title: The synergistic toxicity of the multiple chemical mixtures: implications for risk assessment in the terrestrial environment.
abstract: The combined toxicity of five insecticides (chlorpyrifos, avermectin, imidacloprid, λ-cyhalothrin, and phoxim), two herbicides (atrazine and butachlor) and a heavy metal (cadmium) has been examined with the earthworm acute toxicity test. Toxicological interactions of these chemicals in four, five, six, seven, and eight-component mixtures were studied using the combination-index (CI) equation method. In four-component and five-component mixtures, the synergistic effects predominated at lower effect levels, while the patterns of interactions found in six, seven, and eight-component mixtures displayed synergism. The λ-CY+IMI+BUT+ATR+CPF+PHO combination displayed the most strongly synergistic interaction, with CI values ranging from 0.09 to 0.15. The nature of the interaction changes with the effect level and the relevance of synergistic effects increase with the complexity of the mixture. The CI method was compared with the classical models of concentration addition (CA) and independent action (IA) and we found that the CI method could accurately predict the combined toxicity. The predicted synergism resulted from co-existence of the pesticides and the heavy metal especially at low effect levels may have important implications in risk assessment for the real terrestrial environment.
authors: Key Laboratory of Agro-Product Quality and Safety of Ministry of Agriculture, Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors: Chen
authors: C
authors: Chen
authors: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control/Key Laboratory for Pesticide Residue Detection of Ministry of Agriculture, Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
authors: Yanhua
authors: Y
authors: Wang
authors: Key Laboratory of Agro-Product Quality and Safety of Ministry of Agriculture, Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address: qyzcaas@aliyun.com.
authors: Yongzhong
authors: Y
authors: Qian
authors: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control/Key Laboratory for Pesticide Residue Detection of Ministry of Agriculture, Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
authors: Xueping
authors: X
authors: Zhao
authors: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control/Key Laboratory for Pesticide Residue Detection of Ministry of Agriculture, Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
authors: Qiang
authors: Q
authors: Wang
mesh_terms: D000083:Acetanilides / Q000633:toxicity; D000818:Animals; D001280:Atrazine / Q000633:toxicity; D002104:Cadmium / Q000633:toxicity; D004390:Chlorpyrifos / Q000633:toxicity; D004357:Drug Synergism; D006540:Herbicides / Q000633:toxicity*; D007093:Imidazoles / Q000633:toxicity; D007306:Insecticides / Q000633:toxicity*; D007559:Ivermectin / Q000031:analogs & derivatives / Q000633:toxicity; D019216:Metals, Heavy / Q000633:toxicity*; D000073943:Neonicotinoids; D009570:Nitriles / Q000633:toxicity; D009574:Nitro Compounds / Q000633:toxicity; D009835:Oligochaeta / Q000187:drug effects*; D009946:Organothiophosphorus Compounds / Q000633:toxicity; D010575:Pesticides / Q000633:toxicity*; D011722:Pyrethrins / Q000633:toxicity; D018570:Risk Assessment; D012989:Soil Pollutants / Q000633:toxicity*
chemical_list: D000083:Acetanilides; D006540:Herbicides; D007093:Imidazoles; D007306:Insecticides; D019216:Metals, Heavy; D000073943:Neonicotinoids; D009570:Nitriles; D009574:Nitro Compounds; D009946:Organothiophosphorus Compounds; D010575:Pesticides; D011722:Pyrethrins; D012989:Soil Pollutants; D002104:Cadmium; C082359:imidacloprid; C003135:phoxim; D007559:Ivermectin; C019264:avermectin; C054409:butachlor; D004390:Chlorpyrifos; D001280:Atrazine; C037304:cyhalothrin
keywords: Acute mixture toxicity; Combination index; Eisenia fetida; Heavy metal; Herbicides; Insecticides