化学物质对发光菌的联合毒性评价方法

毒性单位法(TU)的理论基础来源于剂量加和模型(DA),目前仅在二元联合毒性评价中广泛应用。为了确定TU模型适合评价的混合物类型,实验选取5种剂量效应曲线类型不同的物质,采用微板光度计测试了一元、二元混合物对发光菌青海弧菌-Q67(Vibrio-qinghaiensis sp.-Q67)的急性毒性。根据物质的剂量效应曲线形状将物质分为A、B、C 3类,利用毒性单位法(TU)和联合作用定义法分别对AA类、AB类、AC类、BC类混合物进行分析。结果表明,TU法仅适合于由剂量效应曲线接近直线的物质组成的混合物进行联合毒性的评价。以效应为基准、TU模型为框架建立了TU’模型,该模型可以满足对任何类型已知成分的混合物或者未知成分的实际水样之间的多元联合作用的评价。

Method of joint toxicity evaluation of chemicals on luminous bacteria

The theoretical basis of the toxic unit (TU) model that has been widely used in joint toxicity evaluation for binary mixtures is derived from dose-addition (DA) model. In order to investigate the types of mixture which were suitable for TU model, five chemicals, with different shapes of dose-response curve, were selected to measure the acute toxicity of the individual and binary mixture using vibrio qinghaiensis sp.-Q67 (Q67) as the tested bacteria, and the microplate luminometer was used as test instrument. According to the shape of dose-response curves, the five chemicals were divided into three categories (named class A, B and C). The TU model and the assessment model derived from the definition of joint action were employed to evaluate the joint action of binary mixture, including class A and A (mixtures composed by two chemicals in class A), class A and B, class A and C or class B and C. The results showed that TU model was only suitable for joint action assessment of Class A and A mixture composed by the chemicals with linear dose-response curve. The TU' model was firstly developed based on the definition of combined effect and the framework of TU model. This model could meet the multi-component joint action assessment of any type of mixtures known in composition and the natural water sample mixtures with unknown composition.