University Of Tehran Press Pollution 2383-451X 4 3 2018 07 01 Water Quality Assessment Using Water Quality Indicators and Multivariate Analyses of the Old Brahmaputra River 481 493 66019 10.22059/poll.2018.246865.350 EN Md. Simul Bhuyan Institute of Marine Sciences and Fisheries, University of Chittagong, Chittagong, Bangladesh Muhammad Bakar Bangladesh Council of Scientific and Industrial Research, Chittagong, Bangladesh Abu Sayeed Muhammad Sharif Bangladesh Oceanographic Research Institute, Ramu, Cox’s Bazar, Bangladesh Mahmudul Hasan Institute of Marine Sciences and Fisheries, University of Chittagong, Chittagong, Bangladesh Md. Shafiqul Islam Institute of Marine Sciences and Fisheries, University of Chittagong, Chittagong, Bangladesh Journal Article 2017 11 28 The study has been carried out to assess surface water quality of Old Brahmaputra River from September 2015 to March 2016. DO, BOD₅, COD, pH, EC, Chloride, Alkalinity, and Hardness concentrations in water samples have been found to range within 0.66-2.9 mg/L, 21-138 mg/L, 45-250 mg/L, 7.1-7.8, 185-1080 uS/cm, 10-98 mg/L, 85-197 mg/L, and 84-148 mg/L, respectively. Multivariate statistical analyses such as Principal Component Analysis (PCA) and Correlation Matrix (CM) reveal significant anthropogenic intrusion of pollutants in water, while Cluster Analysis (CA) gives decent results that render three different groups of resemblance between the two sampling sites, reflecting the different water quality indicators of the river system. Very strong positive linear relations have been found between Alkalinity vs. Chloride (0.998), COD vs. BOD (0.994), Chloride vs. EC (0.981), Alkalinity vs. EC (0.976), and Hardness vs. EC (0.952) at the significance level of 0.01, which direct their common origin from industrial effluents, municipal wastes, and agricultural activities. River Pollution Index (RPI) indicates that the water of the Old Brahmaputra River varies from low to high pollution. https://jpoll.ut.ac.ir/article_66019_e534e0d4548c8c2092ad80050b4b98c1.pdf