USGS environmental characterization of flood sediments left in the New Orleans area after Hurricanes Katrina and Rita, 2005

The flooding in the greater New Orleans area that resulted from Hurricanes
Katrina and Rita in September, 2005, left behind accumulations of sediments up
to many centimeters thick on streets, lawns, parking lots, and other flat
surfaces. These flood sediment deposits have been the focus of extensive study
by the US Environmental Protection Agency (EPA) and Louisiana Department of
Environmental Quality (LDEQ) due to concerns that the sediments may contain
elevated levels of heavy metals, organic contaminants, and microbes.

The U.S. Geological Survey (USGS) is characterizing a limited number of flood
sediment samples that were collected on September 15-16 and October 6-7, 2005,
from the greater New Orleans area by personnel from the USGS Louisiana Water
Science Center in Baton Rouge. Small samples (< 3 pints each) of wet to dry
flood sediment were collected from 11 localities around downtown New Orleans on
September 15, 2005, and two large samples (40 pints each) of wet flood sediment
were collected from the Chalmette area on September 16. Twelve additional
samples (8-10 pints each) were collected from New Orleans, Slidell, Rigolets,
and Violet on October 6 and 7.

The USGS characterization studies of these flood sediments are designed to
produce data and interpretations regarding how the sediments and any contained
contaminants may respond to environmental processes. This information will be
of use to cleanup managers and DoI/USGS scientists assessing environmental
impacts of the hurricanes and subsequent cleanup activities.

[Summary provided by the USGS.]