Polychlorinated biphenyls affect the activities of gluconeogenic and lipogenic enzymes in rat liver: is there an interference with regulatory hormone actions?

Prenatal exposure to persistent organic pollutants and markers of obesity and cardiometabolic risk in Spanish adolescents

BACKGROUND

Prenatal exposure to persistent organic pollutants (POPs) has been linked to cardiometabolic (CM) risk factors in childhood, but there are no studies evaluating the persistence of these associations into adolescence, a period of relevant changes in endocrine-dependent organ systems and rapid increases in lean and fat mass. We examined the associations of prenatal POP exposures with body mass index (BMI) from age 4 to 18 years, and with other CM risk markers in adolescence.

METHODS

We analysed 379 children from the Spanish INMA-Menorca birth cohort study with measured cord blood POP concentrations. We calculated BMI z-scores at ages 4, 6, 11, 14 and 18 years using the WHO growth reference. Body fat % was measured at 11 and 18 years and waist-to-height ratio (WHtR) and blood pressure (BP) at 11, 14 and 18 years. We measured CM biomarkers in fasting blood collected at age 14 years and calculated a CM-risk score as the sum of the sex-, and age-specific z-scores for waist circumference, mean arterial BP, homeostatic model assessment of insulin resistance, fasting blood triglycerides, and high-density lipoprotein cholesterol (HDL-C) (n = 217). Generalised estimating equations and multivariate linear regression models assessed the associations with repeated and single time-point measures, respectively.

RESULTS

Hexachlorobenzene (HCB) exposure in the third tertile, compared to the first tertile, was associated with higher BMI (β = 0.24; 95% CI: 0.01, 0.47) and WHtR z-score (β = 0.27; 95% CI: 0.04, 0.51). A continuous increase in HCB was associated with an elevated body fat % (β per 10-fold increase = 4.21; 95% CI: 0.51, 7.92), systolic BP (β = 0.32; 95% CI: 0.02, 0.64) and diastolic BP z-score (β = 0.32; 95% CI: 0.02, 0.62) across all ages, and with higher CM-risk score (β = 1.59; 95% CI: 0.02, 3.18) and lipid biomarkers (total cholesterol, triglycerides and low-density lipoprotein cholesterol (LDL-C)) at 14 years. Dichlorodiphenyltrichloroethane (p,p'-DDT) exposure was non-monotonically associated with BMI and systolic BP. p,p'-DDE and Σ-polychlorinated biphenyls (PCBs) (sum of congeners 118, 138, 153, 180) were not associated with adiposity or BP. p,p'-DDT exposure was associated with an increased CM-risk score, and ΣPCBs concentrations with LDL-C in all adolescents and with total cholesterol only in girls (p-sex interaction = 0.05).

CONCLUSION

This first longitudinal study from 4 to 18 years suggests that the previously reported POP associations with child BMI persist later in adolescence and that prenatal POP exposures are associated with major risk factors for adult CM syndrome.

Association of plasma levels of lipid and polychlorinated biphenyls in Iranian adult

Background

Exposure to Polychlorinated biphenyls (PCBs) continues over the world through seafood consumption and indoor exposure to building materials containing PCB. This study aimed to assess the relationship between plasma level of PCB congeners and lipid profile and Body Mass Index (BMI) as well.

Methods

The study population consisted of 181 Iranian adults. Data on BMI, plasma concentration of PCB congeners and serum level of lipid profile including Triglyceride, low-density lipoproteins and high-density lipoproteins, recruited from database of a project entitled “Occupational and environmental exposure to PCBs in Iran”. Multiple linear regression analysis of associations between different quartiles of PCB congeners and various lipid fractions and BMI have been conducted.

Results

A linear increase in average serum Triglyceride and low-density lipoproteins (LDL) levels of participants in first, second, third and fourth quartiles of some PCB congeners was obtained. Following adjustment for age, gender, diet and other variables, only the association between different quartiles of PCB 138, PCB 153, PCB 118 and PCB sum and TG remained statistically significant.

Conclusion

The study showed a significant positive relation between plasma PCBs concentrations and serum level of TG in the study population with normal PCBs levels.

Evaluation of cholinesterase and lipid profile levels in chronic pesticide exposed persons

Background:

Agriculture being the predominant occupation in India with rampant usage of pesticides to meet its enormous population needs. This pesticide abuse is taking a toll on the health of the persons involved in this work.

