Predictors of serum dioxin, furan, and PCB concentrations among women from Chapaevsk, Russia

Determinants of exposure to polychlorinated biphenyls in the Italian population in the last decades

Polychlorinated biphenyls (PCBs) are industrial products extensively used in the past. Because of their widespread presence and toxic effects, the international community adopted control measures to reduce their release into the environment. Currently, PCB concentrations are decreasing, but humans are still exposed. In this paper, we reported the results of a study concerning PCB concentrations in human serum samples collected in Italy over two decades. The aim of the study was to investigate the trend of major determinants of PCB human exposure, several decades after the end of their production. PCB concentrations ranged over three orders of magnitude (from 0.4 to 958 ng/g lipid), with a median value of 85 ng/g lipid. We identified age, sampling year, body mass index, sex, and living near hot spots or being occupationally exposed as relevant factors in determining body burden. Our results can give indications to refine regulatory policies on PCBs in Italy, with particular attention to the disposal of residue PCB-containing products. To improve control measures can further decrease the exposure of citizens to PCBs, limit health implications, and improve citizens' perception about chemical risk management.

Correlates of Persistent Endocrine-Disrupting Chemical Mixtures among Reproductive-Aged Black Women

Black women are exposed to multiple endocrine-disrupting chemicals (EDCs), but few studies have examined their profiles of exposure to EDC mixtures. We identified biomarker profiles and correlates of exposure to EDC mixtures in a cross-sectional analysis of data from a prospective cohort study of 749 Black women aged 23-35 years. We quantified plasma concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), organochlorine pesticides (OCPs), and per- and polyfluoroalkyl substances (PFAS) in nonfasting samples collected at baseline. Demographic, behavioral, dietary, and reproductive covariates were also collected at baseline. We used k-means clustering and principal component analysis (PCA) to describe concentration profiles of EDC mixtures (17 PCBs, 6 PBDEs, 4 OCPs, 6 PFAS), followed by multinomial logistic and multivariable linear regression to estimate mean differences in PCA scores (β) and odds ratios (ORs) of cluster membership with their respective 95% confidence intervals (CIs). Older age (per 1 year increase: β = 0.47, CI = 0.39, 0.54; OR = 1.27, CI = 1.20, 1.35), lower body mass index (per 1 kg/m2 increase: β = -0.14, CI = -0.17, -0.12; OR = 0.91, CI = 0.89, 0.94), and current smoking (≥10 cigarettes/day vs never smokers: β = 1.37, CI = 0.20, 2.55; OR = 2.63, CI = 1.07, 6.50) were associated with profiles characterized by higher concentrations of all EDCs. Other behaviors and traits, including dietary factors and years since last birth, were also associated with EDC mixtures.

Human Biomonitoring of Environmental and Occupational Exposures by GC-MS and Gas Sensor Systems: A Systematic Review

Environmental chemicals and contaminants coming from multiple external sources enter the human body, determining a potential risk for human health. Human biomonitoring (HBM), measuring the concentrations of biomarkers in human specimens, has become an emerging approach for assessing population-wide exposure to hazardous chemicals and health risk through large-scale studies in many countries. However, systematic mapping of HBM studies, including their characteristics, targeted hazardous pollutants, analytical techniques, and sample population (general population and occupationally exposed workers), has not been done so far. We conducted a systematic review of the literature related to airborne hazardous pollutants in biofluids to answer the following questions: Which main chemicals have been included in the literature, which bodily fluids have been used, and what are the main findings? Following PRISMA protocol, we summarized the publications published up to 4 February 2021 of studies based on two methods: gas-chromatography/mass spectrometry (GC/MS) and electronic noses (e-noses). We screened 2606 records and 117 publications were included in the analysis, the most based on GC/MS analysis. The selected HBM studies include measurements of biomarkers in different bodily fluids, such as blood, urine, breast milk, and human semen as well as exhaled air. The papers cover numerous airborne hazardous pollutants that we grouped in chemical classes; a lot of hazardous and noxious compounds, mainly persistent organic pollutants (POPs) and volatile organic compounds (VOCs), have been detected in biological fluids at alarming levels. The scenario that emerged from this survey demonstrates the importance of HBM in human exposure to hazardous pollutants and the need to use it as valid tool in health surveillance. This systematic review represents a starting point for researchers who focus on the world of pollutant biomonitoring in the human body and gives them important insights into how to improve the methods based on GC/MS. Moreover, it makes a first overview of the use of gas sensor array and e-noses in HBM studies.

