Tag: pollution of water

Biological Oxygen Demand (BOD) refers to the amount of dissolved oxygen that aerobic organisms need in order to break down organic material in water over time. Its high value indicates the intense level of microbial pollution.

Maximum prescribed limit of Fe in drinking water is 50 ppm

Water pollution is the contamination of water bodies very often by human activities.

Pollutants which are slowly degradable remain in the environment in an unchanged form for many decades. For example, substances such as dichlorodiphenyltrichloroethane (DDT), plastic materials, heavy metals, many chemicals, and nuclear wastes etc., once released into the environment are difficult to remove. These pollutants cannot be degraded by natural processes and are harmful to living organisms. In the process of environmental pollution, pollutants originate from a source and get transported by air or water or are dumped into the soil by human beings.

All these industries cause water pollution by the water discharged into the rivers. The common industrial pollutants are sulphur, asbestos, poisonous solvents, poly-chlorinated biphenyl, lead, mercury, volatile organic chemicals, etc.

Water pollution is the contamination of water by substances harmful to life.

Pesticides and fertilizers containing chemicals causes water pollution. Pesticides contaminate water as the pesticides are toxic. Fertilizers contain nitrogen and phosphorous, high amount of which is injurious to the underwater organisms. Therefore, the answer is D.

A) Aldrin is a pesticide used to control soil insects such as termites, corn rootworm, wireworms, rice water weevil and grasshoppers.
B) The maximum permissible limits for nitrite and nitrate are 10 ppm and 50 ppm respectively.
C) The maximum permissible limit of fluoride is 2 ppm.

Pesticides are the chemical compounds that are used to kill pests, including insects, rodents, fungi, and weeds.