Environmental Forensics 101

Environmental Forensics is the use of scientific data analysis to answer questions about causation. When the cause of a release is unknown, common questions our clients ask are:

  1. When did the release occur?
  2. How many releases occurred?
  3. Did anyone else contribute?
  4. How much of the cost should the other party have to pay?

Litigation, dispute resolution, and insurance claims are some common applications for Environmental Forensics. These projects require critical thinking in the areas of chemistry, physics, biology, history, and industrial archaeology. Done correctly, multiple lines of reasoning will converge at the best answer for how the environmental injury occurred at some time in the past. The experienced forensics scientist will select complementary techniques from a broad field of options in order to make the strongest and most convincing case. Some forensics methodologies include:

  • Simple Research: Site history, tanks, historic industrial processes, materials, historic aerial photographs, compliance records, and Sanborn fire insurance maps are searched.
  • Crude Oil and Fuel Typing: Identifies petroleum by performing a simple analytical test on whole oil using a Gas Chromatograph with a Flame Ionization Detector (GC/FID). This test produces a chromatogram with product-specific patterns.
  • Comparison to a Reference Standard: Compares chemical content between a known reference sample and actual contaminants in the environment.
  • Diagnostic Species: Identifiesspecific contaminant species indicative of release source or age. For example, gasoline additives such as tetraethyl lead, MtBE, MMT, and ethanol have changed over time, allowing releases to be age-dated. Petroleum weathering indicators and biomarkers are also useful.
  • Fuel Regulatory Specifications: Regulatory specifications for fuel have changed greatly over the years, such as minimum octane for gasoline, minimumcetanefor diesel fuel, mandated fuel dying, and different maximum sulfur contents over time for distillate fuels.
  • Vintage Refining Methods: Changed refining methods over time are imprinted on fuels during their manufacture, allowing fuel age to be determined.
  • Crude Oil and Fuel Age Profiling: Gas Chromatograph using a Mass Spectrometer detector (GC/MS) provides quantitative concentrations of individual hydrocarbons present.
  • Coal Tar vs. Petroleum: Polynuclear aromatic hydrocarbons (PAHs) are found associated with all kinds of industrial sites such as smelters, coal gasification plants, and refineries. Apex uses alkylated PAH profiles with diagnostic source ratios to conclusively determine the source for PAHs found in the environment.
  • Fate and Transport Modeling: Analytical or computer modeling can be performed to either predict future movement of a plume, regress in time to reconstruct where a plume originated, or rule out certain sources as implausible based on site physical characteristics.
  • Carbon Isotope Speciation: This is used both to age date the carbon in hydrocarbons, confirm or rule out a link to petroleum, and also to compare and contrast different samples. This testing uses both radioactive carbon (C14) and stable carbon isotopes (C12 and C13).

These are only a few of the Environmental Forensics methods applied by Apex in determining the source, cause, or age of environmental contaminants. Forensic science is constantly evolving with new methods, or new ways of exploiting existing methods. Regardless of the methods employed, forensic science is an exciting field for Apex’s senior scientists and has benefited numerous Apex clients at scores of sites across the United States.

Apex Associated Press (Apex AP) represents contributions from various authors within the Apex professional community.

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