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Composting and the application of compost to the soil follow the principle of recycling and sustainability. Compost can also have a positive effect on physical, chemical, and biological soil parameters. However, little is known about the origin, concentration, and transformation of persistent organic pollutants (POPs) in compost. We therefore compiled literature data on some priority POPs in compost and its main feedstock materials from more than 60 reports. Our data evaluation suggests the following findings. First, median concentrations of Σ 16 polycyclic aromatic hydrocarbons (PAHs), Σ 6 polychlorinated biphenyls (PCBs), and Σ 17 polychlorinated dibenzo‐p‐dioxins and ‐furans (PCDD/Fs) were higher in green waste (1803, 15.6 μg/kg dry wt., and 2.5 ng international toxicity equivalent [I‐TEQ]/kg dry wt.) than in organic household waste (635, 14.6 μg/kg dry wt., and 2.2 ng I‐TEQ/kg dry wt.) and kitchen waste (not available [NA], 14.9 μg/kg dry wt., 0.4 ng I‐TEQ/kg dry wt.). The POP concentrations in foliage were up to 12 times higher than in other feedstock materials. Second, in contrast, compost from organic household waste and green waste contained similar amounts of Σ 16 PAHs, Σ 6 PCBs, and Σ 17 PCDD/Fs (1915, 39.8 μg/kg dry wt., and 9.5 ng I‐TEQ/kg dry wt., and 1715, 30.6 μg/kg dry wt., and 8.5 ng I‐TEQ/kg dry wt., respectively). Third, concentrations of three‐ring PAHs were reduced during the composting process, whereas five‐ to six‐ring PAHs and Σ 6 PCBs increased by roughly a factor of two due to mass reduction during composting. Σ 17 PCDD/Fs had accumulated by up to a factor of 14. Fourth, urban feedstock and compost had higher POP concentrations than rural material. Fifth, the highest concentrations of POPs were usually observed in summer samples. Finally, median compost concentrations of POPs were greater by up to one order of magnitude than in arable soils, as the primary recipients of compost, but were well within the range of many urban soils. In conclusion, this work provides a basis for the further improvement of composting and for future risk assessments of compost application.

The heat shock protein Hsp70 has been shown to be a promising biomarker in aquatic and terrestrial organisms. However, its analysis in the soil insect Folsomia candida (Collembola) poses many problems as the protein is particularly unstable in this species. Western blotting has shown that the principal degradation fragment has a size of 48 kDa. We have developed a Western blot method that avoids the degradation of Hsp70 and was successful in detecting the protein in the springtail F. candida after a heat shock (12, 18 and 24 h at 32°C). In the second part of the study the organisms were exposed to artificial compressed soil contaminated with the dinitrophenol dinoseb (10, 15 and 20 µg g-1 dry weight [DW]). Hsp70 was analysed in pooled samples (40 to 150 collembola according to age) after 1, 2, 3, 4, 5, 6, 7, 11 and 14 days. The only significant induction was observed after 5 days at 20 µg g-1 DW of dinoseb. The induction patterns over time were dissimilar for the different concentrations and a relatively high variability between the replicates was observed. Our results show that we must be cautious when interpreting biomarker results, especially those for Hsp70.