Reflectance Spectroscopy as a Rapid Tool for Qualitative Mapping and Classification of Hydrocarbons Soil Contamination

Petroleum hydrocarbons are contaminants of particular significance. With production rates of 13.26 million cubic meters of crude oil per day, their potential as soil and water contaminant is apparent. The most commonly used analytic method for assessing Total Petroleum Hydrocarbons (TPH) in soil samples, is based on extraction with 1,1,2-Trichlorotrifluoroethane (Freon 113) , a substance prohibited to use by the EPA. During the past twenty years, a new quantitative methodology has been widely developed that utilizes the reflected radiation of solids. By using this approach, the reflectance radiation across the VNIR-SWIR region (400-2500 nm) is modeled against constituents determined by traditional wet chemistry methods and then used to predict unknown samples. This technology permits rapid and cost-effective measurements of large number of samples and dramatically reducing chemical analytical costs, enabling new dimension of environment monitoring. For diagnosing areas suspected as contaminated and the possibility to control the rehabilitation process, there is a great need for an objective environmentally friendly method to rapidly detect low concentrations of petroleum hydrocarbon in soils. Adopting this approach to evaluate hydrocarbon contamination in soil is obvious and several works have partially demonstrated this application. In this study we adapted the spectral analysis technology reported herein and developed effective steps in which hydrocarbon contamination in soils can be generically extracted rapidly, accurately, and cost effectively solely from reflectance spectroscopy. Artificial diesel kerosene and fuel contaminated samples were analyzed chemically and spectrally. Several statistical models were tested for predicting TPH in soils for a large concentration range (100 10000 ppm) at high precisions levels, as well as identifying fuel type in the soil medium with