Clapper rails as indicators of mercury and PCB bioavailability in a Georgia saltmarsh system

<p> Clapper rails (Rallus longirostris) were used as an indicator species of estuarine marsh habitat quality because of their strong site &filig;delity and predictable diet consisting of mostly benthic organisms. Mercury (Hg) and the polychlorinated biphenyl (PCB) Aroclor 1268 concentrations were determined for sediments, crabs, as well as clapper rail adults and chicks collected from salt marshes associated with the LCP Superfund site in Brunswick, Georgia. Home ranges were established for adult rails, and sediment and crab samples were taken from each individual&rsquo;s range. The study was designed to minimize the spatial variability associated with trophic transfer studies by choosing an endpoint species with a potentially small home range and speci&filig;cally sampling its foraging range. The mean home range for clapper rails was 1.2 ha with a median of 0.28 ha. Concentrations of Hg and Aroclor 1268 were shown to increase with each trophic level. Transfer factors between media followed the same pattern for both contaminants with the highest between &filig;ddler crabs and clapper rail liver. Hg and PCB transfer factors were similar between sediment to &filig;ddler crab and &filig;ddler crab to muscle, however the PCB transfer factor from &filig;ddler crabs to liver was over twice as large as for Hg. PCB congener pro&filig;les did not signi&filig;cantly differ between media types.</p>