DECREASING OF HUMAN HEALTH RISK BY NATURAL ATTENUATION OF A CONTAMINATED SOIL IN SAO PAULO STATE, BRAZIL

摘要

The soil's contamination by organic compounds has been receiving significant attention of environmental control agencies. Natural attenuation (NA) is an option for remediating contaminated sites. This study compared the potential risk to human health associated to the 16 priorities PAHs (USEPA) present in a soil, before and after NA. The contamination source was a crude oil' spill, in Dec/1998, in Sao Paulo, Brazil. This soil was removed, disposed in a containment dike and the samplings were accomplished in Oct/2001 and Mar/2003. The human health risk assessment was based in USEPA's methodology and the exposure pathways studied were oral and dermal contact. The receptor screening considered was the neighborhood eventually exposed. According to USEPA, the acceptable cancer risk ranges between 1 × 10{sup}(-4) and 1 × 10{sup}(-6). Therefore, NA could reduce significantly the cancer risk, just for adults, once the risk values were lower than the target risk level (～1 × 10{sup}(-4)), after NA. For children, the risk level remained greater than the target risk level, suggesting the application of other remediation technologies.