Abstract
An approach to identifying persistent organic contaminants in the environment was developed and executed for Switzerland as an example of an industrialized country. First, samples were screened with an in-house list using liquid chromatography high-resolution mass spectrometry (LC-HRMS/MS) and gas chromatography tandem mass spectrometry (GC–MS/MS) in 13 samples from the Swiss National Soil Monitoring Network and three sediment cores of an urban and agricultural contaminated lake. To capture a broader range of organic contaminants, the analysis was extended with a suspect screening analysis by LC-HRMS/MS of >500 halogenated compounds obtained from a Swiss database that includes industrial and household chemicals identified, by means of fugacity modeling, as persistent substances in the selected matrices. In total, the confirmation of 96 compounds with an overlap of 34 in soil and sediment was achieved. The identified compounds consist generally of esters, tertiary amines, trifluoromethyls, organophosphates, azoles and aromatic azines, with azoles and triazines being the most common groups. Newly identified compounds include transformation products, pharmaceuticals such as the flukicide niclofolan, the antimicrobial cloflucarban, and the fungicide mandipropamid. The results indicate that agricultural and urban soils as well as sediments impacted by agriculture and wastewater treatment plants (WWTPs) are the most contaminated sites. The plausibility of this outcome confirms the combination of chemical inventory, modeling of partitioning and persistence, and HRMS-based screening as a successful approach to shed light on less frequently or not yet investigated environmental contaminants and emphasizes the need for more soil and sediment monitoring in the future.
Highlights
The increasing amount and number of synthetic chemicals in use over the last decades has led to a corresponding increase in the numbers and amounts of contaminants reaching the environment
The objectives of this work were i) to investigate the presence of known and emerging persistent contaminants in 13 representative soils from the Swiss National Soil Monitoring Network (NABO) and in sediment cores from an urban and agricultural lake (Greifensee, Switzerland) based on wide-scope target analysis, ii) to further identify persistent compounds based on suspect screening analysis by liquid chromatography (LC) – high-resolution mass spectrometry (HRMS)/MS using a suspects list of halogenated chemicals that are likely to persist in the environment and reside predominantly in these two matrices, and iii) to highlight the utility and the need of inclusion of these two matrices in future monitoring campaigns
Soils The target analysis in soils confirmed the presence of 33 compounds included in the Eawag-DB as reported in Table S5 and S6 for LC-HRMS and GC–MS/MS analysis, respectively
Summary
The increasing amount and number of synthetic chemicals in use over the last decades has led to a corresponding increase in the numbers and amounts of contaminants reaching the environment. National and international environmental programs since the 1970s have performed a continuous monitoring of persistent organic pollutants (POPs) and further chemicals with persistent, bioaccumulative and toxic characteristics (PBT) are continuously added to the list (Muir and Howard, 2006). While these monitoring programmes are highly important, many chemical substances in wide commercial use are still not measured in environmental samples, and their environmental fate is still unknown (Muir and Howard, 2006). The use of soils and sediment matrices to study chemical contamination throughout time is a significant advantage compared to water samples, where usually no historical samples are available and contaminants have not been recorded and studied in the past
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