EFFECTS OF PHOTOINDUCED TOXICITY OF FLUORANTHENE ON AMPHIBIAN EMBRYOSAND LARVAE

Embryos and newly hatched larvae of three amphibian species, the spott ed salamander (Ambystoma maculatum), the northern leopard frog (Rana p ipiens), and the African clawed frog (Xenopus laevis), were exposed to fluoranthene and ultraviolet (UV) light in two scenarios. Embryos wer e exposed in a laboratory setting from an early developmental stage th rough hatching under artificial UV light and newly hatched larvae were exposed outdoors in varying sunlight intensity levels. Outdoor exposu res greater sensitivity in the toxic response than did laboratory expo sures. In the laboratory, mortality and malformation of X. laevis were the most sensitive indicators of exposure. Xenopus laevis was also th e most sensitive species tested to the effects of UV light alone. Hatc hing success of R. pipiens was monitored outdoors and was not a useful predictive endpoint in the determination of photoinduced toxicity; ho wever, newly hatched larvae were: sensitive to the effects of photoind uced toxicity. Amybstoma maculatum and X. laevis larvae were affected by low (mu g/L) concentrations of fluoranthene in sunlight. These find ings suggest that low levels of polycyclic aromatic hydrocarbons could be acting synergistically with environmental factors such as UV light to place young amphibians at risk.