title: Acute toxicity and genotoxicity of two novel pesticides on amphibian, Rana N. Hallowell.
abstract: Imidacloprid [1-(6-chloro-3-pyridylmethyl)-N-nitro-imidazolidin-2-ylideneamine] and RH-5849 [2'-benzoyl-l'-tert-butylbenzoylhydrazinel] are two pesticides used in China since 1992. In the present study we conducted acute toxicity test, micronucleus (MN) test and comet assay of the two pesticides on amphibian, Rana N. Hallowell, a sensitive organism suitable for acting as the bio-indicator of aquatic and agricultural ecosystems. The values of LC50-48 h of imidacloprid were found to be 165 mg l(-1) for tadpoles of Rana limnocharis and 219 mg l(-1) for tadpoles of Rana N. Hallowell. On the other hand, RH-5849 showed no acute toxicity to tadpoles during the 96 h exposure even it was saturated in the test solutions. There were significant differences in the MN frequencies between the negative controls and the treated groups at the dose of 8 mg l(-1) for imidacloprid (p < 0.05) and 40 mg l(-1) for RH-5849 (p < 0.01). Comet assay found significant differences (p < 0.01) in the distributions of DNA damage grades between the negative controls and groups treated in vitro with 0.05, 0.1, 0.2 and 0.5 mg l(-1) of imidacloprid and 5, 25, 50 and 100 mg l(-1) of RH-5849, respectively. DNA damage scores increased with the exposure levels of the two pesticides and dose-effect relationships were observed for both imidacloprid (r2 = 0.92) and RH-5849 (r2 = 0.98). The MN test and comet assay revealed potential adverse effects of the two pesticides on DNA in the erythrocytes of amphibians in aquatic and agricultural ecosystems.
authors.affiliation: The State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
authors.forename: Shaolong
authors.initials: S
authors.lastname: Feng
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Kong
authors.forename: Xinming
authors.initials: X
authors.lastname: Wang
authors.forename: Lirong
authors.initials: L
authors.lastname: Zhao
authors.forename: Pingan
authors.initials: P
authors.lastname: Peng
mesh_terms: D000818:Animals; D002681:China; D020552:Comet Assay; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D004784:Environmental Monitoring / Q000379:methods*; D006834:Hydrazines / Q000737:chemistry / Q000633:toxicity*; D007093:Imidazoles / Q000737:chemistry / Q000633:toxicity*; D007306:Insecticides / Q000633:toxicity*; D007814:Larva / Q000187:drug effects; D015162:Micronucleus Tests; D009152:Mutagenicity Tests; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010944:Plants; D011898:Ranidae / Q000235:genetics* / Q000378:metabolism; D018709:Statistics, Nonparametric; D023382:Toxicity Tests, Acute
chemical_list: D006834:Hydrazines; D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; C056565:1,2-dibenzoyl-tert-butylhydrazine; C082359:imidacloprid