Current Risk Assessment Approaches to Address Petroleum Hydrocarbon Mixtures in Soils

Abstract

Products that exist as complex chemical mixtures, such as petroleum products, are used widely in commerce, and accidental releases of these products into the environment have led to thousands of contaminated sites nationwide. Developing sound estimates of potential health risks posed by these sites is challenging because of the composition of these products, their behavior in the environment, and the paucity of toxicological information available for many of the component compounds. In developing risk based cleanup goals for petroleum products and other complex commercial mixtures, the simplest approach is to assume that the entire mixture is comprised of the most toxic constituent, particularly when standards are unavailable for each of the components of the mixture. This approach often results in excessively conservative regulatory goals; thus, methods are needed which more accurately reflect the actual composition and aggregate toxicity of the mixture. Three approaches for the development of risk based soil cleanup goals for petroleum hydrocarbon mixtures are identified and illustrated using mineral spirits as an example. For the examples presented, estimates of the proportions of components in mineral spirits were based on virgin, unused product; however, detailed component analysis of weathered samples may permit the calculation of more precise, site specific cleanup goals.

Keywords:

• mineral spirits
• remediation goals
• petroleum products