1. Biological Oxygen Demand (BOD): BOD measures the amount of
 dissolved oxygen consumed by microorganisms during organic matter
 decomposition. High BOD levels can indicate pollution from organic
 waste discharges.
 In water with a BOD level of 6-9 ppm, the water is considered somewhat
 polluted. Levels of 100 ppm or greater, the water supply is considered very
 polluted with organic waste