Map: New Orleans sediment contamination

A recent GNOCDC Numbers Talk newsletter provided links to some great National Resource Defense Council sediment contamination maps. The NRDC analysis and maps were based on Louisiana DEQ samples.

The NRDC analysis overview:

The floodwaters from hurricanes Katrina and Rita swept a mixture of soil, mud from Lake Pontchartrain, and debris into the greater New Orleans area. When the water receded, it left behind a caked layer of muck on streets, yards, porches and playgrounds across the region – sediment that was likely contaminated with heavy metals and toxic chemicals swept up from industrial areas. The U.S. Environmental Protection Agency (EPA) collected hundreds of samples of this sediment throughout the New Orleans region from September 10, 2005 to January 15, 2006, and released the data – absent any analysis – to the public on its website (http://oaspub.epa.gov/storetkp/dw_home) in January 2006.

NRDC has now analyzed the EPA’s sediment data, and the Greater New Orleans Community Data Center has created maps to demonstrate patterns of contamination in the sediment. Although the EPA tested for a variety of contaminants, this analysis focuses on four toxic contaminants that are most widespread in the sediment samples: arsenic, lead, diesel fuel and benzo(a)pyrene. All of these contaminants were detected in sediment throughout the greater New Orleans area, often in concentrations in excess of EPA and Louisiana Department of Environmental Quality (LDEQ) cleanup guidelines for soil in residential areas.

Our analysis of EPA data shows that most districts in New Orleans contain concentrations of arsenic, lead, diesel fuel or cancer-causing benzo(a)pyrene above levels that would normally trigger investigation and possible soil cleanup in the state of Louisiana. Some hot spots in residential neighborhoods have levels of contamination that are ten times, or even more than a hundred times normal soil cleanup levels. For example, a location in Gert Town, Mid-City has arsenic in the soil at a level 6.5 times the Louisiana cleanup level for residential soil, and 200 times the federal health-based level of concern for soil in residential neighborhoods. The Lake Terrace neighborhood in Gentilly has lead in the soil at a level three times the Louisiana cleanup level. Locations in Chalmette and in the St. Roch neighborhood have diesel fuel contamination more than 200 times the Louisiana soil screening cleanup level. A hot spot for benzo(a)pyrene contamination is in Bywater, at the Agricultural Street Landfill, where the levels exceed Louisiana soil cleanup levels by more than fiftyfold. The EPA did not sample unflooded areas, such as the East Bank and West Bank neighborhoods; soil conditions in these areas are unknown.

People returning to New Orleans should take precautions to limit their exposure to the sediment (see Health Advisory, pg. 20). Young children should not play in any areas where there is still sediment on the ground, and it would be best to keep children out of the city until cleanup has occurred. Government agencies must clean up contaminated sediment, and must provide assistance – including information and protective equipment – to people who are trying to clean up their own property. As schools reopen in previously flooded areas, the playgrounds and school yards should be tested to ensure that they have been adequately cleaned before children come back to school.