Levels, Distribution, and Health Risk of Phthalate Esters in Urban Soils of Beijing, China

The content of phthalate esters (PAEs) was investigated in urban soil samples (n = 127, 0-20 cm) collected from a business area (BU), classical garden (CL), culture and educational area (CU), large public green space (LA), residential area (RE), and roadside area (RO) in Beijing. The sum of all PAE contents ranged from 1.9 to 3141.7 ng/g, with an average of 1139.6 +/- 727.6 ng/g. Di-n-butyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP) were the major contaminants in the soil samples. The content of DEHP and DBP in the urban soil of Beijing showed decreasing trends from the center of the city to the suburbs, which was probably because the center of the city has a longer history. In addition, higher DBP content also occurred in the south of the city, which was caused by the existence of several factories that produce commodity chemical and building materials in these areas. Because of its greater age, less disturbance from human activity, and high levels of total organic carbon and black carbon in CL, PAE content in CL was the highest among the six types of land use, followed by RE, CU, BU, LA, and RO. Although in 82.6% of the soil samples, DBP content exceeded the recommended allowable soil content in New York, USA, health risk assessment with CalTOX and Monte Carlo analysis showed that the total cancer risk values of PAEs were lower than the acceptable cancer risk value (10(-6)) and that the risk mainly came from dermal uptake and inhalation exposure pathways.