Objectives:

To evaluate pesticide exposure by assessing serum cholinesterase levels, and comparing them with the serum lipid profile levels which assumes the cardiovascular risk status.

Study Design:

It is a cross-sectional comparative study involving around 283 agricultural farm workers in Rajamahendravaram, Andhra Pradesh. The study period was for about 3 months during pesticide spraying season.

Materials and Methods:

All the blood samples were collected and analysed for biochemical parameters like plasma glucose, blood urea, serum creatinine, and lipid profile and serum cholinesterase levels using XL 640 fully automated random access analyser.

Statistical Analysis Used:

Results were analysed using SPSS software version 20.

Results:

The study group was classified into two groups based on serum cholinesterase levels. It was observed that there were significant alterations in lipid profile levels in the study group with decreased cholinesterase levels when compared to those of normal cholinesterase levels. There was significant negative correlation between cholinesterase levels and non-HDL cholesterol and total cholesterol/HDL ratio.

Conclusion:

This study implicates that the pesticides have an adverse health effect with regard to cardiovascular risk status.

Diabetes Prevalence in Relation to Serum Concentrations of Polychlorinated Biphenyl (PCB) Congener Groups and Three Chlorinated Pesticides in a Native American Population

BACKGROUND

Exposure to persistent organic pollutants (POPs) is known to increase risk of diabetes.

OBJECTIVE

To determine which POPs are most associated with prevalence of diabetes in 601 Akwesasne Native Americans.

METHODS

Multiple logistic regression analysis was used to assess associations between quartiles of concentrations of 101 polychlorinated biphenyl (PCBs) congeners, congener groups and three chlorinated pesticides [dichlorodiphenyldichloroethylene (DDE), hexachlorobenzene (HCB) and mirex] with diabetes. In Model 1, the relationship between quartiles of exposure and diabetes were adjusted only for sex, age, body mass index (BMI), and total serum lipids. Model 2 included additional adjustment for either total PCBs or total pesticides.

RESULTS

Total serum PCB and pesticide concentrations were each significantly associated with prevalence of diabetes when adjusted only for covariates (Model 1), but neither showed a significant OR for highest to lowest quartiles after additional adjustment for the other (Model 2). When applying Model 2 to PCB congener groups and individual pesticides, there were significant omnibus differences between the four quartiles (all ps < 0.042) for most groups, with the exception of penta- and hexachlorobiphenyls, DDE and mirex. However, when comparing highest to lowest quartiles only non- and mono-ortho PCBs [OR = 4.55 (95% CI: 1.48, 13.95)], tri- and tetrachloro PCBs [OR = 3.66 (95% CI: 1.37, -9.78)] and HCB [OR = 2.64 (95% CI: 1.05, 6.61)] showed significant associations with diabetes. Among the non- and mono-ortho congeners, highest to lowest quartile of dioxin TEQs was not significant [OR = 1.82 (95% CI: 0.61, 5.40)] but the OR for the non-dioxin-like congeners was [OR = 5.01 (95% CI: 1.76, 14.24)].

CONCLUSION

The associations with diabetes after adjustment for other POPs were strongest with the more volatile, non-dioxin-like, low-chlorinated PCB congeners and HCB. Because low-chlorinated congeners are more volatile, these observations suggest that inhalation of vapor-phase PCBs is an important route of exposure.

CITATION

Aminov Z, Haase R, Rej R, Schymura MJ, Santiago-Rivera A, Morse G, DeCaprio A, Carpenter DO, and the Akwesasne Task Force on the Environment. 2016. Diabetes prevalence in relation to serum concentrations of polychlorinated biphenyl (PCB) congener groups and three chlorinated pesticides in a Native American population. Environ Health Perspect 124:1376-1383; http://dx.doi.org/10.1289/ehp.1509902.

Analysis of the effects of exposure to polychlorinated biphenyls and chlorinated pesticides on serum lipid levels in residents of Anniston, Alabama

BACKGROUND

Anniston, Alabama, is the site of a former Monsanto plant where polychlorinated biphenyls (PCBs) were manufactured from 1929 until 1971. Residents of Anniston are known to have elevated levels of PCBs. The objective of the study was to test the hypothesis that levels of the various lipid components (total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides) are differentially associated with concentrations of total PCBs and total pesticides, and further that different congeners, congener groups and different pesticides do not have identical associations in serum samples obtained from Anniston residents in a cross-sectional study.

