Today I’m going to talk about: Hazardous wastes I’ve divided my presentation into two parts: First I’d like to introduce the wastes and second I’ll present sourcesof hazardous wastes. So, let’s start with introduce Hazardous Wastes, solid, liquid, or gas wastes that can cause death,illness, or injury to people or destruction of the environment ifimproperly treated, stored, transported, or discarded. Substances areconsidered hazardous wastes if they are ignitable, corrosive, reactive, ortoxic. Mixtures, residues, or materials containing hazardous wastes arealso considered hazardous wastes. Many dangerous substances can be used only with special precautionsthat decrease their risks. When discarded, these substances are no longerunder the direct control of the user and may pose special hazards to peopleor other organisms that come in contact with them. Because of suchpotential risks, hazardous wastes are processed separately from ordinarywastes. There are foor sources of hazardous wastes: Industrial, Agricultural,Household and Medical. A Industrial Wastes Hazardous wastes are generated by nearly every industry; thoseindustries that themselves generate few hazardous wastes nonetheless useproducts from hazardous waste generating industries. Other hazardous wastesare generated in the manufacture of fiber optics and copper wire used inelectronic transmission, as well as magnetic disks, paper for technicalmanuals, photographs for packaging and publicity, and trucks fortransportation of the finished product. B Agricultural Wastes Industry is not alone in generating hazardous wastes. Agricultureproduces such wastes as pesticides and herbicides and the materials used intheir application. Fluoride wastes are by-products of phosphate fertilizerproduction. Even soluble nitrates from manure may dissolve into groundwaterand contaminate drinking-water wells; high levels of nitrates may causehealth problems. C Household Wastes Household sources of hazardous wastes include toxic paints, flammablesolvents, caustic cleaners, toxic batteries, pesticides, drugs, and mercury
from broken fever thermometers. Local waste-disposal systems may refusethese items. If they are accepted, careful monitoring may be required tomake sure soil or groundwater is not contaminated. The householder may beasked to recycle or dispose of these items separately. Renovations of older homes may cause toxic lead paint to flake offfrom walls. Insulation material on furnace pipes may contain asbestosparticles, which can break off and hang suspended in air; when inhaled,they can cause lung disease and cancer. D Medical Wastes Hospitals use special care in disposing of wastes contaminated withblood and tissue, separating these hazardous wastes from ordinary waste.Hospitals and doctors’ offices must be especially careful with needles,scalpels, and glassware, called “sharps.” Pharmacies discard outdated andunused drugs; testing laboratories dispose of chemical wastes. Medicinealso makes use of significant amounts of radioactive isotopes for diagnosisand treatment, and these substances must be tracked and disposed ofcarefully.