Most of the land pollution is caused by pesticides and other chemicals which are added to the soil to grow better crops. Often a pesticides poisons many more organism than those intended. Some of these poisons passes through food chains and eventually reach harmful proportions. Solid wastes is another cause of land pollution.
Pesticides are substances that are used to kill or block the reproductive processes of unwanted organisms. Synthetic pesticides are of concern to us, because of the possible effect upon human health through eating of food or drinking water, contaminated with these chemicals. Most pesticides can put into one of three categories:
Control of insects by insecticides helps to curb disease and protect crops. Organo chlorines are a group of compounds which have been developed and used as insecticides. The best known organochlorin compound is DDT (dichlorodiphenyl trichloro ethane) organo chlorines are stable in the environment, toxic to insects in small amounts, but much less go to humans, and because they are organic compounds not very soluble in water. The advantage of these insecticides is that, bring persistent, they show their biological activity for long periods of time. On the example side, these insecticides by accumulating in the environment also affect many non – target organisms, not just the target pests.
Fungicides are used to check the growth of fungi. Fungi, are plants without chlorophyll, they cannot use solar energy for preparing their food. They live as saprophytes on decaying organic matter or as parasites at the expense of living organisms. Hence they are considered to be a threat to human interests. Fungicides are important because they check the growth of fungi. Organic compounds of Mercury have been used as fungicides. These compounds break down in soil and thus have many disastrous consequences.
Control of soil pollution
The following steps have been suggested to control the soil pollution:
(i) The use of chemical fertilizers can be reduced by applying bio – fertilizers and manures.
(ii) Recycling and recovery of materials appears to be a reasonable solution for reducing soil pollutions. Materials such as paper, gas, and some kinds of plastics can be recycled.
(iii) Control of land loss can be attempted through restoring forest and grass cover to check soil erosion and floods.
(iv) Proper methods should be adopted for the disposal of solid wastes
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