The coastal waters have become seriously polluted with oil, zinc waste and domestic water waste, while suspended solids such as Si, NO3, NH4 and PO4 are at worryingly high levels.
The quality of sediment in the coastal areas and the habitats for many aquatic species has declined.
Plant-protection chemical content in samples taken from marine life in estuaries in the north were found to be higher than the permitted levels.
Plant-protection chemical residues found in bivalve molluscs were 11.14-11.83 mg per one kilo of oyster meat in Sam Son beach and Ba Lat Estuary. The concentration was lower at Tra Co, 1.54 mg per kilo.
|Plant-protection chemical content in samples taken from marine life in estuaries in the north were found to be higher than the permitted levels.|
Aldrin and endrin have been found in nearly all samples taken for analysis with the concentration of between 0.12 and 3.11 mg per kilo.
A red tide phenomenon occurs in Vietnam in the sixth to seventh month of the lunar year in the southern part of the central region. Scientists have discovered 8-16 harmful sea microalgae species with the density of 2×104 cells/liter. The red tide along the Binh Thuan province’s coast has killed shrimp, crab, fish, coral and seaweed.
What pollutes the sea?
The water from streams and creeks enter big rivers which then bring the water to the sea. Meanwhile, there are nearly 10 ‘dead rivers’ (seriously polluted) in Vietnam, namely Thi Vai, Dong Nai in the south and Day, Cau and Nhue in the north.
Meanwhile, the domestic waste sources are also discharged into the sea, such as untreated oil and waste water. The substances which are not biodegradable will be left in coastal areas and then sink to the seabed, while biodegradable substances will dissolve in seawater.
More and more construction works near the sea have arisen. Ports and ports’ activities all have had negative impact on the environment, taking away land for residential quarters, and causing soil and water pollution. They also pollute the air and create noise at ports and nearby areas.
A report shows that the lubricating oil waste discharged by vehicles makes up 50 percent of the polluting sources.
The water turbidity measured at Hai Phong Port area is 418-424 mg per liter, while it is 33-167mg per liter at Da Nang Port.
The oil concentration has exceeded the permitted level of 0.3mg per liter at all the ports: 0,42mg/l at Hai Phong port; 0,6mg/l at Cai Lan port; 0,52mg/lat Vung Tau; 7,57mg/l at Petro Vietso.