摘要
通过天津地区一系列景观水体和配制的模拟溶液,评价应用于大型蚤(Daphnia magna)毒性预测的两种急性Zn-生物配体(BLM)模型(模型A和模型B)的预测能力。采用Visual MINTEQ 2.5.2进行BLM的相关计算和金属形态分析。对一定水化学参数的测定表明,根据Zn对大型蚤的急性毒性数据建立的模型B能够在Zn的生态风险评价中考虑其生物有效性,预测结果准确;以鱼类为对象开发并下调LA50后应用于水蚤毒性预测的模型A的预测值普遍高于实测值。可见,通过调整LA50拓展模型适用性的方法过于简单,还有待进一步研究。
This study takes it as its objective to assess the predictive capacities of two biotic ligand models （BLM） for acute zinc toxicity to Daphnia magna as applied to a number of landscape waters from Tianjin area and the synthetically laboratory-prepared waters. In our research, we have applied the software known as Visual MINTEQ （Version 2.5.2） to calculate the biotic ligand models and the speciation. As is well known, biotic ligand models （BLM） have been developed for various metals and different species. They are also used to incorporate the effect of physico-chemical characteristics on the bioavailability and toxicity of metals. In recent years, the BLM has been proposed to be used as a tool for quantitative evaluation of the working process to study water chemistry effects on the speciation and biological availability of metals in aquatic systems. So far as the ranges of water chemistry parameters are concerned, the model B based on toxicological data of acute zinc to Daphnia rnagna can be regarded as a useful tool for examining the bioavailability in regulatory assessments of zinc. In addition, the predicted value of the effect of the model A was developed in fish bodies and subsequently adopted for Daphnia magna through downward adjustment of LA50, which were generally considered lower than the measured values. To some extent, it can be said that the acute toxicity to Daphnia magna （LC50） was underestimated. And the extension of the method of LA50 to the use of model applicability should be regarded no more the simplest means of calibrating the BLM, which is likely to be suspected. However, focus should be turned on the field validation of chronic Zn-BLM in the future so as to improve the ecological relevancy of zinc risk assessments by reducing and even eliminating the bioavailabilityrelated uncertainty of zinc toxicity.
出处
《安全与环境学报》
CAS
CSCD
2008年第4期5-8,共4页
Journal of Safety and Environment
基金
国家重点基础研究发展计划(2004CB418504)