Biomonitoring of the adult population living near the waste incinerator of Turin: Serum concentrations of PCDDs, PCDFs, and PCBs after three years from the plant start-up

In September 2013 a waste-to-energy (WTE) incinerator located in the Turin area (Piedmont, Northern Italy) started to produce energy by the incineration of municipal solid wastes. The plant, one of the largest WTE incinerator in Europe, burns up to 490,000 tons of waste per year. A health surveillance program was implemented in order to evaluate the potential health effects on the population living near the plant. This program included a biomonitoring study aimed at assessing levels of several environmental contaminants including, among others, PCDDs, PCDFs, and PCBs. Before the WTE incinerator start-up (T₀), a group of 85 subjects (41 "exposed" and 44 "not exposed" subjects) was randomly selected for enrollment by the local health units among individuals aged 36-50 years who had been living in the same area for at least five years prior to the study. Subjects were balanced by exposure area, sex and five-year age classes. As from the study design, the same cohort was re-evaluated after three years of incinerator activity (T₂). A parallel study was conducted on a group of 12 farmers living and/or working in farms located in an area in the range of 5 km around the incinerator. Results of this study did not evidence any impact of the WTE plant on human exposure to PCDDs, PCDFs, and PCBs. In fact, no significant differences were found in the concentrations of PCDDs + PCDFs, DL-PCBs, and NDL-PCBs measured in the population group residing near the plant after three years of activity (T₂) with respect to the control group. A significant decrease of serum concentrations of all the analytes was observed at T₂ in both groups compared to T₀. Serum concentrations of PCDDs, PCDFs, and PCBs in the group of farmers were higher than those observed in the adult population under study.

Freshwater seal as a source of direct and indirect increased human exposure to persistent organic pollutants in a background area

The aim of the study is to investigate POP levels in environmental media (air, snow, soil and sediment), certain food items in the Olkhon district (Irkutsk Region, Russia) and Lake Baikal seal (nerpa) fat and meat in order to define the main pathways of elevated human exposure to POPs in the area. POP levels in soil and air samples and in almost all of the food items from the Olkhon district were comparable to levels in background areas of the Lake Baikal region. Only certain chicken eggs, large fish and blubber of nerpa pups exceeded maximum permissible levels of ΣDDTs and ΣHCHs. The combination of elevated levels of POPs in the Baikal nerpa with the use of Baikal nerpa fat (traditional nutritional habits, feed additives, as well as medicine for humans and domestic animals) results in two pathways for POPs to enter the human body: from seals it enters the human body directly, and indirectly from seals to poultry and livestock and then to the human body. Several scenarios of human exposure to POPs including the incidental ingestion of soil, inhalation of air, and ingestion of food were considered. The largest part of POPs enters the human organism through chicken eggs followed by fish and cow's milk in the scenario without the consumption of nerpa meat and blubber. The high consumption rate of fish as well as the consumption of the fat of nerpa pups or melted fat of nerpa increases the daily intake of POPs 1.3-11 times. The indexes of non-cancer risk and total cancer risk were assessed for residents of the Olkhon district and compared with indexes of risk for the average population of Irkutsk Region. Limiting the use of nerpa fat and meat as food and feed supplement reduces the potential human health risk.

Predictors of plasma polychlorinated biphenyl concentrations among reproductive-aged black women

Polychlorinated biphenyls (PCBs) are a class of lipophilic endocrine-disrupting chemicals with wide industrial use in the U.S. from the 1930s through 1977. Due to their environmental and biological persistence, low levels of PCBs remain detected in wildlife and humans. Although U.S. studies have shown higher serum PCB concentrations among Black women compared with White women, studies of correlates of PCB exposure among Black women are scarce. We examined predictors of plasma PCB concentrations in a cross-sectional analysis of baseline data from a prospective cohort study of 1693 premenopausal Black women aged 23-35 years from Detroit, Michigan (2010-2012). We collected demographic, behavioral, dietary, and medical data via self-administered questionnaires, telephone interviews, and in-person clinic visits, as well as non-fasting blood samples. We measured concentrations of 24 PCB congeners in baseline plasma from a subset of 762 participants. We used linear regression for log-transformed lipid-adjusted PCB concentrations to calculate percentage differences across levels of selected predictors. We did this separately for individual PCBs, sum of total PCBs, and sum of PCBs by degree of chlorination and hormonal activity. PCB concentrations were positively associated with age, duration of urban residence, cigarette smoking, heavy alcohol intake, and being breastfed in infancy, and inversely associated with body mass index (BMI) and lactation duration. The strength of some associations varied by degree of chlorination. For example, a 5-kg/m² higher BMI corresponded to a 2.9% lower summed concentration of tri- and tetra-substituted PCBs (95% CI -4.6%, -1.2%), an 8.3% lower summed concentration of penta- and hexa-substituted PCBs (95% CI -10.0%, -6.5%), and a 12.1% lower summed concentration of hepta-, octa-, nona-, and deca-substituted PCBs (95% CI -13.7%, -10.4%). Likewise, associations for age and being breastfed in infancy were stronger for higher-chlorinated PCBs. Results agree with studies on predictors of PCB body burdens, few of which include large numbers of Black women.

Long-term airborne dioxin exposure and breast cancer risk in a case-control study nested within the French E3N prospective cohort

BACKGROUND

Dioxins, Group 1 carcinogens, are emitted by industrial chlorinated combustion processes and suspected to increase breast cancer risk through receptor-mediated pathways.

OBJECTIVES

We estimated breast cancer risk associated with airborne dioxin exposure, using geographic information system (GIS) methods and historical exposure data.

