Heavy metals in bullfrog (Rana catesbeiana) tadpoles: Effects of depuration before analysis

摘要: Although tadpoles may well be excellent organisms to use as bioindicators of heavy metal contamination, the relationship deposition in body compared tail, and effect sediments or other debris digestive tract on concentrations is unknown. We examined experimental depuration bullfrog (Rana catesbeiana) selenium intact tadpoles, their bodies tails. defined this experiment allowing defecation an elimination process for intestinal contents (=clearing). maintained wild-caught clean water 0, 24, 48, 72 h determine effects clearing concentrations. also metals whole separately. test null hypotheses that no differences occur a function time uncontaminated water, tail tract. rejected these based regression models. Variance chromium (77%) lead (70%) were explained by part (body, body) time; manganese (80%), mercury (64%), (28%), cadmium (25%) variation was only part; arsenic (53%), part, time, weight various parts. For those which variation, both decreased after 24 48 h, but increased slightly thereafter. Clearing, however, did not greatly decrease either tail. These data suggest some (mercury, manganese, cadmium, selenium), has effect, others slight. fresh contained significantly higher all than head, probably reflecting absorbed sediment particles gut.