Nonylphenol and octylphenol in riverine waters and surface sediments of the Pearl River Estuaries, South China: occurrence, ecological and human health risks

The temporal–spatial distribution and risks of nonylphenol (NP) and octylphenol (OP) in the surface waters and sediments from the six major riverine runoff outlets of the Pearl River Estuaries (PRE) were investigated. NP and OP were detected in all samples. It is worth mentioning that the levels of NP and OP in July in waters ranged from 1,740 to 16,200 ng L⁻¹, and from 1,265 to 15,700 ng L⁻¹, respectively; in sediments, they ranged from 28 to 92 ng g⁻¹ dw and from 2.7 to 42 ng g⁻¹ dw, respectively. According to aquatic risk assessment based on hazard quotient (HQ), NP and OP posed a high potential ecological risk (HQ > 1) to relevant aquatic organisms (excluding the alga, Selenastrum capricornutum), indicating that aquatic organisms, in particular crustaceans, have been significantly affected by NP and OP. Although the risk of NP for humans in water was regarded as endurable according to tolerable daily intake, it was higher than the drinking water safety limit (0.5 μg L⁻¹). The results indicated that the heavy contamination caused by NP and OP and their adverse effect on local aquatic organisms in the PRE deserved to arouse wide concern.