ASSESSMENT OF COASTAL WATER QUALITY IN BAI TU LONG NATIONAL PARK, QUANG NINH PROVINCE

Coastal seawater quality plays an important role in protecting the organisms and life of marine ecosystems. This study evaluates the quality of coastal seawater in Bai Tu Long National Park through field measurements and laboratory analyses. The assessment is based on physical, chemical, and biological parameters, and the results are compared to the standards outlined in QCVN 10:2023/BTNMT. The research team surveyed the research area and selected 25 sampling locations along the coast, encompassing both large and small islands in the Bai Tu Long National Park. According to the measurement and analysis results, the average temperature and salinity of coastal seawater are 27.03 ± 0.46°C and 25.69 ± 1.69‰, respectively; the average values of pH, TSS, and DO are all within the permissible limits. The coastal seawater environment is of high quality to protect the underwater habitat through the pH, DO, and TSS parameters. When compared to the standard, the Fe and P parameters are significantly lower than the permissible limit, safeguarding human health and the marine ecosystem. However, the 8% proportion of low DO readings (<5 mg/L) indicates localized hypoxic conditions, necessitating ongoing site-specific monitoring. The total coliform density in seawater exceeded the allowable limit, with an average density of 1414 ± 266 MPN/100 mL. The primary source of biological pollution in this area is the waste from aquaculture, particularly from fish and mollusk cages. During the sampling, it was observed that the fish in the cages were infected with fungal diseases. It is crucial to take timely measures to address pollution and implement effective solutions for managing the discharge of aquaculture waste in the Bai Tu Long National Park area.