Question

"Determination of biological oxygen demand (BOD) can help in suggesting the quality of a water body". Explain.

Answer 1

BOD or Biochemical Oxygen Demand is the amount of dissolved oxygen in a water body, required by microorganisms for the aerobic breakdown of organic matter in the water. Its value for a water sample provides an index for testing or determining the water quality. A high value of BOD corresponds to a greater number of aerobic microbes and organic matter in a water sample/body indicating poor quality of water for consumption. A low BOD indicates clean water eg BOD <1mg for pure water, <5mg O${}_2$/l/5 day for an unpolluted river.