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Summary Assessment of the Results of Sampling of Localized Areas Identified For Focused Investigations Following Hurricane Katrina
Test Results
March 2006
This report summarizes the findings of a re-sampling effort conducted in February 2006 in areas of New Orleans affected by Hurricane Katrina.
- Overview
- Background
- Focused Sample Locations
- Sampling Methodology
- Findings
- Recommendations to Prevent Exposure
- Conclusions
Overview
This more detailed sampling effort was conducted by EPA and LDEQ in flood-impacted residential areas where previous sampling found elevated concentrations of arsenic, lead or benzo(a)pyrene. The release of this report was a multi-agency effort that included the Environmental Protection Agency (EPA), Louisiana Department of Environmental Quality (LDEQ), Centers for Disease Control (CDC), Agency for Toxic Substances and Disease Registry (ATSDR), Federal Emergency Management Agency (FEMA), Louisiana Department of Health and Hospitals (LDHH), and New Orleans Health Department (NOHD).
The goal of the sampling reflected in this report was to determine whether the elevated levels of these chemicals were isolated or whether they were representative of a larger area. To accomplish this goal, samples were collected and mixed together (i.e., composite samples) to characterize the average concentration of these chemicals around the original sampling locations. Unlike previous sampling rounds, these composite samples were not only of the sediment deposited by floodwaters, but also included samples of the underlying soil that existed prior to the Hurricane.
The results of the February 2006 composite samples were compared to the individual sample results collected during Fall 2005. Our findings show that concentrations of arsenic detected in the prior samples were isolated to the original sampling location and were not representative of a larger area. Similarly, the majority of concentrations of benzo(a)pyrene were limited to the original sampling location. However, one localized area in the vicinity of the Agriculture Street Landfill had elevated levels of benzo(a)pyrene. EPA is working with LDEQ and its other Federal partners to determine the appropriate course of action in this localized area.
Elevated concentrations of lead were detected in composite samples that contained underlying soils. The samples were collected in older residential areas of New Orleans with houses that may contain lead-based paint. The elevated levels of lead found in the February 2006 samples are consistent with pre-Katrina conditions. Studies conducted in New Orleans prior to Hurricane Katrina showed both elevated levels of lead and a similar distribution of lead in the soil.
Further analyses of the lead results are underway to try to determine the source of elevated lead in these neighborhoods. Understanding the source of lead informs agencies on the best course of action to take to address the elevated levels. Although the source of the elevated lead has not been clearly established, it is wise to take precautions as lead-based paint may be present in any area with houses built prior to 1978. This report, therefore, provides a list of recommendations residents can use to minimize potential exposure to lead inside and outside their homes.
Background
On December 6, 2005, the Environmental Protection Agency (EPA), Louisiana Department of Environmental Quality (LDEQ), Centers for Disease Control (CDC), Agency for Toxic Substances and Disease Registry (ATSDR), Louisiana Department of Health and Hospitals (LDHH), and the Federal Emergency Management Agency (FEMA) released an environmental assessment summary for several parishes flooded as a result of Hurricane Katrina. These parishes included Jefferson, Orleans, St. Bernard, and Plaquemines Parishes. The assessment summary was based on the results of samples from floodwaters and sediments analyzed throughout the flood-impacted areas. The assessment released in December addressed the results of over 450 sediment samples collected from early September through mid-November 2005, which were analyzed for over 200 organic chemicals and metals. The summary was developed to provide a general assessment of the data collected in this time period.
In the discussion of the sediment data collected in the September through November timeframe, the agencies concluded that, in general, the sediments deposited in areas flooded by Hurricane Katrina in Orleans, St. Bernard, and Plaquemines Parishes are not expected to cause adverse health impacts provided people use common sense, good hygiene and safety practices. The agencies noted that elevated concentrations of some metals and organic chemicals were found in localized areas affected by the flooding. The agencies also indicated that further investigations would be necessary to adequately characterize the nature and extent of contamination in these localized areas.
