The aquatic environments of the Pearl River Delta (PRD) in China have been contaminated by various industrial chemicals from local industries. In this study, the spatial–temporal distribution of six priority phthalate esters (PAEs) in surface water and sediments from the PRD was investigated. The PAEs were detected with total concentrations (Σ6PAEs) ranging from 0.35 to 20.70 μg L−1 in surface water and dry weight ranging from 0.88 to 5.69 μg g−1 in sediments. The Σ6PAEs concentrations in surface water were higher in the wet season than those in the dry season, while the opposite pattern was observed in sediments. Di(2-ethylhexyl) phthalate (DEHP) was the most abundant congener, which was higher than those reported in the literature. Risk quotients for relevant aquatic organisms were obtained and showed that most of these PAEs, in particular, butyl benzyl phthalate, DEHP and di-n-octyl phthalate, have significant potential health and ecological risks for the aquatic environment studied.

A new 1,3-dipolar cycloaddition of oxa(aza)bicyclic alkenes with nitrones has been developed. The operationally simple cycloaddition allows efficient synthesis of fused bicyclic tetrahydroisoxazoles bearing exo- and anti-five member heterocyclic rings (76–99% yields) without any catalyst and additive under mild conditions. The proposed concerted mechanism and the observed selectivity are investigated by DFT calculations of the reaction pathways. This mild and practical [3 + 2] cycloaddition provides an efficient route to access highly functionalized compounds.