METHODS

We designed a case-control study (429 breast cancer cases diagnosed between 1990 and 2008, matched to 716 controls) nested within the E3N (Etude Epidémiologique auprès de femmes de la Mutuelle Générale de l'Education Nationale) cohort. Airborne dioxin exposure was assessed using a GIS-based metric including participants' residential history, technical characteristics of 222 dioxin sources, residential proximity to dioxin sources, exposure duration and wind direction. Odds ratios (OR) and 95% confidence intervals (CI) associated with quintiles of cumulative exposure were estimated using multivariate logistic regression models.

RESULTS

We observed no increased risk of breast cancer for higher dioxin exposure levels overall and according to hormone-receptor status. We however observed a statistically significant OR for Q2 versus Q1 overall (1.612, 95% CI: 1.042-2.493) and for estrogen-receptor (ER) positive breast cancer (1.843, 95% CI: 1.033-3.292).

CONCLUSIONS

Overall, as well as according to hormone-receptor status, no increased risk was observed for higher airborne dioxin exposure. The increased risk for low exposure levels might be compatible with non-monotonic dose-response relationship. Confirmation of our findings is required. Our GIS-based metric may provide an alternative in absence of ambient dioxin monitoring and may allow assessing exposure to other pollutants.

Dioxins levels in human blood after implementation of measures against dioxin exposure in Japan

Background

Over the past few decades, the Japanese Ministry of the Environment has been biomonitoring dioxins in the general Japanese population and, in response to public concerns, has taken measures to reduce dioxin exposure. The objectives of this study were to assess the current dioxin dietary intake and corresponding body burden in the Japanese and compare Japanese dioxin data from 2011 to 2016 and 2002–2010 surveys. We also examined the relationship between blood dioxins and health parameters/clinical biomarkers.

Methods

From 2011 to 2016, cross-sectional dioxin surveys were conducted on 490 Japanese (242 males and 248 females, aged 49.9 ± 7.6 years) from 15 Japanese prefectures. Blood (n = 490) and food samples (n = 90) were measured for 29 dioxin congeners including polychlorinated dibenzo-para-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (Co-PCBs) using gas chromatography coupled with high-resolution mass spectrometry. Using the 2006 World Health Organization toxic equivalence factors, the toxic equivalents (TEQs) were calculated. Clinical biomarkers and anthropometric parameters were also measured and information on lifestyle behaviours collected. Data imputations were applied to account for blood dioxins below the detection limit.

Results

The median (95% confidence interval or CI) blood levels and dioxin dietary intake was respectively 9.4 (8.8–9.9) pg TEQ/g lipid and 0.3 (0.2–0.4) pg TEQ/kg body weight/day. The median blood dioxin level in the 2011–2016 survey was found to have decreased by 41.3% compared to the 2002–2010 surveys. Participants who were older were found to be more likely to have higher dioxin levels. Blood dioxins were also significantly associated with body mass index, triglycerides, docosahexaenoic acid, eicosapentaenoic acid, and dihomo-gamma-linoleic acid levels in blood. Furthermore, associations between blood dioxin and dietary dioxin intake were evident in the unadjusted models. However, after adjusting for confounders, blood dioxins were not found to be associated with dietary dioxin intake.

Conclusions

Blood dioxin levels declined over the past decade. This study showed that the measures and actions undertaken in Japan have possibly contributed to these reductions in the body burden of dioxins in the Japanese population.

Electronic supplementary material

The online version of this article (10.1186/s12199-018-0755-7) contains supplementary material, which is available to authorized users.

Risk for animal and human health related to the presence of dioxins and dioxin-like PCBs in feed and food

The European Commission asked EFSA for a scientific opinion on the risks for animal and human health related to the presence of dioxins (PCDD/Fs) and DL-PCBs in feed and food. The data from experimental animal and epidemiological studies were reviewed and it was decided to base the human risk assessment on effects observed in humans and to use animal data as supportive evidence. The critical effect was on semen quality, following pre- and postnatal exposure. The critical study showed a NOAEL of 7.0 pg WHO2005-TEQ/g fat in blood sampled at age 9 years based on PCDD/F-TEQs. No association was observed when including DL-PCB-TEQs. Using toxicokinetic modelling and taking into account the exposure from breastfeeding and a twofold higher intake during childhood, it was estimated that daily exposure in adolescents and adults should be below 0.25 pg TEQ/kg bw/day. The CONTAM Panel established a TWI of 2 pg TEQ/kg bw/week. With occurrence and consumption data from European countries, the mean and P95 intake of total TEQ by Adolescents, Adults, Elderly and Very Elderly varied between, respectively, 2.1 to 10.5, and 5.3 to 30.4 pg TEQ/kg bw/week, implying a considerable exceedance of the TWI. Toddlers and Other Children showed a higher exposure than older age groups, but this was accounted for when deriving the TWI. Exposure to PCDD/F-TEQ only was on average 2.4- and 2.7-fold lower for mean and P95 exposure than for total TEQ. PCDD/Fs and DL-PCBs are transferred to milk and eggs, and accumulate in fatty tissues and liver. Transfer rates and bioconcentration factors were identified for various species. The CONTAM Panel was not able to identify reference values in most farm and companion animals with the exception of NOAELs for mink, chicken and some fish species. The estimated exposure from feed for these species does not imply a risk.