METHODS

Fasting serum samples were obtained from 575 residents of Anniston who were not on any lipid-lowering medication and were analyzed for 35 PCB congeners, nine chlorinated pesticides, total cholesterol, LDL and HDL cholesterol and triglyceride concentrations. Associations between toxicant concentrations and lipid levels were determined using multiple linear regression analysis.

RESULTS

We observed that elevated serum concentrations of lipids were associated with elevated serum concentrations of ΣPCBs and summed pesticides in analyses adjusted for age, race, gender, BMI, alcohol consumption, smoking and exercising status. The strongest associations were seen for PCB congeners with three, four, or at least eight substituted chlorines. Mono-ortho substituted congeners 74 and 156, di-ortho congeners 172 and 194, and tri- and tetra-ortho congeners 199, 196-203, 206 and 209 each were significantly associated with total lipids, total cholesterol and triglycerides. Serum concentrations of HCB and chlordane also had strong associations with lipid components.

CONCLUSIONS

Increased concentrations of PCBs and organochlorine pesticides are associated with elevations in total serum lipids, total cholesterol and triglycerides, but the patterns are different for different groups of PCBs and different pesticides. These observations show selective effects of different organochlorines on serum concentrations of different groups of lipids. This elevation in concentrations of serum lipids may be the basis for the increased incidence of cardiovascular disease found in persons with elevated exposures to PCBs and chlorinated pesticides.

Potential adverse health effects of persistent organic pollutants on sea turtles: evidences from a cross-sectional study on Cape Verde loggerhead sea turtles

The Cape Verde nesting population of loggerhead sea turtles (Caretta caretta) is the third largest population of this species in the world. For conservation purposes, it is essential to determine how these reptiles respond to different types of anthropogenic contaminants. We evaluated the presence of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) in the plasma of adult nesting loggerheads from Boa Vista Island, Cape Verde, and studied the effects of the contaminants on the health status of the turtles using hematological and biochemical parameters. All turtles had detectable levels of non-dioxin like PCBs, whereas dioxin-like congeners (DL-PCBs) were detected in only 30% of the turtles. Packed cell volume decreased with higher concentrations of PCBs, which suggests that PCB exposure could result in anemia in sea turtles. In addition, a negative association between some OCPs and white blood cells (WBC) and thrombocyte estimate was noted. The DDT-metabolite, p,p'-DDE was negatively correlated with the Na/K ratio and, additionally, a number of correlations between certain PAHs and electrolyte balances were found, which suggest that exposure to these environmental contaminants could affect the kidneys and salt glands in sea turtles. Additionally, several correlations were observed between these environmental pollutants (OCPs and PAHs) and enzyme activity (GGT, ALT, ALP and amylase) and serum protein levels, pointing to the possibility that these contaminants could induce adverse metabolic effects in sea turtles. Our results indicate that anthropogenic pollutants are present in the Cape Verde loggerhead turtle nesting population and could exert negative effects on several health parameters. Because of the importance of this loggerhead nesting population, protective regulations at national and international levels as well as international action are necessary for assuring the conservation of this population.

Evaluation of the association between persistent organic pollutants (POPs) and diabetes in epidemiological studies: a national toxicology program workshop review

BACKGROUND

Diabetes is a major threat to public health in the United States and worldwide. Understanding the role of environmental chemicals in the development or progression of diabetes is an emerging issue in environmental health.

OBJECTIVE

We assessed the epidemiologic literature for evidence of associations between persistent organic pollutants (POPs) and type 2 diabetes.

METHODS

Using a PubMed search and reference lists from relevant studies or review articles, we identified 72 epidemiological studies that investigated associations of persistent organic pollutants (POPs) with diabetes. We evaluated these studies for consistency, strengths and weaknesses of study design (including power and statistical methods), clinical diagnosis, exposure assessment, study population characteristics, and identification of data gaps and areas for future research.

