title: Widespread occurrence of neonicotinoid insecticides in streams in a high corn and soybean producing region, USA.
abstract: Neonicotinoid insecticides are of environmental concern, but little is known about their occurrence in surface water. An area of intense corn and soybean production in the Midwestern United States was chosen to study this issue because of the high agricultural use of neonicotinoids via both seed treatments and other forms of application. Water samples were collected from nine stream sites during the 2013 growing season. The results for the 79 water samples documented similar patterns among sites for both frequency of detection and concentration (maximum:median) with clothianidin (75%, 257 ng/L:8.2 ng/L) > thiamethoxam (47%, 185 ng/L:<2 ng/L) > imidacloprid (23%, 42.7 ng/L: <2 ng/L). Neonicotinoids were detected at all nine sites sampled even though the basin areas spanned four orders of magnitude. Temporal patterns in concentrations reveal pulses of neonicotinoids associated with rainfall events during crop planting, suggesting seed treatments as their likely source.
authors.affiliation: U.S. Geological Survey, California Water Science Center, 6000 J Street, Placer Hall, Sacramento, CA 95819, USA. Electronic address: mhladik@usgs.gov.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Hladik
authors.affiliation: U.S. Geological Survey, Iowa Water Science Center, 400 S. Clinton Street, Iowa City, IA 52244, USA. Electronic address: dwkolpin@usgs.gov.
authors.forename: Dana W
authors.initials: DW
authors.lastname: Kolpin
authors.affiliation: U.S. Geological Survey, Oregon Water Science Center, 2130 SW 5th Avenue, Portland, OR 97201, USA. Electronic address: kkuivila@usgs.gov.
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Kuivila
mesh_terms: D000383:Agriculture; D000818:Animals; D004784:Environmental Monitoring; D006146:Guanidines / Q000032:analysis; D007093:Imidazoles / Q000032:analysis; D007306:Insecticides / Q000032:analysis*; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000032:analysis; D010078:Oxazines / Q000032:analysis; D045483:Rivers / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry; D013025:Glycine max / Q000737:chemistry*; D000077922:Thiamethoxam; D013844:Thiazoles / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*; D003313:Zea mays / Q000737:chemistry*
chemical_list: D006146:Guanidines; D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010078:Oxazines; D013844:Thiazoles; D014874:Water Pollutants, Chemical; C480342:clothianidin; C082359:imidacloprid; D000077922:Thiamethoxam
keywords: Clothianidin; Imidacloprid; Seed treatments; Surface water; Thiamethoxam