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首页> 外文期刊>Environmental toxicology and chemistry >TOXICITY OF TWO INSECTICIDES TO CALIFORNIA, USA, ANURANS AND ITS RELEVANCE TO DECLINING AMPHIBIAN POPULATIONS
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TOXICITY OF TWO INSECTICIDES TO CALIFORNIA, USA, ANURANS AND ITS RELEVANCE TO DECLINING AMPHIBIAN POPULATIONS

机译：两种杀虫剂对美国加利福尼亚州和阿努兰斯的毒性及其与减少两栖动物种群的关系

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Contaminants have been associated with population declines of several amphibian species in California (USA). Pesticides from the Central Valley of California are transported by winds into the Sierra Nevada Mountains and precipitate into wet meadows where amphibians breed. The present study examined the chronic toxicity of two of the insecticides most commonly used in the Central Valley and found in the mountains, chlorpyrifos and endosulfan, to larval Pacific treefrogs (Pseudacris regilla) and foothill yellow-legged frogs (Rana boylii) and discusses the implications of this toxicity to declining amphibian populations. Larvae were exposed to the pesticides from Gosner stages 25 to 26 through metamorphosis. The estimated median lethal concentration (LC50) for chlorpyrifos was 365 μg/L in P. regilla and 66.5 μg/L for R. boylii. Time to metamorphosis increased with concentration of chlorpyrifos in both species, and cholinesterase activity declined with exposure concentration in metamorphs of both species at Gosner stages 42 to 46. For endosulfan, the estimated LC50 was 15.6 μg/L for P. regilla and 0.55 μg/L for R. boylii. All R. boylii exposed to concentrations of greater than 0.8 μg/L died before they entered metamorphosis. Pseudacris regilla remains relatively abundant and is broadly distributed throughout California. In contrast, R. boylii is among the species experiencing severe population declines. The present study adds to the increasing evidence that pesticides are very harmful to amphibians living in areas that are miles from sources of pesticide application.
机译：在美国加利福尼亚，污染物与几种两栖动物的种群减少有关。来自加利福尼亚中央谷地的农药通过风运到内华达山脉，然后沉淀到两栖动物繁殖的潮湿草地上。本研究研究了在中部山谷最常见的两种杀虫剂（毒死rif和硫丹）对幼虫太平洋树蛙（Pseudacris regilla）和山麓黄脚蛙（Rana boylii）的慢性毒性，并讨论了这种毒性对两栖动物数量下降的影响。幼虫通过变态暴露于Gosner阶段25至26的农药。毒死rif的估计中位致死浓度（LC50）在regilla中为365μg/ L，而R. boylii为66.5μg/ L。变态时间随着毒死rif浓度的升高而增加，在Gosner阶段42至46时，两种物种的变态浓度随胆碱酯酶活性的降低而降低。硫丹的估计半数抗虫的LC50为15.6μg/ L，而雷公菌的LC50估计为0.55μg/ L。 L代表R. boylii。暴露于浓度大于0.8μg/ L的所有波立黎体都在进入变态之前死亡。伪君子仍然相对丰富，并在整个加利福尼亚广泛分布。相反，R。boylii属于种群严重减少的物种。本研究增加了越来越多的证据，表明农药对生活在距农药施用源数英里的地区的两栖动物非常有害。

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