Determinants of serum organochlorine pesticide and polychlorinated biphenyl levels in middle-aged Korean adults

The serum levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were measured in a middle-aged Korean population and investigated associations with age, gender, body mass index (BMI), metabolic syndrome (MS), type 2 diabetes mellitus (T2DM), and dietary habits. The median concentrations of 22 OCPs and 34 PCBs in the serum samples were 483 and 216 ng g^-1 lipid, respectively. The most abundant compound was p,p'-DDE, followed by PCB 153, β-HCH, PCB 118, and PCB 180. The results of multiple linear regression and other statistical analyses revealed that serum OCP and PCB levels were higher in women and were positively correlated with age. BMI was positively associated with serum OCP and PCB levels, reflecting the influence of food intake and the preserving effect of body fat. MS and T2DM were significantly associated with serum OCP and PCB levels. The intake of animal foods had positive associations with serum OCP and PCB levels, whereas the intake of phytogenic foods showed negative associations, presumably because of contamination levels in food items and food matrices that governs absorption and excretion of OCPs and PCBs in the body. The relationship between dietary habits and serum OCP and PCB levels were different in participants with MS compared to healthy participants, suggesting MS may alter the influence of food intake on serum OCP and PCB levels.

Secondary sex ratio in relation to exposures to polychlorinated biphenyls, dichlorodiphenyl dichloroethylene and methylmercury

This study was undertaken to assess the potential impact of maternal exposures to polychlorinated biphenyl (PCB), dichlorodiphenyl dichloroethylene (DDE) and methylmercury on the secondary sex ratios (the ratio of male to female live births) over a span of 23 years. The study includes prospective data from three Faroese birth cohorts, with a total of 2,152 healthy mother–child dyads recruited between 1986 and 2009. The Faroe Islands is a subarctic fishing community, where pilot whale meat and blubber are part of the traditional marine diet. Exposures were measured in maternal hair, serum or umbilical cord blood. Confounder adjusted logistic regression models were used to assess the associations between maternal exposures and the secondary sex ratio. A doubling in ΣPCB, p,p’-DDE and mercury concentrations were associated with increased odds by 8% (95% CI = 0–16%), 7% (95% CI = 0–14%) and 9% (95% CI = 2–17%), respectively, of giving birth to a boy. In conclusion, maternal exposure to ΣPCB, DDE and methylmercury was associated with a slightly increased secondary sex ratio. The impact of paternal exposures could not be taken into account and deserves attention.

Changes in serum dioxin and PCB levels in residents around a municipal waste incinerator in Bilbao, Spain

There is a great concern in the Basque Country regarding emissions from waste incineration, in particular that of organochlorines (OCs), including dioxins, furans and polychlorinated biphenyls (PCBs), and their potential effect on human health. In 2005, a municipal solid waste plant (MSWP) started to operate in Bilbao, representing an opportunity to assess the exposure to the aforementioned pollutants among people living at various distances from the plant. In 2006 and 2008, we carried out two cross-sectional studies to quantify and assess changes in levels of these pollutants. The objective of this study was to describe the levels of OCs in the blood serum in 2013 of 127 adults of this prospective cohort, in four centres of population, near to and further away from the MSWP, and to study trends over time since it started to operate. This study shows the levels of OCs have decreased significantly, from 37.2% to 80.1%. Further, levels of OCs in areas near to the MSWP were not found to be higher than those in areas further afield.

The association of peripubertal serum concentrations of organochlorine chemicals and blood lead with growth and pubertal development in a longitudinal cohort of boys: a review of published results from the Russian Children's Study

Organochlorine chemicals and lead are environmental exposures that have endocrine disrupting properties (EDCs) which interfere with many aspects of hormone action. Childhood and adolescence are windows of susceptibility for adverse health effects of EDCs. Our ongoing study, the Russian Children's Study (RCS), is one of the few longitudinal studies investigating the impact of EDCs on growth and puberty in boys. It is conducted in the historically contaminated city of Chapaevsk, in the Samara region. The study focuses on evaluating the associations of persistent organochlorine chemicals and lead with growth and pubertal timing. At enrollment in 2003-2005, we collected blood from 516 boys at ages 8-9 years to measure dioxins, furans, polychlorinated biphenyls (PCBs), chlorinated pesticides and lead. At enrollment and at annual visits through the ages of 18-19 years, a physician performed physical examinations that included pubertal staging and testicular volume measurements. We review the history of Chapaevsk as a research site and summarize published RCS data on the association of peripubertal serum concentrations of organochlorines and blood lead levels with growth, pubertal onset and sexual maturity. Overall, we found that persistent organochlorines and lead negatively affected growth during puberty. Our results also suggest that total toxic equivalents (TEQs), dioxin-like compounds, organochlorine pesticides and lead may delay, while nondioxin-like-PCBs may advance, the timing of male puberty. These findings promoted remediation programs in Chapaevsk, with improvement in health indicators, resulting in Chapaevsk being designated a member of the World Health Organization (WHO) network "Healthy Cities" in 2015.

