Submitted to: Bulletin of Environmental Contamination and Toxicology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/25/2010
Publication Date: 3/14/2010
Citation: Lizotte Jr, R.E., Knight, S.S., Cooper, C.M. 2010. Toxicity evaluation of a conservation effects assessment program watershed, Beasley Lake, in the Mississippi Delta, USA. Bulletin of Environmental Contamination and Toxicology. 84(4):422-426. DOI:10.1007/s00128-010-9551-x. Interpretive Summary: We examined monthly pesticide contamination and their effects on an aquatic invertebrate animal, Hyalella azteca, in Beasley Lake, a Conservation Evaluation Assessment Program watershed in the Mississippi Delta. We looked for seventeen pesticides and metabolites in lake water and leaf litter samples. Effects of contaminated lake water and leaf litter on animal survival and growth were examined. Sixteen pesticides were found in both lake water and leaf litter. Animal survival and growth in lake water and leaf litter were equal or better than uncontaminated water and leaf litter. These results are of interest to regulatory and other agencies and the pesticide industry by providing additional information to improve and sustain lake and flood plain water quality and overall environmental quality using conservation practices.
Technical Abstract: Beasley Lake was assessed monthly in 2005 for biological impairment from 17 historic and current-use pesticides in water and leaf litter using Hyalella azteca (Saussure). Sixteen pesticides were detected in both water and leaf litter with peak detections in spring and summer. Detections ranged from 1-125 ng L-1 in water and 1-539 ng g-1 OC in leaf litter. Ten-day H. azteca survival and growth (mg dw) bioassay results indicated no adverse effects on survival or growth in H. azteca exposed to water or leaf litter. Rather, enhanced growth occurred in both lake water and leaf litter exposures for greater than or equal to 6 months.