Multidimensional soil analysis
Soil remediation monitoring programmes analyse contaminants and metabolite concentrations at three and a half million sites throughout Europe. However, conventional techniques to evaluate both changes in time and in area are often inconclusive due to inability to resolve various contaminants and identify their sources. Compound-specific isotope analysis (CSIA) is an emerging analytical technique that measures the ratios of naturally occurring stable isotopes in environmental samples. These ratios can change in systematic ways during the course of biodegradation. Thus, CSIA can be used to gain information about potential contaminant sources, extent of degradation and co-mingling of contaminant plumes. Scientists initiated the EU-funded project Isosoil to firmly establish concentration-independent CSIA as a user-friendly and powerful tool for soil remediation monitoring. During the first project phase, field and experimental data were generated, methodology for analyses was defined and first samples were analysed. The second and final period of Isosoil witnessed the development of novel extensions to CSIA with ground-breaking methods. New analytical protocols were developed for efficient and reliable extraction of a family of compounds (nitrotoluenes) used to produce dyes, agricultural substances and photographic chemicals for CSIA. Partners are now developing a promising new method for hydrogen isotope analysis of chlorinated and non-chlorinated organic compounds, thus filling an important gap in CSIA. Complementary work led to development of multi-dimensional CSIA for source apportionment and degradation monitoring of chlorinated solvents and nitrotoluenes. The final version of the Isosoil software was made available free of charge for one year. It covers the entire chain from planning and sampling to sample analysis and interpretation of data. Specifically, the user-friendly web interface contains statistical code for optimisation of sampling, an expandable database, a kinetics calculator for reactions and isotope data, and an interpretation framework. Isosoil has demonstrated the ability of concentration-independent CSIA to complement standard concentration monitoring for deeper insight into site-specific processes. Environmental consultants and commercial enterprises offering analytical services will now have a web-based tool for sampling and interpretation of CSIA results.
