1-Effects of Soil Pollution:

        Some pollutants may poison the soil by killing its micro-organisms. Example of such compounds are arsenic, lead, sulpher dioxide, fluoride as well as residues from pesticides, the pollutants may remain in the soil for several years affecting its productivity and fertility and decreases the percentage of oxygen and nitrogen in the soil air.

        The radioactive pollutants which are transmitted from the soil to plants and animals are similarly dangerous. Recently, the discovery of cancer of blood and bones has been related to the increase in the use of radioactive substances and nuclear energy in the peace and war.

        It was found that some radioactive isotopes which result from these applications fall on the cultivable soil. The plant absorbs them and then transmits them to animals and finally to man. As an example the radioactive isotope strontium 90.The plants cannot differentiate between this element and calcium in the soil. Cereals like rice may absorb Sr(90) instead of calcium. The radioactive isotope in them transmitted to man when he eats the rice, where it accumulates in his bones and harms the process of formation of blood cells in the morrow. In cows, which feed  on plants containing this radioactive isotope, Sr(90) accumulates in their bones not the flesh and milk. Therefore, Europeans who feed on meat and milk cows were found to contain 1/6 of the amount of radiation found in the bodies of Japanese who feed on rice which in a main constituent in their meals. Recently many problems have been discovered due to radiation not only at their sources, but also in distant places.