The derivation of water quality criteria for nonylphenol considering its endocrine disrupting features

Nonylphenol (NP) is an endocrine disruptor and causes feminization in various organisms. This study aims to determine the water quality criteria for NP in China based on species sensitivity distribution (SSD) models considering both reproductive and traditional toxicity effects. A total of 17 chronic values with reproductive endpoints and 14 chronic values with traditional endpoints tested with aquatic species resident in China were found in published literature, among which six values were from marine species. As chronic toxicity data for marine species were limited, the acute-to-chronic toxicity ratio methodology was employed to extrapolate from acute-to-chronic toxicity values. The SSD models were then built with a whole set of chronic toxicity values for NP. Based on model simulation, the chronic water quality criterion in fresh water was calculated as 1.37 μg/L and 4.29 μg/L for reproductive endpoints and traditional endpoints, respectively. The criterion in seawater was derived as 1.68 μg/L for traditional endpoints. Although these criteria were derived by a third-party organization not affiliated with the Chinese authority for criteria development, they were obtained from a scientific point of view and can be used to evaluate water quality and ecological risks of nonylphenol in various water bodies.