Testing for Water and Sediment Contamination in the Monterey Peninsula and Salinas Watershed for Select Persistent Organic Pollutants

Triclosan, a broad spectrum antibacterial and antifungal agent, and bifenthrin, a pyrethrin insecticide are both known to be highly toxic to freshwater aquatic life. These chemicals enter the environment through wastewater and agricultural runoff from the highly productive Salinas Valley. The goal of this study was to determine if there were detectable amounts of triclosan and bifenthrin at various points along the Salinas River, in Elkhorn Slough Marine Estuary and in samples of influent and effluent wastewater. Surface water samples, sediment samples at water line, sediment samples under waterline, influent and effluent wastewater samples were collected for analysis. For triclosan analysis, all liquid samples were to be extracted and concentrated using C18 solid-phase extraction (SPE) and/or liquid- liquid extraction. However, the proposed spectrophotometric detection method for triclosan was not selective enough to only react with triclosan in environmental samples. Pyrethroids in sediments were extracted with sonication extraction followed by cleanup with C18 columns. Pyrethroid concentration in water and sediment samples was measured with a pyrethroid ELISA kit. It was anticipated sediments would have a higher triclosan and bifenthrin value than water samples and there would be higher pyrethroid levels found in the environmental samples compared to wastewater samples. The results showed that two of the thirteen testing sites, a Salinas River site and an Elkhorn Slough site, had one ppb pyrethroids present. While this is a very low amount it could potentially be enough to harm certain aquatic species. It was concluded that these locations may have had detectable pyrethroid levels due to the physical characteristics of the locations. A better understanding of the types of chemicals accumulating, or running through the waterways, into local watersheds as a result of human interference can help with future research in this area and current studies looking into common pollutants both in California and elsewhere.