ABSTRACT
Brominated flame retardants (BFRs) have been used intentionally in a wide range of plastics, but are now found in an even wider range of such materials (including children's toys and food contact articles) as a result of recycling practices that mix BFR-containing waste plastics with "virgin" materials. In this study Br was quantified in toy and food contact samples on the assumption that its concentration can be used as a metric for BFR contamination. Subsequently, compound specific determination of BFRs was performed to evaluate the validity of the aforementioned assumption, crucial to render rapid, inexpensive, in situ Br determination in non-laboratory environments (such as waste handling facilities) a viable option for sorting wastes according to their BFR content. We report semi-quantitative compound specific BFR concentrations to give an overview of the distribution of individual BFRs in the analyzed samples. Finally, we evaluated the correlations between waste electrical and electronic equipment (WEEE) related substances (Ca, Sb and rare earth elements (REEs)) and Br as a proxy for identifying poor sorting practices in different waste streams. 26 samples of toys, food-contact articles and WEEE were analyzed with a suite of different techniques in order to obtain comprehensive information about their elemental and molecular composition. The information obtained from principal component analysis about WEEE-related compounds provides new insights into the influence of sorting practices on the extent of products' contamination and bringing out polymer-related trends in the pollutants' signature. 61% of all samples were Br positive: of these samples, 45% had decaBDE concentrations exceeding the concentration limits for PBDEs and their main constituent polymer was - according to the REE signature of such samples - Acrylonitrile Butadiene Styrene (ABS), uses of which include copying equipment, laptops and computers. The ability to better track chemicals of concern and their trends in products is the main requirement for high-level management and control of material cycles to become non-toxic in the future as proposed in the EU's 7th Environmental Action Plan.
Subject(s)
Flame Retardants/analysis , Food Packaging , Halogenated Diphenyl Ethers/analysis , Plastics/chemistry , Play and Playthings , Recycling , Child , Electronic Waste , Food Packaging/standards , Humans , Plastics/standardsABSTRACT
An optimised method for Br quantification as a metric of brominated flame retardant (BFR) concentrations present in Waste Electrical and Electronic Equipment (WEEE) polymers is proposed as an alternative to the sophisticated, yet time consuming GC-MS methods currently preferred. A hand-held X-ray fluorescence (XRF) spectrometer was validated with Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). Customized standard materials of specific BFRs in a styrenic polymer were used to perform an external calibration for hand-held XRF ranging from 0.08 to 12 wt% of Br, and cross-checking with LA-ICP-MS having similar LODs (0.0004 wt% for LA-ICP-MS and 0.0011 wt% for XRF). The "thickness calibration" developed here for hand-held XRF and the resulting correction, was applied to 28 real samples and showed excellent (R(2) = 0.9926) accordance with measurements obtained via LA-ICP-MS. This confirms the validity of hand-held XRF as an accurate technique for the determination of Br in WEEE plastics. This is the first use of solid standards to develop a thickness-corrected quantitative XRF measurement of Br in polymers using LA-ICP-MS for method evaluation. Thermal desorption gas chromatography mass spectrometry (TD-GC-MS) was used to confirm the presence of specific BFRs in WEEE polymer samples. We propose that expressing limit values for BFRs in waste materials in terms of Br rather than BFR concentration (based on a conservative assumption about the BFR present), presents a practical solution to the need for an accurate, yet rapid and inexpensive technique capable of monitoring compliance with limit values in situ.