Fingerprinting PCB patterns among Mohawk women

An evidence map of polychlorinated biphenyl exposure and health outcome studies among residents of the Akwesasne Mohawk Nation

From the 1950s to the 1970s, three Superfund sites discharged polychlorinated biphenyl (PCB)-contaminated waste upstream of the Mohawk Nation at Akwesasne, resulting in PCB contamination of groundwater, soil, and sediment in the surrounding area. Given the persistence of PCBs in the environment and in human tissues, there are continued concerns regarding PCB exposures and the potential for adverse health effects in the community. We developed an evidence map of PCB research at Akwesasne in order to characterize the available data and to highlight potential research needs. Human health and exposure biomarker studies were identified from a literature search based on population, exposure, comparator, and outcome (PECO) criteria. Data extracted from references that met the inclusion criteria after full-text review included study characteristics (e.g., sample size, study design, sampling years), details on PCB measurements (e.g., analytical method, number of congeners analyzed, method detection limits), and results (e.g., PCB levels and summary of study conclusions). We identified 33 studies, conducted between 1986 and 2013, that examined PCB exposure characteristics and health effects in residents of the Akwesasne Mohawk Nation. Organizing this literature into an evidence map including information on study cohort, congener groupings, exposure biomarker characteristics, and health effects allowed us to identify research gaps and to suggest future research priorities for the community. We identified current PCB exposure levels and PCB source characterization as major uncertainties, both of which could be addressed by new studies of PCB concentrations in environmental media.

Public understanding of science and common sense: Social representations of the human microbiome among the expert and non-expert public

The aim of this investigation is to examine the structure and the content of different social groups' representations of the human microbiome. We employed a non-probabilistic sample comprising two groups of participants. The first group (n = 244) included university students. The second group included lay people (n = 355). We chose a mixed-method approach. The data obtained were processed using IRaMuTeQ software. The results allow us to identify the anchoring and objectification processes activated by the two different groups of interviewees. The results could be useful to those in charge of implementing campaigns aimed at promoting health literacy.

Spatio-Temporality and Tribal Water Quality Governance in the United States

Hydrosocial spatio-temporalities—aspects of water belonging to space, time, or space-time—are central to water governance, providing a framework upon which overall hydrosocial relations are constructed, and are fundamental to the establishment of values and central to socio-cultural-political relationships. Moreover, spatio-temporal conceptions may differ among diverse governing entities and across scales, creating “variability” through ontological pluralism, as well as power asymmetries embedded in cultural bias. This paper explores spatio-temporal conceptions related to water quality governance, an aspect of water governance often biased toward technical and scientific space-time conceptions. We offer examples of different aspects of spatio-temporality in water quality issues among Tribes in the United States, highlighting several themes, including spatiotemporal cycles, technological mediation, and interrelationship and fluidity. Finally, we suggest that because water is part of a dynamic network of space-times, water quality may be best governed through more holistic practices that recognize tribal sovereignty and hydrosocial variability.

An Extended Structure-Activity Relationship of Nondioxin-Like PCBs Evaluates and Supports Modeling Predictions and Identifies Picomolar Potency of PCB 202 Towards Ryanodine Receptors

Nondioxin-like polychlorinated biphenyls (NDL PCBs) activate ryanodine-sensitive Ca²⁺channels (RyRs) and this activation has been associated with neurotoxicity in exposed animals. RyR-active congeners follow a distinct structure-activity relationship and a quantitative structure-activity relationship (QSAR) predicts that a large number of PCBs likely activate the receptor, which requires validation. Additionally, previous structural based conclusions have been established using receptor ligand binding assays but the impact of varying PCB structures on ion channel gating behavior is not understood. We used [³H]Ryanodine ([³H]Ry) binding to assess the RyR-activity of 14 previously untested PCB congeners evaluating the predictability of the QSAR. Congeners determined to display widely varying potency were then assayed with single channel voltage clamp analysis to assess direct influences on channel gating kinetics. The RyR-activity of individual PCBs assessed in in vitro assays followed the general pattern predicted by the QSAR but binding and lipid bilayer experiments demonstrated higher potency than predicted. Of the 49 congeners tested to date, tetra-ortho PCB 202 was found to be the most potent RyR-active congener increasing channel open probability at 200 pM. Shifting meta-substitutions to the para-position resulted in a > 100-fold reduction in potency as seen with PCB 197. Non-ortho PCB 11 was found to lack activity at the receptor supporting a minimum mono-ortho substitution for PCB RyR activity. These findings expand and support previous SAR assessments; where out of the 49 congeners tested to date 42 activate the receptor demonstrating that the RyR is a sensitive and common target of PCBs.

