Additionally, all of them pose a threat towards human health as they are toxic, carcinogenic, or act as endocrine disruptors. Persistent organic pollutants (POPs) are a group of chemicals which all share a resistance towards degradation by hydrolysis or photolysis, as well as a potential for long-range transport and bioaccumulation. Additional investigations regarding GC liner performance highlighted the need for isotopically labelled standards during the analysis of thermolabile pesticides. Thus, the efficiency of all the methods was comparable for all model soils. A longer solid-liquid extraction time did not necessarily increase analyte recovery: Extraction for one hour resulted in 88% recovery while 16 hour extraction led to 89%. Statistical analysis of the results implied that the TOC content of the soils did not have significant influence on the extraction efficiency. After clean-up the extracts were measured using a gas chromatography-mass spectrometry (GC-MS) system. For comparison, all soils were also extracted using pressurised liquid extraction and Soxhlet extraction. The matrices were extracted using solid-liquid extraction between 45 minutes and 16 hours. For the presented study, 12 organochlorine pesticides and 7 polychlorinated biphenyls were spiked into four model soils with organic carbon contents between 1.6% - 13.3%. However, the influence of TOC on the analyte recovery has to be known. Agitation solid-liquid-extraction is well suited for this purpose. In order to judge the pollution status of soil and to make monitoring data more easily comparable a simple, yet robust extraction method is needed. This ability is often associated with the total organic carbon content (TOC). Soil is a matrix which can retain these contaminants to a great extent. Due to their stability, they are still considered an environmental problem even though the use of most of them has been phased out several decades ago.
Organochlorine pesticides and polychlorinated biphenyls are toxic, carcinogenic, and have a high potential for bioaccumulation.
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