Atrazine, alachlor, and total inorganic nitrogen concentrations of winter wind-eroded sediment samples.

The objective of this study was to determine if atrazine (2-chloro-4-ethylamino-6-isopropyl-1,3,5-triazine), alachlor [2-chloro-N-(2,6-diethylphenyl-N-(methoxymethyl)acetamide], or inorganic nitrogen was present on wind-eroded sediments collected from road ditch areas in mid to late winter. Sediment samples that had been deposited in ditches on top of snow were collected during the winters of 1994, 1995, and 1996 at randomly selected sites in eastern South Dakota and western Minnesota. Atrazine, atrazine metabolites [deethylatrazine (DEA)(6-chloro-N-1-methylethyl-1,3,5-triazine-2,4-diamine], and deisopropylatrazine (DIA) (6-chloro-N-ethyl-1,3,5-triazine-2,4-diamine), and alachlor were determined by gas chromatography. Total inorganic N (NO(3-) + NH4+) concentration was determined with a nitrogen analyzer. In all years, atrazine was detected in at least 72% of the samples, with a mean concentration of 8.9 ug kg-1 and, while DEA was detected in at least 18% of the samples. Alachlor was detected in at least 27% of the soil samples for all three years with mean sediment concentration of > 5 ug kg-1. Inorganic N concentration of all samples averaged 33 mg kg-1. These data suggest that deposition of wind-eroded sediment contributes to nonpoint source contamination of nontarget areas by agrichemicals.