Researchers from Agroscope, Eawag and ETH have developed a method for the comprehensive detection of organic pollutant residues in soils and sediments. Initial results show that, in addition to known substances, there are also a number of substances detected for the first time.
Tens of thousands of chemicals are in daily use in households and industry. Many of them end up intentionally or unintentionally in the environment, but only a fraction of these are systematically recorded there. In view of the increasing variety of organic substances, it is important on the one hand to improve our state of knowledge of their behaviour in the environment, and on the other hand, to detect undesirable concentrations in reservoirs such as soils and sediments as early as possible.
Researchers from Agroscope, Eawag and ETH have tackled this knowledge gap in a study conducted on behalf of the Federal Office for the Environment. In a first step, a good 9000 chemicals used in the Swiss industrial sector and households and their main substance characteristics were compiled in a database. Models were used to gauge which of these compounds could mainly end up in soils and sediments. This resulted in a candidate list of around 500 halogenated organic substances which are often particularly long-lived. Using mass-spectrometry, these were then looked for in a series of extracts from Swiss Soil Monitoring Network (NABO) soil samples, as well as form sediment cores of the Greifensee. Both soils and sediments can function as long-term, spatially widespread archives of organic compounds, and are therefore particularly well-suited for systematic studies of this kind.
The presence of around 20% (n=96) of the predicted compounds was analytically confirmed, 34 of which were found both in soils and sediments. Examples of substances identified for the first time are the veterinary drug niclofolan, the antibacterial agent cloflucarban (a disinfectant used in medicine and in hygiene products) and the fungicide mandipropamid. Furthermore, a range of already-known industrial chemicals, cosmetics, biocides (non-agricultural pesticides, e.g. disinfectants) and plant-protection products was detected – specifically, increasingly on sites used for agricultural purposes, or which are located in the vicinity of sewage-treatment plants (sediments).
The top priority of this study was to develop and test the suitability of a methodological approach serving on the one hand to systematically detect substances that have been in use for some time, and on the other hand contributing to the early detection of future organic pollutants in the previously ignored compartments soil and sediment. The published paper shows the feasibility of this approach, and can serve as a basis for additional monitoring studies.
- A systematic approach to the combined model-based and analytical-chemical detection of numerous organic compounds in soils and sediments was developed.
- In addition to the expected substances, a range of further substances were detected for the first time.
- The study provides a view below the tip of the iceberg of the many man-made substances in the environment.
- This methodology can serve as a basis for future monitoring studies.