A U.S. Geological Survey report published on September 24 found pesticide totals in groundwater are declining around the United States.
The USGS has been monitoring pesticide concentrations in groundwater for aquifers since 1993 with well locations representing a range of soils, climate, and landforms. It has reported its findings throughout the monitoring, and its latest report shows pesticide levels are decreasing on most pesticides.
The study titled “Multidecadal Change in Pesticide Concentrations Relative to Human Health Benchmarks in the Nation’s Groundwater” focused on concentration changes in 22 pesticides that were included in laboratory analysis from 1993 to 2023. The percentage of wells that had groundwater pesticide concentrations in the moderate concentration category decreased from 7 percent in the first two decades to 1 percent to 2 percent most recently.
Moderate concentrations were those greater than 10 percent of the human health benchmark (HHB) but less than or equal to the HHB. Atrazine, deethylatrazine, alachlor, prometon, and simazine were five pesticides detected at this level.
The report stated that groundwater from domestic or public supply wells is used as a drinking-water source for roughly 13 percent of the U.S. population, and that negative human-health impacts can potentially occur from consuming water with contaminant concentrations below HHBs. With that, it concluded continued monitoring and evaluation of changes in pesticide concentrations in groundwater is important for the protection of human health.
Click here to read the report.