title: Chlorinated pesticides in stream sediments from organic, integrated and conventional farms.
abstract: To determine if current sheep/beef farming practices affect pesticide residues in streams, current-use and legacy chlorinated pesticides were quantified in 100 sediment samples from 15 streams on the South Island of New Zealand. The study involved five blocks of three neighboring farms, with each block containing farms managed by organic, integrated and conventional farming practices. Significantly higher concentrations of dieldrin, ∑ endosulfans, ∑ current-use pesticides, and ∑ chlorinated pesticides were measured in sediments from conventional farms compared to organic and integrated farms. However, streams in the latter two farming categories were not pesticide-free and sometimes contained relatively high concentrations of legacy pesticides. Comparison of measured pesticide concentrations with sediment quality guidelines showed that, regardless of farming practice, mean pesticide concentrations were below the recommended toxicity thresholds. However, up to 23% of individual samples contained chlorpyrifos, endosulfan sulfate, ∑ DDT, dieldrin, or ∑ chlordane concentrations above these thresholds.
authors.affiliation: Department of Chemistry, University of Otago, Dunedin, New Zealand.
authors.forename: Pourya
authors.initials: P
authors.lastname: Shahpoury
authors.forename: Kimberly J
authors.initials: KJ
authors.lastname: Hageman
authors.forename: Christoph D
authors.initials: CD
authors.lastname: Matthaei
authors.forename: Francis S
authors.initials: FS
authors.lastname: Magbanua
mesh_terms: D000383:Agriculture; D000822:Animal Husbandry; D000818:Animals; D002417:Cattle; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D006843:Hydrocarbons, Chlorinated / Q000032:analysis*; D009520:New Zealand; D058871:Organic Agriculture; D010573:Pesticide Residues / Q000032:analysis; D010575:Pesticides / Q000032:analysis*; D045483:Rivers / Q000737:chemistry*; D012756:Sheep; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data
chemical_list: D006843:Hydrocarbons, Chlorinated; D010573:Pesticide Residues; D010575:Pesticides; D014874:Water Pollutants, Chemical
keywords: Current-use pesticides; Farming practices; Historic-use pesticides; Land use; Legacy pesticides; New Zealand; Probable effect concentrations; Threshold effect concentrations