Expression and function of ryanodine receptor related pathways in PCB tolerant Atlantic killifish (Fundulus heteroclitus) from New Bedford Harbor, MA, USA

Atlantic killifish (Fundulus heteroclitus) thrive in New Bedford Harbor (NBH), MA, highly contaminated with polychlorinated biphenyls (PCBs). Resident killifish have evolved tolerance to dioxin-like (DL) PCBs, whose toxic effects through the aryl hydrocarbon receptor (AhR) are well studied. In NBH, non-dioxin like PCBs (NDL PCBs), which lack activity toward the AhR, vastly exceed levels of DL congeners yet how killifish counter NDL toxic effects has not been explored. In mammals and fish, NDL PCBs are potent activators of ryanodine receptors (RyR), Ca(2+) release channels necessary for a vast array of physiological processes. In the current study we compared the expression and function of RyR related pathways in NBH killifish with killifish from the reference site at Scorton Creek (SC, MA). Relative to the SC fish, adults from NBH displayed increased levels of skeletal muscle RyR1 protein, and increased levels of FK506-binding protein 12 kDa (FKBP12) an accessory protein essential for NDL PCB-triggered changes in RyR channel function. In accordance with increased RyR1 levels, NBH killifish displayed increased maximal ligand binding, increased maximal response to Ca(2+) activation and increased maximal response to activation by the NDL PCB congener PCB 95. Compared to SC, NBH embryos and larvae had increased levels of mtor and ryr2 transcripts at multiple stages of development, and generations, while levels of serca2 were decreased at 9 days post-fertilization in the F1 and F2 generations. These findings suggest that there are compensatory and heritable changes in RyR mediated Ca(2+) signaling proteins or potential signaling partners in NBH killifish.

Cultural and health implications of fish advisories in a Native American community

INTRODUCTION

Fish advisories are issued in an effort to protect human health from exposure to contaminants, but Native American communities may suffer unintended health, social, and cultural consequences as a result of warnings against eating local fish. This paper focuses on the Mohawk community of Akwesasne, which lies downstream from a Superfund site, and explores how fish advisories have impacted fish consumption and health.

METHODS

65 Akwesasne community members were interviewed between March 2008 and April 2009. Interviews were semi-structured, lasted from 30-90 minutes and consisted of open-ended questions about the impacts of environmental contamination on the community. Detailed field notes were also maintained during extensive visits between 2007-2011. Interviews were transcribed, and these transcripts as well as the field notes were analyzed in NVivo 8.0. This research received approval from the Akwesasne Task Force on the Environment Research Advisory Committee, as well as the Brown University Institutional Review Board.

RESULTS

Three-quarters of the 50 Akwesasne Mohawks interviewed have ceased or significantly curtailed their local fish consumption due to the issuance of fish advisories or witnessing or hearing about deformities on fish. Many of these respondents have turned to outside sources of fish, from other communities or from grocery stores. This change in fish consumption concerns many residents because cultural and social connections developed around fishing are being lost and because fish has been replaced with high-fat high-carb processed foods, which has led to other health complications. One-quarter of the 50 interviewees still eat local fish, but these are generally middle-aged or older residents; fish consumption no longer occurs in the multi-generational social context it once did.

CONCLUSIONS

Human health in Native American communities such as Akwesasne is intimately tied to the health of the environment. Fish advisories should not be used as an institutional control to protect humans from exposure to contaminants; if Akwesasne are to achieve optimal health, the contaminated environment has to be remediated to a level that supports clean, edible fish.

Lower serum testosterone associated with elevated polychlorinated biphenyl concentrations in Native American men

BACKGROUND

Polychlorinated biphenyls (PCBs) and chlorinated pesticides are endocrine disruptors, altering both thyroid and estrogen hormonal systems. Less is known of action on androgenic systems.

OBJECTIVE

We studied the relationship between serum concentrations of testosterone in relation to levels of PCBs and three chlorinated pesticides in an adult Native American (Mohawk) population.

METHODS

We collected fasting serum samples from 703 adult Mohawks (257 men and 436 women) and analyzed samples for 101 PCB congeners, hexachlorobenzene (HCB), dichlorodiphenyldichloroethylene (DDE), and mirex, as well as testosterone, cholesterol, and triglycerides. The associations between testosterone and tertiles of serum organochlorine levels (both wet weight and lipid adjusted) were assessed using a logistic regression model while controlling for age, body mass index (BMI), and other analytes, with the lowest tertile being considered the referent. Males and females were considered separately.

