ARS | Publication request: CONTAMINANT RESULTS FROM AGRICULTURE AND DRAINAGE CHANGES ON A FLOOD CONTROL RESERVOIR IN MISSISSIPPI, USA

Submitted to: Ecological Society of America Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 15, 2002
Publication Date: N/A

Technical Abstract: Analyses were conducted in water and sediment for 8 metals and 46 pesticides/contaminants at 25 stream/river locations within the Yalobusha River watershed and at 9 locations within Grenada Lake reservoir in north Mississippi. Most pesticides were detected seasonally at low concentrations in contributing streams of the watershed. Atrazine, a triazine herbicide, was the only current use pesticide found in significant concentrations in streams draining into Grenada Reservoir. It was also detected in reservoir water samples but at two orders of magnitude less than contributing stream levels. Concentrations of atrazine, however, were highest in lake sediments, but detection rate was only 57%. Naturally occurring metals were found in high concentrations, particularly aluminum and iron. Residual contaminants such as DDT were not detected or were detected in low concentrations, predominately in lake sediments. Sediment deposition rates from channelization, channel incision, and watershed use (agriculture and silviculture) ranged from less than 1 cm/yr to about 5 cm/yr since 1954 as determined by Cs-137 analysis. With the exception of possible effects from atrazine, continued long-term agricultural production in the watershed does not appear a cause for significant concerns about water quality.