r(2) = 0.20), with smaller size associated with more errors of commission. There was an interaction between splenium size and PCB exposure. The smaller the splenium, the larger the association between PCBs and errors of commission. If the association between PCBs and response inhibition is indeed causal, then children with suboptimal development of the splenium are particularly vulnerable to these effects. These data await replication.

Relationship between PCBs in blood and d-glucaric acid in urine

The polychlorinated biphenyls (PCBs) have been demonstrated to be inducers of hepatic microsomal enzymes and some of their effects such as hormonal imbalance, and alteration of lipid and porphyrin metabolism could be ascribed to this mechanism. For this reason, the urinary excretion of d-glucaric acid (DGA), an indirect indicator of enzymatic induction, was suggested as a biological marker of effect following exposure to PCBs. The aim of the present study was to investigate whether any inductive effects resulting from exposure to these compounds through ingestion of contaminated food could be detected early by measuring urinary DGA (U-DGA). U-DGA was measured in 73 subjects exposed to PCBs due to ingestion of PCB-contaminated food and levels ranged from 1.7 to 12.4 mmol/mol creatinine, with a mean value of 5.96 mmol/mol creatinine. These values were higher than those usually found in the general population. Sex and smoking habits did not affect U-DGA excretion, while age and alcohol intake were significantly correlated with U-DGA excretion, a finding in agreement with the results of other investigations. Neither total PCB blood concentration nor PCB chlorine content was significantly correlated with U-DGA excretion, and only the PCB 138 congener was weakly correlated with U-DGA levels. The results indicate that, for exposure to PCB resulting in blood concentrations up to 394 μg/l, no statistically significant effect of these persistent organochlorine compounds on human enzyme induction could be demonstrated, as measured by DGA urinary excretion.

Pharmacokinetics and blood levels of polychlorinated biphenyls.

Despite the enormous number of reports on polychlorinated biphenyl (PCB) toxicology, both the causal interpretation of epidemiological studies and the risk assessment of human exposures have been hampered by the lack of information on the pharmacokinetics of various PCB isomers and congeners. Thus, the assessment of exposure by means of measuring either total PCBs or individual congeners in the blood has so far been unsatisfactory. For example, the concentration and the pattern of congeners in the blood did not correlate with that at site(s) of action. In fact, the same levels of blood PCBs correlated with either toxic effects or no effects (both in clinical and epidemiological studies). In addition, when toxicity caused by PCBs was observed, the severity of the signs did not correlate with blood levels. Reasons for such a qualified failure are manifold and include different ways of reporting blood measurements, the different toxicological characteristics of each PCB, and different timing of sampling the blood, etc. Therefore, only limited conclusions can be drawn concerning what blood PCB measurements mean.

Human exposure to polychlorinated biphenyls and health effects: a critical synopsis.

Polychlorinated biphenyls (PCBs) are a mixture of chemicals. Some congeners of the mixture are highly persistent both in the environment and in humans. Although PCBs have not been used commercially since about 1977 in the US, they can still be detected in human blood and tissues in this country. PCB levels are declining and are often no longer detectable in younger people. A cursory review of recent animal studies is provided. Studies to determine whether PCBs cause cancer in humans, neurobehavioural effects, abnormal thyroid and immune function in children and low birth weight are discussed in more detail. These studies are inconclusive and do not provide clinical evidence that PCBs at levels encountered with human exposure produce adverse health effects. The differences in PCB blood or tissue concentrations between controls and cases, or between the upper and lower end of various environmentally exposed groups of children or adults, are small. Although some effects are statistically significantly different, they do not appear to be biologically significant. Many studies on the effects of PCBs are difficult to interpret because the range of normal values for clinical and neurobehavioural tests are not provided or appropriately considered, there was no, or inadequate, control for potential confounders. In occupational mortality studies, exposures were much higher. In some studies, various specific cancers were elevated. However, these appear to be chance observations resulting from multiple comparisons since the increase of specific cancers was not consistent between studies and was no longer present in some cohorts when studies were repeated at a later date with longer follow-up. Overall, the data fail to demonstrate conclusive adverse health effects of PCBs at concentrations encountered with human exposures.

Cognitive development in preschool children prenatally exposed to PCBs and MeHg

A number of epidemiological studies have shown predictive relationships between prenatal exposure to polychlorinated biphenyls (PCBs) and subtle deficits in cognitive development in infancy through the preschool years [Child Dev. 56 (1985) 853; J. Pediatr. 116 (1990) 38; J. Pediatr. 134 (1999) 33; Toxicol. Lett. 102–103 (1998) 423; Neurotox. 21 (6) (2000) 1029–1038]. However, since not all studies have demonstrated these relationships (J. Pediatr. 119 (1991) 58–63), debate regarding the role of prenatal PCB exposure in cognitive development continues. The current study was designed to provide additional data to assist in resolving this question. Two hundred twelve children enrolled in the Oswego Newborn and Infant Development Project were assessed using the McCarthy Scales of Children's Abilities at 38 months of age, followed by a reassessment at 54 months of age. The relationship between prenatal exposure to PCBs (cord blood PCBs) and McCarthy performance was assessed at both ages after first controlling for a wide range of important predictors of cognitive development, including socioeconomic status (SES), maternal IQ, maternal education, home environment, cigarette smoking, and many others. Cord blood PCBs were statistically significant predictors of small but measurable deficits in McCarthy performance at 38 months of age. Moreover, a significant interaction between cord blood PCBs and maternal hair mercury (MeHg) was found, such that negative associations between prenatal MeHg exposure and McCarthy performance were found in subjects with higher levels of prenatal PCB exposure. No relationship between PCBs and/or MeHg and McCarthy performance was observed when the children were reassessed almost 1.5 years later (54 months of age). Inspection of the age-related trajectory of McCarthy performance revealed that the more highly exposed children caught up with the least exposed children by 54 months. Although the current data partially replicate the findings of Jacobson et al., Patandin et al., and Walkowiak et al. [J. Pediatr. 116 (1990) 38; J. Pediatr. 134 (1999) 33; Lancet 358 (2001) 1602], results reported here suggest that functional recovery may occur. Moreover, the interaction between PCB and MeHg cannot be considered conclusive until it has been replicated in subsequent investigations.