title: Combined toxicity of butachlor, atrazine and λ-cyhalothrin on the earthworm Eisenia fetida by combination index (CI)-isobologram method.
abstract: Pesticides in the environment do not appear singly and usually occur as complex mixtures and their combined effect may exhibit toxicity to organisms. The individual and combined toxicities of two herbicides, atrazine and butachlor and an insecticide λ-cyhalothrin have been examined to the earthworm Eisenia fetida, as a non-target terrestrial organism, in artificial soil and filter paper tests. The order of toxicity for the individual pesticides was ranked as atrazine>λ-cyhalothrin>butachlor in both tests. We applied the combination index (CI)-isobologram method which is widely used to study chemical interactions to determine the nature of toxicological interactions of the pesticides and it allows computerized quantitation of synergism, additive effect and antagonism. For most cases in artificial soil test, synergism was observed in majority of the mixtures except for the combination of butachlor plus λ-cyhalothrin. This particular combination displayed opposite interaction in filter paper test. The CI method was compared with the classical models of Concentration Addition (CA) and Independent Action (IA) and we found that CI method could accurately predict the combined toxicity and can serve as a useful tool in ecotoxicological risk assessment.
authors.affiliation: 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.forename: Chen
authors.initials: C
authors.lastname: Chen
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Quality and Standard for Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; 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.forename: Yanhua
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Quality and Standard for Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; 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.forename: Xueping
authors.initials: X
authors.lastname: Zhao
authors.affiliation: 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.forename: Yongzhong
authors.initials: Y
authors.lastname: Qian
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Quality and Standard for Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; 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. Electronic address: qiangwang2003@vip.sina.com.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000083:Acetanilides / Q000633:toxicity*; D000818:Animals; D001280:Atrazine / Q000633:toxicity*; D004347:Drug Interactions; D054750:Ecotoxicology / Q000379:methods*; D023381:Endpoint Determination; D009570:Nitriles / Q000633:toxicity*; D009835:Oligochaeta / Q000187:drug effects*; D010575:Pesticides / Q000633:toxicity*; D011722:Pyrethrins / Q000633:toxicity*; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000633:toxicity*
chemical_list: D000083:Acetanilides; D009570:Nitriles; D010575:Pesticides; D011722:Pyrethrins; D012987:Soil; D012989:Soil Pollutants; C054409:butachlor; D001280:Atrazine; C037304:cyhalothrin
keywords: Acute mixture toxicity; Atrazine; Butachlor; Combination index method; Eisenia fetida; λ-Cyhalothrin