Levels, distribution, and sources of organophosphate flame retardants and plasticizers in urban soils of Shenyang, China

Seventy-four soil samples from the road greenbelts, residential areas, drylands, waste grasslands, education lands, industrial areas, city parks, and rural homesteads of Shenyang city, China, were collected and analyzed for 13 organophosphate esters (OPEs). OPEs were detected in all analyzed soil samples, which indicate that OPEs are ubiquitously environmental contaminants. The ∑13OPEs concentrations ranged from 0.039 to 0.95 mg/kg dry weight (dw), with the mean and median concentrations of 0.23 and 0.16 mg/kg dw, respectively. The pollution levels of OPEs in different land use types were different; the concentrations of OPEs in dryland soils were maximum and in city park soils were minimum. Of 13 OPEs, tri-iso-butyl phosphate (TiBP), tris-(1-chloro-2-propyl) phosphate (TCPP), tri-butoxyethyl phosphate (TBEP), and tris[2-chloro-1-(chloromethyl) ethyl] phosphate (TDCP) were the most abundant OPEs, contributing 42.0 ± 12.8, 12.4 ± 2.32, 6.31 ± 1.88, and 5.76 ± 1.86% of ∑13OPEs, respectively. Principal component analysis (PCA) and absolute principal component score-multiple linear regression (APCS-MLR) suggested that OPE pollution in soils may be derived from atmospheric deposition, road runoff and vehicular traffic emission, and wastewater/reclaimed water irrigation and sludge application, their contributions were accounting for 62.4, 17.6, and 20.0%, respectively. As compared to the results from other studies, the pollution of OPEs in the urban soils of Shenyang is relatively serious.