Determinants of plasma PCB, brominated flame retardants, and organochlorine pesticides in pregnant women and 3 year old children in The Norwegian Mother and Child Cohort Study

BACKGROUND

Exposure to persistent organic pollutants (POPs) during prenatal and postnatal life has been extensively studied in relation to adverse health effects in children.

OBJECTIVES

The aim was to identify determinants of the concentrations of polychlorinated biphenyls (PCBs), brominated flame retardants (polybrominated diphenyl ethers, PBDEs; polybrominated biphenyl, PBB), and organochlorine pesticides (OCPs) in blood samples from pregnant women and children in The Norwegian Mother and Child Cohort Study (MoBa).

METHODS

Blood samples were collected from two independent subsamples within MoBa; a group of women (n=96) enrolled in mid-pregnancy during the years 2002-2008 and a group of 3 year old children (n=99) participating during 2010-2011. PCB congeners (74, 99, 138, 153, 180, 170, 194, 209, 105, 114, 118, 156, 157, 167, and 189), brominated flame retardants (PBDE-28, 47, 99, 100, 153, 154, and PBB-153), as well as the OCPs hexachlorobenzene (HCB), oxychlordane, 4,4'dichlorodiphenyltrichloroethane (DDT), and 4,4'dichlorodiphenyldichloroethylene (DDE) were measured in both pregnant women and children.

RESULTS

Age, low parity, and low pre-pregnant BMI were the most important determinants of increased plasma concentrations of POPs in pregnant women. In 3 year old children, prolonged breastfeeding duration was a major determinant of increased POP concentrations. Estimated dietary exposure to PCBs during pregnancy was positively associated with plasma concentrations in 3 year old children, but not in pregnant women. Plasma concentrations were approximately 40% higher in children compared to pregnant women.

CONCLUSIONS

Several factors associated with exposure and toxicokinetics, i.e. accumulation, excretion and transfer via breastmilk of POPs were the main predictors of POP levels in pregnant women and children. Diet, which is the main exposure source for these compounds in the general population, was found to predict PCB levels only among children. For the PBDEs, for which non-dietary sources are more important, toxicokinetic factors appeared to have less predictive impact.

My Winding Road: From Microbiology to Toxicology and Environmental Health

I would certainly never have predicted that I would become the director of the National Institute of Environmental Health Sciences (NIEHS) and the National Toxicology Program (NTP) when I was a Jewish girl growing up in Teaneck, New Jersey. My family stressed the importance of education. Yet for a girl there were many not-so-subtle suggestions that the appropriate careers were in teaching or nursing, and the most important thing was to be a wife and mother. Well, I can't disagree with the latter, although I would have to add grandmother to that list of achievements. My parents were both college graduates, but my mom only taught high school English for one year before leaving the field to start our family. My dad returned from World War II and joined his brother in accounting. After my first sister was born, my father joined my mother's family jewelry business and helped to open a second retail store. My mother helped my dad out during the busy times—Christmas and wedding season—but otherwise focused on our growing family of three girls and one boy. This became increasingly challenging when it became clear that my little brother was severely retarded and would require extra care.

The spatial distribution of human exposure to PCBs around a former production site in Slovakia

We evaluated concentrations of 15 PCB congeners in blood serum of 2047 adults, 431 8-9-year old children and 1134 mother-child pairs born in 2001-2003. These subjects were long-standing residents living up to 70 km (to the north) and up to 50 km (to the south) of the former Chemko Strážske PCB production facility in the Michalovce district of Slovakia. We plotted serum concentration against distance from the plant both with and without consideration of the direction of their homes from the site. The decrease in exposure with distance could be described by an exponential function which was dependent on direction and climatic parameters. By kriging we created maps depicting predicted isoconcentration contours for sex- and age-adjusted serum concentration of ∑PCBs for the same group of children, adults and mothers. The principle of our risk analysis was to relate serum concentration data, reflecting PCB body burden, using the critical concentrations established by the French Agency for Food, Environmental and Occupational Health & Safety (ANSES 2010) as thresholds below which the probability of effects on health is regarded as negligible. We conclude that 10 years ago, around 200,000 residents were at risk in this densely populated area. Exposure has since decreased but the mechanism for this has not yet been studied.