RESULTS

Testosterone concentrations in males were inversely correlated with total PCB concentration, whether using wet-weight or lipid-adjusted values. The odds ratio (OR) of having a testosterone concentration above the median was 0.17 [95% confidence interval (CI), 0.05-0.69] for total wet-weight PCBs (highest vs. lowest tertile) after adjustment for age, BMI, total serum lipids, and three pesticides. The OR for lipid-adjusted total PCB concentration was 0.23 (95% CI, 0.06-0.78) after adjustment for other analytes. Testosterone levels were significantly and inversely related to concentrations of PCBs 74, 99, 153, and 206, but not PCBs 52, 105, 118, 138, 170, 180, 201, or 203. Testosterone concentrations in females are much lower than in males, and not significantly related to serum PCBs. HCB, DDE, and mirex were not associated with testosterone concentration in either men or women.

CONCLUSIONS

Elevation in serum PCB levels is associated with a lower concentration of serum testosterone in Native American men.

Congener profiles of occupational PCB exposure versus PCB exposure from fish consumption

The composition of polychlorinated biphenyl (PCB) congeners in serum samples is compared between a cohort previously exposed to PCBs from working at a capacitor plant (n=180) and a cohort of Great Lakes sport-caught fish eaters (n=217). Fourteen congeners were measured in both samples. A multiple logistic regression model differentiating the two groups as a function of relative proportions amongst congeners 74, 138, 153, 180, and 201 correctly classifies more than 99% of the people (395/397); higher proportions of congeners 74, 153, and 201 characterize capacitor plant workers, while higher proportions of congeners 138 and 180 characterize fish eaters. The pattern is driven by the relative amounts of 74+153+201 compared to 138+180; all of the fish eaters, but only 5% of the capacitor plant workers, have a greater percent of 138+180 than 74+153+201. Consideration of combinations of congener levels and their relative proportions is relevant to tracking route of exposure and may also be relevant to modeling effects on health outcomes.

Environmental and occupational exposures and serum PCB concentrations and patterns among Mohawk men at Akwesasne

A study was conducted to address the question of how fish consumption, occupation, and outdoor air affected serum PCB concentrations and congener patterns among 139 Native American men living near three hazardous waste sites. They were interviewed about their residential, occupational, and dietary histories, and donated 20 ml of venous blood for congener-specific PCB analysis. The similarity in the congener pattern between that found in the serum and that detected in local environmental samples was measured by calculating the Euclidean distance between them. The results indicated that serum PCB concentrations were positively associated with cumulative lifetime exposures to PCBs from local fish consumption and occupation. However, participants who lived in the last 10 years at Raquette Point, which is the area of the Reserve closest to the hazardous waste sites and the only location where elevated levels of PCBs were found in outdoor air, did not have higher serum PCB concentrations than participants who lived elsewhere at Akwesasne. Regarding pattern matching, Mohawk men with the greatest cumulative lifetime exposure to PCBs from local fish consumption had a serum PCB congener pattern that more closely resembled that in fish caught off-shore from one of the hazardous waste sites than did men who ate less local fish. Similarly, Mohawk men who were occupationally exposed to PCBs were more likely than those without occupational exposure to have a serum PCB congener pattern that was similar to that of Aroclor 1248, the commercial PCB mixture used locally. The serum PCB congener pattern of Raquette Point residents more closely resembled the pattern in outdoor air only if the men ate relatively few local fish. The study is among the first to demonstrate that outdoor air may affect serum PCB congener patterns, at least in the absence of heavy fish consumption.

PCBs and cognitive functioning of Mohawk adolescents

This paper reports on the relationships between the cognitive functioning and PCB current body burdens of adolescents in the Mohawk Nation of Akwesasne where there is concern about industrial pollution of the environment. Three cognitive tests (Woodcock Johnson-Revised, Test of Memory and Learning, and Ravens Progressive Matrices) provide 13 subtests that allow a variety of cognitive outcomes to be assessed. A summary measure of PCB level was created from the congeners detected in at least 50% of the participants. The most notable finding was the significant negative relationship between PCB levels and two separate measures of long term memory. There was also a negative relationship with a measure of comprehension and knowledge. Significant relationships were not large, but provide evidence of subtle negative effects of PCB exposure.

