The National Water-Quality Assessment (NAWQA) and National Stream Quality Accounting Network (NASQAN) programs of the USGS provide historical and current water quality data for pesticides in surface water systems across the US.  Generally these datasets are considered by US EPA when developing exposure profiles in human health dietary and aquatic ecological risk assessments for specific pesticide registration actions.  However, the data usually are considered supplemental due to assumed inadequacies in sampling designs in the general context of �targeting� monitoring in time and space relative to particular use patterns of pesticide products.  There is general interest in extracting more value from the NAWQA and NASQAN data for two reasons.  First, the programs contain large numbers of samples that increase as these taxpayer-funded programs continue, currently on the order of > 30 thousand for many analytes, and second, because large numbers of pesticide active ingredients, and in some cases, degradates, are included in the robust and sensitive multiresidue analytical methods used by USGS.  In this presentation using data for the organophosphate insecticide chlorpyrifos we make inferences on peak annual concentrations nationally and by domain using analyses from a centile estimation method and compare these inferences to data summaries from other monitoring programs, watershed-scale pesticide fate and transport modeling, and biomonitoring of a specific human urinary metabolite in a weight-of-evidence approach to assess reliability of the inferences.

Interpretation of peak concentration estimates for a typical NAWQA/NASQAN surface water monitoring dataset using a weight-of-evidence approach

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.