Brunelli Elvira, Bernabò Ilaria, Berg Cecilia, Lundstedt-Enkel Katrin, Bonacci Antonella, Tripepi Sandro
Department of Ecology, University of Calabria, Via P. Bucci, 87036 Rende (Cosenza), Italy.
Aquat Toxicol. 2009 Jan 31;91(2):135-42. doi: 10.1016/j.aquatox.2008.09.006. Epub 2008 Sep 18.
Endosulfan is a widely used organochlorine pesticide with well-documented neurotoxic effects in both humans and laboratory animals (mammals and fish). Neurotoxicity has been implied also in amphibians after short-term exposure to endosulfan. Little is known about effects of chronic exposure of endosulfan in amphibians. Previously, we examined the short-term toxicity of endosulfan in common toad (Bufo bufo) tadpoles and determined the LC50 value to 0.43 mg/L. In the present study, we investigated the effects of endosulfan on B. bufo tadpoles after chronic exposure to ecologically relevant concentrations. Tadpoles were exposed in a static renewal test, from shortly after hatching (Gosner stage 25) to completed metamorphosis, to 0.01, 0.05 and 0.1mg endosulfan/L (nominal). The exposure period lasted 43-52 days. Mortality, larval growth (mass), development (reached Gosner stage at various times and deformities presence), metamorphosis and behaviour (swimming activity) were monitored regularly over the entire course of larval development. Our results show that 0.05 and 0.1mg endosulfan/L caused impaired behaviour, prolonged time to metamorphosis, increased incidences of mouth and skeletal malformations as well as mortality, and reduced body weight (observed also at 0.01 mg/L) in B. bufo tadpoles. Behavioural effects occurred at exposure day 4, before any other effects occurred, indicating a neurotoxic effect. Endosulfan levels found in groundwater and surface water range from 0.1 to 100 microg/L and after extraordinary runoff events, concentrations exceed 0.5 mg/L in surface water. Our results indicate that endosulfan may negatively affect wild frog populations in agricultural areas.
硫丹是一种广泛使用的有机氯农药，在人类和实验动物（哺乳动物和鱼类）中具有充分记录的神经毒性作用。短期接触硫丹后，两栖动物也被认为存在神经毒性。关于硫丹对两栖动物的慢性暴露影响知之甚少。此前，我们研究了硫丹对普通蟾蜍（Bufo bufo）蝌蚪的短期毒性，并确定其半数致死浓度（LC50）为0.43毫克/升。在本研究中，我们调查了硫丹在生态相关浓度下长期暴露对普通蟾蜍蝌蚪的影响。蝌蚪在静态更新试验中，从孵化后不久（戈斯纳25期）到完全变态，暴露于0.01、0.05和0.1毫克硫丹/升（标称值）。暴露期持续43 - 52天。在幼虫发育的整个过程中定期监测死亡率、幼虫生长（体重）、发育（在不同时间达到戈斯纳阶段及是否存在畸形）、变态和行为（游泳活动）。我们的结果表明，0.05和0.1毫克硫丹/升导致普通蟾蜍蝌蚪行为受损、变态时间延长、口腔和骨骼畸形发生率增加以及死亡率上升，体重减轻（在0.01毫克/升时也有观察到）。行为影响在暴露第4天出现，早于任何其他影响，表明存在神经毒性作用。在地下水和地表水中发现的硫丹水平范围为0.1至100微克/升，在异常径流事件后，地表水中的浓度超过0.5毫克/升。我们的结果表明，硫丹可能对农业地区的野生蛙类种群产生负面影响。
