Assessment of the quality of surface water of An Ha Canal, Duc Hoa District, Long An Province

LUONG QUANG TUONG - NGUYEN DANH HIEN - DO THI THAO - NGUYEN THI TUYET NGA - TRAN THANH (Faculty of Environmental and Food Engineering, Nguyen Tat Thanh University)


Duc Hoa is a rural district of Long An Province in the Mekong Delta region of Vietnam. Duc Hoa District is undergoing rapid industrialization and urbanization and the district’s domestic, agricultural and industrial demands for water are rapidly increasing. Therefore the district’s An Ha canal system has received a large amount of waste from households and industries. This study conducted household-leveled surveys and collected water samples at 20 locations with GPS navigation for creating monitoring data to offer water quality protection. This study’s results indicate that the water of An Ha canal system is polluted. The concentrations of organic pollution in surface water of An Ha canal system such as Ammonium-Nitrogen (NH4+-N), Nitrate -Nitrogen (NO2--N), Phosphate (PO43--P) exceeds the thresholds B2 level according to QCVN 08-MT:2015/BVMT. An urgent action to control urban pollution should be required to protect this canal system.

Keywords: Canal system, surface water, polluted water.

1. Introduction

Among the world’s total of 2.7% freshwater [1], early human civilization had spread along the river banks, Human body contains about 60% of water and water is being used in most of human activities in different ways [2-3]. Now this resource becomes scarce, exhaustion and threatening development of aquatic life in the river system and human activities around the world. It is thought that water pollution is one of important environmental problems, especially in developing countries and areas [4-5], Many developing countries use polluted surface water for their life, which has in most cases led to negative effects of polluted water use on human health, including Vietnam. According to various provinces Report of the State of the Environment of the Department of Environment and Natural Resources in Vietnam, the surface water of the Mekong River Delta was partially polluted in areas such as industrial, agricultural and aquaculture areas. In recent years, the water quality of rivers, ditches and canals has started to exceed the levels permitted by Vietnamese standards, especially in relation to organic pollution. This problem can only worsen if there is no action to prevent the source of the pollution.

Long An is a province in the Mekong Delta region of southern Vietnam [6]. Demand for water in Long An Province is rapidly increasing for domestic needs, agriculture and industry. On the other hand, run-off from agricultural fields laden with pesticides and herbicides, discharge of untreated sewage into rivers and lakes, and dumping of industrial wastes are also increasing. In Long An Province, Duc Hoa District had many industrial parks, large and small businesses. Problem is that point source water pollution from industrial parks, waste disposal and treatment facilities is proving difficult to manage. This wastewater contributed to high and increasing levels of water pollution. Cases of serious and repeated pollution infringements by many enterprises in many Canals of Duc Hoa District in Long An Province. Duc Hoa is a rural district of Long An Province. An Ha canals in this district received a large amount of waste from households and industries.

Water quality in this canal was strongly influenced by anthropogenic activities including urban development and expansion, increasing industrial and agricultural practices. Polluted water is of great concern to the aquatic organism, plants, humans. All of this wastewater is discharged into An Ha canal, effecting on Vam Co Dong River, as the water source of more than one third of the population of Long An.

What is need to protect this canal by remediation strategies, such as river dredging and sewage interception, have been taken to restore polluted canals in Duc Hoa District. However, little attention has been paid to the recovery of this canal system. before strategies, water quality in An Ha canal necessitated close investigation and monitoring. Therefore, it is necessary to conduct a monitoring program that indicate water quality variation in An Ha canal.

This research area may cover areas of anthropogenic pollution. An objective of this research is necessary to create the survey data and the data observation of water elements by environmental management for offering water quality protection in An Ha Canal, Duc Hoa District, Long An Province.

2. Material and Methods

2.1. Description of the Study Area

The research team has conducted household level surveys and field work obtaining the water samples at 20 points along An Ha canal, Duc Hoa District, Long An Province in August 2020. The sampling location and sample designation are shown Figure 1.

Figure 1: Sample location map at An Ha Canal 

Sample location map at An Ha Canal 

Source: Google Earth

2.2. Description of the Study Area

Firstly, we conducted household level surveys with 50 residents around this canal from location A1 (Kinh Rau Ram Bridge) to location A20. Secondly, field work was conducted to obtain the water samples at 20 locations. Each sample were collected and stored with 2 liters in a plastic bottle in a refrigerator at 40C with proper storage in the laboratory of Nguyen Tat Thanh University where proper equipment was in operation. Analysis of activities performed at this laboratory and before filtration, pH, EC, TDS, 0C of water samples were determined using a combination of pH, conductivity, total dissolved solids and temperature measurement (Mi805 Milwaukee, CO, USA). Dissolved oxygen (DO) is determined by Milwaukee Dissolved Oxygen Meter (MW 600, CO, USA). The HI83399-02 is a multi-parameter photometer for measuring important water quality parameters such as NO3--N, NO2--N, NH4+-N, PO43--P, in this study. 

