Kết quả khảo sát chất lượng nước biển và trầm tích đáy vùng biển ven bờ hải Hải Phòng và Phú Yên

Abstract

Marine ecosystems are integral to the advancement of a sustainable blue economy; however, they are increasingly subjected to pressures from marine pollutants. In this context, it is imperative to conduct regular and systematic monitoring and assessment of seawater and seabed sediment quality—initially prioritized in coastal marine areas extending from the shoreline to 12 nautical miles seaward. This zone encompasses both internal waters, over which the State exercises full, absolute, and exclusive sovereignty, and the territorial sea, which is under the complete and undivided sovereignty of Vietnam. This study focuses on assessing the trends and changes in the quality of seawater and bottom sediments in two coastal marine areas (extending up to 12 nautical miles from the shore) of Hai Phong City and Phu Yen Province from 2023 to 2024, based on two representative transects, with the aim of identifying potential pollution issues specific to each region. The survey was conducted at locations categorized as nearshore, midshore, and offshore, and included analyses of heavy metals (As, Cd, Pb, Cr, Cu, Zn, Hg), mineral oils, organic substances (Cyanide, Phenol), and microorganisms (Coliform). The results indicate that most seawater quality parameters meet the Vietnamese National Technical Regulation (QCVN 10-MT:2015/BTNMT), although localized pollution was observed at certain sampling sites. For instance, the concentration of mineral oils exceeded the permissible limit at a nearshore site in 2023 (0.40 mg/L), and levels of heavy metals in sediments (As, Pb, Cr) in Hai Phong increased in 2024. Marine sediments in both study areas comply with QCVN 43:2017/BTNMT, but show a tendency to accumulate heavy metals over time.