Lead distributions and risks in New Orleans following Hurricanes Katrina and Rita.

During the last four years, significant effort has been devoted to understanding the effects that Hurricanes Katrina and Rita had on contaminant distribution and redistribution in New Orleans, Louisiana, USA, and the surrounding Gulf Coast area. Elevated concentrations were found for inorganic contaminants (including As, Fe, Pb, and V), several organic pollutants (polycyclic aromatic hydrocarbons, pesticides, and volatiles) and high concentration of bioaerosols, particularly Aeromonas and Vibrio. Data from different research groups confirm that some contaminant concentrations are elevated, that existing concentrations are similar to historical data, and that contaminants such as Pb and As may pose human health risks. Two data sets have been compiled in this article to serve as the foundation for preliminary risk assessments within greater New Orleans. Research from the present study suggests that children in highly contaminated areas of New Orleans may experience Pb exposure from soil ranging from 1.37 microg/d to 102 microg/d. These data are critical in the evaluation of children's health.

Metal concentrations in schoolyard soils from New Orleans, Louisiana before and after Hurricanes Katrina and Rita.

The long-term environmental impact and potential human health hazards resulting from Hurricanes Katrina and Rita throughout much of the United States Gulf Coast, particularly in the New Orleans, Louisiana, USA area are still being assessed and realized after more than four years. Numerous government agencies and private entities have collected environmental samples from throughout New Orleans and found concentrations of contaminants exceeding human health screening values as established by the United States Environmental Protection Agency (USEPA) for air, soil, and water. To further assess risks of exposure to toxic concentrations of soil contaminants for citizens, particularly children, returning to live in New Orleans following the storms, soils collected from schoolyards prior to Hurricane Katrina and after Hurricane Rita were screened for 26 metals. Concentrations exceeding USEPA Regional Screening Levels (USEPA-RSL), total exposure, non-cancer endpoints, for residential soils for arsenic (As), iron (Fe), lead (Pb), and thallium (Tl) were detected in soil samples collected from schoolyards both prior to Hurricane Katrina and after Hurricane Rita. Approximately 43% (9/21) of schoolyard soils collected prior to Hurricane Katrina contained Pb concentrations greater than 400mgkg(-1), and samples from four schoolyards collected after Hurricane Rita contained detectable Pb concentrations, with two exceeding 1700mgkg(-1). Thallium concentrations exceeded USEPA-RSL in samples collected from five schoolyards after Hurricane Rita. Based upon these findings and the known increased susceptibility of children to the effects of Pb exposure, a more extensive assessment of the soils in schoolyards, public parks and other residential areas of New Orleans for metal contaminants is warranted.

Spatial distribution of lead concentrations in urban surface soils of New Orleans, Louisiana USA.

Immediately following hurricane Katrina concern was raised over the environmental impact of floodwaters on the city of New Orleans, especially in regard to human health. Several studies were conducted to determine the actual contaminant distribution throughout the city and surrounding wetlands by analyzing soil, sediment, and water for a variety of contaminants including organics, inorganics, and biologics. Preliminary investigations by The Institute of Environmental and Human Health at Texas Tech University concluded that soils and sediments contained pesticides, semi-volatiles, and metals, specifically arsenic, iron, and lead, at concentrations that could pose a significant risk to human health. Additional studies on New Orleans floodwaters revealed similar constituents as well as compounds commonly found in gasoline. More recently, it has been revealed that lead (Pb), arsenic, and vanadium are found intermittently throughout the city at concentrations greater than the human health soil screening levels (HHSSLs) of 400, 22 (non-cancer endpoint) and 390 µg/g, respectively. Of these, Pb appears to present the greatest exposure hazard to humans as a result of its extensive distribution in city soils. In this study, we spatially evaluated Pb concentrations across greater New Orleans surface soils. We established 128 sampling sites throughout New Orleans at approximately half-mile intervals. A soil sample was collected at each site and analyzed for Pb by ICP-AES. Soils from 19 (15%) of the sites had Pb concentrations exceeding the HHSSL threshold of 400 µg/g. It was determined that the highest concentrations of Pb were found in the south and west portions of the city. Pb concentrations found throughout New Orleans in this study were then incorporated into a geographic information system to create a spatial distribution model that can be further used to predict Pb exposure to humans in the city.

Spatial and temporal evaluation of metal concentrations in soils and sediments from New Orleans, Louisiana, USA, following hurricanes Katrina and Rita.

During January 2006, soil and sediment samples from 75 sites in the New Orleans (LA, USA) area were collected and tested for 26 inorganic elements. The study design was intended to provide a spatial pattern of metal concentrations within the city following hurricanes Katrina and Rita. The sampling design included four transects that traversed the city in a north-south direction and three transects that traversed the city in an east-west direction. Contaminant concentrations were determined at multiple sites within each transect and compared to U.S. Environmental Protection Agency soil screening criteria pertaining to human health. Concentrations of Pb and As exceeded the criteria indiscriminately throughout the city. Of the 75 sites, 14 (19%) exceeded the soil screening criteria for Pb, and 73 (97%) exceeded the criteria for As. Forty-three of the 75 sites coincided with a previous sampling event in October 2005. Metal concentrations were evaluated for temporal comparisons using a pair sampled t test. Arsenic concentrations differed significantly over time, but Pb concentrations did not.

Metal distributions in New Orleans following hurricanes Katrina and Rita: A continuation study.

In late October 2005, twenty-seven metals were determined in soils and sediment layers deposited by floodwaters (flood sediments) within New Orleans, Louisiana. Samples originated from 43 sites along four transects, at an industrial canal, and near the Superdome. The sampling design encompassed flooded and nonflooded areas as well as differing economic strata within the city. Results from this effort confirmed findings of our previous study designed to quantify contaminant profiles in the aftermath of Hurricane Katrina. The expanded sampling from this most recent investigation revealed that arsenic (As) and lead (Pb) concentrations exceeded United States Environmental Protection Agency (USEPA) soil screening criteria indiscriminately throughout the city. However, As and Pb concentrations were lower along St. Charles Avenue, an area largely unaffected by hurricane related flooding. Toxicant concentrations did not exceed soil screening criteria values for lead within any flood sediments or for 32 of 37 soil samples, but arsenic concentrations in 40 of 43 samples exceeded screening criteria.

Assessment of pathogens and toxicants in New Orleans, LA following Hurricane Katrina.

Storm surge associated with Hurricane Katrina and the breach of levees protecting New Orleans, Louisiana allowed floodwaters from Lake Pontchartrain to inundate 80% of the city. Environmental samples were collected during September 16-18, 2005 to determine immediate human and wildlife health hazards from pathogens and toxicants in the floodwaters. Baseline information on potential long-term environmental damage resulting from contaminants in water and sediments pumped into Lake Pontchartrain was also collected. Concentrations of aldrin, arsenic, lead, and seven semivolatile organic compounds in sediments/soils exceeded one or more United States Environmental Protection Agency (USEPA) thresholds for human health soil screening levels and high priority bright line screening levels. High numbers of Aeromonas spp., pathogenic Vibrio spp., and other coliform bacteria were found in floodwater samples. Alligator and snake tissues did not contain excessive toxicant concentrations. Initial findings suggest numerous environmental contaminants are present in New Orleans and support the need for further evaluation of the extent of those threats.