Using a geographic information system to assess local scale methylmercury exposure from fish in nine communities of the Eeyou Istchee territory (James Bay, Quebec, Canada)

Exposure to methylmercury is a concern for those who rely on fish as a traditional food in the Eeyou Istchee territory of James Bay, Quebec, Canada, because industrial land uses overlap with community water bodies where fish are harvested. Consequently, this study assessed if traditional practices, particularly fishing, increased the risk of exposure to methylmercury from the consumption of locally harvested fish. We designed a geographic information system (GIS) that included land use and fish methylmercury tissue concentrations to assess clustering of potential hot spots. We also used generalized linear models to assess the association of fish consumption to blood organic-mercury concentrations, and logistic regression models to assess the probability of fish exceeding the safety threshold for methylmercury tissue concentrations in areas of high intensity land use. The GIS demonstrated significant clustered hot spots around regions of hydroelectric and mining land use. Our results also revealed that adult consumption of pike, lake trout and/or walleye, and child consumption of pike or walleye were significantly associated with blood organic-mercury concentrations. Further, large fish harvested in a community with high intensity land use yielded a 77% probability that the fish exceeded the safety threshold. From a human exposure perspective, our study highlights the need for further research on children who consume fish from this region

Subsistence fishing in the Eeyou Istchee (James Bay, Quebec, Canada): A regional investigation of fish consumption as a route of exposure to methylmercury

Fishing is part of the traditional activities of Indigenous people in Canada. However, it is also a route of exposure to methylmercury, a known neurotoxicant, and this is a concern for those who rely on fish as part of their diet. The probable weekly intake (PWI) of methylmercury from six species of fish was calculated for Indigenous community members (N = 1406), grouped by age and sex, and compared to Canadian and international provisional reference doses to assess exposure. Mixed-effects regression models were also used to estimate the input of methylmercury into the blood, and Hazard Quotients (HQ) were used to assess potential effects. Of the species of fish in our study, walleye and lake trout contributed the most to methylmercury intake. There was a positive association between the consumption of walleye and the total blood mercury concentrations of mercury in women and men (R2A = 0.40 and 0.47, respectively), and to a lesser extent, children. Similar results were observed for the consumption of lake trout. The 95th-percentile HQ for girls (3.16) and boys (3.18) from the consumption of lake trout was relatively high, and to a lesser extent, so was the HQ for walleye and pike. The consumption of some species of fish increases the exposure to methylmercury, however, taking a balanced approach, there are health benefits associated with the consumption of fish that must be considered. To mitigate future exposure to methylmercury, we recommend follow-up blood monitoring and local-geospatial-based assessments

Health measures of Eeyouch (Cree) who are eligible to participate in the on-the-land Income Security Program in Eeyou Istchee (northern Quebec, Canada)

Participation in on-the-land programs that encourage traditional cultural activities may improve health and well-being. The Income Security Program (ISP) - a financial incentive-based on-the-land program - for Eeyouch (Cree) hunters and trappers in Eeyou Istchee was created as a result of the 1975 James Bay and Northern Quebec Agreement to help mitigate the effects of hydroelectric development on the Cree people of northern Quebec, Canada. Beyond the ISP's financial incentives, little is known about the health measures of those who are eligible to participate in the ISP (i.e. spent ≥120 days on-the-land during the previous year). Therefore, this paper's objective was to assess the health measures of northern Quebec Cree, who were eligible for participation in the ISP

The self-reported behaviour of Iiyiyiu Aschii Cree and the worry about pollution from industrial and hydroelectric development in northern Quebec, Canada

Worry is influenced by environmental pollution and affects individual health and well-being; however, little is known about this association in Indigenous communities. Using logistic regression models, we examined self-reported responses among Cree adults to the question "Are you worried about the pollution of the environment (land, water or air) in Iiyiyiu Aschii?" to assess if increased worry was associated with proximity to industrial and hydroelectric development, whether increased worry was associated with self-reported behavioural changes of water consumption type in the community or bush, and days spent on-the-land. Proximity to multiple industrial and hydroelectric development sites was associated with increased worry about pollution. Notably, the decreased consumption of tap water in the community was significantly associated with increased worry, but time-on-the land was not. Overall, our study provides new findings concerning development in a Cree territory in northern Quebec, Canada, and the worry about pollution's association with self-reported behavioural changes.This work had financial contributions from the Niskamoon Corporation (agreement number 2005.06) and the Canadian Institutes of Health Research (FRN 156396)

Wood smoke black carbon from Indigenous traditional cultural activities in a subarctic Cree community

Indoor concentrations of black carbon (BC) were measured when wood was burned for traditional cultural activities in a study in a Cree community located in subarctic Canada. The study also included an intervention using a propane-fuelled heater to mitigate in situ BC. Mass concentrations of BC were measured in a game-smoking tent for 39 days and in hunting cabins on the west coast of James Bay, Canada, for 8 days. Five-minute averaged BC mass concentration (N = 12,319) data were recorded and assessed using optimised noise-reduction averaging. Mean BC mass concentrations were lower in hunting cabins (mean = 8.25 micrograms per cubic metre (µg m-3)) and higher in the game-smoking tent (mean = 15.46 µg m-3). However, excessive BC peaks were recorded in the game-smoking tent (maximum = 3076.71 µg m-3) when the fire was stoked or loaded. The intervention with the propane heater in a hunting cabin yielded a 90% reduction in measured BC mass concentrations. We do not presume that exposure to BC is of concern in hunting cabins with appropriate wood-burning appliances that are well-sealed and vent outside. In game-smoking tents, we advise that persons take intermittent breaks outside of the tent for fresh air

Complex environmental contaminant mixtures and their associations with thyroid hormones using supervised and unsupervised machine learning techniques

Evaluating complex mixtures and their associated health effects poses a challenge in human populations. Herein, we assess the association between 17 organic and metal contaminants in blood with thyroid hormones in a remote Indigenous (First Nations) region from Quebec, Canada (n=526). Using principal component analysis (PCA) to reduce the number of variables, we generated varimax rotated principal component (PC) loadings of contaminants on these uncorrelated synthetic axes. Associations with levels of thyroid hormones (TSH, free T4, and total T3) were conducted using multivariable linear regression methods with the participant PC loadings and adjusting for covariates. Additionally, Bayesian kernel machine regression (BKMR) analysis was used to evaluate the univariate contaminant exposure effect as well as the contaminant mixture effects on levels of thyroid hormones. Significant and positive associations were found between total T3 and PC-2 (high positive nickel and cadmium loadings), total T3 and PC-3 (negative association with negative loading for nickel and positive loading for cadmium) and TSH and PC-1 (high positive loadings for organic contaminants). No significant observations were observed for free T4. BKMR provided additional insight into the PCA results and suggested that nickel, and not cadmium, was responsible for driving the observed effects with this effect remaining when evaluating the entire mixture. BKMR analysis did not support the association of TSH with organic contaminants that were found in the PCA regression. Our findings reinforced other studies which showed that metals such as nickel may alter thyroid hormone levels and highlighted how complex environmental mixtures interact with each other. These observations represent an important step to determining how complex mixtures of contaminants can be assessed in human populations, especially those living a subsistence lifestyle who may have high body burdens of contaminants, and to help understand the resultant net effect of exposures on endogenous thyroid hormones utilizing novel machine learning statistical methods