Development of star shape water quality index for effective environmental communication Development of star shape water quality index for effective environmental communication Development of star shape water quality index for effective environmental communication
LITERATURE REVIEW
Water pollution in river basins of Vietnam
Vietnam is home to 697 rivers, streams, canals, and 38 inter-provincial lakes, organized into 16 main river basins and 3,045 intra-provincial rivers and streams The total annual river flow is approximately 830 to 840 billion cubic meters, with significant contributions from transboundary rivers, including the Mekong, Red, Bang Giang - Ky Cung, and Ma rivers.
The Ca River, Se San River, and Dong Nai River collectively account for approximately 63% of Vietnam's surface water resources These resources are unevenly distributed both spatially and temporally, with around 70-80% of the water flow occurring during the rainy season In contrast, the dry season contributes only about 20-30% of the total annual water supply (Phạm Anh Cường et al., 2021).
According to the National Report on Environment State for the period 2016-2022, significant efforts to manage environmental pollution have resulted in good water quality in major river basins such as the Red - Thai Binh, Ma, Vu Gia - Thu Bon, and Mekong systems The VN_WQI analysis of average annual monitoring data from 2016-2020 indicates that water quality in these basins is primarily rated as "moderate" to "good," making it suitable for aquaculture, irrigation, and domestic use after treatment However, certain areas, including the Cau River near Thai Nguyen city and sections of the Nhue River in Hanoi, exhibit poor water quality Notably, pollution hotspots are found in the Nhue - Day river basin, Cau river basin, and Dong Nai river system, particularly in urban areas with high socio-economic activity, such as central Hanoi and Ho Chi Minh City.
Figure 1.1: Summary the WQI results of 9 main river basins in period 2016-2020
(Phạm Anh Cường et al., 2021)
River basins in Vietnam primarily face pollution from organic matter and nutrients, with pesticide contamination largely absent at most monitoring sites Oil and heavy metal pollution is localized, typically linked to navigation, industrial activities, or mining (Hoi, 2020) Many river basins exhibit high total suspended solids (TSS) and turbidity levels, often surpassing the A2 threshold set by QCVN 08-MT:2015/BTNMT, with some areas exceeding the B1 threshold, particularly during flood seasons While this turbidity is a natural characteristic of the rivers, it significantly impacts the suitability of river water for domestic use (Phạm Anh Cường et al., 2021).
The surface water environment in river basins is facing significant challenges, including organic and nutrient pollution from urban areas and craft villages, as well as increasing salinization, particularly in the estuary regions of the Vu Gia - Thu Bon river basin and southern rivers This dual crisis of water quantity and quality is becoming increasingly evident in Vietnam.
1.1.2 Source of river water pollution a) Domestic Wastewater
The Vietnam Environment Administration reports that over 3,650,000 m³ of domestic wastewater is released into the environment each year, with only 15 to 30% undergoing treatment prior to discharge.
Red-Thai Binh River Basin
Vu Gia-Thu Bon River Basin
Dong Nai River system Basin
Extremely Polluted Polluted Poor Moderate Good Very good
Untreated domestic wastewater in rural areas constitutes approximately 60% of the total wastewater volume, leading to severe pollution issues In response, 49 centralized urban wastewater treatment plants have been established nationwide, with a combined capacity of 1,181,380 m³/day-night However, only about 15% of urban wastewater is collected and treated, and merely 21.35% of urban centers classified as level IV or higher have centralized treatment systems In rural regions, most households lack access to centralized wastewater collection and treatment, with only 4% of sludge being treated Additionally, the cost of drainage and wastewater treatment services is significantly low, averaging just 10% of clean water prices, which covers only 10% of the actual treatment costs (Hoi, 2020).
The results of inefficient domestic wastewater management are reflected in the water quality in the river sections running through the densely residential areas such as Dong
The Bac Hung Hai irrigation system, spanning 200 km across Hanoi, Bac Ninh, Hung Yen, and Hai Duong, is a significant hotspot for water pollution, primarily due to domestic wastewater, which constitutes 58.47% of the total 453,195 m³ of wastewater generated daily According to the Government's Report No.238/BC-CP dated May 20, 2020, monitoring by the Vietnam Environment Administration in 2019 revealed that over 90% of the monitoring sites within this system exhibited levels of organic pollution, nutrients, and microorganisms that exceeded the B1 threshold of QCVN 08-MT:2015/BTNMT.
By 2020, the Ministry of Planning and Investment reported that there were 730 operational industrial clusters covering a total area of 22,336 hectares, with 9,363 factories actively functioning within these clusters.
As of the end of 2020, only 141 industrial clusters in Vietnam, representing 19.3% of operational clusters, had a centralized wastewater treatment system in place (Cường et al., 2021) Additionally, a review conducted in 1951 identified 1,951 craft villages, comprising 1,062 new and 889 traditional villages, yet less than 10% of their production wastewater was treated prior to environmental discharge (Nguyen, 2020).
The effectiveness of environmental protection efforts in industrial clusters and craft villages nationwide is hindered by inadequate planning and synchronization Although the legal framework for environmental protection is relatively comprehensive, enforcement by authorities remains weak Additionally, significant investment is needed to enhance technical infrastructure for environmental protection, yet access to capital is limited Most concerning is the alarmingly low awareness among infrastructure investors, enterprises, and production facilities in these industrial clusters regarding compliance with environmental protection laws (World Bank, 2019).
The lack of planning in wastewater treatment from manufacturing activities has led to significant pollution in hotspots like the Cau River basin, where over 4,000 waste sources, including 3,555 production and business establishments, 144 industrial parks, 238 health facilities, and 140 craft villages, discharge waste directly Monitoring by the Vietnam Environment Administration in 2020 revealed that the dissolved oxygen (DO) levels in the main stream of the Cau River ranged from 3.5 to 6.2 mg/L, with the lowest value at Hoa Long point failing to meet the B1 threshold of QCVN 08-MT:2015/BTNMT Additionally, chemical oxygen demand (COD) values were reported to range from 6.
The study observed that the water quality parameters in the Cau River varied significantly, with BOD5 levels ranging from