Persistent Organic Pollutants in Source-Separated Compost and Its Feedstock Materials—A Review of Field Studies
- Rahel C. Brändliab,
- Thomas D. Bucheli *b,
- Thomas Kuppera,
- Reinhard Furrerc,
- Franz X. Stadelmannb and
- Joseph Tarradellasa
- a Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratory of Environmental Chemistry and Ecotoxicology (CECOTOX), Faculty of Architecture, Civil and Environmental Engineering, CH-1015 Lausanne, Switzerland
b Agroscope FAL Reckenholz, Swiss Federal Institute for Agroecology and Agriculture, Reckenholzstrasse 191, CH-8046 Zürich, Switzerland
c National Center for Atmospheric Research, Boulder, CO 80307-3000
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.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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