Organophosphate flame retardants emitted from thermal treatment and open burning of e-waste

Organophosphate flame retardants (OPFRs) have been increasingly produced and consumed since the gradual phase-out of polybrominated diphenyl ethers. Primitive recycling of e-waste can be a significant input source of OPFRs to the environment. Thermal treatment and open burning of typical e-wastes were conducted in a closed chamber to examine the emissions and the size distribution patterns of particle-bound OPFRs from these processes. The sum emission factors of OPFRs were 3.70 × 10⁴-3.65 × 10⁵ ng g^-1 by thermal treatment and 5.22 × 10³-9.27 × 10⁴ ng g^-1 by open burning. The output-input mass ratios of OPFRs for plastic casings were 0.030-116 and 0.012-7.1 by thermal treatment and open burning, respectively, and were 0.11-40 and 0.0014-6.7 for printed circuit boards. The size distribution patterns of OPFRs were characterized by one unimodal peak (0.56-1.0 μm) for thermal treatment and bimodal peaks (0.56-1.0 or 1.0-1.8 and 10-18 μm) for open burning. Particle-bound OPFRs appeared to form in affiliation with particles rather than by adsorption or deposition from the gaseous phase to particulate organic matter. With increasing amounts of OPFRs used in a variety of consumer products, the emissions of OPFRs to the environment are expected to increase continuously in the future.