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首页> 外文期刊>Environmental toxicology and chemistry >EFFECT OF pH AND RELEASE~(~R) ON TWO LIFE STAGES OF FOUR ANURAN AMPHIBIANS
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EFFECT OF pH AND RELEASE~(~R) ON TWO LIFE STAGES OF FOUR ANURAN AMPHIBIANS

机译：pH和释放〜（〜R）对四种Anuran两栖动物生命周期的影响

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摘要

Using three native Canadian and one exotic anuran species, the interactive toxicity of pH and the forestry used-herbicide Release~(~R) (triclopyr [3,5,6-trichloro-2-pyridl-oxyacetic acid]) was assessed. Embryonic and larval (Gosner 25) stages of Rana pipiens, Rana clamitans, Bufo americanus, and Xenopus laevis were exposed to treatments for at least 96 h in a static-renewal system using a central composite rotatable design. Mortality and the prevalence of malformations were modeled using generalized linear models with a profile deviance approach to obtain confidence intervals. Consistent trends of greater toxicity with lower pH were observed, with the majority of models (five of seven models) showing significant (p < 0.05) inverse relations. Larval lethal concentration estimates were eight to twenty-three times less than those observed for embryos, indicating that the larval stages were more sensitive to treatments. Further, the median lethal concentration (LC50) values for the larvae were below the expected environmental concentration (EEC) as calculated by Canadian regulatory authorities for Release. Species sensitivity was similar, with an average larval 96-h LC50 of 0.89 mg acid equivalents (AE)/L at pH 5.5 and 1.6 mg AE/L at pH 7, suggesting that X. laevis is a reasonable surrogate for native amphibians in laboratory toxicity testing. For the embryo tests, R. pipiens were slightly less sensitive in comparison with the other three species. Based on a hazard quotient analysis (EEC/LC50 > 1) for the most sensitive larval life stages, higher tier ecotoxicological testing under more realistic environmental conditions is strongly recommended.
机译：使用加拿大的三种本土物种和一种外来的无环物种，评估了pH值和林业使用的除草剂Release〜（〜R）（三氯吡喃[3,5,6-三氯-2-吡啶基-氧乙酸]）的相互作用毒性。使用中央复合可旋转设计，在静态更新系统中将树蛙，美洲蛙，美洲蟾蜍和非洲爪蟾的胚胎和幼虫阶段（Gosner 25）暴露至少96小时。死亡率和畸形患病率采用广义线性模型和轮廓偏差法进行建模，以获得置信区间。在较低的pH值下观察到一致的毒性增加趋势，大多数模型（七个模型中的五个）显示出显着的（p <0.05）逆关系。幼虫致死浓度的估计值比胚胎观察到的少8至23倍，这表明幼虫阶段对治疗更敏感。此外，幼虫的中值致死浓度（LC50）值低于加拿大释放管理机构所计算的预期环境浓度（EEC）。物种敏感性相似，在pH 5.5时平均幼体96-h LC50为0.89 mg酸当量（AE）/ L，在pH 7时平均为1.6 mg AE / L，这表明X. laevis是实验室中天然两栖动物的合理替代品毒性测试。对于胚胎测试，与其他三个物种相比，pipiens R.pipiens的敏感性略低。根据对最敏感的幼体生命阶段的危害商分析（EEC / LC50> 1），强烈建议在更现实的环境条件下进行更高级别的生态毒理学测试。

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