Submitted to: Bulletin of Environmental Contamination and Toxicology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 6, 2004
Publication Date: March 1, 2004
Citation: Moore, M.T., Lizotte Jr., R.E., Cooper, C.M., Smith Jr., S., Knight, S.S. 2004. Survival and growth of Hyalella Azteca exposed to three Mississippi oxbow lake sediments. Bulletin of Environmental Contamination and Toxicology. 72:777-783. Interpretive Summary: Intensive agricultural pesticide use in the Mississippi Delta has been well documented. Occasionally after a storm event, these pesticides are potentially moved off the field and into lakes, rivers, and streams. Over time, large rivers have changed their course, resulting in the creation of oxbow lakes. These lakes are former river channels that have been cut off from the main flow of the river. These lakes historically received agricultural runoff including pesticides and sediments. The objective of this research was to examine the bottom sediment of three Delta oxbow lakes. Concentrations of pesticides found in the sediment were examined. Biological tests were then conducted on the sediment using organisms typically found in lake bottom sediments. These organisms were allowed to live on the collected sediment for ten days, then they are counted (for survival) and weighed (for growth). It was determined that the there were no serious effects of the Delta oxbow lake sediments on the survival and growth of the organisms.
Technical Abstract: Three Mississippi Delta oxbow lake sediments were collected and analyzed for potential biological impairment from historic pesticide contamination. Sediments were collected from Mossy Lake, Three Mile Lake, and Macon Lake in west central Mississippi. These oxbow lakes were formed after being cut off from the main channel of larger river systems. After formation, these lakes provide excellent historical data for fate of environmental contaminants, particularly legacy pesticides such as DDT. Core samples of lake sediments were collected and returned to the USDA ARS NSL. Samples were examined for concentrations of 17 legacy and current use pesticides. Using the amphipod, Hyalella azteca, bioassessments were conducted to examine the effects of these sediments on Hyalella survival and growth (length and weight). Results indicated no observed statistically significant differences in survival or growth of Hyalella in the three sediments when compared to control organisms. It was determined that no observable biological impairment occurred from the oxbow lake sediments.