Regionally representative hair mercury levels in Canadian First Nations adults living on reserves

Constantine Tikhonov,Amy Ing,Tonio Sadik,Hing Man Chan,Malek Batal,Harold Schwartz,Lesya Marushka,Karen Fediuk

doi:10.17269/s41997-021-00508-5

Abstract

ObjectiveThe primary objective of this participatory study was to assess the current body burden of mercury among First Nations adults.MethodsThe First Nations Food, Nutrition and Environment Study (2008–2018) collected regionally representative data from First Nations adults living on reserves south of the 60th parallel. Mercury was analyzed in hair as a preferred biomarker for prolonged exposure. Hair samples, a 5 mm bundle cut from the occipital region, were collected from the participants who gave consent and measured for total mercury concentrations using cold vapor atomic fluorescence spectrophotometry.ResultsIn total, 3404 First Nations adults living in 92 communities provided hair samples. This represents 52.5% of the respondents to the household surveys. The mean hair mercury concentrations were 0.56 μg/g among all participants and 0.34 μg/g among women of childbearing age (WCBA). There were 64 exceedances of Health Canada’s mercury biomonitoring guidelines (44 WCBA, 8 women aged 51+ years, 3 men aged 19–50 years, and 9 men aged 51+ years).ConclusionCurrent mercury exposure no longer presents a significant clinical health risk in most of the First Nations population south of the 60th parallel across Canada. However, mercury exposure continues to be an ongoing environmental public health concern that requires continued monitoring and assessment. Women of childbearing age (19–50 years) and older individuals living in northern ecozones and Quebec have higher mercury exposures, often exceeding Health Canada’s guidelines. Careful risk communication and risk management programs need to focus on northern ecozones and Quebec.

Highlights

Mercury (Hg) is widely spread and persistent in the environment (AMAP/UN Environment, 2019)
Mercury component estimation weights were calculated for each region based on the data on hair mercury samples
The FNFNES mercury biomonitoring results, especially for the British Columbia region, appear similar to the First Nations Biomonitoring Initiative (AFN, 2013), which was led by the Assembly of First Nations, in collaboration with First Nations and Inuit Health Branch (FNIHB), and developed the first national estimate of the body burden of 97 environmental chemicals, including total mercury (Table 4)

Summary

Introduction

Mercury (Hg) is widely spread and persistent in the environment (AMAP/UN Environment, 2019). Hg is emitted by natural sources such as forest fires, volcanoes, and geologic deposits. Anthropogenic sources, including coal-burning, metals smelting, gold and silver mining, and chlor-alkali production using mercury or mercury compounds, can emit equal amounts or even more Hg in the environment (UN Environment, 2013, 2019). Anthropogenic emissions, in gaseous elemental form, are relatively stable in the atmosphere (Kim et al, 2016; Ma et al, 2019). Mercury can be transported by air currents over very long distances and deposited on the landscape and in the ocean, where it is further transformed into different chemical forms (ECCC, 2016; Schroeder & Munthe, 1998)

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