Metal levels in southern leopard frogs from the Savannah River Site: Location and body compartment effects

Citation
J. Burger et J. Snodgrass, Metal levels in southern leopard frogs from the Savannah River Site: Location and body compartment effects, ENVIR RES, 86(2), 2001, pp. 157-166
Citations number
33
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Environment/Ecology,"Pharmacology & Toxicology
Journal title
ENVIRONMENTAL RESEARCH
ISSN journal
0013-9351 → ACNP
Volume
86
Issue
2
Year of publication
2001
Pages
157 - 166
Database
ISI
SICI code
0013-9351(200106)86:2<157:MLISLF>2.0.ZU;2-B
Abstract
Tadpoles have been proposed as useful bioindicators of environmental contam ination; yet, recently it has been shown that metal levels vary in differen t body compartments of tadpoles. Metals levels are higher in the digestive tract of bullfrog (Rana catesbeiana) tadpoles, which is usually not removed during such analysis. In this paper we examine the heavy metal levels in s outhern leopard frog (R. utricularia) tadpoles from several wetlands at the Savannah River Site and test the null hypotheses that (1) there are no dif ferences in metal levels in different body compartments of the tadpoles, in cluding the digestive tract; (2) there are no differences in heavy metal le vels among different wetlands; and (3) there are no differences in the rati o of metals in the tail/body and in the digestive tract/body as a function of metal or developmental stage as indicated by body weight, Variations in heavy metal levels were explained by wetland and body compartment for all m etals and by tadpole weight for selenium and manganese. In all cases, level s of metals were higher in the digestive tract than in the body or tail of tadpoles. Metal levels were highest in a wetland that had been remediated a nd lowest in a wetland that was never a pasture or remediated (i.e., was tr uly undisturbed). Although tadpoles are sometimes eaten by fish and other a quatic predators, leopard frogs usually avoid laying their eggs in ponds wi th such predators. However, avian predators will eat them. These data sugge st that tadpoles can be used as bioindicators of differences in metal level s among wetlands and as indicators of potential exposure for higher-trophic -level organisms, but that to assess effects on the tadpoles themselves, di gestive tracts should be removed before analysis. (C) 2001 Academic Press.