Question

Common indicator organism of water pollution is
(A) Escherichia coli
(B) Cholera vibrio
(C) Salmonella typhi
(D) Entamoeba histolytica

Answer 1

Hint: The Common indicator organism of water pollution is a Gram-negative, facultatively anaerobic, rod- shaped, coliform bacteria, and also this bacteria is also found in the intestine of warm-blooded organisms like birds and mammals.

Complete step by step answer:
A common indicator organism of water pollution is Escherichia coli. Escherichia coli is transmitted to water bodies through fecal matter. Detection of Escherichia coli in water bodies indicates that the water is contaminated with fecal matter and is not suitable for drinking. If this water is used for drinking, it can be serious for our health.
There are various methods to detect the pollution level in water bodies. Some of them are:
- Physico-chemical indicators:
Physico-chemical indicators are the standard 'water quality' indicators that the majority of people are aware of. They include dissolved oxygen, pH, temperature, salinity, and nutrients (nitrogen and phosphorus). They also include measures of toxicants like insecticides, herbicides, and metals.
- Biological indicators:
Biological indicators are direct measures of the health of the fauna and flora within the waterway. Commonly used biological indicators in freshwater include various measures of macroinvertebrate or fish diversity, benthic algal growth, and benthic oxygen demand.
- Flow indicators: In freshwater, changes to flow are often the best explanation for aquatic ecosystem health degradation; the Murray- Darling system is an example of this. Assessing the changes is therefore important. Changes to natural flow caused by humans are varied and include changes to peak flows, base flows, no-flow periods, and seasonality of flows.
So, the correct answer is ‘Escherichia coli’.

Note: The bacterium Escherichia coli (E. coli for short) is crucial in modern biotechnology. Scientists use it to store DNA sequences from other organisms, to supply proteins, and to check protein function. Escherichia coli is also present in our intestine and helps in the breakdown of the food we eat.