Abstract: Dahuofang Reservoir is a major drinking water source in Liaoning Province, the water safety of which is important for this area. In this study, we collected water samples from the reservoir and three main inflow rivers and measured the contents of phthalic acid esters (PAEs). After that, we analyzed the spatial distribution and seasonal variation of PAEs. The results showed that the PAEs content in the reservoir area increased first and then decreased from east to west. In the three rivers, there was a gradual increase trend of PAEs content from upstream to downstream. The PAEs showed seasonal variation, with an order of summer>spring>autumn. Dibutyl phthalate (DBP) was detected in all sampling locations. DBP and di2ethylhexyl phthalate (DEHP) had a certain homology and were negatively related to the concentration of total nitrogen and total phosphorus in water. The results of risk exposure model showed that the non-carcinogenic risk index of DBP in Dahuofang Reservoir was far less than 1, which would not be harm to human body.

Key words: spatial-temporal pattern, gradient differentiation, Zhangye, ecosystem service value, Dahuofang Reservoir, phthalic acid ester, health risk assessment.