Phthalate esters in surface water of Songhua River watershed associated with land use types, Northeast China

The ubiquitous presence of phthalate esters (PAEs) in the environment and their potential role as endocrine disruptors of marine organisms has attracted much attention. The presence of PAEs in different water sources collected from the Songhua River mainstream and its tributaries has been determined in this study. The total concentration of the seven PAEs (Sigma PAEs) detected was found to range from 1.153 to 7.867 mu g L-1, with di(2-ethylhexyl) phthalate (DEHP) present as the predominate PAE congener. Dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), and DEHP were present in all of the water samples analyzed. The concentration of Sigma PAEs in the Songhua River mainstream was shown to decrease initially, with a subsequent increase being detected due to inflow from branch tributaries contaminated with higher concentrations of PAEs. Analysis of land type usage, in this agriculture-dominated river watershed, also revealed an increase in Sigma PAE concentration in waters flowing through forested area. The concentration of Sigma PAEs in river waters also had a significant positive correlation with both agricultural and urban areas (p < 0.05); however, anthropogenic activities were not the only determining factor determining the Sigma PAE concentration in this river watershed. Ecological risk assessment revealed that the levels of DMP and DEP in all waters were generally low, representing a relatively low ecological risk to marine organisms; however, DBP was present at medium or high risk levels, whilst DEHP also displayed high risk levels.