TP9 Ecotoxicology of Reptiles
Tuesday, 15 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(RIC-1117-842119) Mercury and metal levels in snakes and tadpoles from the Mobile/Tensaw Delta, Mobile, Alabama.

Abalos, M¹, Albrecht, J¹, Rice, T¹, ¹ University of South Alabama, Department of Biological Sciences, Mobile, Alabama, USA

ABSTRACT- Mobile Bay, Mobile, AL, became a part of the country's National Estuary Program (NEP) in 1995. Included in the NEP study area is the Bay proper and the Mobile/Tensaw Delta. The Delta is one of the nation's largest river deltas and much of it remains in a natural state. The drainage basin of the Mobile/Tensaw Delta covers over 75% of the state of Alabama. Hence, a variety of human impacts over this large area could be funneling into the Delta. Of great concern to the citizens around Mobile Bay is the presence of mercury in food fish. However, it would be beneficial to measure levels of toxicants such as mercury, or heavy metals such as lead, in animals other than fish that are more abundant or occupy important ecological positions in the Delta. Surveys of the amphibians and reptiles in the Delta indicate that the bronze frog (Rana clamitans) and the Eastern ribbon snake (Thamnophis sauritus) are especially abundant and easily collected. Our goal was to measure mercury and heavy metals in these two species because they are not as commonly studied as higher profile species such as fish or birds. Ribbon snakes and tadpoles were collected from intact and clear-cut areas in the Delta. Whole animal tissue was processed for mercury and heavy metals. Both snake and tadpoles contained measurable amounts of mercury and heavy metals, but these levels did not appear high enough to be of concern. No appreciable differences in mercury or metal levels were observed between animals collected from clear-cut vs intact areas. Using these two species as bioindicators, the Mobile/Tensaw Delta appears to be relatively free of effects from mercury or heavy metals. However, other indicators of contamination in the Mobile/Tensaw Delta should be examined.

Key words: mercury, metals, snakes, tadpoles