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 sources
of 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 if
improperly treated, stored, transported, or discarded. Substances are
considered hazardous wastes if they are ignitable, corrosive, reactive, or
toxic. Mixtures, residues, or materials containing hazardous wastes are
also considered hazardous wastes.
Many dangerous substances caan 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 organisms that come in contact with them. Because of such
potential risks, hazardous wastes are processed separately from ordinary
There are foor sources of hazardous wastes: Industrial, Agricultural,
Household and Medical.
A Industrial Wastes
Hazardous wastes are generated by nearly every industry; those
industries that themselves generate few hazardous wastes nonetheless use
products from hazardous waste geenerating industries. Other 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 product.
B Agricultural Wastes
produces such wastes as pesticides and herbicides and the materials used in
their application. Fluoride wastes are by-products of phosphate fertilizer
production. Even soluble nitrates from manure may dissolve into groundwater
and contaminate drinking-water wells; high levels of nitrates may cause
C Household Wastes
Household sources of hazardous wastes include toxic paints, flammable
solvents, caustic cleaners, toxic batteries, pesticides, drugs, and mercury
from broken fever thermometers. Local waste-disposal systems may refuse
these items. If they are accepted, careful monitoring may be required to
make sure soil or groundwater is not contaminated. The householder may be
asked to recycle or dispose of these items separately.
Renovations of older homes may cause toxic lead paint to flake off
from walls. Insulation material on furnace pipes may ccontain asbestos
particles, 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 with
blood 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 and
unused drugs; testing laboratories dispose of chemical wastes. Medicine
also makes use of significant amounts of radioactive isotopes for diagnosis
and treatment, and these substances must be t