Forensic Investigation of Chlorinated Solvent Plume, Los Angeles, California.

ZymaX was retained to forensically investigate a chlorinated solvent plume beneath a manufacturing facility in which solvent degreasers had been used. TCE and PCE were detected in the groundwater beneath the site and adjacent industrial areas. ZymaX used ¹³C compound specific isotope analysis (CSIA) to differentiate between potential offsite and onsite sources. It was determined that an offsite upgradient source of TCE had migrated onto the site and comingled with a smaller onsite PCE/TCE release.  The onsite PCE/TCE source was found to be degrading. Read more about this investigation in CSIA in Chlorinated Solvent Investigations – Two Case Studies given by Yi Wang, PhD, Zymax Forensics Laboratory. (PDF, 1.03 Mb)

Identification of Petroleum Products at a Marine Terminal

Zymax was retained to analyze free product, soil, and water samples containing petroleum products released over a considerable number of years at a site in the Port of Los Angeles.  The product in many of the samples showed an advanced degree of weathering, which complicated the identification of the products.  The analytical results and the interpretation were used by the client in successful litigation.

Forensic Investigation of Chlorinated Solvent Plume, New York, New York. 

PCE and TCE were detected in the groundwater beneath this architecture operation.  ZymaX was retained to identify multiple sources, if any, and to determine whether the detected TCE was the result of degrading PCE or a distinct TCE product release.   Using ¹³C, ³⁷C, and ²H compound specific isotope analysis (CSIA), ZymaX identified two distinct PCE plumes and one TCE plume. δD analysis also indicated that TCE had not migrated into adjacent wells. Read more about this investigation in CSIA in Chlorinated Solvent Investigations – Two Case Studies given by Yi Wang, PhD, Zymax Forensics Laboratory. (PDF, 1.03 Mb).

ZymaX analyzed several product samples from a large free-product plume (groundwater contaminated by liquid pollutants and flowing from a specific source) with a suite of chemical tests used by ZymaX to characterize petroleum fuels. The plume was found to contain leaded gasoline and diesel. The formulation of the gasoline was consistent with gasolines manufactured 20 to 30 years ago. The diesel also showed evidence of having been released at least 10 years in the past. We also determined the relative amounts of gasoline and diesel in the samples. We analyzed hydrocarbons dissolved in groundwater at the site using a suite of analyses specifically for water and soil. These showed, in addition to the gasoline and diesel in the plume, unleaded gasoline. The client was a relatively recent operator at the site, and had a documented spill of unleaded gasoline. The client was able to argue from these data and our interpretation that the gasoline and diesel were released prior to his operations at the site, and that his responsibility was restricted to only a portion of the groundwater contamination.

Alkylate process to identify a specific gasoline, Midwest United States

In a project in the Midwest, a refinery site with a number of historical operators had several plumes of contaminated groundwater running underneath it. Zymax chemical testing of a large number of product samples established that the plumes contained a mixture of gasoline and diesel. The diesel was similar in all the samples, but at least four different types of gasoline were identified, both leaded and unleaded. The hydrocarbon compositions of the leaded gasoline enabled identification of the process used to generate the alkylates in the gasoline. Alkylates are branched chain hydrocarbons added to gasoline to boost the octane levels. Two different alkylate catalysts have been used by refiners, and each catalyst produces a different ratio of specific alkylate hydrocarbons. A knowledge of the alkylate process that was used to produce a specific gasoline helped to identify the operator responsible for that gasoline.