Hazardous wastes can be in the form of solid, liquid or gas and can cause illness, injury or death to people or even destruction in the environment, if not properly treated, stored, transported or discarded. There are different types of wastes, for instance, there are harmless wastes and there are harmful wastes. Harmless wastes may include such wastes like those from natural or non-synthetic foods.
Substances are considered hazardous wastes if they are:
- Ignitable or combustible: capable of burning or causing fire.
- Corrosive: able to corrode steel or harm organism because of extreme acidic or basic properties.
- Reactive: able to explode or produce toxic cyanide or sulfide gas.Toxic: containing substances that are poisonous.
Mixtures, residues, or materials containing harmful wastes are also considered hazardous wastes. Many dangerous substances can be used only with special precautions that decrease their risks. When discarded, these substances are no longer under the direct control of the user and may pose special hazards to people or other organism that come in contact with them. Because of such potential risks, hazardous wastes are processed from ordinary wastes.
Sources of Hazardous Wastes
There are various sources of hazardous wastes which includes: industrial wastes, agricultural wastes, household wastes, medical wastes.
Industrial Wastes: this types of wastes are generated by nearly every industry; those industries that themselves generate few hazardous wastes nonetheless use products from hazardous wastes generating industries. For examples, in computer software industry, writing software programmes generates little hazardous waste but the manufacture of computers involves many industrial processes.
Hazardous wastes are generated in the manufacture of fiber optics and copper wire used in electronic transmission, as well as magnetic disks, paper for technical manuals, photographs for packaging and publicity and trucks for transportation of the finished products.
Agricultural Wastes: Industry is not alone in generating hazardous wastes. Agriculture produces such as pesticides and herbicides and the materials used in their application. Fluoride wastes are by-product of phosphate fertilizer production. Even soluble nitrate from manure may dissolve into groundwater and contaminate drinking water wells; high level of nitrate may cause health problems.
Household Wastes: Household sources of hazardous wastes include toxic paints, flammable solvents, caustic cleaners, toxic batteries, pesticides, drugs and mercury from broken thermometers.
Local wastes disposal system may refuse these items. If they are accepted, careful monitoring may be required to make sure soil or groundwater is not contaminated. The household may be asked to recycle or dispose of these items separately.
Renovation of older homes may cause toxic lead paint to flake off from walls. Insulation material on furnace pipes may contain asbestos particles, which can break off and hang suspended in air; when inhaled, they can cause lung disease and cancer.
Medical Wastes: Hospitals use special care in disposing of wastes contaminated with blood and tissue, separating these hazardous wastes from ordinary waste. Hospitals and doctors’ offices must be careful with needles, scalpels and glassware, called “sharps”.
Medicine also makes use of significant amounts of radioactive isotopes for diagnosis and treatment and these substances must be tracked and disposed of carefully.
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