Mapping of phthalate esters in suburban surface and deep soils around a metropolis-Beijing, China

• PAEs levels and patterns in both surface and deep soil were studied.
• Hot spots were identified by spatial mapping.
• PAEs sources were analyzed.
• Volatilization fluxes from soil were calculated by model.

For a safety of public health, it is crucial to understand the soil quality in suburban metropolis with rapid urbanization. The levels and compositional patterns of 13 phthalate esters (PAEs) in both surface and deep soil were analyzed in suburban Beijing for the first time. The geochemical distribution was mapped to identify several “hot spots” in the southern and southeastern areas, which could direct the future management and remediation. PAEs were ubiquitous contaminants and di(2-ethylhexyl) phthalate (DEHP), di-isobutyl phthalate (DiBP) together with di-n-butyl phthalate (DBP) were three dominant species in both layers. The total concentrations in the surface and deep soils were 0.02–2.90 mg kg− 1 (median: 0.38 mg kg− 1) and 0–1.51 mg kg− 1 (lower median: 0.12 mg kg− 1), respectively. The assessment of eco-toxicological effect of the abundant PAEs suggests that no environmental risk would occur at the present level in suburban Beijing. The modeling volatilization flux of six EPA-PAEs was from 5.07 × 10− 3 ng h− 1 for dimethyl phthalate (DMP) to 1.88 × 10− 6 ng h− 1 for di-n-octyl phthalate (DOP). A relationship between volatilization flux (Fv) and octanol-water partition coefficient (Kow) was employed to predict the fluxes of other PAEs from soil to atmosphere. The surface soil could continue to be the source of atmospheric contamination of PAEs in a long term, which deserves further attentions.