title: Sediment-associated pesticides in an urban stream in Guangzhou, China: implication of a shift in pesticide use patterns.
abstract: Pesticide use patterns in China have changed in recent years; however, the study of the environmental fate of current-use pesticides (CUPs) and their ecotoxicological significance in aquatic ecosystems is limited. In the present study, sediments were collected from an urban stream in the Chinese city of Guangzhou. Sediment-associated legacy organochlorine pesticides and CUPs-including organophosphates, pyrethroids, fipronil, and abamectin-were analyzed. Additionally, the relative toxicity of the sediments was evaluated with 10-d bioassays using Chironomus dilutus. Fifteen of 16 sediments collected from the stream were acutely toxic to C. dilutus, with 81% of the samples causing 100% mortality. Abamectin, fipronil, and pyrethroids (mainly cypermethrin) were identified as the principal contributors to the noted toxicity in the midges, with median predicted toxic units of 1.63, 1.63, and 1.03, respectively. Sediments taken from downstream sites, where residential and industrial regions were located, had elevated CUP concentrations and sediment toxicity compared with upstream sites. The present study is the first of its kind to link sediment CUPs, fipronil, and abamectin concentrations with toxicity in urban streams in China with a focus on shifting pesticide usage patterns.
authors: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China.
authors: Huizhen
authors: H
authors: Li
authors: Baoquan
authors: B
authors: Sun
authors: Michael J
authors: MJ
authors: Lydy
authors: Jing
authors: J
authors: You
mesh_terms: D000383:Agriculture / Q000706:statistics & numerical data; D000818:Animals; D002681:China; D002947:Cities; D054750:Ecotoxicology; D004784:Environmental Monitoring; D058735:Environmental Policy; D019015:Geologic Sediments / Q000737:chemistry*; D010575:Pesticides / Q000032:analysis*; D045483:Rivers / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data*
chemical_list: D010575:Pesticides; D014874:Water Pollutants, Chemical