CONCLUSIONS

Heterogeneity of the studies precluded conducting a meta-analysis, but the overall evidence is sufficient for a positive association of some organochlorine POPs with type 2 diabetes. Collectively, these data are not sufficient to establish causality. Initial data mining revealed that the strongest positive correlation of diabetes with POPs occurred with organochlorine compounds, such as trans-nonachlor, dichlorodiphenyldichloroethylene (DDE), polychlorinated biphenyls (PCBs), and dioxins and dioxin-like chemicals. There is less indication of an association between other nonorganochlorine POPs, such as perfluoroalkyl acids and brominated compounds, and type 2 diabetes. Experimental data are needed to confirm the causality of these POPs, which will shed new light on the pathogenesis of diabetes. This new information should be considered by governmental bodies involved in the regulation of environmental contaminants.

Chronic exposure to PCBs (Aroclor 1254) exacerbates obesity-induced insulin resistance and hyperinsulinemia in mice

Evidence from recent epidemiological studies has emerged implicating exposure to environmental toxicants as a novel risk factor for the development of type 2 diabetes (T2D) and the metabolic syndrome in the general population. Humans and other organisms in high trophic levels of the food chain consume persistent organic pollutants (POP) through their diet. Few experimental studies demonstrating cause and effect are available and evidence for a direct association between accumulation of POP and T2D is preliminary; however, the possibility exists that lipophilic chemicals that accumulate in fatty tissue may disrupt cellular function and metabolic homeostasis. Chronic exposure of diabetes-prone C57B/6 mice to a polychlorinated biphenyl (PCB) mixture (Aroclor 1254, 36 mg/kg/wk, 20 wk) alone or in combination with high-fat diet impairs carbohydrate metabolism was compared to vehicle-treated control animals. Specifically, PBC exposure was found to produce hyperinsulinemia in both lean and diet-induced obese mice and exacerbated whole-body insulin resistance in obese mice. These changes in carbohydrate metabolism in response to Aroclor 1254 occurred without marked effect on body weight in both lean and obese mice. Our results demonstrate a causative association between PCB exposure and obesity-induced insulin resistance and hyperinsulinemia independent of body weight changes, an observation that contributes to a growing body of evidence suggesting that exposure to environmental pollutants represents a novel risk factor contributing to the diabetes epidemic.

PCB 126 and other dioxin-like PCBs specifically suppress hepatic PEPCK expression via the aryl hydrocarbon receptor

Dioxins and dioxin-like compounds encompass a group of structurally related heterocyclic compounds that bind to and activate the aryl hydrocarbon receptor (AhR). The prototypical dioxin is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a highly toxic industrial byproduct that incites numerous adverse physiological effects. Global commercial production of the structurally similar polychlorinated biphenyls (PCBs), however, commenced early in the 20(th) century and continued for decades; dioxin-like PCBs therefore contribute significantly to total dioxin-associated toxicity. In this study, PCB 126, the most potent dioxin-like PCB, was evaluated with respect to its direct effects on hepatic glucose metabolism using primary mouse hepatocytes. Overnight treatment with PCB 126 reduced hepatic glycogen stores in a dose-dependent manner. Additionally, PCB 126 suppressed forskolin-stimulated gluconeogenesis from lactate. These effects were independent of acute toxicity, as PCB 126 did not increase lactate dehydrogenase release nor affect lipid metabolism or total intracellular ATP. Interestingly, provision of cells with glycerol instead of lactate as the carbon source completely restored hepatic glucose production, indicating specific impairment in the distal arm of gluconeogenesis. In concordance with this finding, PCB 126 blunted the forskolin-stimulated increase in phosphoenolpyruvate carboxykinase (PEPCK) mRNA levels without affecting glucose-6-phosphatase expression. Myricetin, a putative competitive AhR antagonist, reversed the suppression of PEPCK induction by PCB 126. Furthermore, other dioxin-like PCBs demonstrated similar effects on PEPCK expression in parallel with their ability to activate AhR. It therefore appears that AhR activation mediates the suppression of PEPCK expression by dioxin-like PCBs, suggesting a role for these pollutants as disruptors of energy metabolism.

