Mechanistic modeling of persistent organic pollutant exposure among Indigenous Arctic populations: motivations, challenges, and benefits

Indigenous Arctic populations experience elevated exposures to many environmental contaminants compared to groups residing in southern Canada. This is largely due to consumption of traditional foods, some of which (ringed seals, beluga whales, narwhals, etc.) have relatively high concentrations of persistent organic pollutants. Models of contaminant fate, transport, and bioaccumulation represent powerful tools to explore this exposure issue, wherein combined models can be used to mechanistically and dynamically describe the entire sequence of events linking chemical emissions into the environment to ultimate contaminant concentrations in indigenous Arctic populations. In this review, various approaches adapted and applied to understanding indigenous Arctic contaminant exposure are explored, including early models describing body burdens in single traditional food species to more recent approaches holistically examining uptake and bioaccumulation in entire food chains. The applications of these models are also discussed, including attempts to i) identify chemical properties favouring transport to, and bioaccumulation in, the Arctic, ii) clarify the main determinants of temporal trends observed in indigenous Arctic biomonitoring, iii) explore the impacts of permanent and temporary dietary transitions on current and future indigenous Arctic contaminant exposures, and iv) correlate modeled early-life pollutant exposures with measured health impacts. The review demonstrates the effectiveness of mechanistic model approaches in investigating indigenous Arctic contaminant exposure, and confirms their utility in continued improvements to understanding associated risk in this unique population context.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Solubilities of acidic pesticides in water and liquid and supercritical carbon dioxide

The potential of supercritical fluid technology for water analysis has been recognized for nearly a decade. In an effort to broaden the knowledge required to implement methods for the direct extraction of water samples, we have investigated the partitioning of chlorinated, acidic pesticides and phenols between water and carbon dioxide. A high-pressure stainless steel extraction vessel with on-line HPLC detection was constructed for solubility and partitioning experiments. The solubility of pentachlorophenol in both water and liquid CO2 was determined at ambient temperatures as a function of pressure. A solubility isotherm was also constructed at 28.1°C for CO2. Solubility isotherms of 2,4-dichlorophenoxyacetic acid in liquid and supercritical (SC) CO2 have been measured at (21.0, 26.3, and 34.8) °C. Naphthalene solubility in SC CO2 was measured at 34.7°C and compared with literature values to ensure correct function of the apparatus. Measurements were performed at pressures up to 250 bar

Future human health research directions for the Canadian Northern Contaminants Program

Studies conducted in the mid-1980s and early 1990s demonstrated that persistent organic pollutants (POPs) and metals were reaching the Arctic ecosystem at unexpectedly high levels, many of which had no Arctic or Canadian sources. Epidemiological and toxicological studies in Canada and in other countries have found that these contaminants may pose a risk to human health. The objective of this paper is to provide the foundation for the discussion on future northern human health research under the Northern Contaminants Program (NCP) in Canada. This short discussion of human health priorities will help guide a path forward for future northern human health research in Canada to address on-going and new health concerns related to contaminants exposure in the Canadian Arctic