Development of seawater quality criteria for phenanthrene based on toxicity data of native species in the Bohai Sea.

Phenanthrene (Phe), one of the most commonly detected polycyclic aromatic hydrocarbons, poses a potential threat to marine ecosystems due to its strong toxicity to aquatic organisms. Developing marine water quality criteria (WQC) is critical to effectively control Phe pollution. This study conducted 10 acute toxicity tests and 4 chronic toxicity tests using native species in the Bohai Sea, China and found that the half-lethal/effective concentrations (LC/EC) of Phe for all tested organisms were in the range of 0.198-50.142 mg/L. Among them, the mysid Neomysis awatschensis was the most sensitive species, and the rotifer Brachionus plicatilis was the least sensitive. In terms of chronic toxicity, the range of no-observed-effect concentrations (NOECs) for the four tested organisms was 0.0156-4.00 mg/L. Based on the toxicity data and other data collected from existing databases and literature, the established species sensitivity distribution (SSD) model revealed that the marine WQC for Phe was 39.55 μg/L. Furthermore, the reliability of the derived criteria was verified by measuring multiple endpoints of Skeletonema costatum and Brachionus plicatilis after chronic exposure to Phe. Finally, the environmental concentrations of Phe in the Bohai Sea were determined to be 8.0-318 ng/L, and the joint probability curve (JPC) results showed that the ecological risk of Phe was acceptable. This study provides a reference for developing seawater quality standards for Phe.