title: Use of toxicity identification evaluations to determine the pesticide mitigation effectiveness of on-farm vegetated treatment systems.
abstract: Evidence of ecological impacts from pesticide runoff has prompted installation of vegetated treatment systems (VTS) along the central coast of California, USA. During five surveys of two on-farm VTS ponds, 88% of inlet and outlet water samples were toxic to Ceriodaphnia dubia. Toxicity identification evaluations (TIEs) indicated water toxicity was caused by diazinon at VTS-1, and chlorpyrifos at VTS-2. Diazinon levels in VTS-1 were variable, but high pulse inflow concentrations were reduced through dilution. At VTS-2, chlorpyrifos concentrations averaged 52% lower at the VTS outlet than at the inlet. Water concentrations of most other pesticides averaged 20-90% lower at VTS outlets. All VTS sediment samples were toxic to amphipods (Hyalella azteca). Sediment TIEs indicated toxicity was caused by cypermethrin and lambda-cyhalothrin at VTS-1, and chlorpyrifos and permethrin at VTS-2. As with water, sediment concentrations were lower at VTS outlets, indicating substantial reductions in farm runoff pesticide concentrations.
authors: Department of Environmental Toxicology, University of California, Davis, CA, USA. jwhunt@ucdavis.edu
authors: John
authors: J
authors: Hunt
authors: Brian
authors: B
authors: Anderson
authors: Bryn
authors: B
authors: Phillips
authors: Ron
authors: R
authors: Tjeerdema
authors: Bryan
authors: B
authors: Largay
authors: Melanie
authors: M
authors: Beretti
authors: Amanda
authors: A
authors: Bern
mesh_terms: D000383:Agriculture; D033304:Amphipoda / Q000502:physiology; D000818:Animals; D001673:Biodegradation, Environmental; D004390:Chlorpyrifos / Q000633:toxicity; D003621:Daphnia / Q000502:physiology; D003976:Diazinon / Q000633:toxicity; D019015:Geologic Sediments / Q000737:chemistry; D009570:Nitriles / Q000633:toxicity; D010575:Pesticides / Q000633:toxicity*; D011722:Pyrethrins / Q000633:toxicity; D012989:Soil Pollutants / Q000633:toxicity*; D018675:Toxicity Tests; D014873:Water Pollutants / Q000633:toxicity*
chemical_list: D009570:Nitriles; D010575:Pesticides; D011722:Pyrethrins; D012989:Soil Pollutants; D014873:Water Pollutants; C017160:cypermethrin; D004390:Chlorpyrifos; C037304:cyhalothrin; D003976:Diazinon