Addressing speciation in the effect factor for characterisation of freshwater ecotoxicity-the case of copper
Addressing speciation in the effect factor for characterisation of freshwater ecotoxicity-the case of copper
复制标题
DOI：
10.1007/s11367-011-0305-7
复制
发表时间：
2011-09-01
影响因子：
4.8
通讯作者：
Hauschild, Michael Z.
中科院分区：
文献类型：
--
作者：
Christiansen, Karen S.;Holm, Peter E.;Hauschild, Michael Z.
在生命周期影响评价（LCIA）中，生态毒性效应因子（EF）的确定是基于报告物质总溶解浓度的试验数据。尽管公认的影响化学形态和物理化学特性的水生系统的毒性溶解的金属，这些属性不被考虑时，计算表征因子（CF）的金属。据推测，在已发表的测试结果中，报告的Cu的EC 50值变化的主要原因在于测试介质中Cu的不同形态模式，并且Cu的毒性主要由游离Cu 2+离子引起。因此，游离铜离子浓度应取代总溶解金属浓度时，确定EF。该研究是基于发表的生态毒性研究报告的急性和慢性EC 50数据铜大型蚤和不同种类的鱼类和藻类的审查。使用Visual MINTEQ模型计算了Cu在不同介质中的形态分布。根据USEtox（TM）表征模型中应用的表达式计算EF。报告的Cu的EC 50值显示，对于相同的生物体，存在一到几个数量级的变化，但研究表明，较大的变化是由影响金属形态的测试介质的水化学差异引起的。计算的游离Cu ~（2+）浓度与已报道的EC_（50）值之间的关系表明，Cu对D.可以从自由离子浓度预测magna。其他结果证实，游离Cu 2+离子浓度取决于[Cu]/[DOC]比，因为当介质含有超过1 mg/L DOC时，大部分总溶解Cu以Cu-DOC复合物形式存在，并且因为此类复合物中的Cu对测试生物体的可用性有限。水环境中Cu的EF应以游离Cu ~（2+）浓度为基础。
Determination of the ecotoxicity effect factor (EF) in life cycle impact assessment (LCIA) is based on test data reporting the total dissolved concentration of a substance. In spite of the recognised influence of chemical speciation and physico-chemical characteristics of the aquatic systems on toxicity of dissolved metals, these properties are not considered when calculating characterization factors (CFs) for metals. It is hypothesised that the main cause of the variation in reported EC50 values of Cu among published test results lies in different speciation patterns for Cu in the test media, and that the toxicity of Cu is predominantly caused by the free Cu2+ ion. Hence, the free Cu2+ ion concentration should substitute the total dissolved metal concentration when determining the EF.The study was based on a review of published ecotoxicity studies reporting acute and chronic EC50 data for Cu to Daphnia magna and to different species of fish and algae. The speciation pattern of Cu in the different media applied in the studies was calculated using the Visual MINTEQ model. EFs were calculated according to the expression applied in the USEtox (TM) characterization model.Reported EC50 values for Cu show variations of one to several orders of magnitude for the same organism, but the study indicates that the large variation is caused by differences in water chemistry of the test media influencing the metal speciation. The relationship between the calculated free Cu2+ ion concentration and reported EC50 values indicates that the aquatic ecotoxicity of Cu to D. magna can be predicted from the free ion concentration. Other results confirm that the free Cu2+ ion concentration depends on the [Cu]/[DOC] ratio since the majority of the total dissolved Cu is present as Cu-DOC complexes when the media contains more than 1 mg/L of DOC, and since Cu in such complexes has limited availability to the test organisms.These results suggest that speciation should be taken into account in the modelling of both EFs and fate factors for LCIA, and the EF for Cu in the aquatic environment should be based on the concentration of the free Cu2+ ion.