Does long term residency near industry have an impact on the body burden of polychlorinated dibenzo-p-dioxins, furans, and polychlorinated biphenyls in older women?

BACKGROUND

For the retrospective study of environment and health linkages biomarkers of exposure are required. Polychlorinated dibenzo-dioxins and furans (PCDD/F) and polychlorinated biphenyls (PCBs) have been useful markers in some settings. This is the first study of PCDD/F body burden in a population based sample from the UK.

AIMS AND METHODS

The authors aimed to investigate whether long term residents close to a heavy chemical industrial complex (Teesside, UK) had a higher body burden and distinct pattern of PCDD/F and PCBs. We measured current levels of PCDD/F and PCBs in a population based sample of older women (mean 64 years, range 42-79 years). Forty women were recruited, 20 living near (zone A: 0.1-2.7 km) and 20 distant (zone C: 5-40 km) from industry during 2000-03. The authors ascertained occupational exposure to lung carcinogens, residential history, consumption of local produce, breast feeding, diet, and height and weight.

RESULTS

The mean body burden measured on lipid basis in ng/kg for the whole sample was: WHO-TEQ (PCDD/Fs): 29.9, 2378TCDD: 4.0, PCB 118:16200, PCB156: 13100. Body burdens were similar to others reported from industrialised countries, except that mean 2378TCDD was slightly higher. Mean ages, body mass index, and lifelong dietary patterns were similar in both zones. The authors found no significant difference in mean body burden levels between zones A and C before or after adjustment for covariates. All congener patterns were consistent with an urban background pattern, and there was no significant difference between congener compositions in the two zones. The TCDD body burden increased with age with accelerated increments above age 70.

CONCLUSION

Long term residency near heavy and chemical industry did not have an effect on women's body burden of PCDD/Fs and PCBs on Teesside, UK. The body burden of PCDD/F and PCBs was not a suitable biomarker for chronic, non-occupational exposure to industrial air pollution.

Polychlorinated biphenyl (PCB) exposure assessment by multivariate statistical analysis of serum congener profiles in an adult Native American population

The major determinants of human polychlorinated biphenyl (PCB) body burden include the source and route of exposure and the toxicokinetic processes occurring after uptake. However, the relative importance of each factor for individual subjects cannot currently be determined. The present study characterizes levels and patterns of PCB congeners in a large cohort of adult Akwesasne Mohawks with historical PCB exposure. Total serum PCB ranged from 0.29 to 48.32 ng/g and was higher in adult men than in women (median of 3.81 vs. 2.94 ng/g). The mean serum congener profile for the full cohort was dominated by persistent penta- to hepta-chlorinated biphenyls; several labile congeners were also prominent. In order to provide additional information on individual body burden determinants, multivariate exploratory data analysis techniques were applied to the congener-specific serum PCB data. A self-training receptor model, polytopic vector analysis (PVA), was employed to determine the number, composition, and relative proportions of independent congener patterns that contributed to the overall serum PCB profile for each Mohawk subject. PVA identified five such patterns, each of which was characterized by a unique mix of congeners. One pattern observed in a limited number of Mohawks was similar to those reported for air sampled near contaminated sediment deposits at Akwesasne and for volatilized Aroclor 1248 and is hypothesized to reflect recent inhalation exposure in these subjects. A second pattern was consistent with unaltered Aroclor 1254. A third pattern, resembling Aroclor 1262 but without labile congeners, was correlated with age and is interpreted as representing a lifetime PCB accumulation profile. The final two patterns were dominated by subsets of major persistent congeners and are hypothesized to reflect intermediate bioaccumulation profiles and/or differences in individual toxicokinetics. The results confirm the utility of a multivariate exploratory analysis approach to congener-specific PCB data and provide additional insight into the exposure and individual factors that determine PCB body burden in this population.

Using biomarkers to characterise contaminant exposure among eaters of Great Lakes and St. Lawrence River fish

Analyses of xenobiotics in human tissues are used to screen individuals whose habits or environments put them at high risk of overexposure, for the surveillance of exposure patterns over time and between places, and as part of research to identify the sources and pathways of exposure in a population. Both study goals and technical considerations should guide the choice of which xenobiotics to sample and in which tissues. Understanding the absorption and distribution of the specific compound to be measured is essential to the choice of when to sample and how to interpret results. Laboratory quality is of major concern. A particular issue in the statistical treatment of results are those near to the laboratory's detection limit. Theoretical concepts are discussed in the context of studies of xenobiotic exposure among eaters of Great Lakes and St. Lawrence River sport fish.