Chất lượng nước mặt kênh rạch tỉnh An Giang từ 2009 đến 2016

J Viet Env 2018, 10(2):113-119 DOI: 10.13141/jve.vol10.no2.pp113-119 R E S E A R C H A R T I C L E Surface water quality in canals in An Giang province, Viet Nam, from 2009 to 2016 Chất lượng nước mặt kênh rạch nội đồng tỉnh An Giang, Việt Nam, giai đoạn 2009 đến 2016 NGUYEN, Hong Thao Ly*; NGUYEN, Thanh Giao Department of Environmental Management, College of Environment and Natural Resources, Can Tho University 3/2 Street, Ninh Kieu District, Can Tho City, Viet Nam The present study evaluates the surface water quality in the canals of An Giang province in the period from 2009 to 2016 The results showed that surface water of the canals was contaminated by organic matter and microorganisms which makes it not suitable for water supply and conservation of aquatic life The water quality parameters such as 3dissolved oxygen (DO), biological oxygen demand (BOD), total suspended solids (TSS), orthophosphate (P-PO4 ) and coliforms levels in the wet season were found to be higher than those in the dry season The problem of organic and microorganic pollution over a long period of time without solutions leads to declines in water quality and then quantity as well Agriculture is the main activity contributing to pollution of surface water in interior canals along with the activities of daily life, industry and services This causes pollution of the surface water on Hau River due to its exchange of water with the connected canals Good agricultural practices should be implemented to limit the pollution of surface water resources of the Mekong Delta Nghiên cứu nhằm đánh giá diễn biến chất lượng nước mặt kênh rạch nội đồng tỉnh An Giang giai đoạn 2009 – 2016 Kết cho thấy nước mặt kênh rạch nội đồng ô nhiễm hữu vi sinh vật Nguồn nước không phù hợp cho mục đích cấp nước sinh hoạt bảo tồn thực vật thủy sinh Các tiêu hàm lượng oxy hòa tan (DO), 3nhu cầu oxy sinh hóa (BOD), tổng chất rắn lơ lửng (TSS), orthophosphate (P-PO4 ) coliforms mùa mưa cao mùa khô Vấn đề ô nhiễm hữu vi sinh vật diễn thời gian dài chưa có giải pháp xử lý làm cho chất lượng nước suy giảm dẫn đến suy giảm trữ lượng Nơng nghiệp hoạt động góp phần làm ô nhiễm nguồn nước mặt kênh rạch nội đồng bên cạnh hoạt động sinh hoạt, công nghiệp dịch vụ Điều dẫn đến nước mặt sơng Hậu có đặt tính nhiễm tương tự trao đổi nước với kênh rạch nội đồng Thực hành sản xuất nông nghiệp thân thiện môi trường cần sớm triển khai để hạn chế ô nhiễm nguồn nước mặt quan trọng khu vực đồng sông Cửu Long Keywords: coliforms; dissolved oxygen concentration; in-field canals; surface water quality; suspended solids Introduction An Giang is an upstream province of the Lower Mekong River System and one of the four key economic regions of Viet Nam It has a unique hydrological regime and closely relies on Mekong river water regime with two major rivers: Tien river (80-km long) and Hau river (100-km long) The system of rivers and canals of the province has 280 routes with a general density of about 0.72 km/km , creating favorable conditions for the development of agricultural, industrial and service economy In 2012, the agricultural production value of the province was over VND 8,000 billion and tends to increase over years (up to 2.3% compared to that of 2011) (An Giang People’s Committee, 2015) Average GDP growth rate was 8.63% (period 2011-2015) (An Giang People’s Committee, 2015) Along with the socio- * Corresponding author Email: lyb1404632@student.ctu.edu.vn economic development, water pollution has been increased In agricultural production, due to abuse of plant protection chemicals or pesticides, polluted water sources in canals and ditches affect human health and environment In aquaculture, due to mass farming, lack of planning, inappropriate following the technical processes, along with the large amount of feed used and improper feeding also causes contamination of water environment Industrial zones are still in the development stage, factories and production facilities are still scattered and not concentrated in the industrial zones As a result, untreated or improperly treated waste is one of the causes of water pollution in the rivers In addition, domestic wastewater from rural to urban areas has not been planned for wastewater collection and treatment systems or the investment in construction of hydroelectric dams in the up- 113 http://dx.doi.org/10.13141/JVE ISSN 2193-6471 J Viet Env 2018, 10(2):113-119 stream also contributes to a great impact on quality of surface water sources of the area Field canals in An Giang province are directly affected by socio-economic development activities such as traditional villages and poor agricultural practices This study aims to evaluate long-term surface water quality in the field canals in comparison with Hau river over eight-year period (2009-2016) to find out common and specific pollutants in some canals and river in An Giang province Table Sampling sites of field canals and Hau river Research methodology Monitoring data of eight years (2009-2016) on water quality in Hau river and field canals including pH, temperature, total suspended solids (TSS), dissolved oxygen (DO), biochemical oxygen demand (BOD), nitrogen nitrate (NO3 -N), 3orthophosphate (PO4 -P), and coliforms were provided by An Giang Department of Natural Resources and Environment at 20 sampling locations which were shown in Figure (see coordinates of the sampling locations in Table 1) The period of 2009-2016 was selected since the water quality parameters were regularly monitored three times per year (March, June, and September) The difference in mean values between the surface water quality parameters at the sampling sites was analyzed by one-way ANOVA using IBM SPSS statistics for Windows, version 20.0 (IBM Corp., 2011); Duncan was used to compare the difference in surface water quality parameters at a significance level of 5% (p