Relatively high concentrations of the biocide TBT were found in one vinyl wallpaper out of four, one glove out of four and three vinyl flooring products out of five – from 0.5 to 47 mg TBT/kg plastic. The investigation also showed that organo-tin additives other than TBT are used in shower curtains, vinyl flooring, vinyl wallpapers and bags. One shower curtain and one bag were also found to contain cadmium – a prohibited substance in Denmark and many other nations.

No immediate health hazard is associated with the use of these products, but as tin compounds can be released from PVC, their TBT content will contribute to the total environmental loading from this biocide. The other tin compounds detected have not been investigated so thoroughly, but they degrade slowly and can under certain circumstances accumulate in the environment. Companies which import the products containing excessive quantities of cadmium have been ordered by the Danish Chemical Inspection Service to stop all sales immediately and to dispose of all residual stocks.

It is not TBT but other organo-tin compounds, such as those of dibutyltin and dioctyltin, which are used to stabilise PVC. In the case of clear PVC, there are at present no alternatives to tin stabilisers, but alternatives like calcium-zinc or barium-zinc compounds can be used in other PVC products. Although now prohibited, cadmium was previously used to stabilise clear PVC.

“The companies that manufacture the goods are responsible for the substances they contain,” commented Danish EPA Director-General Steen Gade. “And it is entirely unacceptable that – intentionally or unintentionally – they should contain such additives as the biocide TBT. Such practices are responsible for the uncontrolled dispersal of TBT in the environment. These companies – and therefore the industry – must take immediate action.”

Gade also believes that regulation is necessary in this area. “The Commission of the European Community is just now in the process of assessing the risks involved and the need for regulation and we are, of course, sending our latest results to the Commission, so that they can be included in this ongoing task. It is my earnest hope that this latest knowledge together with our investigations from last year will help to demonstrate the necessity of regulation,” he said.

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