Predictors of serum polychlorinated biphenyl concentrations in Anniston residents

The Anniston Community Health Survey was a community-based cross-sectional study of Anniston, Alabama, residents who live in close proximity to a former PCB production facility to identify factors associated with serum PCB levels. The survey comprises 765 Anniston residents who completed a questionnaire interview and provided a blood sample for analysis in 2005-2007. Several reports based on data from the Anniston survey have been previously published, including associations between PCB exposure and diabetes and blood pressure. In this study we examine demographic, behavioral, dietary, and occupational characteristics of Anniston survey participants as predictors of serum PCB concentrations. Of the 765 participants, 54% were White and 45% were African-American; the sample was predominantly female (70%), with a mean age of 55 years. Serum PCB concentrations varied widely between participants (range for sum of 35 PCBs: 0.11-170.4 ng/g wet weight). Linear regression models with stepwise selection were employed to examine factors associated with serum PCBs. Statistically significant positive associations were observed between serum PCB concentrations and age, race, residential variables, current smoking, and local fish consumption, as was a negative association with education level. Age and race were the most influential predictors of serum PCB levels. A small age by sex interaction was noted, indicating that the increase in PCB levels with age was steeper for women than for men. Significant interaction terms indicated that the associations between PCB levels and having ever eaten locally raised livestock and local clay were much stronger among African-Americans than among White participants. In summary, demographic variables and past consumption of locally produced foods were found to be the most important predictors of PCB concentrations in residents living in the vicinity of a former PCB manufacturing facility.

Combined impact of lead, cadmium, polychlorinated biphenyls and non-chemical risk factors on blood pressure in NHANES

High blood pressure is associated with exposure to multiple chemical and non-chemical risk factors, but epidemiological analyses to date have not assessed the combined effects of both chemical and non-chemical stressors on human populations in the context of cumulative risk assessment. We developed a novel modeling approach to evaluate the combined impact of lead, cadmium, polychlorinated biphenyls (PCBs), and multiple non-chemical risk factors on four blood pressure measures using data for adults aged ≥ 20 years from the National Health and Nutrition Examination Survey (1999-2008). We developed predictive models for chemical and other stressors. Structural equation models were applied to account for complex associations among predictors of stressors as well as blood pressure. Models showed that blood lead, serum PCBs, and established non-chemical stressors were significantly associated with blood pressure. Lead was the chemical stressor most predictive of diastolic blood pressure and mean arterial pressure, while PCBs had a greater influence on systolic blood pressure and pulse pressure, and blood cadmium was not a significant predictor of blood pressure. The simultaneously fit exposure models explained 34%, 43% and 52% of the variance for lead, cadmium and PCBs, respectively. The structural equation models were developed using predictors available from public data streams (e.g., U.S. Census), which would allow the models to be applied to any U.S. population exposed to these multiple stressors in order to identify high risk subpopulations, direct intervention strategies, and inform public policy.

Predictors of serum chlorinated pesticide concentrations among prepubertal Russian boys

BACKGROUND

Few studies have evaluated predictors of childhood exposure to organochlorine pesticides (OCPs), a class of lipophilic persistent chemicals.

OBJECTIVES

Our goal was to identify predictors of serum OCP concentrations-hexachlorobenzene (HCB), β-hexachlorocyclohexane (β-HCH), and p,p-dichlorodiphenyldichloroethylene (p,p´-DDE)-among boys in Chapaevsk, Russia.

METHODS

Between 2003 and 2005, 499 boys 8-9 years of age were recruited in a prospective cohort. The initial study visit included a physical examination; blood collection; health, lifestyle, and food-frequency questionnaires; and determination of residential distance from a local factory complex that produced HCB and β-HCH. Fasting serum samples were analyzed for OCPs at the U.S. Centers for Disease Control and Prevention. General linear regression models were used to identify predictors of the boys' serum HCB, β-HCH, and p,p´-DDE concentrations.

RESULTS

Among 355 boys with OCP measurements, median serum HCB, β-HCH, and p,p´-DDE concentrations were 158, 167, and 284 ng/g lipid, respectively. Lower body mass index, longer breastfeeding duration, and local dairy consumption were associated with higher concentrations of OCPs. Boys who lived < 2 km from the factory complex had 64% (95% CI: 37, 96) and 57% (95% CI: 32, 87) higher mean HCB and β-HCH concentrations, respectively, than boys who lived ≥ 5 km away. Living > 3 years in Chapaevsk predicted higher β-HCH concentrations, and having parents who lacked a high school education predicted higher p,p´-DDE concentrations.

CONCLUSIONS

Among this cohort of prepubertal Russian boys, predictors of serum OCPs included consumption of local dairy products, longer local residence, and residential proximity to the local factory complex.

PCBs and OH-PCBs in serum from children and mothers in urban and rural U.S. communities

East Chicago, Indiana is a heavily industrialized community bisected by the Indiana Harbor and Ship Canal, which volatilizes ~7.5 kg/yr polychlorinated biphenyls (PCBs). In contrast, the rural Columbus Junction, Iowa area has no known current or past PCB industrial sources. Blood from children and their mothers from these communities were collected April 2008 to January 2009 (n = 177). Sera were analyzed for all 209 PCBs and 4 hydroxylated PCBs (OH-PCBs). Sum PCBs ranged from nondetect to 658 ng/g lw (median = 33.5 ng/g lw). Sum OH-PCBs ranged from nondetect to 1.2 ng/g fw (median = 0.07 ng/g fw). These concentrations are similar to those reported in other populations without high dietary PCB intake. Differences between the two communities were subtle. PCBs were detected in more East Chicago mothers and children than Columbus Junction mothers and children, and children from East Chicago were enriched in lower-molecular weight PCBs. East Chicago and Columbus Junction residents had similar levels of total and individual PCBs and OH-PCBs in their blood. Concentrations of parent PCBs correlated with concentrations of OH-PCBs. This is the first temporally and methodologically consistent study to evaluate all 209 PCBs and major metabolites in two generations of people living in urban and rural areas of the United States.

