Human health risk assessment of metals exposure through subsistence foods consumption and subsistence harvest activities near a mining transport road in northwest Alaska

Historical transport of ore concentrate over a 50-mile haul road from the Red Dog zinc/lead mine in northwest Alaska to a seaport has been associated with elevated lead levels on moss growing near the road and with concerns about the safety of subsistence foods. As part of a comprehensive evaluation of potential impacts to human health and the environment from metals released during overland transport of ore concentrate, a human health risk assessment was conducted. Exposure to site-related metals through subsistence food consumption, water ingestion, and incidental soil ingestion was evaluated for three scenarios: child subsistence use, adult subsistence use, and adult combined occupational and subsistence use. The risk assessment used local subsistence food consumption data and subsistence harvest area information, along with metal concentrations from soil, water, caribou, fish, ptarmigan, berries, and sourdock collected on or near the road and port. The results, along with other lines of evidence, indicate that risks associated with subsistence food consumption and harvest activities are well within acceptable limits for each scenario and that subsistence foods remain safe to eat. Additionally, human health risks are not elevated even when data from restricted areas of the road and port are included.