2.3. Statistical Analyses

Mean values and standard errors of water quality parameters were calculated from replicates, to be done within each treatment on one sampling time to understand differences between the control and the experiment. This differences compared to National Standards of [7-8] and WHO Guidelines [9].

3. Results and discussion

3.1. Social Survey

Figure 2: Water resources situation by household level surveys

Water resources situation by household level surveys

There were 50 questionnaires in the survey results, corresponding to 50 households living around the An Ha canal, to be detailed as following:

+ According to the assessment of the current An Ha canal environment in figure 2, there were 84% households mentioned the polluted water in An Ha canal, 16% households don't know about that. Main reasons causes water pollution in this area, there are 26% of Industrial activities, 28% of Agricultural activities, 36% Household activities, 6% of Transportation activities and others.

+ Almost participants pointed out that reducing pollution of this canals, it was very important to protect this canals. They suggested that relocation of small manufacture factory and handicraft go into industrial zones. Placing banners at canal sections prohibits unconscious people from throwing garbage away or even creating spontaneous landfills. Concern about the degradation of water quality is now widespread among this public area. Apart from the visible improvement in the water quality, the awareness generated is an indicator of its success to protect the water quality managements [10]. In recent years it became clear that the polluted condition of this canal was strongly effected, and this had necessitated close investigation and monitoring.

3.2. Water quality

Table 1. Summary of descriptive analysis of this study

Summary of descriptive analysis of this study

Source: According to the author's calculation


a (QCVN 08-MT, 2015)- B2: National Technical Regulation on Surface Water Quality, Vietnam.

b (QCVN 01-BYT, 2009): National technical regulation on drinking water quality, Vietnam.

c (World Health Organization, 2006): A compendium of standards for wastewater reuse in the Eastern Mediterranean Region from WHO, for Jordanian Standard.

Table 1 illustrated the concentration of the analyzed in-situ parameters of this study with air temperature 26-280C at the laboratory of Nguyen Tat Thanh University. Results of indicators at the beginning and end of experiments compared to National Standards (QCVN 08-MT:2015/BVMT and QCVN 01-BYT, 2009) and also World Health Organization 2006.

The water temperature in this study ranged from 28.1 ± 0.0oC to 30.3 ± 0.0oC with an average 29.02 ± 0.68-C. In practical terms, this means that this water temperature affects the high solubility of many chemical compounds and thus the effects of some pollutants on aquatic life, for example, Optimal growth performance of aquatic weeds and aquatic animals with temperatures in the range of 20 - 30oC [11-12].

Figure 3: A- pH, B- Electrical conductivity (EC), C- Dissolved oxygen concentration (DO), D- Total dissolved solids (TDS) in water

A- pH, B- Electrical conductivity (EC), C- Dissolved oxygen concentration (DO), D- Total dissolved solids (TDS) in water

Source: According to the author's calculation

Figure 3A showed that the average pH value recorded 5.19 ± 0.82. The pH concentration had a range from 3.54 ± 0.01 to 6.58 ± 0.01. Many sampling points was not within the thresholds B2 in (QCVN 08-MT:2015/BVMT) and (World Health Organization, 2006) for conserving aquatic ecology and for animals with the threshold of pH 6-9. But results showed the low value of pH at location A1, A4, A5, A12, A18, A19, A20 and even under the permitted limit B2. This point may affect the environment conditions and human health around here. Especially, location A19 and A20 located the downstream of this canal, and then surface water flows into Vam Co Dong river.

Figure 3B illustrated an average of electrical conductivity 528 ± 167 µs/cm. The electrical conductivity had a range from 242 ± 2.1 to 899 ± 0.7 µs/cm. The conductivity had significantly changed in 20 locations.

Figure 3C presented that Dissolved oxygen levels had a highest value 9.55 ± 0.07 mg/l and the lowest was 0.4 ± 0.0mg/l due to the weather or the rainy season. Dissolved oxygen  (DO) is very important in aquatic ecology [13], if the DO concentration was low, causing the organisms lose activity or even death. The experiment average of TDS was 263 ± 84 mg/l and this range ranged from 122 ± 0.70 to 451 ± 0.71 mg/l in Figure 2D, The trend of total dissolved solids was a limit standard of National Standards as concentration of TDS < 1000 mg/l [8] - National technical regulation on drinking water quality and WHO.

