Although chemicals have been traditionally regulated on an individual basis in aquatic ecosystems, they often co-exist as different types of complex mixtures. Laboratory assays were conducted for assessing the responses of rare minnow (Gobiocypris rarus) to individual and mixture chemicals [trace element cadmium (Cd), thiamethoxam, deltamethrin, malathion and prochloraz]. Data obtained from 96 h semi-static toxicity assays implied that deltamethrin elicited the highest toxic effect on the various developmental phases (larval, juvenile and adult phases) of G. rarus with LC₅₀ values ranging from 0.00061 to 0.25 mg a.i. L⁻¹, followed by prochloraz, malathion and Cd with 96-h LC₅₀ values ranging from 0.49 to 1.1, from 7.1 to 26, and from 7.6 to 15 mg a.i. L⁻¹, respectively. Thiamethoxam elicited the lowest toxic effect on the organisms with 96-h LC₅₀ values ranging from 38 to 202 mg a.i. L⁻¹. Larval phase was not always the most sensitive period in the three detected phases to most of chemicals. Chemical combinations containing deltamethrin and malathion displayed synergetic responses to the larvae of G. rarus. Besides, the binary mixtures of Cd-deltamethrin and Cd-prochloraz also exhibited synergetic response to rare minnows. Our results indicate that extra information is necessary to develop practical criteria for selecting chemical combinations that require legislative attention according to their likelihood to exert synergetic responses. Thence, more investigations on mixture toxicities of various chemicals should be taken as a priority for producing synergetic interaction to improve the environmental risk assessment of chemicals.

尽管传统上在水生生态系统中对化学品进行了单独的监管，但它们通常以不同类型的复杂混合物形式共存。进行了实验室分析，以评估稀有min鱼（Gobiocypris rarus）对单个和混合化学物[痕量元素镉（Cd），噻虫嗪，溴氰菊酯，马拉硫磷和丙草胺的反应]。从96小时半静态毒性测定数据得到暗示，溴氰菊酯引起上的各个发育阶段（幼虫，幼年和成年阶段）的最高毒性作用G.鲫与LC _50个值范围从0.00061到0.25毫克的AI大号^-1，其次是前氯唑，马拉硫磷和镉的96小时LC ₅₀值分别为0.49至1.1、7.1至26和7.6至15 mg ai L ^-1。噻虫嗪对生物的毒性最低，其96 h LC ₅₀值为38至202 mg ai L ^-1。在三个检测阶段中，幼虫期并非始终是对大多数化学物质最敏感的时期。含有溴氰菊酯和马拉硫磷的化学组合对罗氏沼虾的幼虫表现出协同反应。此外，Cd-溴氰菊酯和Cd-丙草胺的二元混合物也对稀有小鱼表现出协同反应。我们的结果表明，额外的信息对于制定实用的标准是必要的，这些标准用于根据需要发挥协同作用的可能性来选择需要立法关注的化学组合。因此，应将更多关于各种化学物质的混合物毒性的研究作为产生协同相互作用以改善化学物质环境风险评估的优先事项。