The index of pollution in a polluted lake is

Read the table and answer the following questions. How was threat to the lake due to pollution of the lake discovered ?

Environmental issues || Pollution n types of pollution || air pollution act n its controll || smog || noise pollution || water pollution and its controll || BOD eutrophication || biological magnification || solid waste || hospital wastes

General introduction | | Kinds OF pollution | | Kinds OF pollutants

The pollutant is

The cause of thermal pollution of lakes, rivers and estuaries is:

Define the terms pollution and pollutants.