Murphy and Morrison reported in 2006 that since the publication of the first edition of Introduction to Environmental Forensics in 2002, the science of environmental forensics has matured appreciably. In 2005, Environmental Forensics: A Contaminant Specific Guide was published in the forensic series by Elsevier with the intent of providing the user with a means to access the forensic methodologies on a contaminant-specific basis.
In contrast, this 2nd Edition of Introduction to Environmental Forensics is designed to provide the reader with a methodological organization of the forensic tools available and as a complementary reference to the Contaminant Specific Guide. Additional forensic methods in this second edition include chapters on laser ablation inductively coupled mass spectrometry (LA-ICPMS), manual- and computer-controlled scanning electron microscope (SEM) techniques and x-ray diffraction, pattern recognition methodologies, expanded chapters on sampling techniques and statistical methods, and a presentation of several emerging forensic techniques. In this edition and subsequent editions of Introduction to Environmental Forensics, methods of general applicability will be emphasized and the Contaminant Specific Guide will provide forensic approaches for specific contaminants. We would be grateful to readers for suggestions for improvement. “Forensic” is related to “forum” and refers to any public discussion or debate.
In the United States “forensic” most often refers to courtroom or litigation proceedings. However, environmental forensics may also provide the fact basis for mediated or negotiated transactions or for any public inquiry related to environmental matters. Questions that environmental forensics seeks to answer are:
- Who caused the contamination?
- When did the contamination occur?
- How did the contamination occur? (For example, was it an accidental spill or a series of routine operating releases?)
- How extensive is the contamination?
- Are the test results valid? Is there evidence of fraud?
- What levels of contamination have people been exposed to?
- Can environmental forensics assist in allocating remediation costs?
The contexts of environmental forensic investigations include liability allocation at hazardous waste sites where multiple parties are involved, site assessments for property transfers, insurance litigation, toxic torts, and cost allocation among multiple parties found liable for releasing contaminants into the environment. Environmental forensic investigations frequently deal with the historical release of contaminants. Generally there are two sources of information in conducting an investigation, namely:
- The documentary record, including statements by witnesses or other knowledgeable individuals, aerial photographs, insurance maps, and electronic information copied from computer hard drives, and
- Measurement or sampling data.
Once the historical information has been acquired and evaluated, one can then identify which forensic technique is most suited for answering the forensic question(s) of concern and how to appropriately use the selected methodology. For example, chemical or isotope concentration data can be used in different ways to answer forensic questions, including:
- Tracer techniques based on the presence or absence of a particular chemical.
- Ratio techniques where the relative amounts of two or more chemicals are compared.
- Trend techniques where the spatial or temporal variation of a concentration, or a ratio, is of interest.
- Quantity techniques that depend on the integrated concentration over space or time, i.e., the mass of a chemical, to provide forensic information.
A forensic investigation may involve multiple forensic techniques and applications that are evaluated to answer the forensic question of interest. For example, identifying the source of and age dating a hydrocarbon spill may be of interest. The presence or absence of lead, methyl tertiary butyl ether (MTBE), or other additives, for example, may provide this crucial information that provides insight regarding the source or age of the release. The ratio of different hydrocarbon components or octane readings may provide the basis to distinguish different fuels or brands. The spatial variation of a contaminant plume or its growth over time may assist in both source identification and age dating. Finally, the total mass or volume of petroleum hydrocarbons in the environment may be compared to inventory or leak detection records for source identification.
The most successful forensic investigations rely on the approach of selecting the most applicable techniques from numerous methodologies. An investigation relying on the results of a single forensic technique, exclusive of other available tools, is frequently successfully challenged when contrary evidence based on multiple forensic approaches is introduced. When forensic evidence is arrayed as multiple, but independent lines of evidence, a stronger scientific case, less susceptible to scientific challenge, emerges. This book is intended to provide you with your own toolbox of forensic techniques.
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