Seasonal distribution of phthalate esters in surface water of the urban lakes in the subtropical city, Guangzhou, China.

Urban lakes are vulnerable to the accumulation of toxic and/or potentially toxic contaminants, such as phthalate esters (PAEs) from urban stormwater runoff, atmospheric deposition, as well as untreated discharge of industrial wastewater and municipal sewage. The concentrations of 16 PAEs in surface water from 15 urban lakes in the subtropical city, Guangzhou, were measured, respectively in spring, summer and winter 2006, to elucidate the effect of the seasonal variation in climate conditions on the distribution of PAEs. Seasonal variations of the Sigma(16)PAEs concentrations, ranging, respectively from 0.47 to 6.19 microg L(-1) and from 24.9 to 221 microg g(-1), were measured in the dissolved and suspended particulate matter (SPM) phases. The highest concentrations of PAEs were present in summer. The spatial distribution of PAEs was site-specific. Of the 16 PAEs, dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP), di(4-methyl-2-pentyl) phthalate (DMPP), di(2-ethylhexyl) phthalate (DEHP) were present in all the samples analyzed, and dominated by DnBP, DiBP and DEHP. Composition profile of PAEs indicated that the application of DnBP/DiBP is relatively high in the Pearl River Delta (PRD). Longer/branching alkyl PAEs likely adsorb to SPM in aquatic environments. Normalized partition coefficient (K(OC)) between the dissolved water and SPM was correlated with n-octanol/water partition coefficient (K(OW)) to understand the environmental behavior of PAEs.