Focused Sample Locations
Based on original sampling from Fall 2005 which found elevated concentrations of arsenic, lead, or benzo(a)pyrene in flood-impacted residential areas, EPA and LDEQ identified 43 areas for further investigation. To address public concerns, EPA and LDEQ also identified the neighborhood in the immediate vicinity of the former Thompson-Hayward pesticide blending facility as an area requiring further sampling. The goal of this focused sampling investigation was to determine whether the elevated levels of these chemicals were isolated to the specific location that had been identified, or whether they were representative of a larger area.
Sampling Methodology
In mid-February 2006, EPA and LDEQ collected up to 10 composite samples within a 500-foot radius of each of the 43 original sample locations in flood-impacted areas. Each composite was created by combining four discrete samples. Each composite sample was analyzed for the individual analyte that was elevated in the original sediment sample. For example, if lead was detected above 400 milligrams per kilogram (mg/kg) in the original sediment sample, the composite samples were analyzed only for lead. Similarly, composite samples collected in areas of potentially elevated arsenic were analyzed only for arsenic and composite samples collected in areas of potentially elevated benzo(a)pyrene were analyzed only for benzo(a)pyrene. The composite samples collected near the Thompson-Hayward facility were analyzed for a complete spectrum of pesticides, including DDT, DDE, DDD, dieldrin, and heptachlor epoxide.
The samples were collected from the top 2 to 3 inches of surface material that could contain both sediment and underlying soil. In some cases, only soil was collected if sediment was no longer present at that location. In more limited cases, only sediment was collected. The location and analytical results for each composite sample analyzed are posted on the EPA Hurricane Katrina web site.
Findings
View results | Download data | Daily reports: Feb. 16-22, 2006
The results of the sampling conducted in February indicate that concentrations of arsenic over a larger area in which an individual may come in contact with soil and sediment are not expected to cause any chronic health impacts. Assuming long-term (i.e., 30-year) exposures to children and adults in a residential setting, all of the arsenic concentrations fell within EPA’s excess lifetime cancer risk range of 1 in 10,000 to 1 in 1,000,000. The highest arsenic concentration detected (13.8 mg/kg) was slightly higher than the Louisiana statewide background concentration for arsenic of 12 mg/kg, but well within EPA’s risk range and below the screening level protective of non-cancer impacts (22 mg/kg).
The results of the composite samples collected in the immediate vicinity of the Thompson-Hayward facility, including one sample collected in a local schoolyard and one sample collected near a local playground, indicated that concentrations of pesticides in the area would not be expected to cause any adverse health impacts. Assuming long-term exposures to children and adults in a residential setting, all of the concentrations of pesticides detected in the composite samples were well within EPA’s excess lifetime cancer risk range of 1 in 10,000 to 1 in 1,000,000.
The results of the composite samples from the Agriculture Street Landfill indicated that benzo(a)pyrene was detected in one sample at 15.6 mg/kg. Assuming long-term exposures to children and adults in a residential setting, this concentration exceeds EPA’s excess lifetime cancer risk range. However, the analytical results from other composite samples in the area of the Agriculture Street Landfill did not contain benzo(a)pyrene above EPA’s excess lifetime cancer risk range, including samples collected at the Moton Elementary School. These data indicate that benzo(a)pyrene contamination is not a widespread problem within this neighborhood, but, instead, is limited to a small area at the north end of the site.
Lead concentrations exceeded EPA and LDEQ’s soil screening level for lead (400 mg/kg) in 57 of 147 composite samples collected in the areas where lead was previously detected in the samples collected in Fall 2005. Lead concentrations in “soil only” samples and “soil mixed with sediment” samples collected in Orleans Parish ranged from below the 400 mg/kg screening level to 3960 mg/kg. The highest lead levels were detected in soil samples.
Elevated lead levels in soil are common in older cities throughout the United States. EPA’s 1996 report, Distribution of Soil Lead in the Nation’s Housing Stock, estimated that 23 percent of privately owned homes in the US built before 1980 had soil-lead levels above 400 mg/kg, and that 3 percent had levels exceeding 5,000 mg/kg. In New Orleans, researchers from Xavier University reported soil lead levels as high as 4298 mg/kg prior to Hurricane Katrina (PAH and Metals Mixtures in New Orleans Soil and Sediment, The Science of the Total Environment, Mielke et al., 2001).
