乐果、铜和锌对水生生物的联合毒性研究

为通过不同生物等级的模式生物研究乐果、铜和锌的联合毒性，以明亮发光杆菌和斑马鱼胚胎为受试模式生物，通过混合毒性指数法（MTI法）评价了乐果、铜和锌的联合毒性效应。结果表明：明亮发光杆菌毒性测试显示，暴露测试15 min时，乐果、铜和锌的EC₅₀值分别为123、0.53 mg·L^-1和1.71 mg·L^-1；暴露测试30 min时，EC₅₀值分别为122、0.50 mg·L^-1和1.54 mg·L^-1。乐果-铜和乐果-锌暴露15 min测得的MTI分别为0.69和0.60。斑马鱼胚胎毒性测试显示，暴露72 h后乐果、铜和锌的LC50值分别为0.31、1.67 mg·L^-1和369 mg·L^-1。乐果-铜和乐果-锌暴露72 h后测得的MTI分别为0.70和0.75。研究表明，乐果和铜、锌分别混合后的联合毒性均有所增强，整体毒性表现为部分相加作用，因此两类物质在环境中的残留会对水生生物及其他生物造成潜在危害。

Combined toxicity of dimethoate, copper and zinc to aquatic organisms

To study the combined toxicity of dimethoate, copper and zinc, photobacterium phoshoreum and zebrafish eggs were used as model organisms. The combined toxicity of dimethoate-copper and dimethoate-zinc was evaluated by mixture toxicity indices(MTI). Toxicity test of photobacterium phoshoreum:the EC₅₀ of dimethoate, copper and zinc after 15 min exposure were 123, 0.53 mg·L^-1 and 1.71 mg·L^-1 respectively. The EC₅₀ after 30 min were 122, 0.50 mg·L^-1 and 1.54 mg·L^-1. The MTI of dimethoate-copper and dimethoate-zinc after 15 min were 0.69 and 0.60. Toxicity test of zebrafish eggs:the LC50 of dimethoate, copper and zinc exposed after 72 h of exposure were 0.31, 1.67 mg·L^-1 and 369 mg·L^-1. The MTI of dimethoate-copper and dimethoate-zinc after 72 h were 0.70 and 0.75. The combined toxicity of dimethoate-copper and dimethoate-zinc was enhanced, and the overall toxicity showed a partially additive effect. Therefore, the residues of these two substances in the environment has the potential to cause harm to aquatic and other organisms.