Pesticides in Streams

Data on concentrations of  73 commonly used pesticides and 7 pesticide degradation products (list of herbicides - list of insecticides) were used from sites on streams that drained watersheds that had primarily agricultural, or urban land use.  These sites were sampled in NAWQA study units begun in 1991 and 1994. A subset of all  NAWQA stream sites that had sufficient data (109 sites) to calculate yearly mean concentrations were used for contaminant  plots. Contaminant exceedances were defined using both human-health and aquatic-life standards and guidelines..

Pesticides in ground water 

Data on concentrations of  73 commonly used pesticides and 7 pesticide degradation products (list of herbicides - list of insecticides) were used from shallow wells screened near the top of the water table where land use within 500 meter radius was primarily agricultural or urban. These wells were sampled in NAWQA study units begun in 1991 and 1994. Contaminant exceedances were defined using only human-health standards.