This study aims at assessing changes in the surface water quality in Dong Nai province (2010- 2014). In addtion, the pollutant loads of wastewater sources were calculated till 2020–2030 with 03 wastewater treatment scenarios serving for the local environmental management. The water quality index (WQI) showed the surface water quality of Dong Nai Province to be gradually improved during the dry season but significantly declined in the rainy season in the last 5 years due to high concentrations of suspended solids (SS), Fe and microorganism - especially in the 3rd segment of Dong Nai river through Bien Hoa City. | TAÏP CHÍ PHAÙT TRIEÅN KH&CN, TAÄP 19, SOÁ T6- 2016 Assessing changes in surface water quality and pollutant load in Dong Nai province Thi Diem Huong Bui Institute of Meteorology, Hydrology, Oceanology and Environment Ngoc Tuan Le* University of Sciences, VNU- HCM (Received on 17th December 2015, Accepted on November 21th 2016 ) ABSTRACT This study aims at assessing changes in the current status certainly relates to pollutant loads surface water quality in Dong Nai province (2010from waste water sources in the province. 2014). In addtion, the pollutant loads of Pollutant loads of domestic and industrial wastewater sources were calculated till 2020–2030 wastewater in Bien Hoa city are the highest (40 % with 03 wastewater treatment scenarios serving for per source), livestock activities in Xuan Loc the local environmental management. The water district account for 20 %; aquaculture activities in quality index (WQI) showed the surface water Nhon Trach district contribute more than 75 % of quality of Dong Nai Province to be gradually the corresponding total loads, etc. in which loads improved during the dry season but significantly of BOD5, COD and SS are significant, about declined in the rainy season in the last 5 years due 581,570 tons, 1,035,403 tons and 639,153 tons per to high concentrations of suspended solids (SS), Fe year, respectively, and tend to increase in the rd and microorganism - especially in the 3 segment future, requiring appropriate solutions. of Dong Nai river through Bien Hoa City. This Keywords: pollutant load, surface water, water quality, water quality index INTRODUCTION According to Cooke et al. [1], surface water quality can be assessed through the pollutant loads and concentration. Previously, the river water quality is assessed through the concentration of individual pollutant compared to local standards, thence compared to general evaluation approaches through Water Quality Index (WQI) as NSF WQI (USA), Bhargava-WQI (India), .