Acute alteration of cardiac ECG, action potential, I(Kr) and the human ether-a-go-go-related gene (hERG) K+ channel by PCB 126 and PCB 77

Polychlorinated biphenyls (PCBs) have been known as serious persistent organic pollutants (POPs), causing developmental delays and motor dysfunction. We have investigated the effects of two PCB congeners, 3,3',4,4'-tetrachlorobiphenyl (PCB 77) and 3,3',4,4',5-pentachlorobiphenyl (PCB 126) on ECG, action potential, and the rapidly activating delayed rectifier K+ current (I(Kr)) of guinea pigs' hearts, and hERG K+ current expressed in Xenopus oocytes. PCB 126 shortened the corrected QT interval (QTc) of ECG and decreased the action potential duration at 90% (APD(90)), and 50% of repolarization (APD₅₀) (P<0.05) without changing the action potential duration at 20% (APD₂₀). PCB 77 decreased APD₂₀ (P<0.05) without affecting QTc, APD₉₀, and APD₅₀. The PCB 126 increased the I(Kr) in guinea-pig ventricular myocytes held at 36°C and hERG K+ current amplitude at the end of the voltage steps in voltage-dependent mode (P<0.05); however, PCB 77 did not change the hERG K+ current amplitude. The PCB 77 increased the diastolic Ca²⁺ and decreased Ca²⁺ transient amplitude (P<0.05), however PCB 126 did not change. The results suggest that PCB 126 shortened the QTc and decreased the APD₉₀ possibly by increasing I(Kr), while PCB 77 decreased the APD₂₀ possibly by other modulation related with intracellular Ca²⁺. The present data indicate that the environmental toxicants, PCBs, can acutely affect cardiac electrophysiology including ECG, action potential, intracellular Ca²⁺, and channel activity, resulting in toxic effects on the cardiac function in view of the possible accumulation of the PCBs in human body.

Impact of nutrition on PCB toxicity

Studies are evolving which suggest that nutritional intervention can modify pathologies of diseases associated with environmental toxic insults. The diet is a major route of exposure to environmental toxins, such as persistent organic pollutants and heavy metals. Many persistent organics, such as polychlorinated biphenyls (PCBs), bioaccumulate in our bodies and "bioremediation" is extremely difficult. Furthermore, many environmental toxins induce signaling pathways that are oxidative stress-sensitive and similar or the same as the ones associated with the etiology and early pathology of many chronic diseases. There is now increasing evidence that exposure to PCBs can contribute to the development of inflammatory diseases such as atherosclerosis. Activation, chronic inflammation, and dysfunction of the vascular endothelium are critical events in the initiation and acceleration of atherosclerotic lesion formation. Our studies indicate that an increase in cellular oxidative stress and an imbalance in antioxidant status are critical events in PCB-mediated induction of inflammatory genes and endothelial cell dysfunction. We also have evidence that the plasma membrane microdomains called caveolae play an important role in endothelial activation and toxicity mediated by coplanar PCBs. Caveolae are particularly abundant in endothelial cells and play a major role in endothelial trafficking and the regulation of signaling pathways associated with the pathology of vascular diseases. There is a great need to further explore this nutritional paradigm in environmental toxicology and to improve our understanding of the relationship between nutrition and lifestyle, exposure to environmental toxins and disease. Our studies suggest that certain dietary fats can increase the risk of environmental insult induced by PCBs, while other dietary factors may provide protection. Nutrition may provide the most sensible means to develop primary intervention and prevention strategies of diseases associated with many environmental toxic insults.

High serum PCBs are associated with elevation of serum lipids and cardiovascular disease in a Native American population

We have investigated the relationships among the concentration of total serum polychlorinated biphenyls (PCBs), various PCB congener groupings, and three pesticides to total serum lipids in humans with and without self-reported cardiovascular disease. Blood samples were obtained from 335 adult Akwesasne Mohawks, and were analyzed for 101 PCB congeners, mirex, dichloro-diphenyl-dichloro-ethylene (DDE), and hexachlorobenzene (HCB), as well as serum triglycerides and cholesterol. Structural equation modeling, following the definition of latent variables by means of confirmatory factor analysis, was used to analyze the relationships between serum lipids with PCBs and heart disease. There were significant associations among PCBs, lipids, age, and body mass index (BMI), a fact which justified the application of the structural equation model. Gender of the participant was unrelated to any of the remaining study variables. The results of this study are consistent with a model in which age is considered as both an exogenous explanatory variable and a biological driving mechanism for the acquisition of PCBs. Moreover, the results of this study are consistent with the conclusion that PCBs, acting through P450 enzymes, are directly responsible for increased synthesis of cholesterol and triglycerides, substances known to be major risk factors for cardiovascular disease.

