Environmental Forensic Microscopy (EFM) is a multidisciplinary sub-division of forensic science that can also analyze complex environmental research questions by combining microscopy techniques with analytical and forensic methods.
The identification, characterization, and quantification of materials and compounds in a variety of matrices (such as soils, sediments, water, etc.) are feasible by EFM's potential for comprehensive and detailed analysis of environmental samples. EFM can have a vast array of applications in tackling varied research or crime-related questions, including the determination of sources of contamination, the evaluation of the degree of degradation, and figuring out the fate and transport of toxins, glass, or any other particles that bears forensic significance due to being uniquely found in a certain area/region.
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Environmental Case Studies
EFM has proven useful for identifying pollution sources in various environmental matrices. Chen et al., in a 2017 study, utilized EFM to distinguish and locate the exact origin of polycyclic fragrant hydrocarbons (PAHs) in the residue from a stream in China. The researchers were able to identify two main sources of PAHs by combining scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and finally, principal component analysis (PCA) for the statistical analysis of the results, which demonstrated that the source was the exhaust systems of the vehicles. The affected region's environmental health can be improved, and effective pollution control strategies can be developed using this information that would otherwise have been unnoticed.
EFM has also been utilized to evaluate the level of contamination in various environmental matrices. Hagmann et al. In 2019 paper involved EFM to evaluate the degree of metal pollution in soils from a modern site in New Jersey, USA. The researchers identified the presence of dormant microbes in the contaminated soils by combining phosphatase activity and bacterial density measurements with SEM-EDX. Using this information, effective strategies for remediating soil can be created and restore the soil's functional potential. EFM can also assist in gaining an understanding of the fate and transport of pollutants across a variety of environmental matrices.
In a 2018 study, Schafer et al. investigated the distribution and movement of microplastics in German Rhine River sediments using EFM. The researchers were able to track the distribution and transport of various kinds of microplastics in sediments by combining SEM-EDX, fluorescence microscopy, and Fourier-transform infrared spectroscopy (FTIR). Therefore, it is clear that effective strategies for controlling pollution and preventing further environmental degradation can be developed using this information, and also raising awareness about how microplastics can be found in virtually any part of the ecosystem nowadays.
EFM can be a valuable tool in criminal investigations by helping to identify and link physical evidence to a potential suspect. One example of EFM being used to pinpoint a suspect or group of suspects is the case of the 2001 anthrax attacks that transpired in the United States.
EFM fighting crime
EFM was used to analyze the anthrax spores inside the letters targeted at several media outlets and government facilities. By using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), the police could identify the spores' unique chemical make-up and morphology, which helped narrow down the possible sources of the anthrax.
In other cases, EFM was used to help identify a suspect in a hit-and-run accident. By analyzing the paint chips recovered from the victim's clothing and the car involved in the accident, researchers could identify the vehicle's make and model and ultimately link it to a specific perpetrator. This information and other circumstantial evidence have led to the arrest and conviction of suspects in the past.
Overall, EFM can provide valuable information in criminal investigations, helping to identify and link physical evidence to potential suspects and ultimately leading to the resolution of cases.
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How else can EFM prove useful?
In spite of the current encouraging research breakthrough, there are still a lot of areas of EFM that require additional investigation and thorough understanding. The development of new analytical techniques capable of providing information about the chemical and physical nature of various environmental matrices that is more comprehensive and precise than the ones currently used is one potential area of future improvement.
The relatively underutilized microscopy methods, like confocal microscopy coupled with Raman spectroscopy, can, for instance, provide more in-depth data on the chemical and spatial distribution of various materials in environmental samples. Integrating EFM with other analytical and modeling strategies, such as molecular dynamics simulations and machine learning, is another potential area for future research. The further exploration of EFM in the study of microplastics is a research area of increasing importance due to the ubiquitous nature of these particles, which stems from the wide use of plastics in the modern world.
Other complex mixtures, such as those found in electronic waste or contaminated soils, could help shed light on these materials' negative environmental impact and help kickstart the development of improved waste management ideas. In conclusion, Environmental Forensic Microscopy is an innovative and potent conglomeration of multiple analytical techniques for resolving difficult forensic or environmental issues.
Sources:
- Millete & Brown 2015 Introduction to Environmental Forensics p. 487 http://dx.doi.org/10.1016/B978-0-12-404696-2.00013-8
- Webster et al. 2009 Identifying Transfer Mechanisms and Sources of Decabromodiphenyl Ether (BDE 209) in Indoor Environments Using Environmental Forensic Microscopy Environ. Sci. Technol. 2009, 43, 3067–3072
- Hagman et al. Environmental forensic characterization of former rail yard soils located adjacent to the Statue of Liberty in the New York/New Jersey harbor Science of The Total Environment Volume 690, 10 November 2019, Pages 1019-1034 https://doi.org/10.1016/j.scitotenv.2019.06.495
- Thoonen et al. 2016 Automatic forensic analysis of automotive paints using optical microscopy Forensic Sci Int ;259:210-20 doi: 10.1016/j.forsciint.2015.12.040
- Forensic Case Files: Bruce Ivins and the Anthrax Attacks https://locardslab.com/tag/microscopy/
Further Reading
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