Microorganisms involved in biodegradation of organic matter in the receiving water body consume lot of oxygen and as a result there is a sharp decline in dissolved oxygen. This causes mortality of fish and other aquatic creatures, excessive growth of planktonic algal bloom, distinct colour or water bodies and deterioration of the water quality. If the BOD value of a water body is higher, the amount of dissolved oxygen is lower and the polluting potentials is higher in that water.