Written by Steve Henshaw, P.G., President & CEO, EnviroForensics
On June 17, 2010 the Indiana Department of Environmental Management (IDEM) once again adjusted their guidance regarding the regulation of Total Petroleum Hydrocarbons (TPH) and revised pertinent sections of their Risk Integrated System of Closure (RISC) Technical Guidance Document. A special RISC TPH Work Group has determined that the investigation, delineation and/or remediation of TPH in ground water are no longer warranted, unless protection of drinking water wells is necessary. This development could significantly impact environmental cleanup projects where releases of petroleum products have occurred.
The term TPH refers to an accumulation of hydrocarbon compounds that make up a variety of petroleum products. Not all of the compounds that fall in this category have been researched individually by toxicologists, such that closure levels could be established. Those that do have closure levels are considered Contaminants of Concern (COCs) at cleanup sites, which are commonly the more toxic compounds and are regulated individually. The non-specific TPH is also regulated as a COC based on surrogate toxicological data. Continue reading “IDEM’s Changes to TPH Procedures for Ground Water”