Coordinated Pesticide Reconnaissance Study of Surface Waters in California

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Pesticides are used throughout the State of California in both urban and agricultural settings and are routinely detected in surface water. Each year, new pesticides are introduced to the market and often become detected in surface water. It can take several years or more for routine monitoring programs to acquire the capability to detect new and understudied pesticides of concern because established programs are typically slow to adapt and lag times in the development of analytical methods for new pesticides can be lenghtly. This means that it can take a long time to identify if a new or understudied pesticide is present and impacting surface waters.

Map showing approximate sampling locations.

Map showing approximate sampling locations

This study will utilize the unique analytical capabilities of the USGS Pesticide Fate Research Group, Organic Chemistry Research Laboratory to assess the occurrence of a large suite of current-use pesticides and pesticide degradates (including numerous understudied compounds) in surface waters within California. Water and sediment samples will be collected and analyzed from sites undergoing concurrent, routine water chemistry and toxicity monitoring by various State entities. Analyses conducted by the USGS will greatly expand upon the work conducted by these groups and aid in evaluating their toxicity testing data. The results of this study will be used by the cooperator to determine what emerging pesticides are present in surface water and if any are present above known toxicity values, to prioritize which pesticides, if any, warrant further investigation, and to evaluate models and monitoring protocols.

The proposed study will be a two year reconnaissance of current-use pesticides and pesticide degradates in surface-water and suspended sediment samples collected from 12 sites located throughout California. Samples will be collected from six urban runoff influenced sites and 6 sites primarily influenced by agricultural runoff. Samples will be collected three times per year for two consecutive years at each site and will consist of a combination of wet and dry season events. Samples will be collected by various State entities following State mandated Surface Water Ambient Monitoring Program protocols. Water samples will be analyzed at the USGS PFRG laboratory by two analytical methods (GC/MS and LC/MS/MS) for a suite of 152 pesticides and degradates. Suspended sediments associated with these water samples will be analyzed for 125 pesticides and degradates by GC/MS.