Which of the following is not a human source of water pollution?

Correct option is D

The correct answer is Humus matter.
Humus matter:
· Humification leads to the accumulation of a dark-coloured amorphous substance called humus.
· That is highly resistant to microbial action and undergoes decomposition at an extremely slow rate.
· Being colloidal in nature it serves as a reservoir of nutrients.
· The humus is further degraded by some microbes and the release of inorganic nutrients occurs through the process known as mineralisation.
· Crops such as wheat are grown in fine clayey soils because they are rich in humus and are very fertile.
Thus, humus matter is not a human source of water pollution. Information Booster
Pollution is any undesirable change in physical, chemical or biological characteristics of air, land, water or soil.
Water pollution:
· Whenever harmful substances such as sewage, toxic chemicals, silt, etc., get mixed with water, the water becomes polluted.
· The substances that pollute water are called water pollutants.
Additional Information Sewage:
· It is wastewater released by homes, industries, hospitals, offices and other users.
· It also includes rainwater that has run down the street during a storm or heavy rain.
· The water that washes off roads and rooftops carries harmful substances with it.
· Sewage is liquid waste including domestic and industrial wastewater that pollute water sources.