Harold Schwartz

Development of a method for the analysis of PCB congeners and organochlorine pesticides in blood/serum.

A method for the determination of environmentally relevant PCB congeners and organochlorine pesticides in human blood/serum is described. The method is validated through recovery experiments with standards and reproducibility of quality control samples.

Congener specific analysis of toxaphene in serum using ECNI-MS

A method for the determination of environmentally relevant toxaphene congeners (eg chlorinated bornanes (CHBs)) in serum is described. Four chlorinated bornane congeners are predominant in serum.

Association between fish consumption, dietary omega-3 fatty acids and persistent organic pollutants intake, and type 2 diabetes in 18 First Nations in Ontario, Canada

BACKGROUND First Nations (FNs) populations in Canada experience a disproportionally higher rate of obesity and type 2 diabetes (T2D) compared to the general population. Recent data suggest that a high consumption of fish may help prevent T2D. On the other hand, fish might also be a potential source of environmental contaminants which could potentially be a risk factor for T2D. OBJECTIVE To investigate the potential associations between self-reported T2D and consumption of locally-harvested fish, dietary long-chain omega-3 fatty acids (n-3FAs) and persistent organic pollutants intake among adult FNs living on reserve in Ontario. DESIGN Data from the First Nations Food Nutrition and Environment Study, which included a cross-sectional study of 1429 Ontario FNs adults living in 18 communities across 4 ecozones in 2012 were analyzed. Social and lifestyle data were collected using household interviews. The consumption of locally-harvested fish was estimated using a traditional food frequency questionnaire along with portion size information obtained from 24hr recalls. Fish samples were analyzed for the presence of contaminants including dichlorodiphenyldichloroethylene (DDE) and polychlorinated biphenyls (PCBs). Dietary intakes of DDE and PCBs were estimated using community-specific levels of DDE/PCBs in fish species. Multiple logistic regression models adjusted for potential covariates including age, gender, body mass index, physical activity, total energy intake, smoking, and education were developed. RESULTS The prevalence of T2D in Ontario FNs was 24.4%. A significant positive association between fish consumption of one portion per week and more and T2D compared to no fish consumption was found (OR=2.5 (95% CI: 1.38-4.58). Dietary DDE and PCBs intake was positively associated with T2D (OR=1.09 (95%CI: 1.05-1.75) for DDE and OR=1.07 (95%CI: 1.004-1.27) for PCBs) per unit increase in DDE/PCBs while n-3-FAs intake, adjusted for DDE/PCBs intake, showed an inverse effect against T2D among older individuals (OR=0.86 (95% CI: 0.46-0.99). CONCLUSION Our results support previous findings that exposure to DDE and PCBs may increase the risk of T2D. Elevated levels of contaminants in fish may counteract with potentially beneficial effects of n-3FAs from fish consumption. However, the overall health benefits of high consumption of fish with a high n-3 FAs content may outweigh the adverse effect of contaminants.Background: First Nations (FNs) populations in Canada experience a disproportionally higher rate of obesity and type 2 diabetes (T2D) compared to the general population. Recent data suggest that a high consumption of fish may help prevent T2D. On the other hand, fish might also be a potential source of environmental contaminants which could potentially be a risk factor for T2D. Objective: To investigate the potential associations between self‐reported T2D and consumption of locally‐harvested fish, dietary long‐chain omega‐3 fatty acids (n‐3FAs) and persistent organic pollutants intake among adult FNs living on reserve in Ontario. Design: Data from the First Nations Food Nutrition and Environment Study, which included a cross‐sectional study of 1429 Ontario FNs adults living in 18 communities across 4 ecozones in 2012 were analyzed. Social and lifestyle data were collected using household interviews. The consumption of locally‐harvested fish was estimated using a traditional food frequency questionnaire along with portion size information obtained from 24hr recalls. Fish samples were analyzed for the presence of contaminants including dichlorodiphenyldichloroethylene (DDE) and polychlorinated biphenyls (PCBs). Dietary intakes of DDE and PCBs were estimated using community‐specific levels of DDE/PCBs in fish species. Multiple logistic regression models adjusted for potential covariates including age, gender, body mass index, physical activity, total energy intake, smoking, and education were developed. Results: The prevalence of T2D in Ontario FNs was 24.4%. A significant positive association between fish consumption of one portion per week and more and T2D compared to no fish consumption was found (OR=2.5 (95% CI: 1.38–4.58). Dietary DDE and PCBs intake was positively associated with T2D (OR=1.09 (95%CI: 1.05–1.75) for DDE and OR=1.07 (95%CI: 1.004–1.27) for PCBs) per unit increase in DDE/PCBs while n‐3‐FAs intake, adjusted for DDE/PCBs intake, showed an inverse effect against T2D among older individuals (OR=0.86 (95% CI: 0.46–0.99). Conclusion: Our results support previous findings that exposure to DDE and PCBs may increase the risk of T2D. Elevated levels of contaminants in fish may counteract with potentially beneficial effects of n‐3FAs from fish consumption. However, the overall health benefits of high consumption of fish with a high n‐3 FAs content may outweigh the adverse effect of contaminants. HighlightsPOPs exposure from fish consumption was positively associated with T2D.n‐3 fatty acids intake was negatively associated with T2D among older individuals.POPs concentrations in locally‐harvested fish need to be monitored.Dietary advice need to balance risk and benefits.

