A review on environmental isotope analysis of aquatic micropollutants: Recent advances, pitfalls and perspectives

An increasing amount of organic micropollutants (OMPs) are detected in aquatic environments and occur in water supplies worldwide. OMPs pose a severe threat to freshwater resources and present a potential danger to ecosystems and human health, even at trace concentrations. Compound-specific isotope analysis (CSIA) is one of the key techniques for identifying the origin and fate of environmental pollutants in aquifers and for characterizing their transformation processes. Considered as relatively mature for environmental monitoring of some well-studied industrial hydrocarbons at contaminated sites, the technique still encounters many analytical challenges in the context of diffuse pollution for other organic compounds. The present review provides a comprehensive overview on the latest technical developments concerning isotope ratio analyses of OMPs such as pesticides, various industrial compounds, pharmaceuticals and personal care products (PPCPs), and nitroaromatic compounds and organic explosives (NACs/OEs). Based on a compilation of nearly 200 CSIA-studies of OMPs, we describe the analytical challenges and address common pitfalls that can be encountered in a context of diffuse pollution in wastewater, surface waters or groundwater. Our work gives an update on instrumental developments and advances in analytical approaches for CSIA-techniques for carbon, nitrogen, hydrogen, and chlorine stable isotopes. Furthermore, the review accounts for perspectives provided by associated innovations, such as sample processing for CSIA applications of the different OMPs in the context of diffuse pollution in aquatic environments. • Organic micropollutants (OMPs) in the aquatic environment are of increasing concern. • CSIA has great potential for evaluating the environmental fate of micropollutants. • Critical assessment of the latest analytical advances in CSIA applied to diffuse pollution. • Recent advances in extraction techniques improve feasibility of micropollutant CSIA. • CSIA applied at catchment scale depends on general advances in analytical chemistry.