title: Pesticides in ground water beneath irrigated farmland in Nebraska, August 1978.
abstract: During the 1978 irrigation season, 14 ground water samples were collected in the Central Platte region of Nebraska, an area known to have high nitrate-nitrogen (NO3--N) levels, and analyzed for the presence of 13 pesticide residues. Atrazine levels ranged from 0.06 microgram/liter to 3.12 microgram/liter and were correlated to NO3--N concentrations with a coefficient of r = +0.55. Nitrate-nitrogen concentrations were measured as indicators of deep percolation from irrigated lands and ranged from 17.1 mg/liter to 34.3 mg/liter. Alachlor levels ranged from less than 0.01 microgram/liter to 0.71 microgram/liter. The amounts of 2,4-D were indeterminate because of experimental problems. Levels of the herbicides silvex and EPTC were below the limits of detectability. Levels of the organochlorine insecticides endrin, gamma-BHC (lindane), dieldrin, DDT and its primary metabolite DDE, heptachlor and its primary derivative heptachlor epoxide, and methoxychlor were all below the detectable limits of 0.005-0.010 microgram/liter.
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000032:analysis; D001280:Atrazine / Q000032:analysis; D003634:DDT / Q000032:analysis; D009329:Nebraska; D010575:Pesticides / Q000032:analysis*; D013997:Time Factors; D014867:Water / Q000032:analysis*; D014873:Water Pollutants / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D010575:Pesticides; D014873:Water Pollutants; D014874:Water Pollutants, Chemical; D014867:Water; D015084:2,4-Dichlorophenoxyacetic Acid; D003634:DDT; D001280:Atrazine