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Sublethal effects of lead on northern leopard frog ( Rana pipiens ) tadpoles
Author(s) -
Chen TeHao,
Gross Jackson A.,
Karasov William H.
Publication year - 2006
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/05-356r.1
Subject(s) - metamorphosis , leopard frog , tadpole (physics) , larva , biology , snout , rana , zoology , amphibian , ecology , anatomy , physics , particle physics
Northern leopard frogs ( Rana pipiens ) were exposed to environmentally relevant concentrations of lead in water (3, 10, and 100 μg/L as lead nitrate) from the embryonic stage to metamorphosis. Survival, growth, deformity, swimming ability, metamorphosis, and lead tissue concentrations were evaluated. Tadpole growth was significantly slower in the early stages (Gosner stages 25–30) in 100 μg/L treatment. More than 90% of tadpoles in the 100 μg/L treatment developed lateral spinal curvature, whereas almost all the tadpoles in the other groups were morphologically normal. Spinal deformity was associated with abnormal swimming behavior. Maximum swimming speed of tadpoles in the 100 μg/L treatment was significantly lower than that in the other groups. No significant effect of lead exposure was found on percentage metamorphosis, snout‐vent length, mortality, and sex ratio of metamorphs. Time to metamorphosis was delayed in 100 μg/L treatment. Lead tissue concentrations in the tadpoles ranged from 0.1 to 224.5 mg/kg dry mass, were positively related to lead concentrations in the water, and fell within the range of tissue concentrations of wild tadpoles found in previous studies. According to our results, the current U.S. Environmental Protection Agency freshwater‐quality chronic criterion for lead (2.5 μg/L) is appropriate to protect northern leopard frog larvae.