Submitted to: Chemistry and Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/30/2010
Publication Date: 12/4/2010
Citation: Lizotte Jr, R.E., Knight, S.S., Bryant, C.T. 2010. Sediment quality assessment of Beasley Lake: Bioaccumulation and effects of pesticides in Hyalella azteca. Chemistry and Ecology. 26(6):411-424. DOI:10.1080/02757540.2010.522997. Interpretive Summary: We examined sediment 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 in 2004 and 2008. We looked for seventeen pesticides and metabolites in sediment samples and animal tissues. Effects of contaminated sediments on animal survival and growth were examined. Fourteen pesticides were found in sediment and thirteen in animal tissues. Animal survival in Beasley Lake sediments and were similar in 2004 and 2008. Animals grew smaller in 2004 than in 2008 and these smaller animals coincided with higher levels of pesticides in animal tissues. 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 is a Conservation Evaluation Assessment Program (CEAP) watershed in the intensively cultivated Mississippi Delta, USA. Lake sediment quality at three sites was evaluated in 2004 and 2008 for biological impairment and uptake (viz. body residues) from 14 pesticides and three metabolites using Hyalella azteca (Saussure). Eleven pesticides and three metabolites were detected in sediment among the three sites in 2004 and all compounds examined among the three sites in 2008 with the herbicide atrazine having the greatest concentrations. Twenty-eight-day H. azteca survival and growth (mg w/w) indicated no survival effects at any site for either year but growth impairment occurred in H. azteca exposed to sediments in 2004 whereas growth enhancement occurred in H. azteca exposed to sediments at one site in 2008. Pesticides observed in animal body residues occurred more frequently and in greater concentrations in 2004 versus 2008. Thirteen pesticides were detected in animal body residues in 2004 with the insecticide chlorpyrifos occurring in the greatest concentrations and six pesticides in 2008 with the legacy insecticide p,p’-DDT occurring in the greatest concentrations. H. azteca body residues of seven pesticides, two herbicides, three insecticides, one insecticide metabolite, and p,p’-DDT, were associated with growth.