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Water Quality Study
of Bays in Coastal Mississippi
Water Quality Report
October 28, 2005

Project Number 05-0926
-EPA, Region 4, SESD, Athens, Georgia

[ Full Report | EnviroMapper for Hurricanes Katrina and Rita ]

Executive Summary

EPA's Region 4 Science & Ecosystem Support Division (SESD), in cooperation with the Mississippi Department of Environmental Quality (MDEQ), conducted a water quality study in the rivers and bays along the Mississippi coast following Hurricanes Katrina and Rita. The study was completed during the period September 26-30, 2005. The study area encompassed major bay systems on the Mississippi coast including Bangs Lake, Bayou Casotte, the Pascagoula and West Pascagoula River systems, the Back Bay of Biloxi, St. Louis Bay, and the Pearl River. The objective of this study was to provide sediment and water quality data in each major bay system along the Mississippi Sound. Flow was also measured at the seaward boundary of each system for estimating both conventional and toxic pollutant loadings entering the Mississippi Sound at the time of the study. This study was not designed to identify specific pollutant sources within each system or provide definitive information on the potential long term effects of the hurricanes on human or ecological health.

Findings from the EPA and MDEQ joint survey of coastal Mississippi following Hurricanes Katrina and Rita showed few detectable priority pollutant type compounds in the studied bays and rivers. In general, the pollutants present were detected in favorable concentrations when compared to EPA's National Ambient Water Quality Criteria for surface waters and the National Oceanic and Atmospheric Administration (NOAA) published effect levels for sediment. Dissolved oxygen concentrations were determined to be above the State's adopted minimum criteria at all but two of the thirty-nine surface water locations. Bacteriological densities at the study locations were less than EPA's promulgated enterococci criteria for coastal waters. Overall, the data collected by EPA shows that few water quality criteria were exceeded during the study. An exception was algal growth results in Back Bay of Biloxi and Bayou Casotte that exceeded 5 mg/l (dry weight). Dioxin results for the five sediment samples collected were all well below the EPA screening value for residential soils. The results of this study may be used as the basis for future targeted water quality studies by MDEQ and/or the EPA.

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Water Quality Study
of Bays in Coastal Mississippi
October 2005
The following document is in Acrobat PDF format. It contains 123 pages and its size is 1.04 MegaBytes Full Report


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