Biological Oxygen Demand (BOD), is a parameter to monitor the quality of water. It measures ______.

Biochemical oxygen demand measures the organic contamination of water by the oxygen microbes need to break it down.

A high value means a large load of biodegradable organic matter and heavy pollution.

It does not measure inorganic contamination such as dissolved metals or salts.

It is not a measure of the pH or acidity of the water.

It also does not indicate the salinity of the water.

Clean water has a low biochemical oxygen demand while sewage has a very high one.