The Origin and Recycling of Hazardous Chemicals in Plastic Consumer Products

Abstract

Andrew Turner - Associate Professor in Geochemistry, Pollution and the Environment at the University of Plymouth, UK. Plastics are easy to manufacture, durable, lightweight and corrosion-resistant, and for the past forty years have been the most used type of material in a wide range of sectors. However, the materials and energy used for their manufacture and both managed and mismanaged disposal have resulted in a variety of environmental impacts. Consequently, the past decade has seen well-publicised drives for a reduction in single-use plastics and an increase in plastic recycling. One problem with recycling some plastics is that historical materials may have contained hazardous additives or residues, such as polybrominated diphenyl ether and polybrominated biphenyl flame retardants, and the heavy metals, cadmium and lead, that have subsequently contaminated the recyclate. In a circular economy, these additives have found their way into new consumer goods where they are neither expected nor desired. One area where this problem is particularly significant and that is illustrated in this presentation is black plastics. Thus, domestic black plastic is not generally recycled because of its incompatibility with current infrared sorting devices. As a result, black plastic for new consumer goods appears to be sourced to a significant extent from electronic waste plastic that has not been screened or separated adequately. Results of x-ray fluorescence analyses of several hundred black plastic consumer goods reveals that many products, including coat-hangers, tool handles, toys and games, apparel, kitchen utensils, food packaging, thermos flasks and items of jewellery, contain significant quantities (sometimes exceeding 100 ug g-1) of brominated flame retardants and/or heavy metals and in signatures consistent with old electronic plastics. In some cases, consumer goods would be non-compliant (and hazardous) with respect to existing directives and regulations on electrical waste. Moreover, and unknown to the consumer, there are also cases where new goods could be classified as hazardous wastes, and conventional incineration may result in the emission of harmful products including brominated dioxins. The wider environmental problems and health risks associated with a circular economy involving contaminated materials are discussed and recommendations to reduce the problems addressed.