Occurrence and distribution of organophosphate flame retardants (OPFRs) in soil and outdoor settled dust from a multi-waste recycling area in China

Abstract

Distribution of 12 organophosphate flame retardants (OPFRs) was determined in soil and outdoor settled dust samples collected from a multi-waste (electronic, plastic, and rubber wastes and abandoned household-appliances and vehicles) recycling area, that encompassed different modes of operation i.e. open (ORS) and semi-closed recycling (SCRS). Among the twelve OPFRs analyzed, eleven were detected at a frequency of 75%–100% in all soil and dust samples. In soil samples, ΣOPFR concentrations were significantly higher at ORS (122–2100ng/g) than at SCRS (58.5–316ng/g) and nearby farmlands (37.7–156ng/g). The ΣOPFR concentrations in dust samples were higher than those in soil samples with spatial distribution similar to that observed for soil, decreasing from ORS (1390–42,700ng/g) to SCRS (914–7940ng/g). Tris(2-chloroisopropyl) phosphate (TCIPP) was the major OPFRs in both soil (<MDL–1370ng/g) and dust (39.9–16,300ng/g) samples. Chlorinated OPFRs [TCIPP, tris(1,3-dichloroisopropyl) phosphate (TDCIPP) and tris(2-chloroethyl) phosphate (TCEP)] and aryl-OPFRs [triphenyl phosphate (TPHP), tris(methylphenyl) phosphate (TMPP)] exhibited spatial difference between ORS and SCRS. Principle component analysis (PCA) of OPFR concentrations revealed that TCIPP, TDCIPP, TPHP, TMPP originated from similar sources. TMPP was assessed to pose eco-toxicological risk (risk quotient values: RQs) in the soil ecosystem. The median estimated daily intake (EDI) of OPFRs via soil and outdoor settled dust ingestion (based on average ingestion rate) was 3.14×10−1ng/kgbw/day for adults at ORS. Our results suggest that waste recycling is an important source of chlorinated- and aryl-OPFRs in the environment.