Quality Control Assessment in the River of Kajang, Selangor, Malaysia

This paper investigates the biochemical oxygen demand (BOD) and the pH level along Jelok River, Kajang, Selangor, Malaysia. The BOD and pH level are of major interest as microbial activity. Five water sampling locations along the river have been selected. To test the pH level of each water sample, a pH meter was used. To test the BOD of each water sample, the 5-days BOD test was conducted. Using the collected data, the Pearson’s correlation coefficient between the pH and BOD was calculated. The computed Pearson correlation coefficient is -0.67988, indicating that pH does affect BOD of the water, specifically for this river. In addition, it demonstrates that when pH value increases, BOD of the water will decrease. The results show that water pH was quite stable, range between 7.05 to 7.65, while BOD fluctuates wildly, range between 1.4 to 4.3 mg/L. According to the BOD value, the high BOD value was found along the bridge at Changkat Road with 4.3 mg/L, and the lowest was found to be the one at Shell Petrol Station along Semenyih Road with BOD value of 1.4 mg/L. From the findings, public and authority shall be alert of the water performance and actions are necessary to preserve the water quality along this river. In addition, it is recommended to compare the water quality parameters among few rivers in future studies.