Risk-Based Corrective Action (RBCA) at Petroleum Contaminated Sites: The Rationale for RBCA and Natural Attenuation.

Risk-Based Corrective Action RBCA is a new phrase heard among engineers, researchers and regulators in the environmental remediation field. The phrase and acronym, pronounced like the name Rebecca, represent a more enlightened, perhaps mature approach to old problems. RBCA is not a new technology but rather a formal framework for decision making when planning environmental remediation goals. I restrict my discussion to RBCA as applied to petroleum contaminated sites because they have recently emerged as the newest testing ground of the RBCA concept. Clearly, the key to developing objective cleanup criteria for soil and water remediation is to focus upon risk assessment. However, unlike polychlorinated biphenyls, dioxin and lead, whose soil cleanup criteria were developed based upon their associated risks, cleanup criteria for petroleum contamination is generally not based upon human health risk. Instead, the criteria are almost as varied as the states that developed the standards. In 1991, a survey revealed that 42 out of 50 states utilize the measure of total petroleum hydrocarbons TPH in regulatory oversight and that soil cleanup goals spanned a range of 10 to 10,000 parts per million ppm TPll.3