Pesticides are applied in agricultural and urban areas to control weeds, insects, and other pests.  These chemicals can be transported off-site into streams and ground water where they partition between water and sediment and degrade over time.  Both the parent pesticides and the degradates can potentially cause adverse effects on aquatic organisms and human health.

The USGS Pesticide Fate Research project is a series of studies to assess the occurrence, transport, and fate of current-use pesticides in surface and ground waters throughout California.  Analytical methods are developed to measure pesticide concentrations in water, sediments, and biological tissues at environmentally-relevant levels.  Field studies are conducted to determine the spatial and temporal occurrence of these pesticides and their degradates.  Complimentary laboratory studies are conducted to understand the factors controlling partitioning and degradation rates in the environment.  By collaborating with toxicologists and ecologists, the potential effects on aquatic organisms and human health can be assessed.

Our research is part of a larger USGS effort to look at fate and effects of pesticides on a national scale for the USGS Toxic Substances Hydrology Program - Pesticide Studies project.