Accumulation of organic contaminants in sentinel mallards utilizing confined disposal facilities at Hamilton Harbour, Lake Ontario, Canada

Abstract

Organochlorine analysis was performed on adult and juvenile farm-raised mallards (Anas platyrhynchos) released and collected at three experimental sites in southern Ontario: Hamilton Harbour Confined Disposal Facility (CDF); Winona Sewage Lagoons (SL); and Big Creek Marsh, Canada. Collections were scheduled at 10, 30, and 70 days after release. Hamilton Harbour CDF and Winona SL are known to be contaminated whereas Big Creek Marsh is a relatively clean, natural site. All sites are important resting and feeding areas for migratory and resident waterfowl. Breast muscle concentrations of polychlorobiphenyls (PCBs) in ducks collected 10 days after release (160.8 μg/kg, wet wt) at Hamilton Harbour CDF were more than 5300 times greater than day “0” birds (0.03 μg/kg). All ducks collected from Hamilton Harbour CDF had PCB concentrations exceeding Health and Welfare Canada and United States Food and Drug Administration (FDA) guidelines for edible poultry. Concentrations of DDE (216.9 μg/kg), hexachlorobenzene (0.9 μg/kg), dieldrin (1.9 μg/kg), and 1,2,4,5,-tetrachlorobenzene (24.9 μg/kg) were significantly elevated in ducks utilizing Winona SL. Concentrations of 1,2,3,4-tetrachlorobenzene, mirex, and photomirex were elevated at one or more of the sites. Ducks from Big Creek Marsh had lower contaminant concentrations than ducks from the other study sites. It is not clear whether bioaccumulation of organochlorines at these sites would pose a potential hazard to migratory and resident mallards; however, other duck species such as diving ducks that have more contact with sediments and sediment-derived foods would probably be at much higher risk.