Fifth national survey of pesticides in groundwater in New Zealand.

The article presents a survey on pesticides in groundwater in New Zealand. A 2006 national survey took 163 wells as samples with the aims to update the national overview of pesticides in groundwater systems in the country, to investigate temporal variation in pesticide concentrations between surveys and to identify environmental factors associated with pesticide contamination of groundwater. Results showed that there were pesticides in 11 of the 14 participating regions, identifying 31 or 19% wells tested positive for pesticides.