Identification and seasonal variation of PM 2.5 -bound organophosphate flame retardants from industrial parks and the associated human health risk

Organophosphate flame retardants (OPFRs) have become pervasive environmental pollutants. However, there is a lack of information available regarding PM -bound OPFRs emitted from industrial parks dedicated to the manufacturing and processing of metal-related products. In this study, 15 OPFRs in PM were identified from two industrial parks specializing in aluminum products and the deep processing of metals, respectively. The seasonal variations and health risks of OPFRs were investigated. The PM and OPFR concentrations were 26.0-203 μg/m and 12.4-6.38 × 10 pg/m , respectively. The OPFRs concentrations in the aluminum-processing industrial park exceeded those found in the metal-fabrication industrial park. Among the chloro-, aryl-, and alkyl-substituted OPFRs (i.e., Cl-OPFRs, aryl-OPFRs, and alkyl-OPFRs), Cl-OPFRs were the predominant homologues in the two parks (69.3% and 51.4%) and the control site. Tetraethyl diphosphate and tris(2-chloroethyl) phosphate were the most commonly occurring homologues in the aluminum and metal-fabrication industrial parks, respectively. Seasonal variations of the target OPFRs were observed, although there were slightly different concentrations between the sites. The correlation and principal component analyses with multiple linear regression identified metal waste disposal as the leading source of OPFRs in metal parks (68.0%), followed by traffic emissions (25.3%), adhesives and flame retardants in construction-related substances (3.82%), and mechanical emissions (2.85%). The health risk assessment showed that the hazard quotients for non-carcinogenic risk were