Many industrial zones nationwide failed to operate their waste treatment systems properly and have dumped large amounts of industrial waste with high levels of toxic chemicals into the environment, according to Dr Le Trinh, from Viet Nam Environmental Science and Development Institute.
Trinh said industrial waste and wastewater were major contributors to environmental pollution.
Industrial and urban wastewater has caused serious water pollution in many channels in HCM City, including the Tham Luong, Ba Bo and An Ha channels, according to the institute.
Statistics from a 2015 conference reviewing the status of the river network in Viet Nam in the 2005-2015 period showed that about 1.1 million cubic metres of industrial wastewater was dumped into rivers per day in 2010. This is estimated to increase to 2.4 million cubic metres by 2020.
Dong Nai River in southern Bien Hoa City receives about 111,000 cubic metres of wastewater everyday from more than 10,000 industrial production businesses and hundreds of craft villages.
Many businesses have wastewater treatment plants, however, they often fail to operate properly. Neighbouring hospitals have also dumped a large amount of untreated wastewater into the river, according to Deputy Head of the Environment Crime Prevention Police Department, Duong Van Linh.
There are many criteria used to evaluate the level of water pollution. Physical properties include total dissolved solids (TDS) and total suspended solids (TSS), chemical properties include pH level, salinity, dissolved oxygen (DO) and toxic chemical levels, and there can also be pollution by microbial elements, according to Dr Tran Ba Thoai, member of the executive branch of the Viet Nam Association of Endocrinology.
Wastewater from industrial and production zones operating around Cau River contains high levels of TSS, metals and oil, according to the national environment status in 2012.
Wastewater coming from different production industries has different effects on water resources.
Wastewater from engineering and mechanical industries often contains oil and suspended solids, while wastewater from businesses in food production contains more organic pollutants. Wastewater from the garment weaving and dying industries often contain sodium hydroxide, alum, and other chemicals involved in scouring and dying.
In addition, the massive developments surrounding mineral exploitation and processing sites cause adverse impacts on water resources.
The breakup of stone caused in mining and blasting activities speed up the dissolving of chemicals into surrounding water resources. The process of mine dewatering also causes changes in the physical and chemical characteristics of water around mining areas, according to the report.
Water in these areas often contain higher levels of heavy metal ions, organic compounds and radioactive elements compared with surface and ocean water.
Mercury, cyanide, arsenic, antimony and sulphur are needed in gold extraction, and water in these gold mining areas can be polluted by heavy metals, the above toxic substances and also lead. All of these are considered serious threats to both domestic and agricultural water use, according to the report.
As water pollution is occurring in thousands of river branches and streams, we should prioritise recovering these small contaminated water courses rather than simply waiting for a new policy on water pollution control to be made available, said Director of the Environment and Community Research Centre, Nguyen Ngoc Ly.
Management of chemically caused water pollution is still inefficient due to a lack of adequate policies related to chemical use, poor mechanisms to punish violations, a lack of human resources and poor business practices, Tin Tuc (News) reported.
An average of 9,000 people die every year in Viet Nam from poor quality water and unsanitary conditions, and approximately 200,000 people are found to have contracted cancer with the main cause suspected to be polluted water, according to Health Ministry statistics.