|Smith Jr, Sammie|
|Folmar, Henry - MISSISSIPPI DEQ|
Submitted to: Mississippi Water Resources Research Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: February 15, 2004
Publication Date: April 22, 2004
Citation: Cooper, C.M., Smith Jr, S., Folmar, H. 2004. Pesticide concentrations in surface waters of Mississippi lakes and reservoirs [abstract]. Mississippi Water Resources Research Conference. p. 38. Technical Abstract: Surface water samples from lakes and reservoirs throughout Mississippi were collected and analyzed on a seasonal basis during 2002-2003 as part of a water quality survey. The purpose of the pesticide study was to produce a significant addition of baseline information to 1) ascertain current conditions and 2) provide concentrations of some mainstream current-use and legacy pesticides for future comparisons. Over 100 sites were sampled during the year-long period, resulting in over 8000 individual analyses from 473 collections throughout the state. Temporal analysis reflected application timing, general runoff patterns and pesticide dissipation. Although the frequency of pesticide detection increased greatly from winter to spring, concentrations above 0.1 µg/L were uncommon. Summer and fall detections were also significantly fewer than spring for almost all compounds. Low concentrations (mean = 0.0474 µg/L) of 'DDT were present in almost all samples (95.8% occurrence). Detections of bifenthrin, a pyrethroid insecticide; methyl parathion, an organophosphate insecticide; atrazine, a triazine herbicide used primarily for corn, and fipronil, a new corn insecticide, were widespread, especially in spring samples. Other commonly used agricultural compounds were also seasonally present. Overall, frequency of pesticide occurrence was higher than desired, but concentrations were quite low. Of the pesticides that have EPA or state of Mississippi water quality criteria, only ten collections were excessive. Survey collections are not intended as substitutes for the robust sampling protocol needed for regulatory purposes, but they serve as an adequate screening tool for specific sites or pesticides.