HA12 Environmental Risk Assessment: Global Perspectives
B115 & B116
8:00 AM - 12:00 PM, Thursday
() The Bermuda Amphibian Project: A comprehensive approach to assessing ecotoxicological impacts on Bermuda's amphibians.
Bacon, J.1, Fort, D.2, 1 Bermuda Zoological Society, Warwick, Bermuda2 Fort Environmental Laboratories, Inc., Stillwater, OK, USA
ABSTRACT- The Bermuda Amphibian Project was initiated in 1995 in response to concerns that amphibian populations in Bermuda were declining. Of the three species that had inhabited the islands since the late 1880s, one (Eleutherodactylus gossei) was feared extinct and the other two (E. johnstonei and Bufo marinus) were felt to have declined in numbers. The early findings indicated that resident amphibians were being exposed to a number of environmental stressors. Results showed 1) significant DDE and heavy metal (cadmium, chromium, copper and zinc) concentrations in soil samples and amphibian tissues; 2) high parasite loads in both species; and 3) evidence of immunosuppression in B. marinus specimens collected from two contaminated sites. Subsequent investigations into the increase in deformities in B. marinus populations have involved a series of coordinated laboratory and field studies. Modified FETAX screening assays, TIE, mixture analyses, and laboratory-based microcosm studies using water and sediment collected from four Bermuda sites were performed. Concurrently, in situ larval mortality rates and malformation types were also determined and total petroleum hydrocarbon (TPH) and metal residues were measured in metamorphs from the same sites. Results indicate that TPH and heavy metals present in the sediments at breeding sites are responsible, at least in part, for the deformities being observed. Conversely, no evidence of encysted trematode larvae was found in 80 malformed metamorphs suggesting that parasites are not responsible for the deformities. Current and planned research includes further immunological competence work, an examination of pond snails for parasites, examination of other potentially effected wildlife, population modeling, and a reproductive assessment of B. marinus at selected sites. Together with a comprehensive public education program and epidemiology, these investigations are providing a comprehensive picture of ecological health in Bermuda.
Key words: amphibians, Bermuda, Bufo marinus, deformities