Application of Stable Isotopes in Environmental Studies

Identification, Tracing and removal of environmental pollutants, especially surface and groundwater, sediment and soil pollutants, are very important. Recently, isotope analysis methods have been widely used to identify and determine the processes of natural degradation of organic pollutants such as insecticides, pesticides, pharmaceutical wastes, petroleum, volatile organic compounds, and solvents, as well as mineral compounds such as nitrates. Also, the isotope ratio analysis is increasingly used to identify and determine the source of organic and inorganic pollutants and to investigate the fate of these pollutants in groundwater and soil. An important feature of this approach is that it allows degradative losses of contaminants to be distinguished from those caused by non-destructive processes such as dilution, dispersion, and sorption. Isotope ratio mass spectrometry allows the determination of the ratio of stable isotopes (such as hydrogen, carbon, nitrogen, oxygen and sulfur) in various environmental pollutants. It should be noted that environmental forensics is considered as a discipline to investigate and determine the factors responsible for the emission of environmental pollution. In environmental forensics, isotope analysis has responded to questions such as the nature of pollutants, especially the oil spill, the source of its release, the amount of weathering and its duration, and how to dispose of the pollutant over time. In fact, the isotopic composition of pollutants can be used as an invisible signature or fingerprint to determine the sources of pollution. In addition, the results of the isotope analysis provide useful information on kinetics and the mechanism of degradation processes of environmental pollutants.