Residential proximity to industrial combustion facilities and risk of non-Hodgkin lymphoma: a case-control study

BACKGROUND

Residence near municipal solid waste incinerators, a major historical source of dioxin emissions, has been associated with increased risk of non-Hodgkin lymphoma (NHL) in European studies. The aim of our study was to evaluate residence near industrial combustion facilities and estimates of dioxin emissions in relation to NHL risk in the United States.

METHODS

We conducted a population-based case-control study of NHL (1998-2000) in four National Cancer Institute-Surveillance Epidemiology and End Results centers (Detroit, Iowa, Los Angeles, Seattle). Residential histories 15 years before diagnosis (similar date for controls) were linked to an Environmental Protection Agency database of dioxin-emitting facilities for 969 cases and 749 controls. We evaluated proximity (3 and 5 km) to 10 facility types that accounted for >85% of U.S. emissions and a distance-weighted average emission index (AEI [ng toxic equivalency quotient (TEQ)/year]).

RESULTS

Proximity to any dioxin-emitting facility was not associated with NHL risk (3 km OR = 1.0, 95% CI 0.8-1.3). Risk was elevated for residence near cement kilns (5 km OR = 1.7, 95% CI 0.8-3.3; 3 km OR = 3.8, 95% CI 1.1-14.0) and reduced for residence near municipal solid waste incinerators (5 km OR = 0.5, 95% CI 0.3-0.9; 3 km OR = 0.3, 95% CI 0.1-1.4). The AEI was not associated with risk of NHL overall. Risk for marginal zone lymphoma was increased for the highest versus lowest quartile (5 km OR = 2.6, 95% CI 1.0-6.8; 3 km OR = 3.0, 95% CI 1.1-8.3).

CONCLUSIONS

Overall, we found no association with residential exposure to dioxins and NHL risk. However, findings for high emissions and marginal zone lymphoma and for specific facility types and all NHL provide some evidence of an association and deserve future study.

Genetic modification of the association between peripubertal dioxin exposure and pubertal onset in a cohort of Russian boys

BACKGROUND

Exposure to dioxins has been associated with delayed pubertal onset in both epidemiologic and animal studies. Whether genetic polymorphisms may modify this association is currently unknown. Identifying such genes could provide insight into mechanistic pathways. This is one of the first studies to assess genetic susceptibility to dioxins.

OBJECTIVES

We evaluated whether common polymorphisms in genes affecting either molecular responses to dioxin exposure or pubertal onset influence the association between peripubertal serum dioxin concentration and male pubertal onset.

METHODS

In this prospective cohort of Russian adolescent boys (n = 392), we assessed gene-environment interactions for 337 tagging single-nucleotide polymorphisms (SNPs) from 46 candidate genes and two intergenic regions. Dioxins were measured in the boys' serum at age 8-9 years. Pubertal onset was based on testicular volume and on genitalia staging. Statistical approaches for controlling for multiple testing were used, both with and without prescreening for marginal genetic associations.

RESULTS

After accounting for multiple testing, two tag SNPs in the glucocorticoid receptor (GR/NR3C1) gene and one in the estrogen receptor-α (ESR1) gene were significant (q < 0.2) modifiers of the association between peripubertal serum dioxin concentration and male pubertal onset defined by genitalia staging, although not by testicular volume. The results were sensitive to whether multiple comparison adjustment was applied to all gene-environment tests or only to those with marginal genetic associations.

CONCLUSIONS

Common genetic polymorphisms in the glucocorticoid receptor and estrogen receptor-α genes may modify the association between peripubertal serum dioxin concentration and pubertal onset. Further studies are warranted to confirm these findings.

Development and validation of prediction models for blood concentrations of dioxins and PCBs using dietary intakes

BACKGROUND

Dioxins and PCBs accumulate in the food chain and might exert toxic effects in animals and humans. In large epidemiologic studies, exposure estimates of these compounds based on analyses of biological material might not be available or affordable.

OBJECTIVES

To develop and then validate models for predicting concentrations of dioxins and PCBs in blood using a comprehensive food frequency questionnaire and blood concentrations.

