Biological Oxygen Demand (BOD) is a standard criterion for assessing the quality of water.

Microbial activity BOD measures the amount of dissolved oxygen used by microorganisms (like bacteria) as they decompose organic matter in water.

Pollution indicator Higher BOD indicates a greater presence of organic matter, often suggesting pollution from sources like sewage, animal waste, or decaying plants.

Aquatic life impact Excessive organic matter decomposition can deplete oxygen levels in water, harming aquatic life that depends on dissolved oxygen for survival.

Therefore, BOD serves as a valuable tool for monitoring water quality and identifying potential pollution issues.