Figure 4: A- Ammonium-Nitrogen (NH4+-N), B - Nitrate -Nitrogen (NO2--N), C- Phosphate (PO43--P) in water

A- Ammonium-Nitrogen (NH4+-N), B - Nitrate -Nitrogen (NO2--N), C- Phosphate (PO43--P) in water

Source: According to the author's calculation

The term ammonia (NH4+-N) includes non-ionized (NH3) and ionized (NH4+). The NH4+-N levels for all the monitored points on An Ha only are shown in figure 4A. All values NH4+-N in this research area exceeded 0.9 mg/l NH4+-N of thresholds B2 of QCVN 08-MT-2015 / BVMT. This trend NH4+-N came from location A4 to A20, being higher than location A1, A2, A3. Especially, location A20 reached the highest value with 81.85 ± 2.75 mg/l, it may be concerned the polluted water at the end of downstream, it can affect Vam Co Dong river. All NO2--N content in figure 4B also exceeded 0.5 mg/l NO2--N of thresholds B2 of QCVN 08-MT-2015/BVMT. Concentration NO3--N was nearly 0.00 mg/l in 20 locations, that was not a good thing for aquatic life because the polluted surface waters may contain less than 1 mg/l of nitrate NO3--N [14].

Figure 4C showed that most PO43--P in water in An Ha canal exceeded thresholds B2 of QCVN 08-MT-2015/BVMT. The high concentration of PO43--P was 16.15 ± 0.21 mg/l at location A6, 13.45 ± 0.07 mg/l at location A2 and 9.2 ± 0.0 mg/l at location A7. Ammonium, Nitrite and phosphate levels were very high at all points, caused polluted water, effecting conservation of aquatic ecology in this research area.

4. Conclusion

Survey results mentioned the polluted water in An Ha canal. Following to the water quality in this research, concentrations of organic pollution such as Ammonium-Nitrogen (NH4+-N), Nitrate -Nitrogen (NO2--N), Phosphate (PO43--P) in surface water from An Ha canal, putting at risk households relying on these regions in a use of polluted water because this values exceeded the thresholds B2 (QCVN 08-MT:2015/BVMT). Main reason was that Duc Hoa District was undergoing rapid industrialization and urbanization, has expanding population and growing economy, and is undergoing rapid industrialization and urbanization. This situation suggests solution for efficient water treatment technologies for discharging waste water to environment. It is of the utmost importance that good strategies be developed for the management of safe water for public supply [15]. First one, educating residents of this rural district to understand the effects of contaminated water on their health is essential in further years. Second one is that long-term water quality monitoring program with more frequent testing should be considered.

Acknowledgement: This research is funded by Nguyen Tat Thanh University, Ho Chi Minh city, Vietnam.


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Khoa Kỹ thuật Thực phẩm và Môi trường

Đại học Nguyễn Tất Thành


Long An là một tỉnh thuộc vùng đồng bằng sông Cửu Long, trong đó Đức Hòa là huyện nằm ở phía Bắc tỉnh Long An. Huyện Đức Hòa đang trong quá trình công nghiệp hóa và đô thị hóa nhanh chóng, nhu cầu sử dụng nước của khu vực này ngày càng tăng nhanh cho nhu cầu sinh hoạt, nông nghiệp và công nghiệp. Kênh An Hạ là một tuyến kênh chính chảy qua huyện Đức Hòa, nên đã tiếp nhận một lượng lớn nguồn nước thải từ các hộ gia đình và khu công nghiệp. Nghiên cứu của chúng tôi bao gồm phiếu khảo sát đánh giá ô nhiễm môi trường và thu thập mẫu nước đại điện với địa điểm có định vị GPS để tạo cơ sở dữ liệu quan trắc thực tế nhằm đề xuất bảo vệ chất lượng nguồn nước mặt ở đây. Từ kết quả của điều tra khảo sát, hầu như người tham gia phỏng vấn điều đánh giá có tình trạng ô nhiễm nước ở kênh An Hạ. Đồng thời kết quả phân tích cho thấy nồng độ ô nhiễm hữu cơ cao như Amoni-Nitơ (NH4+ -N), Nitrit -Nitơ (NO2- -N), Phosphat (PO43- -P) trong nước mặt kênh An Hạ hầu hết vượt ngưỡng B2 trong (QCVN 08-MT: 2015/BVMT). Kết luận rằng, một hành động cần thiết phải được đưa ra để kiểm soát ô nhiễm tại hệ thống kênh này.

Từ khóa: Kênh An Hạ, chất lượng nước mặt, ô nhiễm nước.

[Tạp chí Công Thương - Các kết quả nghiên cứu khoa học và ứng dụng công nghệ, Số 24, tháng 9 năm 2020]