High Resolution GC/MS Method for Chlorinated Pesticides in Wastewater

The East Bay Municipal Utility District has a NPDES permit requirement to monitor for organochlorine pesticides in its final effluent. The currently approved method for NPDES monitoring is EPA Method 608. This method is not sensitive enough to measure pesticides at concentrations of interest for NPDES compliance. In addition the method can yield false positives near the method detection limits. In response to these issues, the EBMUD Office of Regulatory Compliance developed Data Quality Objectives (DQOs) for this analysis. As part of the DQOs, the EBMUD Laboratory was tasked to develop a method sensitive enough to confirm detected concentrations near the EPA Method 608 detection limits. The method developed is a solid phase extraction method followed by HR GC/MS analysis. The presentation reviews the development of the extraction, cleanup, and analysis steps. The method performance is also evaluated.