Feathers as bioindicators of PCB exposure in clapper rails

Abstract

In this study we used feathers to biomonitor exposure to the polychlorinated biphenyl (PCB) Aroclor 1268 congener mixture in clapper rails (Rallus longirostris). This species has been used as an indicator species of environmental damage for the LCP superfund site located in Brunswick, GA, USA which is contaminated with Aroclor 1268, a congener mixture that has been used in limited amounts elsewhere and therefore can be used as a contaminant marker. The Aroclor 1268 congener mixture, including congener profiles, were quantified in feathers using gas chromatography (GC). Concurrently, each sample was quantified for the total Aroclor 1268 congener mixture using an enzyme-linked immunosorbant assay (ELISA) and compared to the GC results to determine if ELISA was an efficient method for quantifying or qualifying PCBs in feathers. ELISA consistently quantified PCB loads over an order of magnitude lower than the GC. Based on sample replication, extraction recovery, and sample spike, it appears that GC is the more reliable method of detection and that ELISA methods may be more suitable for qualitative exposure assessment for this particular Aroclor. Moreover, since all clapper rails from the LCP site had the Aroclor 1268 congener mixture in their feathers, this experiment showed that birds were returning to the site to breed despite the adverse effects experienced by this population from the contamination revealed in previous studies. This study also supports the utility of feathers as a non-lethal mechanism by which to biomonitor PCBs in the environment.

Feathers as a Biomonitoring Tool of Polyhalogenated Compounds: A Review.

“…Following this, Van den Steen et al performed an experimental evaluation of the usefulness of feathers as a nondestructive biomonitor of PCBs in European Starlings ( Sturnus vulgaris ). Later still, several studies have evaluated the influence of external contamination on organic contaminant levels found in the feathers of several bird species − as well as the correlations between levels in feathers and internal tissues. ,,,, Some studies have even reported on the concentrations of organic pollutants in feathers from museum collections. , …”

Is the LCP Superfund Site an Ecological Trap for Clapper Rails?

“…The specifi c PCB extractions for the feathers used in this study are described in detail by Summers et al (2010). In brief, the primary PCB congeners that compose Aroclor 1268 were quantifi ed in primary fl ight feathers.…”

“…Using these congeners and their respective ratios allows accurate identifi cation of Aroclor 1268 in biological media. An experiment using chicken feathers incubated in contaminated sediment was performed to determine if PCBs could be washed off the outside of the feather completely (Summers et al 2010). No PCBs were detected in these chicken feathers regardless of washing methods.…”

“…Hatch year (HY) birds will also have completed their fi rst prebasic molt and acquired their fi rst basic plumage by that time (Eddleman and Conway 1998). Although PCBs are lipophillic, recent studies have shown that feathers can be used as a nondestructive biomonitor for persistent organic pollutants (Dauwe et al 2005, Summers et al 2010. Also, Aroclor 1268 concentrations in tissues from birds used in this study for other toxicological investigations (Cumbee et al 2008;Gaines et al 2003;Novak et al 2006;Rodriguez-Navarro et al 2002) demonstrated that there is limited movement of the PCB hydrologically and there is no evidence that birds from the nearby reference sites forage in the LCP marsh.…”

To pluck or not to pluck: the hidden ethical and scientific costs of relying on feathers as a primary source of DNA

“…While feather plucking has been used to test for toxic chemicals in birds, feathers represent the concentration of pollutants during their formative stage only and may have significant contaminants on their outer surface. On the other hand, blood represents current circulating concentrations, and correlates much better with concentrations found in internal organs and tissues (Van den Steen et al 2007, Summers et al 2010). As both feather plucking and blood collection require a similar level of disturbance (i.e., capture), it seems prudent to simply take a blood sample in this and many other sampling scenarios given the additional scientific information likely to be obtained.…”