Question

High coliform count in water is an indicator of
A. Hardness of water
B. Oil pollution
C. Sewage contamination
D. Industrial pollution

Answer 1

The word ‘Coliform’ refers to the Coliform bacteria. These bacteria are present in the digestive tract of humans and are excreted by them in their faeces. Coliform bacteria are present in the environment and the faeces of almost all warm-blooded animals and humans.

Complete answer: Coliform bacteria are rod-shaped, gram-negative bacteria. They are motile or non-motile bacteria which have the ability to ferment lactose with the production of acid and gas when incubated at a temperature of 35-37 degree Celsius. Coliform bacteria are commonly used as an indicator of sanitary quality of water and food. The word sewage commonly refers to wastewater that contains faeces, urine and laundry wastes. The water supply which is distributed for drinking purposes undergoes a test for total coliform bacteria. High coliform count in water indicates sewage contamination.
a) The hardness of water refers to the amount of magnesium and calcium dissolved in the water. Hard water has a high content of dissolved minerals in it. In simple terms, water hardness is noticed when your hands still feel slimy after washing with water and soap.
b) Spilling of oil in water bodies such as rivers, lakes and oceans is called oil pollution. Aquatic animals are greatly affected by oil pollution. Birds and mammals die from hypothermia due to the inability to repel water and insulate from the cold water.
c) The waste produced by industrial activity which includes wastes from factories, mills, industries, and mining operations are called industrial wastes. Pollution of the air, the soil, or nearby water sources, eventually ends up in the sea caused by industrial wastes.
So, option C is the correct answer.

Note: High coliform count in drinking water increases the risk of contracting a water-borne illness. The only reliable way to know if your water is safe is testing for bacteria. Approved tests for total coliform bacteria include the membrane filter, multiple tube fermentation, MPN and MMO-MUG ("Colilert") methods.