How many streams and wells were sampled?
Water samples for pesticide analysis were collected from 186 streams within the 51 Study Units, bed-sediment samples were collected from 1,052 stream sites, and fish samples were collected from 700 stream sites. Ground-water samples were collected from 5,047 wells in 187 ground-water study areas (each study generally included 20 to 30 wells). Shallow ground water (generally less than 20 feet below the water table) was sampled in agricultural, urban, and undeveloped areas, mostly from new or existing observation wells or domestic supply wells. Deeper ground water was sampled from wells that tap major aquifers, which was almost exclusively from existing wells used either for domestic or public supply. Fewer stream sites were sampled for water because the study of each site requires numerous water samples over time, whereas bed-sediment, fish, and ground water studies were based on one sample per site.
