Eight main sources of solid wastes are as follows:
1. Municipal solid wastes 2. Industrial Solid Wastes 3. Mining solid wastes 4. Fertilizers 5. Pesticides and Biocides 6. Excretory products of humans and livestock 7. Electronic wastes 8. Hospital Wastes.
1. Municipal solid wastes:
These are solid wastes from home, offices, stores, schools, hospitals, hotels etc. These domestic solid wastes one usually, thrown in municipal garbage collecting cans or on road side open waste lands. They are collected by municipality vehicles to certain garbage disposal site. They are dumped over a large area of land which becomes the breeding ground of flies and rats. Usually they are not burnt to reduce the volume because burning would cause air pollution which is still more dangerous.
2. Industrial Solid Wastes:
Most of the toxic industrial wastes are dumped on waste lands for slow and gradual decomposition. Some industries dump their effluents on barren land, road sides creating very unhygenic environment for the local population. Some of the effluents have heavy metals which pollute the ground water through seepage during the monsoon season. Some heavy metals have been found slowly accumulating on formland soils. One such most toxic heavy metal is cadmium which is present in traces in some fertilizers.
3. Mining solid wastes:
They include mine dust, rock tailing, slack and slag. Open cast mining completely spoil the surrounding soil. Toxic chemicals and metals present in the mining wastes destroy vegetation and produce many deforminities in animals and human beings.
4. Fertilizers:
Chemical fertilizers increase soil fertility and gives better crop yield in lesser time. Shortly, the land becomes saline, acidic or alkaline and looses fertility.
5. Pesticides and Biocides:
These toxic chemicals used in crop field which are not ecofriendly. They enter into crop and then into primary and secondary consumers. Even human beings are affected due to bio-magnification.
6. Excretory products of humans and livestock:
In underdeveloped and developing countries, the poor sanitory conditions aggravate soil pollution. The excreta of man and animals, digested sewage sludge used as manure pollute the soil. Several germs present in such wastes contaminate soil, vegetables, and water bodies causing severe health hazards.
7. Electronic wastes:
The latest solid waste that has appeared in last twenty years commonly known as e-wastes is no less harmful. Irreparable computer and electronic goods. Frequently, more efficient and user friendly electronic items appear in the market thus discarding the old generation equipment which simply become garbagesor solid wastes.
Over half of the e-wastes generated in developed countries are exported to developing countries where they ultimately increase the e-garbage proportions.
8. Hospital Wastes:
Hospitals generate hazardous wastes that contain disinfectants, other harmful chemicals and pathogenic microorganism. Such wastes require careful treatment and disposal. The use of incinerators is crucial for disposal of hospital wastes.