Environmental contaminants assessment for frequently harvested migratory waterfowl in the Northeast Atlantic flyway.

Waterfowl serve as indicators of ecosystem health and represent a pathway of contaminant exposure for hunters who consume them. In the northeast Atlantic Flyway, data on baseline contaminant loads in waterfowl are lacking. We assessed five species of commonly harvested (and consumed) waterfowl for mercury, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans, polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and per- and polyfluoroalkyl substances (PFAS). We found that Canada geese (Branta canadensis) and wood ducks (Aix sponsa) had lower contaminant burdens than mallards (Anas platyrhynchos), American green-winged teal (Anas carolinensis), and American black ducks (Anas rubripes). Regardless of species, all samples contained detectable levels of PCBs and at least one OCP and PFAS. Mercury and OCPs posed limited non-cancer risks to human consumers who follow current waterfowl consumption advisories. Based on a probabilistic risk assessment, lower consumption rates were required to reduce risks from PCBs compared to other contaminants. Protective human consumption advisories depend in part on the level of allowable cancer risk and whether contaminants were considered toxicologically to act individually or collectively. Accordingly, revisions to consumption advisories to protect public hunter health given these new data hinge upon risk management decisions. These data can be used to update waterfowl consumption advisories in the northeast Atlantic Flyway and inform future research into the health effects of legacy and contemporary contaminants on the sustainability of waterfowl populations.