New USGS Study Published on Pesticides and Degradation Products in Groundwater

USGS has published a new study that finds pesticides and their degradation products are common in groundwater, but at low concentrations that are unlikely to be of concern to human health. The study is the first to assess more than 100 pesticide degradates in groundwater at the national level. Some of the significant findings include that:

• At least one pesticide or degradate was detected in just over 40% of untreated groundwater samples collected from 1,204 wells that provide tap water form major aquifers used for drinking water in the U.S.
• About 30% of the samples contained at least one pesticide degradate.
• About one-quarter of the samples contained more than one pesticide (pesticide mixtures).

The pesticides were compared to their human-health benchmarks (or “parent” pesticide” benchmarks) to determine the potential to impact human health, or were computed and summed for pesticide mixtures. Overall, pesticides were found to be of potential concern for human health in 1.6% of wells though no pesticide exceeded its benchmark or sum of mixture ratios exceeded 1.0. For more information, read the full article in Environmental Science and Technology.