Mercury Contamination of Arctic Spiders and Insects

Mercury (Hg) is a contaminant of global concern because of its potential to biomagnify in food webs and cause adverse health effects in humans and wildlife. Mercury emitted in temperate and tropical regions can be transported to the Arctic where it is deposited across the landscape. After reaching aquatic systems, inorganic forms of Hg (IHg) can be methylated to the toxic and bioaccumulative form, methylmercury (MeHg). The High Arctic of Greenland comprises many low-lying aquatic ecosystems, primarily characterized by permafrost and snowmelt ponds and wetlands. Insects and their spider predators that live near these aquatic systems may accumulate concentrations of MeHg that pose a risk to insectivorous birds. The purpose of the present study was to assess Hg levels in Arctic insects and spiders from High Arctic aquatic systems. In summer 2022, 8,591 insects and 1,351 spiders were collected from eight locations in Northwest Greenland. Specimens were composited by collection site and taxa and analyzed for total Hg (IHg + MeHg). THg concentrations for all samples ranged from 57-1,100 µg/kg dry weight (dw), suggesting that some taxa had Hg concentrations that exceeded the previously published risk thresholds for insectivorous birds. This analysis will provide insight into the extent of mercury contamination in Arctic insects and spiders.