PAH/Metal exposure and effects assessment in Chattanooga


Principal Investigator: Sean M Richards
Abstract: South Chattanooga is an urban area embedded with waste from local industry. A 1991 study describes 42 hazardous waste sites located in South Chattanooga, 13 of these sites are listed as Superfund sites. This waste is due to decades of clandestine and illegal dumping (both in the local creek and on land), and continual deposition from contaminated creek floodwaters and airborne effluent. As a result of the dumping and deposition, polycyclic aromatic hydrocarbons (PAH) and heavy metals have permeated South Chattanooga soil. In the 1950s and 1960's the Chattanooga government relocated thousands of people to South Chattanooga to facilitate construction of a large development in their former home of downtown Chattanooga. Many homes and schools were built on former dumpsites in South Chattanooga. It was only after decades of residence that these dumpsites were formally declared as hazardous waste and Superfund Sites. The people living in South Chattanooga are largely minority, undereducated, and impoverished. For decades, they have voiced concern about health effects due to living in South Chattanooga. Their proximity to these dumps and exposure from periodic flooding warrants concern. This concern is further substantiated by the recent detection of PAHs and metals in their yards, community gardens, playgrounds, and school grounds. Many of these toxicants exceed the EPA and ATSDR guidelines for safe soil. The city and state have attempted to address these concerns. In 1986 and 1995, two epidemiological studies were conducted. At the completion, the principal investigators conceded that both studies were extremely flawed in design and implementation; due to these flaws, the investigators ultimately concluded that the data were unusable. Aside from these two failed attempts, little else has been done to examine health issues in South Chattanooga. Epidemiological studies are inherently difficult to conduct. Differences in lifestyle, race, diet, and stress are especially confounding variables. To properly address the concerns of South Chattanooga residents and department of health officials, we propose to collect soil and small mammals (rodents) in the South Chattanooga area to measure the presence and potential for exposure and effects of living in such close proximity to these contaminated soils. Small mammals are well-established surrogates in toxicology and environmental toxicology and will remove the variables that confound epidemiological studies. Ultimately, our results will provide a quantitative and defensible assessment of the risk that residents assume by living in South Chattanooga. To address the concerns, our research aims to: 1) measure the potential for exposure to PAH and metals by quantifying these toxicants in the soil. 2) Measure the biological availability of PAHs and metals by quantifying these toxicants in tissues of small mammals. 3) Measure exposure by quantifying biological indicators in small mammals. 4) Measure the effects of exposure by quantifying PAH-DNA adducts in small mammals. 5) Quantify the potential for the residents of South Chattanooga to be exposed and affected by PAHs and metals present in area soil by using the data generated in this study in a probabilistic risk assessment.
Funding Period: 2004-09-30 - 2008-08-31
more information: NIH RePORT