Web Release Date: October 25,
Effects of Hurricanes Katrina and Rita on the Chemistry of Bottom Sediments in Lake Pontchartrain, Louisiana, USA
and
U.S. Geological Survey, 8027 Exchange Drive, Austin Texas, U.S. Geological Survey, 3039 Amwhiler Road, Atlanta Georgia, U.S. Geological Survey, Denver Federal Center, West 6th Avenue and Kipling Street, Lakewood, Colorado, U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California, and U.S. Geological Survey, 3535 S. Sherwood Forest Blvd., Baton Rouge, Louisiana
Received for review April 18, 2006
Revised manuscript received September 4, 2006
Accepted September 6, 2006
Abstract:
The effects of Hurricanes Katrina and Rita and the subsequent unwatering of New Orleans, Louisiana, on the sediment chemistry of Lake Pontchartrain were evaluated by chemical analysis of samples of street mud and suspended and bottom sediments. The highest concentrations of urban-related elements and compounds (e.g., Pb, Zn, polycyclic aromatic hydrocarbons, and chlordane) in bottom sediments exceeded median concentrations in U.S. urban lakes and sediment-quality guidelines. The extent of the elevated concentrations was limited, however, to within a few hundred meters of the mouth of the 17th Street Canal, similar to results of historical assessments. Chemical and radionuclide analysis of pre- and post-Hurricane Rita samples indicates that remobilization of near-shore sediment by lake currents and storms is an ongoing process. The effects of Hurricanes Katrina and Rita on the sediment chemistry of Lake Pontchartrain are limited spatially and are most likely transitory.
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