Question

Eicchornia (water hyacinth) is sensitive to which kind of pollution?
A. Faecal matter
B. DDT
C. Fertilizers
D. Pb and Cd

Answer 1

The introduction of any toxic or harmful components which cause contamination to the natural environment by involving certain changes, is known as pollution. The foreign material or material that causes pollution is called pollutants.

**Complete answer :**
Pollution is caused by any harmful materials when they are introduced in the environment and can be any substance as solid, liquid and gas or any type of energy such as heat energy, sound or radioactive sources. Pollution of any kinds caused by the contaminants are harmful and have a negative effect on the environment and wildlife.
There are some types of natural pollution that are the result of some natural events such as forest fires and volcanic actions which can cause pollution but pollution generally refers to the addition of harmful compounds due to human activity or anthropogenic activities.
Air pollution, land pollution and water pollution are the three major types of pollution. Air pollution is caused by the addition of harmful gases like carbon monoxide, sulphur dioxide, nitrogen oxides and other chemical vapours that can alter the natural balance of gases in the air to a dangerous level. It is caused by the burning of fossil fuels and automobiles. Land pollution is caused by solid wastes which have not been decomposed properly. In addition to domestic wastes, commercial or industrial waste also forms a significant portion of land pollution.
Water pollution takes place when chemicals or dangerous foreign chemicals and substances are introduced into the water bodies. The main type of pollutants causing water pollution are chemicals, sewage waste, pesticides and fertilizers from agricultural runoff as well as metals like lead or mercury. These pollutants decrease the oxygen levels in the water causing harm to the aquatic flora and fauna.
Various ways are implemented to access the degree of pollution and as a remedy to decrease the effects of pollution. To counteract the dangerous situation raised by pollution several biotic means are also used to determine water pollution.
Eichornia or commonly known as water hyacinth has a prolific growth and is one of the fastest growing plants. Due to their high growth rate and invasiveness, they are often used as a means of control of environmental pollution. The plant has a tendency to accumulate toxin materials easily and are prone to contamination caused by metal pollution. They are extremely tolerant and bear high capacity for uptake of heavy metals especially mercury, lead and cadmium. This characteristic of water hyacinth makes it extremely useful for bio cleaning of metal pollutants. They act as bio indicators to assess various degrees of metal pollutants.

>So, the correct answer is option D) Pb and Cd

Note: Eichornia or water hyacinth are prolific breeders and have a high capacity to absorb and accumulate heavy metals especially metals like cadmium, lead and mercury.