Assessing trace-metal exposure to American dippers in mountain streams of southwestern British Columbia, Canada

Abstract

To develop a suitable biomonitor of metal pollution in watersheds, we examined trends in exposure to nine trace elements in the diet (benthic invertebrates and fish), feathers (n = 104), and feces (n = 14) of an aquatic passerine, the American dipper (Cinclus mexicanus), from the Chilliwack watershed in British Columbia, Canada. We hypothesized that key differences may exist in exposure to metals for resident dippers that occupy the main river year-round and altitudinal migrants that breed on higher elevation tributaries because of differences in prey metal levels between locations or possible differences in diet composition. Metals most commonly detected in dipper feather samples in decreasing order were Zn > Cu > Hg > Se > Pb > Mn > Cd > Al > As. Resident dipper feathers contained significantly higher mean concentrations of mercury (0.64 microg/g dry wt), cadmium (0.19 microg/g dry wt), and copper (10.8 microg/g dry wt) relative to migrants. Mass balance models used to predict daily metal exposure for dippers with different diets and breeding locations within a watershed showed that variation in metal levels primarily was attributed to differences in the proportion of fish and invertebrates in the diet of residents and migrants. In comparing predicted metal exposure values to tolerable daily intakes (TDI), we found that most metals were below or within the range of TDI, except selenium, aluminum, and zinc. Other metals, such as cadmium, copper, and arsenic, were only of concern for dippers mainly feeding on insects; mercury was only of concern for dippers consuming high fish diets. The models were useful tools to demonstrate how shifts in diet and breeding location within a single watershed can result in changes in exposure that may be of toxicological significance.

Environmental contaminants in excrement of Iowa's nesting and wintering Bald Eagles (Haliaeetus leucocephalus)

“…These results can serve as a baseline for comparison with future studies of contaminant exposure in Bald Eagles across Iowa as well in other locations. The contaminant levels we observed in excrement samples collected from Bald Eagles were within the range of concentrations reported in other avian species (Ek et al 2004, Morrissey et al 2005, Tiller et al 2005, Berglund et al 2010, Costa et al 2013, Martinez-Haro et al 2013). The majority of these studies, it should be noted, focused on passerines and waterfowl.…”

“…Only one other study that we are aware of has used excrement to examine contaminant exposure in a raptor (Ek et al 2004). Average contaminant levels in our samples from Bald Eagles were relatively similar to those documented in Peregrine Falcons (Ek et al 2004), but tended to be lower than average levels documented in most non-raptors (Morrissey et al 2005, Tiller et al 2005, Berglund et al 2010, Costa et al 2013, Martinez-Haro et al 2013). Because of differences among bird species in physiology and life history it is difficult to draw inferences about the likely impacts of the contaminant levels we observed by comparing our results to these other studies.…”

A review on exposure and effects of arsenic in passerine birds

“…However, other studies did not find differences in As concentrations by age, gender or body condition Geens et al, 2010;Janssens et al, 2001;Morrissey et al, 2005). It has been suggested that this may be due to the low concentrations of As or a small sample size in some studies Morrissey et al, 2005).…”

Bioaccumulation and regional distribution of trace metals in fish of the Tibetan Plateau

“…Besides those of natural origins, anthropogenic trace elements in the environment are mainly derived from mining process, metal smelting, coal and petroleum combustion, oil burning, incineration of waste, cement production and other industrial emissions (Yang and Rose 2005). To some extent, trace metals can undergo long-range atmospheric transport through adsorption by dust (Morrissey et al 2005). During transportation, trace elements are removed from the atmosphere by wet and dry deposition and deposited in remote locations far from the emission sources (Bergamaschi et al 2002;Battarbee et al 2009).…”