Question

Which of the following is an indicator of water pollution?
A.Salmonella
B.Pseudomonas
C.Coliform bacteria
D.Yeast

Answer 1

Hint: To answer this question, you must recall the various indicators of water pollution. The microbes that can indicate water pollution must be such that are present in water polluting substances and thus its detection can be an indicator for pollutants.

Complete step by step solution:
Water pollution is commonly indicated by coliform bacteria. They are gram negative, rod shaped, anaerobic bacteria that are present in the intestines of warm blooded vertebrates like birds and mammals. Thus it is also present in the fecal matter and is also transmitted to various water bodies through it. As a result, we can say, that the presence of coliform bacteria in water would indicate that the water body is contaminated by fecal matter and thus unsuitable for drinking.
A very common example of coliform bacteria is Escherichia coli (E. coli). It has crucial uses in biotechnology. It is used for storage of DNA sequences, supply of proteins and to check protein function. It is also present in human intestines and helps to break down food.

Thus, the correct option is C.

Note: The pollution level in water can be indicated using various methods, namely physico-chemical indicators, biological indicators and flow indicators.
Physico-chemical indicators include measures of standard parameters like dissolved oxygen, salinity, pH, temperature, nutrients, insecticides and metals
Biological indicators include measures of invertebrate or fish diversity, algal growth and biological oxygen demand. The indication of pollution by coliform bacteria is also a type of biological indicator
Flow indicators involve the detection of change in the flow of water to provide the explanation for degradation of water quality.