Seasonal Variation on Dissolved Oxygen, Biochemical Oxygen Demand and Chemical Oxygen Demand in Terengganu River Basin, Malaysia

The rise in human population densities and the pace of development had intensified the depletion of the water quality. This study aimed to analyze the concentration of dissolved oxygen (DO), biochemical oxygen demand (BOD) and chemical oxygen demand (COD) during wet season and dry season at Terengganu River in 2016. A total of 29 monitoring stations in the study area were selected and three water quality parameters were analyzed using descriptive statistics and the correlation matrix methods. The DO ranged from 2.11 to 8.07 mg L-1, COD from 2.24 to 39 mg L-1 and BOD from 0.67 to 6.52 mg L-1 for the wet season while in dry season, DO ranged from 2.30 to 6.05 mg L-1, COD from 1.9 to 20.48 mg L-1 and BOD from 0.04 to 13.99 mg L-1. Spearman’s correlation test shows there was a weak correlation between DO and COD during wet season, while in the dry season, there was a weak correlation between DO-COD and DO-BOD. This study also found out that urbanization and anthropogenic activities in the area can gave the more impact towards seasons and water quality deterioration in Terengganu River, Malaysia.