| This investigation explores the selection of species and endpoints for monitoring contaminants in wildlife, and investigates the use of a specific sampling matrix—the feather—to assess dietary exposure to metallic and organic pollutants in a minimally invasive manner. Feather and blood samples of nestling black-crowned night-herons (BCNH; Nycticorax nycticorax) collected from Pea Patch Island, Delaware revealed elevated concentrations of aluminum, barium, iron, lead, magnesium, manganese, and mercury when compared to samples from Baltimore Harbor and Holland Island, Maryland (reference site). Because of its known deleterious effects on wildlife and the lack of controlled study in species other than waterfowl, lead was chosen from among these elements for further investigation into its distribution and effects in nestling BCNHs experimentally dosed in the field. Lead accumulated in feathers of 15-day old herons following intraperitoneal exposure ten days prior, and levels in feathers showed strong correlation with values in other internal organs. Furthermore, lead concentrations in feathers were associated with delta-aminolevulinic acid dehydratase depression and reduced tarsus growth rate. In a companion study, activity of cytochrome P450, a biomarker of organic contaminant exposure, was measured in developing feathers of mallards ( Anas platyrhynchos) and black ducks (Anas rubripes) treated with beta-napthoflavone, a known inducing agent. All methods of measuring induction in feather pulp (i.e., traditional enzyme assays, immunoblotting, and immunohistochemistry) gave results that corresponded with the incidence of induction in liver. Immunohistochemical staining proved to be a valid method of assessing P450 activity in a single wing, body, or tail feather, and was successfully used to detect induction in osprey tail feathers collected from a polluted site. Finally, indices were created to assess the utility of terrestrial vertebrate species in the biomonitoring of persistent organic pollutants, cholinesterase-inhibiting pesticides, mercury, lead shot, and petroleum crude oil, and to predict their vulnerability to each of these contaminants. Twenty-five species occurring on the North American Atlantic coast were ranked for each contaminant or contaminant class using Utility and Vulnerability Indices, incorporating elements of exposure potential, geographic occurrence, ease of collection, history of use in contaminant monitoring, sensitivity, and resilience of population. |
