MP5 Agrochemicals and Pesticides
Monday, 14 November 2005: 8:00 AM - 5:30 PM in Exhibit Hall

(BUD-1117-832751) Survey for Synthetic Pyrethroids within the San Diego Creek/Newport Bay Watershed.

Budd, R¹, Bondarenko, S¹, Gan, J¹, ¹ UC, Riverside, CA, USA

ABSTRACT- The Upper Newport Bay is an ecological reserve located within Orange County, CA. It is a marine estuary that provides habitat for nearly 200 species of birds, and several species of fish, mammals and native plants. The primary freshwater inlet for the estuary is the San Diego Watershed, which is the primary drainage area for the cities of Santa Ana, Tustin, Lake Forest and Irvine. With the increasing encroachment of urban sprawl, there has been a dramatic shift in land use within the San Diego Watershed from agricultural to urban landscapes. There is a concern that this shift in land use will result in an increase of non-source pollution from individual homesteads that use pesticides to aid in insect and weed control. The use of pyrethroids has increased steadily in both agricultural and urban settings as a replacement for organophosphate insecticides. Pyrethroids commonly have high aquatic toxicity, and contamination of surface streams by pyrethroids is of concern. In addition, nursery use has also increased drastically since 1995 as mandated for red and imported fire ant quarantine. The objective of this study was to determine the presence and spatial variability of pyrethroids within the watershed. Sediment grab samples were taken from locations within the watershed. Samples were collected during wet and dry seasons to compare storm water runoff with base flow concentrations. The samples were collected at the outlets of existing nurseries, within drainage channels, and within the estuary. Samples were analyzed for pyrethroids using gas chromatography with electron-capture detection. A spatial analysis was conducted to assess correlation between land use and pyrethroid concentrations.

Key words: Pyrethroid, Urban runoff, Monitorring