The geographic pattern of sample locations that exceeded the soil screening level for lead appears to correspond to older housing (built before 1978) that can contain interior and exterior lead-based paint. To further characterize the locations that exceeded the soil screening level of 400 mg/kg, samples from these locations are being evaluated to identify the potential sources of lead contamination, such as lead-based paint, through a chemical speciation process. EPA and LDEQ are also examining the applicability of the lead-paint based final rule issued under Section 403 of the Toxic Substance Control Act (40 CFR § 745.65). This rule defines a “soil-lead hazard” as “bare soil on residential real property or on the property of a child-occupied facility that contains total lead equal to or exceeding 400 parts per million (mg/kg) in a play area or average of 1,200 parts per million of bare soil in the rest of the yard based on soil samples” (40 CFR § 745.65(c)).
Recommendations to Prevent Exposure
Because of the historical problems with lead-based paint and elevated lead levels in soil; federal, state and local government agencies have recommended for years, that all children under the age of 6 years old living in New Orleans should be tested for lead. In 2000, 14 percent of the children tested in New Orleans had elevated blood lead levels of greater than 10 micrograms of lead per deciliter of blood. The Louisiana Childhood Lead Poisoning Prevention Program (LACLPPP) and the New Orleans Health Department (NOHD) provide information on how families can decrease the risk of lead exposure and where to get a blood lead test. NOHD also received a grant from the U.S. Conference of Mayors to develop a Lead-Safe House. The New Orleans Lead-Safe House was the first of its kind in the U.S. and is used to temporarily house families while their homes undergo lead abatement. The following are recommendations that state and federal Lead Poisoning Prevention Programs have developed to help parents protect their children from exposure to lead in the home and in their neighborhoods.
In the home:
- Keep children away from peeling paint inside the home.
- When cleaning up around homes in affected neighborhoods, shower and change clothes after finishing work and before playing with your children.
- Place washable doormats or rugs at all entries of your home. Have everyone wipe their feet or leave their shoes at the door to ensure lead-containing dust will not be tracked into the house.
- Wash doormats, rugs, cleaning rags, and work clothes separately from other family laundry.
- Frequently wash a child’s hands, especially after playing outside, before they eat, and at bedtime.
- Do not let children put dirty hands, toys or other items that might have dust on them in their mouths.
- When cleaning the home, wet-mop floors and damp-wipe surfaces.
Outside the home:
- Keep children from playing in bare dirt. Cover bare dirt with grass, bushes, or 4-6 inches of lead-free wood chips, mulch, soil, or sand.
- Keep young children away from areas, such as old fences or houses, where paint is peeling, chipping, chalking, cracking or damaged.
If you are concerned about paint, dust, and/or soil lead hazards contact the Louisiana Childhood Lead Poisoning Prevention Program at (504) 219-4413 or the Director of Health, City of New Orleans, (504) 658-2500.
Conclusions
The results of the composite samples collected in February 2006 support the conclusions of the December 6, 2005 summary assessment that the sediments in most of the areas flooded by the hurricanes are not expected to cause adverse health impacts. The concentrations of arsenic detected in samples collected in Fall 2005 were not found to be representative of the average concentration of arsenic in the areas around the original sample locations. Similarly, the concentrations of benzo(a)pyrene at most of the Fall 2005 sample locations were not found to be representative of the benzo(a)pyrene concentrations in the areas around the original locations.
Elevated concentrations of lead were detected in composite samples collected during February 2006 at several locations in older residential areas of New Orleans. However, the elevated levels of lead found in the February 2006 samples are consistent with pre-Katrina conditions. Studies conducted in New Orleans prior to Hurricane Katrina showed both elevated levels of lead and a similar distribution of lead in the soil. The recommendations listed above should be followed as residents re-enter these areas to reduce exposure to lead, particularly for children’s exposure.
More focused analyses of the lead results are underway to try to determine the source of elevated lead in these neighborhoods. Understanding the source of lead informs agencies on the best course of action to take to address the elevated levels. EPA is working with LDEQ and its other Federal partners to determine the appropriate course of action for the localized area of elevated benzo(a)pyrene at the north end of the Agriculture Street Landfill.