铜和异噻唑啉酮类化合物对大型溞的联合毒性研究

Joint toxicity of copper and isothiazolinones to Daphnia Magna

异噻唑啉酮类化合物在杀菌、海洋防污等领域的广泛使用和长期排放,对非靶标生物造成了极大的风险.铜是海洋防污中应用最为广泛的无机活性物质和杀菌灭藻剂中常用的稳定剂.因此,研究铜和异噻唑啉酮类化合物的联合毒性效应有着重要的生态意义.本研究测定了CuCl_(2)、甲基异噻唑啉酮(MIT)和1,2-苯并异噻唑啉-3-酮(BIT)对大型溞(Daphnia Magna)的一元、二元急性毒性,以毒性单位(TU)和混合毒性指数(MTI)评价混合物的作用类型.选取浓度加和(Concentration Addition,CA)模型与独立作用(Independent Action,IA)模型为参考并结合三维偏差响应面分析混合物毒性相互作用与浓度变化的规律.结果表明,CuCl_(2)、MIT和BIT对大型溞的48 h-EC_(50)分别为0.84、1.06和3.90 mg·L^(-1).CuCl_(2)-MIT和CuCl_(2)-BIT混合体系在等毒性比例下的毒性作用符合IA模型,当混合物中一种化合物进入低效应浓度区间,毒性作用相对IA模型发生偏移.当混合物组分间毒性差异较大会导致某一组分处于无效应浓度而使混合物的作用模式符合CA模型.本研究可为探索铜与异噻唑啉酮类化合物联合暴露的环境风险评估提供参考.

With the widespread use and continuous emission of isothiazolinones in sterilization,marine antifouling and other fields,isothiazolinones posed a huge risk to non-target organisms.Copper is the most widely used inorganic active substance and stabilizer in marine antifouling agents.Therefore,it is of great ecological significance to study the joint toxicity of copper and isothiazolinones.The single and binary acute toxicity of CuCl_(2),methylisothiazolinone(MIT)and 1,2-benzoisothiazolinone(BIT)to Daphnia Magna were determined in this study.Mixture Toxicity Index(MTI)and Toxicity Unit(TU)were used to estimate the toxic interactions between the mixtures.Concentration addition(CA)model and independent action(IA)model were selected as the reference and in combined with three-dimensional deviation response surface were adopted to analyze the toxic interaction with the change of concentration.The results showed that the 48 h-EC50values of CuCl_(2),MIT and BIT to Daphnia Manga were 0.84 mg·L^(-1),1.06 mg·L^(-1)and 3.90 mg·L^(-1),respectively.CuCl_(2)-MIT and CuCl_(2)-BIT mixture systems accorded with the IA model at equal toxicity ratio.When one compound in the mixture was in the range of low effect concentration,the toxicity of mixture systems deviated from the IA model.Big toxicity difference between the components of the mixture could result in one component at the concentration with no effect and even the action mode of the mixture following the CA model.This study can provide a reference for exploring the environmental risk assessment of the combined exposure of copper and isothiazolinones.