Lead, mercury and other metal(loids) in Bald Eagles (Haliaeetus leucocephalus, kitpu) in Nova Scotia (Mi’kma’ki)

Abstract

Multiple tissues and feather types from seven adult male bald eagles (Haliaeetus leucocephalus, kitpu) were analysed for lead, mercury, arsenic, selenium, uranium and other elements via ICP-MS and direct mercury analyzer. Lead concentrations were consistently highest in bone tissue. Mercury concentrations were most elevated in organ tissues (heart, liver, kidney) but did not exceed published toxicity thresholds for large birds. Molar concentrations of selenium (Se) and mercury (Hg) for all tissues are correlated, and molar Hg:Se ratios were below published demethylation thresholds for waterbird mercury toxicity. Even so, it is recommended that eagle nestlings be monitored for mercury, given their higher vulnerability. Arsenic concentrations were detected in muscle, heart, kidney and liver tissues, but not in feathers, blood or bone. Uranium was measurable in all feather matrices, but not in any soft tissues or bone. Neither arsenic nor uranium were at concentrations of concern. Feather types exhibited consistent patterns, with the smaller nape feathers being below or close to detection limits for most elements. Primary, secondary and tertiary flight feathers from the seven sampled eagles were consistent in having more detectable element concentrations. To date, this dataset is among the very few to compare multiple tissues and feather types for a wide range of environmentally and biologically important elements for bald eagles.

Keywords: arsenic, blood, bone, feather, metals, mercury, muscle, organs