Hurricane Floodwater and Sediment Sampling Shows Toxic Locations

WASHINGTON, DC, October 14, 2005 (ENS) - The U.S. Environmental Protection Agency (EPA) is offering the EnviroMapper - a new tool on its website to display test results from floodwater and sediment sampling in areas of Louisiana impacted by Hurricanes Katrina and Rita.

Air monitoring and ambient water data will be added as they become available. The EnviroMapper for Hurricanes Katrina and Rita combines interactive maps and aerial photography to help zoom into sites or areas of interest.

Data from other states will be added as it becomes available.

Data from EPA and Louisiana Department of Environmental Quality sampling sites can be searched by zip code, address, facility, watershed, or latitude/longitude.

In addition, the "By Facility" option provides access to sampling data directly adjacent to or nearby specific manufacturing and chemical facilities.


New Orleans houses were destroyed by flood waters after hurricane Katrina blew through the area and the levees broke, flooding the city for weeks. Some homes floated off their foundations and bumped into others. (Photo by Marvin Nauman courtesy FEMA)
Some views allow you to select or de-select layers of information such as street names or bodies of water. The earliest data available on this Web tool is from September 3, 2005.

EPA emergency response personnel are working in partnership with the Federal Emergency Management Agency (FEMA) and state and local agencies to help assess the damage, test health and environmental conditions, and coordinate cleanup from Hurricanes Katrina and Rita. In emergency situations such as this, the EPA serves as the lead agency for the cleanup of hazardous materials, including oil and gasoline.

In coordination with the Louisiana Department of Environmental Quality, EPA personnel performed chemical sampling of New Orleans flood waters for over 100 priority pollutants such as volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs), total metals, pesticides, herbicides, and polychlorinated biphenyls (PCBs).

The data have been reviewed and validated through a quality assurance process to ensure scientific accuracy.

The data were compared to EPA's drinking water maximum contaminant levels and action levels or to health guidance values calculated by the Agency for Toxic Substances and Disease Registry (ATSDR), an agency within the Centers for Disease Control.

ATSDR minimum risk levels (MRLs) exist for some chemicals and levels measured were compared to MRLs, when available. For hazardous substances for which there are no MRLs, hte ATSDR developed exposure models based on current available toxicity information.

Flood water sampling data for biological pathogens from September 3 on are being posted as they become available.

To date, E. coli levels remain greatly elevated and are much higher than EPA’s recommended levels for contact. Based on sampling results, emergency responders and the public should avoid direct contact with standing water when possible.

Sediment, for the purposes of the hurricane response sampling effort, is being defined as residuals deposited by receding flood waters which may include historical sediment from nearby water bodies, soil from yards, road and construction debris, and other material.


Flooded New Orleans homeowner Michael Caswell tries to save a few items amidst the toxic debris. (Photo by Marvin Nauman courtesy FEMA)
Preliminary results indicate that some sediment may be contaminated with bacteria and fuel oils. Human health risks may exist from contact with sediment deposited from receding flood waters. As sediments begin to dry, EPA will perform air sampling to monitor potential inhalation risks and will also assess long-term exposure scenarios.

E. coli was detected in sediment samples but no standards exist for determining human health risks from E. coli in soil or sediment

The EPA worked closely with the ATSDR to determine sediment exposure scenarios. MRLs exist for some chemicals and levels measured were compared to MRLs when available. For hazardous substances for which there is no MRL, the ageny developed exposure models based on current available toxicity information.

MRLs are available at

Find the EnviroMapper at:

The results of a private sampling effort released Thursday show that sediment samples collected from three neighborhoods contained arsenic, benzo(a)pyrene and petroleum hydrocarbons at levels exceeding EPA and Louisiana Department of Environmental Quality standards.

On September 16, 2005, Subra Company was assisted by Altamont Environmental with sediment and surface water sampling in five residential areas in New Orleans, Chalmette and Meraux that were impacted by flood waters from Hurricane Katrina. The sampling was conducted to assess potential organic and inorganic contamination of those residential areas.

Regulatory Criteria were exceeded at the following sample locations:

After evaluating the data Subra Company President Wilma Subra said, "The community members should not have been allowed to return to the areas where they could come in contact with the contaminated sediments."

"Community members have been allowed to return to the sampled residential areas to check on and clean up their homes. The community members were not provided with information about the contamination nor provided with protective equipment to minimize their exposure to the toxic chemicals in the sediment," Subra said.

"The cumulative impacts of the large number of toxic chemicals in the sediment pose a risk to community members and response personnel working in the area without protective equipment," she said.

Subra urged the EPA to require that cleanup levels be met before community members are allowed to return to the contaminated areas.

The sampling project was performed by Subra Company and The Louisiana Environmental Action Network and Altamont Environmental and was sponsored by Mitchell Kapor Foundation.

The full Subra report is available at