Open AccessEnvironmental quality assessment of sandy beaches in Ha Long - Cat Ba area (Vietnam)
Author(s) -
Thu Trang Cao Thi,
Lan Tran Dinh,
Thu Huong Do Thi,
Ha Tran Manh,
Thu Ha Nguyen Thi,
Kha Pham Thi,
Nguyen Van Bach,
Nam Le Van,
Ngoc Dinh Hai
Publication year - 2022
Publication title -
vietnam journal of marine science and technology/vietnam journal of marine science and technology (vietnam academy of science and technology)
Language(s) - English
Resource type - Journals
ISSN - 1859-3097
DOI - 10.15625/1859-3097/16061
Subject(s) - wet season , benthic zone , water quality , dry season , environmental science , hydrology (agriculture) , nutrient , sediment , pollution , fauna , sand mining , oceanography , ecology , geology , biology , paleontology , geotechnical engineering
The environmental quality of 6 famous sand beaches of the Ha Long - Cat Ba area was surveyed in July 2018 (the rainy season) and March 2019 (the dry season). The results showed that the pore water layer below the sand surface contained some pollutants exceed the critical value of QCVN 10:2015/BTNMT for coastal water and ASEAN criteria, including TSS, ammonium and nitrate. In the rainy season, the pore water quality was lower than that in the dry season, indicating that the tourism waste had an influence on the sandy beach water quality. Among the studied beaches, Ha Long and Bai Dai (Van Don) shown pore water pollution, the rest beaches were low to moderate pollution. Pore water in sandy beaches was charecterised by low dissolved oxygen saturation and high mineralization compared to that in sea water. This confirms the role of sandy beaches in providing mineral nutrients to the sea. Analysis of the sediment grain size at the sandy beaches showed that the beach quality was from medium to good. 47 species of benthic fauna had been found in sandy beaches of Ha Long - Cat Ba area, of which the dominant species were molluscs, followed by crustaceans, polychaetes and echinoderms. The biodiversity of sandy beaches in study area was in average level.