Spatial Distribution And Risk Of Organophosphate Esters In Residential Soil Of China

With the restriction and ban on the utilization of brominated flame retardants,the production and usage of organophosphate esters(OPEs)have significantly increased in recent years.Up to now,OPEs are frequently detected in various environment media and biota,while there is few research reported their occurrence in soil,especially for the residential soil which is closely related to human life and health.Consequently,in order to fully understand the occurrence and risk level of OPEs in soil of residential areas in China,the present study firstly established the sampling method and analytical method for detecting OPEs in soil.In addition,the concentration and composition profile of OPEs in residential soils of 89 cities from 32provincial-level administrative regions were detected,and the distribution and influence factors of OPEs were analyzed.Further,the ecological risk and health risk associated with soil of residential area were evaluated.The specific conclusions are as follows:(1)There was no significant difference of OPEs concentrations and profiles in soils from different residential areas of the same city.Therefore it is reasonable that the pollution level of one residential soil sample was chosen to represent that of one city in the large-scale investigations of pollutants in the environment due to the difficulties and limitations of sampling method.Additionally,the most satisfactory extraction effect is ultrasonication and centrifugation with acetonitrile.Except for the relative low recovery of TEP,the recoveries of other twelve OPEs were all at the acceptable range,and most of compounds occurred the recoveries of > 70%.(2)The concentration of ∑OPEs in residential soil of China ranged from 1.70 to179 ng/g dw,with a mean value of 17.5 ± 27.3 ng/g dw,which was lower than the contaminated levels in point source soils and urban soils.Chlorinated OPEs were the major pollutants,and tris(1-chloro-2-propyl)phosphate(TCIPP),tris(2-butoxyethyl)phosphate(TBOEP),tris(2-chloroethyl)phosphate(TCEP)and triphenyl phosphate(TPHP)were found relatively high concentrations.(3)The pollution levels of OPEs in residential soils from different regions were various.The contaminated levels in the Bohai Rim,the Yangtze Delta and Shanxi province were apparently higher than other regions,which was attributed by the production and usage of OPEs,as well as the relatively developed industrial level.Among the three kinds of cities,the most serious OPEs pollution occurred in prefecture-level city(20.2 ng/g dw),followed by provincial capital(17.9 ng/g dw)and county town(14.1 ng/g dw),which was affected by the usage of OPEs products and behaviors of local residents.(4)Environmental parameters(total organic carbon(TOC),precipatation and temperature)were not the major factors influencing OPEs level in residential soil,while socioeconomic parameters(population density and per capita GDP)played important roles in OPEs contamination in residential soils of undeveloped regions and cities(R = 0.54-0.85,P < 0.05).(5)The ecological and health risks of OPEs in residential soil were relatively low,and chlorinated OPEs were the main contributors.It indicated that more attention should be paid on the production and usage of chlorinated OPEs in future.