Human toxicity assessment of WEEE recycling process

The generation of Waste Electric- and Electronic Equipment (WEEE) is growing quickly, producing vast amounts that are not sustainably disposed. WEEE consists of a considerable portion of plastic containing harmful chemicals, like legacy brominated frame retardants (BFRs), which are not easily recycled. With the aim to deal with WEEEs, the European research project Plast2BCleaned developed an innovative dissolution-based recycling process. The process requires the use of chemicals and demands that all workers who have contact with such chemicals follow applicable health & safety measures. However, there is currently a lack of data for most chemicals regarding human toxicity during their use phase, which creates an information gap in Life Cycle Assessment studies that consider the human toxicity of these chemicals. Thus, the goal of this study was to assess human toxicity impacts on plant workers during the Plast2BCleaned recycling process, as a complementary aspect to assessing life cycle impacts of WEEE recycling. Exposure and potential toxicity effects were identified for relevant steps of the process, such as during the filling of a solvent (to be mixed with plastics during the dissolution process) and during storage of the final products (where the chemicals are emitted in the air in a closed environment for a limited time). The USEtox scientific consensus model was used to determine the impacts of this exposure for humans working in the process, by adapting underlying aspects for direct emissions and for chemicals released from materials for the three selected solvents. The concentration in air, characterisation factors and impact scores for each chemical in different steps of the process were determined. Endpoint impact results (expressed in Disability Adjusted Life Years - DALYs) for different solvents and BFRs were obtained. The results show that all three chemicals have their concentration levels below the regulated Threshold Limit Values (TLVs). The estimated emissions of solvents to the air during the filling process and in a spillover scenario, exceeds the TLVs by a factor of 5 to 10. However, in the study conservative time for the filling was assumed and in the real scenario safe short term exposure limit is not exceeded. The endpoint impact results for human toxicity in terms of DALYs are very low for the given worker’s exposure time to the chemicals. Our study is a starting point for combining direct worker effects with life cycle impacts.