The analytical methods become more and more sensitive
to show the enviromental pollutants in extremly small quantities. The chemical
methods, like rapid tests, can make possible the examination on the spot,
on a simple way, right where the pollution happened.
The exagerated manuring of the agricultural fields is the cause of the high nitrate and phosphate concentration in the ground and surface water. The consequence is the multiply of the algae (and other plants) in the water, than the process of the putrefaction consume the oxigen from before the organism (plants and animals) living in the water.
The results of nitrogen or oxygen examination in the water, the hardness and the electric conductivity of water and pH will show the quality and the properties of water. Even if there is no pollution in the water, the hardness and pH are important for other fields: washing (dosing of detergents), suitable conditions in the aquarium, prevention of boiler scale, etc.