METHODS

Prediction models were built on data from one study (n=195), and validated in an independent study group (n=66). We used linear regression to develop predictive models for dioxins and PCBs, both sums of congeners and 33 single congeners (7 and 10 polychlorinated dibenzo-p-dioxins and furans (PCDDs/PCDFs), 12 dioxin-like polychlorinated biphenyls (PCBs: 4 non-ortho and 8 mono-ortho), sum of all the 29 dioxin-like compounds (total TEQ) and sum of 4 non dioxin-like PCBs (∑ CB-101, 138, 153, 183=PCB(4)). We used the blood concentration and dietary intake of each of the above as dependent and independent variables, while sex, parity, age, place of living, smoking status, energy intake and education were covariates. We validated the models in a new study population comparing the predicted blood concentrations with the measured blood concentrations using correlation coefficients and Weighted Kappa (К(W)) as measures of agreement, considering К(W)>0.40 as successful prediction.

RESULTS

The models explained 78% (sum dioxin-like compounds), 76% (PCDDs), 76% (PCDFs), 74% (no-PCBs), 69% (mo-PCBs), 68% (PCB(4)) and 63% (CB-153) of the variance. In addition to dietary intake, age and sex were the most important covariates. The predicted blood concentrations were highly correlated with the measured values, with r=0.75 for dl-compounds 0.70 for PCB(4), (p<0.001) and 0.66 (p<0.001) for CB-153. К(W) was 0.68 for sum dl-compounds 0.65 for both PCB(4) and CB-153. Out of 33 congeners 16 (13dl-compounds and 3 ndl PCBs) had К(W)>0.40.

CONCLUSIONS

The models developed had high power to predict blood levels of dioxins and PCBs and to correctly rank subjects according to high or low exposure based on dietary intake and demographic information. These models underline the value of dietary intake data for use in investigations of associations between dioxin and PCB exposure and health outcomes in large epidemiological studies with limited biomaterial for chemical analysis.

Effects of a chitosan intake on the fecal excretion of dioxins and fat in rats

We evaluated the effects of the intake of various dietary fibers on the fecal excretion of dioxins in rats. The rats were fed five types of dietary fiber diets, including a chitosan diet and control diet, for 20 d and then dioxins (120 ng/rat) were orally administered on day 15. The excretion of fecal dioxins was significantly higher in the chitosan group than in the control group, and dioxin excretion was positively correlated with fecal fat excretion. A comparison of the different types of chitosan showed that the efficacy of chitosan for fecal fat excretion was partly related to its viscosity. The chitosan intake promoted fecal dioxin excretion when the rats were exposed to highly toxic dioxins, and this excretion of fecal dioxins was related to the fecal fat excretion, suggesting that chitosan might be useful for reducing the adverse effects caused by lipophilic xenobiotics.

Dioxin and polychlorinated biphenyl concentrations in mother's serum and the timing of pubertal onset in sons

BACKGROUND

Animal studies have demonstrated that timing of pubertal onset can be altered by prenatal exposure to dioxins or polychlorinated biphenyls (PCBs), but studies of human populations have been quite limited.

METHODS

We assessed the association between maternal serum concentrations of dioxins and PCBs and the sons' age of pubertal onset in a prospective cohort of 489 mother-son pairs from Chapaevsk, Russia, a town contaminated with these chemicals during past industrial activity. The boys were recruited at ages 8 to 9 years, and 4 years of annual follow-up data were included in the analysis. Serum samples were collected at enrollment from both mothers and sons for measurement of dioxin and PCB concentrations using high-resolution mass spectrometry. The sons' pubertal onset--defined as pubertal stage 2 or higher for genitalia (G) or pubic hair (P), or testicular volume >3 mL--was assessed annually by the same physician.

RESULTS

In multivariate Cox models, elevated maternal serum PCBs were associated with earlier pubertal onset defined by stage G2 or higher (4th quartile hazard ratio = 1.7 [95% confidence interval = 1.1- 2.5]), but not for stage P2 or higher or for testicular volume >3 mL. Maternal serum concentrations of dioxin toxic equivalents were not consistently associated with the sons' pubertal onset, although a dose-related delay in pubertal onset (only for G2 or higher) was seen among boys who breast-fed for 6 months or more.

CONCLUSIONS

Maternal PCB serum concentrations measured 8 or 9 years after sons' births--which may reflect sons' prenatal and early-life exposures--were associated with acceleration in some, but not all, measures of pubertal onset.

Temporal trends in serum concentrations of polychlorinated dioxins, furans, and PCBs among adult women living in Chapaevsk, Russia: a longitudinal study from 2000 to 2009

BACKGROUND

The present study assessed the temporal trend in serum concentrations of polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls (PCBs) among residents of a Russian town where levels of these chemicals are elevated due to prior industrial activity.

METHODS

Two serum samples were collected from eight adult women (in 2000 and 2009), and analyzed with gas chromatography-high-resolution mass spectrometry.

RESULTS

The average total toxic equivalency (TEQ) decreased by 30% (from 36 to 25 pg/g lipid), and the average sum of PCB congeners decreased by 19% (from 291 to 211 ng/g lipid). Total TEQs decreased for seven of the eight women, and the sum of PCBs decreased for six of eight women. During this nine year period, larger decreases in serum TEQs and PCBs were found in women with greater increases in body mass index.

CONCLUSIONS

This study provides suggestive evidence that average serum concentrations of dioxins, furans, and PCBs are decreasing over time among residents of this town.