title: Combined toxicity of imidacloprid and three insecticides to the earthworm, Eisenia fetida (Annelida, Oligochaeta).
abstract: Although the earthworm Eisenia fetida has been used in many ecotoxicological studies in recent years, most of these studies have only focused on assessing the effects of individual insecticides. In the present study, we aimed to compare the individual and combined toxic effects of imidacloprid and three insecticides (phoxim, chlorpyrifos, and lambda-cyhalothrin) on E. fetida. We showed that imidacloprid had the highest intrinsic toxicity to the worms in filter paper contact test, followed by phoxim and lambda-cyhalothrin, while the least toxicity was found from chlorpyrifos. Moreover, 14-day soil toxicity test revealed that the highest toxicity was still detected for imidacloprid with an LC50value of 2.82 (2.61∼3.17) mg a.i. kg-1dry weight (DW), followed by chlorpyrifos with an LC50value of 384.9 (353.5∼440.3) mg a.i. kg-1DW. Meanwhile, a relatively less toxicity was found for lambda-cyhalothrin with an LC50value of 560.3 (475.9∼718.5) mg a.i. kg-1DW, while the lowest toxicity to E. fetida was observed for phoxim with an LC50value of 901.5 (821.3∼1017) mg a.i. kg-1DW. In addition, significant synergistic responses were found from the ternary mixture of imidacloprid-phoxim-lambda-cyhalothrin and quaternary mixture of imidacloprid-phoxim-chlorpyrifos-lambda-cyhalothrin in both bioassay systems. Therefore, our findings highlighted that the simultaneous presence of several insecticides in the soil environment might lead to increased toxicity, resulting in serious damage to the nontarget organisms compared with individual insecticides.
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control/Key Laboratory for Pesticide Residue Detection of Ministry of Agriculture/Laboratory (Hangzhou) for Risk Assessment of Agricultural Products of Ministry of Agriculture, Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang, 310021, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Cang
authors.affiliation: Institute for the Control of Agrochemicals of Zhejiang Province, Hangzhou, 310020, China.
authors.forename: Dejiang
authors.initials: D
authors.lastname: Dai
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control/Key Laboratory for Pesticide Residue Detection of Ministry of Agriculture/Laboratory (Hangzhou) for Risk Assessment of Agricultural Products of Ministry of Agriculture, Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang, 310021, China.
authors.forename: Guiling
authors.initials: G
authors.lastname: Yang
authors.affiliation: Quality Supervision Division, Zhejiang Provincial Department of Agriculture, Hangzhou, 310020, China.
authors.forename: Yijun
authors.initials: Y
authors.lastname: Yu
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control/Key Laboratory for Pesticide Residue Detection of Ministry of Agriculture/Laboratory (Hangzhou) for Risk Assessment of Agricultural Products of Ministry of Agriculture, Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang, 310021, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Lv
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control/Key Laboratory for Pesticide Residue Detection of Ministry of Agriculture/Laboratory (Hangzhou) for Risk Assessment of Agricultural Products of Ministry of Agriculture, Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang, 310021, China.
authors.forename: Leiming
authors.initials: L
authors.lastname: Cai
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control/Key Laboratory for Pesticide Residue Detection of Ministry of Agriculture/Laboratory (Hangzhou) for Risk Assessment of Agricultural Products of Ministry of Agriculture, Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang, 310021, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control/Key Laboratory for Pesticide Residue Detection of Ministry of Agriculture/Laboratory (Hangzhou) for Risk Assessment of Agricultural Products of Ministry of Agriculture, Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang, 310021, China. wangyanh79@hotmail.com.
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000818:Animals; D004390:Chlorpyrifos / Q000633:toxicity; D004357:Drug Synergism; D054750:Ecotoxicology / Q000379:methods*; D007093:Imidazoles / Q000633:toxicity*; D007306:Insecticides / Q000633:toxicity*; D007928:Lethal Dose 50; D000073943:Neonicotinoids; D009570:Nitriles / Q000633:toxicity; D009574:Nitro Compounds / Q000633:toxicity*; D009835:Oligochaeta / Q000187:drug effects*; D009946:Organothiophosphorus Compounds / Q000633:toxicity; D011722:Pyrethrins / Q000633:toxicity; D012989:Soil Pollutants / Q000633:toxicity*; D018675:Toxicity Tests
chemical_list: D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009570:Nitriles; D009574:Nitro Compounds; D009946:Organothiophosphorus Compounds; D011722:Pyrethrins; D012989:Soil Pollutants; C082359:imidacloprid; C003135:phoxim; D004390:Chlorpyrifos; C037304:cyhalothrin
keywords: Combined pollution; Earthworm; Neonicotinoid insecticide; Synergistic effect; Terrestrial ecotoxicology