Health risk assessment of inorganic arsenic exposure through fish consumption in Yellowknife, Northwest Territories, Canada

Yellowknife, Northwest Territories, Canada, is located near two closed gold mines. Elevated arsenic concentrations reported in fish are a public health concern. We collected 180 samples of three species of commonly consumed fish in 2013-2018 and analyzed arsenic species, including inorganic arsenic (As(III) and As(V)), monomethylarsonate (MMA), dimethylarsinic acid (DMA), and arsenobetaine. The average total arsenic concentration in fish muscle tissue was 2.30 +/- 1.72 mu g/g dry weight, and that in burbot liver tissue was 3.16 +/- 2.49 mu g/g dry weight. Nontoxic arsenobetaine was the main arsenic species in fish muscle (mean = 58.6 +/- 34.5%), whereas DMA was the predominant species in burbot liver (mean = 76.6 +/- 21.6%). On average, inorganic arsenic species accounted for less than 20% of the arsenic detected in fish. Data on the consumption of locally caught fish were collected from 1611 residents in Yellowknife in 2017 and 2018, including 1417 general residents and 194 members of the Yellowknives Dene First Nation. We evaluated the health risks from inorganic arsenic exposure using Monte Carlo simulations. Our results indicated that there were negligible non-cancer health risks, and the cancer risk was below the baseline cancer risk level of arsenic exposure among the Canadian general population.