Landscape care pesticide residues in residential drinking water wells

A survey of water from 53 residential drinking water wells in a small residential community in south-central Connecticut was carried out. Actual usage of pesticides by the community was unknown although 66 per cent of homeowners participating in the study reported intermittent use. Samples were analysed for 19 pesticides. At least one pesticide residue was found in 6 out of 53 wells which was a low frequency of detection. However, for several pesticides the detection methods were not sensitive enough and detection limits were not low enough. Average concentrations of detected pesticides were just above the levels of detection. No levels of pesticide exceeded any maximal contamination levels for drinking water or any reference dose. The study indicated that, although pesticide levels were low, residues could potentially contaminate the deep groundwater used by homeowners.