Environmental contaminants as risk factors for developing diabetes

The contribution of exposure to persistent organic pollutants (POPs) to the incidence of diabetes has received little attention until recently. A number of reports have emerged, however, concerning elevated diabetes in persons occupationally exposed to dioxin. United States (US) Air Force personnel in Vietnam who sprayed Agent Orange containing dioxin as a contaminant had elevated rates of diabetes, leading to US government compensation for diabetes in these veterans. Recent studies in populations exposed to polychlorinated biphenyls (PCBs) and chlorinated pesticides found a dose-dependent elevated risk of diabetes. An elevation in risk of diabetes in relation to levels of several POPs has been demonstrated by two different groups using the National Health and Nutrition Examination Survey (NHANES), a random sampling of US citizens. The strong associations seen in quite different studies suggest the possibility that exposure to POPs could cause diabetes. One striking observation is that obese persons that do not have elevated POPs are not at elevated risk of diabetes, suggesting that the POPs rather than the obesity per se is responsible for the association. Although a specific mechanism is not known, most POPs induce a great number and variety of genes, including several that alter insulin action. Because diabetes is a dangerous disease that is increasing in frequency throughout the world, further study of the possibility that exposure to POPs contributes to the etiology of diabetes is critical.

Diabetes in relation to serum levels of polychlorinated biphenyls and chlorinated pesticides in adult Native Americans

BACKGROUND

Recent research suggests that diabetes, a condition whose incidence is increasing, is associated with exposure to polychlorinated biphenyls (PCBs) and chlorinated pesticides.

OBJECTIVES

We investigated the potential association between diabetes and serum levels of PCBs, dichlorodiphenyldichloroethylene (DDE), hexachlorobenzene (HCB), and mirex in a cross-sectional study of an adult Native-American (Mohawk) population.

METHODS

Through a standardized questionnaire we collected demographic, medical, and lifestyle information from 352 adults, > or =30 years of age. We collected fasting serum samples that were analyzed for 101 PCB congeners, DDE, HCB, and mirex along with fasting glucose, triglycerides, and cholesterol. Participants who had fasting-glucose values > 125 mg/dL and/or who were taking antidiabetic medication were defined as persons with diabetes. We conducted logistic regression to assess the potential association between organochlorine serum levels and diabetes, while controlling for the potential confounding variables of age, body mass index (BMI), smoking, sex, and serum lipid levels. Organochlorine serum levels were categorized in tertiles, and the lowest tertile was used as the reference category.

RESULTS

The prevalence of diabetes was 20.2%. The odds ratio (OR) of having diabetes for participants in the highest tertile of total PCB concentration compared with the lowest tertile was 3.9 (95% confidence interval, 1.5-10.6). The corresponding ORs for DDE and HCB were even higher. Elevated serum mirex was not associated with diabetes. After adjustment for other analytes, the OR for HCB remained significant, whereas ORs for PCBs and DDE remained elevated but not statistically significant. In contrast, after adjustment for other analytes, the OR for mirex became statistically significant and indicated an inverse association.

CONCLUSIONS

In this study of adult Native Americans, elevated serum PCBs, DDE, and HCB were positively associated with diabetes after controlling for potential confounders, whereas a negative association was observed for mirex.

Increased rate of hospitalization for diabetes and residential proximity of hazardous waste sites

BACKGROUND

Epidemiologic studies suggest that there may be an association between environmental exposure to persistent organic pollutants (POPs) and diabetes.

OBJECTIVE

The aim of this study was to test the hypothesis that residential proximity to POP-contaminated waste sites result in increased rates of hospitalization for diabetes.

METHODS

We determined the number of hospitalized patients 25-74 years of age diagnosed with diabetes in New York State exclusive of New York City for the years 1993-2000. Descriptive statistics and negative binomial regression were used to compare diabetes hospitalization rates in individuals who resided in ZIP codes containing or abutting hazardous waste sites containing POPs ("POP" sites); ZIP codes containing hazardous waste sites but with wastes other than POPs ("other" sites); and ZIP codes without any identified hazardous waste sites ("clean" sites).

