Environmental testing of flame retardants
BFR compounds have an inhibitory effect on the ignition of combustible organic materials and are highly effective in plastics and textile applications such as electronics, clothes and furniture. BFRs are commonly used as a means of reducing the flammability of a product; however, some can have a negative effect on the environment and human health. The EU-funded 'Life cycle assessment of environment-compatible flame retardants (prototypical case study)' (ENFIRO) project investigated possible substitutes for three BFRs and compared their hazard, exposure, fire and application performance, using the results to conduct risk and impact assessments. The consortium involved partners from industry, small and medium-sized enterprises (SMEs), research organisations, and universities. In total, 14 halogen-free flame retardants (HFFRs) were selected and studied in five applications, which included printed circuit boards (PCBs), electronic components, injection moulded products, textile coatings and intumescent paint. ENFIRO aimed to create a comprehensive dataset on the viability, application and environmental safety of BFRs, together with a life cycle assessment of alternative flame retardants (FRs). In addition, the project would recommend certain retardant/product combinations for future study, using risk and impact assessment studies as a basis. Project partners studied FR/product combinations that included metal-based FRs, phosphorous-based FRs and nanoclay-based FRs in PCBs, paints and polymers for environmental and toxicological risks, viability of industrial implantation and fire safety. Application of the FR in products was also studied and the results were used along with socioeconomic information to render a complete life cycle assessment. Fire performance tests were conducted to measure the severity of the toxicity, smoke and heat flux of alternative HFFRs against BFRs in fire incidents. Researchers investigated primarily thermoplastics, but also thermosets (epoxy) and elastomers (EVA) and received valuable support from the stakeholder forum on the formulations. The objective of hazard characterisation was to perform ecotoxicological studies of selected HFFRs using water and sediment toxicity tests. Health hazard characterisation of the HFFRs was performed at a molecular and cellular level, with emphasis on geno-, endocrine-, and neurotoxicity using in vitro studies and a limited number of ex vivo validation studies. These included acute toxicity tests on the water flea Daphnia magna, cytotoxity studies on rat livers, cell respiration assays, and tests for endocrine disruption, mutagenicity and neurotoxicity. Information on exposure pathways was collected and modelled, and knowledge gaps were identified. Experiments were carried out to fill these gaps, including determining water solubilities of the organic HFFRs, leaching of HFFRs from polymers to water and emissions from polymers to air. Persistency tests were also conducted and field study samples (indoor and outdoor) collected and analysed. Results from tests were used to conduct a risk assessment of the alternative FRs, which in turn was used together with socioeconomic information to create an LCA. The ENFIRO approach and the results can be used in similar substitution studies, such as the EU's Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) regulation that addresses the production and use of chemical substances and the potential impact on human health and the environment.
