Waste landfills "safe for PVC disposal"

Simulation studies find limited breakdown, low release of potentially toxic additives

PVC plastic can be "safely" landfilled, according to the results of studies carried out by German and Swedish universities over several years with funding from the PVC and related industries. The findings serve to alleviate concerns over the potential environmental impacts of PVC at the end of its life-cycle, according to the European Council of Vinyl Manufacturers (ECVM), one of the project's backers.

Depending on specific applications, virtually all PVC products contain additives such as phthalate plasticisers or heavy metals such as lead, zinc or organotin compounds. The research project was designed to investigate how PVC degrades in landfills and estimated the extent to which volatile chlorinated compounds might be lost in landfill gas or toxic additives in liquid leachate. According to the results, which were announced yesterday, PVC's contribution to any of these problems is low or negligible.

The universities conducting the project were the Technical University of Hamburg-Harburg in Germany, the University of Linköping in Sweden and Chalmers Technical University, also in Sweden. In addition to ECVM, the project was funded by the European Council for Plasticisers and Intermediates, the European Stabiliser Producers Association, the Organotin Environmental Programme Association and PVC manufacturer Hydro Polymers.

The research involved simulating landfill conditions in the laboratory and taking samples from actual landfills in Italy, Germany and Sweden. According to the project summary, the results "allow the prediction of long-term behaviour of PVC products under these conditions for centuries".

A principal conclusion of the research is that the PVC polymer itself is resistant in landfill conditions and does not break down to produce vinyl chloride monomer, the polymer's toxic building block. The presence of vinyl chloride in landfill gas therefore does not come from PVC, the researchers conclude.

The scientists did find some release of PVC additives, however, especially during the transition phase that landfills undergo from their early "acidogenic" state to the more stable "methanogenic" state. In particular, the project revealed that the plasticiser DINA could leach out of PVC cables in significant quantities.

Release levels of other plasticisers, as well as stabilisers, were reported to be lower, however. For heavy metals and organotins stabilisers, levels in leachate were found to be "very low and...usually attributable to surface wash-off". The scientists also estimated that PVC items contribute only 5% of lead and less than 1% of all zinc in landfills.

Follow Up:
ECVM, tel: +32 2 676 7443.

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