RESULTS

Compared with the hospitalization rates for diabetes in clean sites, the rate ratios for diabetes discharges for people residing in POP sites and "other" sites, after adjustment for potential confounders were 1.23 [95% confidence interval (CI), 1.15-1.32] and 1.25 (95% CI, 1.16-1.34), respectively. In a subset of POP sites along the Hudson River, where there is higher income, less smoking, better diet, and more exercise, the rate ratio was 1.36 (95% CI, 1.26-1.47) compared to clean sites.

CONCLUSIONS

After controlling for major confounders, we found a statistically significant increase in the rate of hospitalization for diabetes among the population residing in the ZIP codes containing toxic waste sites.

Multigenerational study of the hepatic effects exerted by the consumption of nonylphenol- and 4-octylphenol-contaminated drinking water in Sprague-Dawley rats

Our multigenerational study evaluates the hepatic effects of the xenoestrogens nonylphenol (NP), and 4-octylphenol (4OP) on male and female rats when they are exposed uninterruptedly, from conception to adult age, to tap water containing 25ppm of NP or 4OP. Our results showed that these compounds did not induce any change in liver/body weight ratio (relative liver weight, RLW). In the morphological analysis we did not find evident signs of cytotoxicity. The most relevant findings were the presence of both an increase in the apoptotic index and in the percentage of binuclear hepatocytes in livers from exposed animals. Additionally, our study revealed the presence of hepatocellular glycogenosis (mainly in 4OP-exposed rats): the type of glycogen accumulated was in aggregates (gamma-glycogen), a non-functional form of glycogen. This study demonstrates that, at levels close to those described in the environment, NP and 4OP are capable of inducing a number of hepatic effects, potentially related with adaptive, and/or metabolic alterations of liver tissue.

Hospitalization rates for coronary heart disease in relation to residence near areas contaminated with persistent organic pollutants and other pollutants

Exposure to environmental pollutants may contribute to the development of coronary heart disease (CHD). We determined the ZIP codes containing or abutting each of the approximately 900 hazardous waste sites in New York and identified the major contaminants in each. Three categories of ZIP codes were then distinguished: those containing or abutting sites contaminated with persistent organic pollutants (POPs), those containing only other types of wastes ("other waste"), and those not containing any identified hazardous waste site ("clean"). Effects of residence in each of these ZIP codes on CHD and acute myocardial infarction (AMI) hospital discharge rates were assessed with a negative binomial model, adjusting for age, sex, race, income, and health insurance coverage. Patients living in ZIP codes contaminated with POPs had a statistically significant 15.0% elevation in CHD hospital discharge rates and a 20.0% elevation in AMI discharge rates compared with clean ZIP codes. In neither of the comparisons were rates in other-waste sites significantly greater than in clean sites. In a subset of POP ZIP codes along the Hudson River, where average income is higher and there is less smoking, better diet, and more exercise, the rate of hospitalization for CHD was 35.8% greater and for AMI 39.1% greater than in clean sites. Although the cross-sectional design of the study prevents definite conclusions on causal inference, the results indirectly support the hypothesis that living near a POP-contaminated site constitutes a risk of exposure and of development of CHD and AMI.

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 (Sigma PCBs), Sigma DDTs, Sigma chlordanes, dieldrin, and mirex were determined in 44 fat biopsies and 48 blood samples. Blood concentrations of Sigma 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 Sigma 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 Sigma 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 (increasing blood urea nitrogen, decreasing albumin:globulin ratio), carbohydrate (decreasing glucose), and ion (increasing sodium, decreasing 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.

PCB 118 induces ultrastructural alterations in the rat liver

Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants that bioaccumulate in the food chain and thus pose a health risk to humans and other animals. In this study, PCB 118 was added to the diets of Sprague Dawley rats for 13 weeks in concentrations of 2, 20, 200, 2000 p.p.b. to the females and 10, 100, 1000 and 10000 p.p.b. to the males. The chemical was dissolved in corn oil; animals that served as the control received corn oil in the diets devoid of PCB. Use of transmission electron microscopy and stereology revealed significant (P<0.05) elevation in the mean volume fraction of smooth reticulum profiles (20 p.p.b.), peroxisomes (200, 2000 p.p.b.) and lipid droplets (2000 p.p.b.) in the females. Hepatocytes from the males exhibited a significant increase in the mean volume fraction of lipid droplets at 10000 p.p. b. (P<0.05). Interactions between large quantity of estrogen and the PCB probably would account for more profound alterations in the liver of female Sprague-Dawley rats than in the males.