Congener specific analysis of polychlorinated biphenyls (PCBs) in serum using GC/MSD

A new congener specific method has been developed for extraction and quantitative determination of PCB contaminants of serum. After liquid-liquid extraction and chromatographic fractionation with Carbopack-C/florisil column, the analytes were identified and quantified utilizing gas chromatography/mass spectrometry (GC/MSD) using selected ion monitoring (SIM) technique. Recoveries of 35 non-planar PCB congeners (#18, 28, 31, 44, 49, 52, 60, 66, 74, 82, 87, 99, 101, 105, 110, 114, 118, 128, 138, 141, 146, 151, 153, 156, 157, 158, 167, 170, 171, 180, 183, 185, 187, 189 and 194) and 5 non-ortho (coplanar) congeners (#37, 77, 81, 126 and 169) from spiked serum were between 55-115%.

A total diet study and probabilistic assessment risk assessment of dietary mercury exposure among First Nations living on-reserve in Ontario, Canada

Abstract Methyl Mercury (MeHg) exposure is a global environmental health concern. Indigenous peoples around the world are susceptible to MeHg exposure from often higher fish consumption compared to general populations. The objective of this study was to estimate dietary exposure to methylmercury (MeHg) among First Nations living on‐reserve in the province of Ontario, Canada. A total diet study was constructed based on a 24‐h recall from the First Nations Food, Nutrition, and Environment Study (FNFNES), and measured contaminant concentrations from Health Canada for market foods, and FNFNES for traditional foods. A probabilistic assessment of annual and seasonal traditional food consumptions was conducted for 1429 adult participants. Results were compared to exposures in the general Canadian population and reference values from Health Canada for adults and women of childbearing age (ages 19–50). Results indicated traditional foods to be the primary contributor to the dietary total MeHg intake (72%). The average dietary total MeHg exposure in the First Nations population in Ontario (0.039 &mgr;g/kg/d) was 1.6 times higher than the general Canadian population; however, the majority (97.8%) of the population was below the reference values. Mercury concentrations in participants’ hair samples (n = 744) ranged from 0.03 to 13.54 &mgr;g/g, with an average of 0.64 &mgr;g/g (geometric average of 0.27 &mgr;g/g). Less than 1% of the population had a hair mercury value above the 6 &mgr;g/g level, and 1.3% of women of child bearing age had values greater than 2 &mgr;g/g. Fish species contributing to the MeHg intake included pickerel‐walleye, pike, perch and trout. Only 7.9% of the population met the recommended fish consumption rate of two, 3.5 oz servings per week from the American Heart Association. Therefore, consumption of lower trophic level fish can be promoted to provide the maximum nutritional benefit with minimal risk of MeHg exposure. HighlightsA total dietary MeHg exposure assessment was conducted for 1429 First Nations participants.Traditional foods contributed to 72% of the dietary MeHg intake.The average dietary MeHg was 0.039 &mgr;g/kg/d.The majority (97.8%) of the population was below the reference values.Only 7.9% of the population ate two servings of fish per week.

Risk assessment of dietary lead exposure among First Nations people living on-reserve in Ontario, Canada using a total diet study and a probabilistic approach

Indigenous peoples have elevated risk of lead (Pb) exposure as hunted traditional food can be contaminated with lead-containing ammunition. Recent scientific consensus states that there is no threshold level for Pb exposure. The objective of this study was to estimate dietary exposure to Pb among First Nations living on-reserve in the province of Ontario, Canada. A total diet study was constructed based on a 24-h recall and Pb concentrations for traditional foods from the First Nations Food, Nutrition, and Environment Study (FNFNES) and Pb concentrations in market foods from Health Canada. A probabilistic assessment of annual and seasonal traditional food consumption was conducted. Results indicate that traditional foods, particularly moose and deer meat. are the primary source of dietary Pb intake (73%), despite providing only 1.8% of the average caloric intake. The average dietary Pb exposure (0.21μg/kg/d) in the First Nations population in Ontario was 1.7 times higher than the dietary Pb exposure in the general Canadian population. Pb intake was associated with an estimated average increase in systolic blood pressure of 1.2mmHg. These results indicate that consumption of foods hunted with Pb containing ammunition and shot puts the population at elevated risk of Pb toxicity.

Partition coefficients of tetrachlorobenzene isomers between water and sodium dodecylsulfate micelles: relation to toxicity

Abstract Water-micelle partition coefficients for tetrachlorobenzenes were measured using a diffusion technique. The results show that the enchanced toxicity and tissue accumulation of the 1,2,4,5-isomer is not related to its lipophilicity.

The Relationship between Persistent Organic Pollutants Exposure and Type 2 Diabetes among First Nations in Ontario and Manitoba, Canada: A Difference in Difference Analysis

We previously studied the association between fish consumption and prevalence of type 2 diabetes (T2D) in Manitoba and Ontario First Nations (FNs), Canada and found different results. In this study, we used a difference in difference model to analyze the data. Dietary and health data from the First Nations Food Nutrition and Environment Study, a cross-sectional study of 706 Manitoba and 1429 Ontario FNs were analyzed. The consumption of fish was estimated using a food frequency questionnaire. Fish samples were analyzed for dichloro diphenyldichloro ethylene (DDE) and polychlorinated biphenyls (PCBs) content. Difference in difference model results showed that persistent organic pollutant (POP) exposure was positively associated with T2D in a dose-response manner. Stronger positive associations were found among females (OR = 14.96 (3.72–60.11)) than in males (OR = 2.85 (1.14–8.04)). The breakpoints for DDE and PCB intake were 2.11 ng/kg/day and 1.47 ng/kg/day, respectively. Each further 1 ng/kg/day increase in DDE and PCB intake increased the risk of T2D with ORs 2.29 (1.26–4.17) and 1.44 (1.09–1.89), respectively. Our findings suggest that the balance of risk and benefits associated with fish consumption is highly dependent on the regional POP concentrations in fish.