SORPTION CAPACITY OF PAHS IN RHODE ISLAND SOILS ALONG AN URBAN TO RURAL GRADIENT

Many contaminants, including polycyclic aromatic hydrocarbons (PAH), stem from fossil fuel combustion, automotive related releases, and other non-point pollution sources. Some PAH compounds are carcinogens and their presence in the environment has resulted in health concerns for the general public. This influx of PAH contaminants is partially linked to the increased numbers of registered automobiles and fossil fuel consumption over the past years. This has resulted in increased PAH concentrations in the atmosphere, soils, and water resources, particularly in urban areas.

PAHs can enter the environment via dry/wet particle and gaseous deposition, both of which are major non-point pollution sources within the United States. Most soils in New England have a naturally low and location-dependent PAH sorption capacity, which, once exceeded may permit PAH influxes to reach deeper parts of the subsurface, potentially polluting drinking water resources. Because of continuous influx of PAHs from the atmosphere, a general trend of increasing PAH concentrations in soils and sediments is to be expected. In this experiment, four locations throughout Rhode Island - a coastal, rural, suburban, and urban site – have been selected for further analysis. Results from sorption isotherm experiments demonstrate that the PAH concentrations increase with closer distance to urban areas. This information can be useful in establishing the need for best management practices that reduce the amount of PAH loading in stormwater runoff and other non-point sources.