Environmental Engineering Reference
Prevention, tertiary Amelioration of a disease to reduce disability or depen-
dence resulting from it. Conventional medical treatment and restoration
of health and well-being to the extent possible. Voluntary action by the
Primary health care Application of the principles of health education, nutri-
tion, immunization, water and sanitation, maternal and child care and family
planning, control of endemic diseases, treatment of common diseases, and
provision of essential drugs [World Health Organization (WHO)].
Public health “Public health is the science and art of preventing disease,
prolonging life, and promoting physical and mental health and efficiency
through organized community efforts for the sanitation of the environment,
the control of community infections, and education of the individual in
principles of personal hygiene, the organization of medical and nursing
services for the early diagnosis and preventive treatment of disease, and
the development of the social machinery that will ensure every individual
in the community a standard of living adequate for the maintenance of
Sanitation The effective use of measures that create and maintain healthy
environmental conditions. Among these measures are the safeguarding of
food and water, proper sewage and excreta disposal, and the control of
disease-carrying insects and animals.
Sanitize To reduce microorganism level to an acceptable level, usually by the
continuous application of heat or chemicals at suitable concentrations and
Sterilization The process of killing all microorganisms, including spores.
Susceptible A person or animal presumably not possessing sufficient resis-
tance against a particular pathogenic agent to prevent contracting infection
or disease if or when exposed to the agent. 3
Teratogen An agent (radiation, virus, drug, chemical) that acts during preg-
nancy to produce a physical or functional defect in the developing offspring.
Substances that have caused defects are methylmercury and thalidomide.
Some environmental pollutants may be both carcinogenic and teratogenic.
TLV (threshold limit value) The average 8-hour occupational exposure limit
This means that the actual exposure level may sometimes be higher, some-
times lower, but the average must not exceed the TLV. TLVs are calculated
to be safe exposures for a working lifetime.
Toxicity, acute condition Adverse effects occurring shortly after the adminis-
tration or intake of a single or multiple dose of a substance (oral rat LD 50 ).
Conditions classified as acute include viruses, colds, flu, and other respi-
ratory conditions; headaches, gastrointestinal disorders, and other digestive
conditions; accidental injuries; genitourinary disorders; diseases of the skin;
and other acute conditions. A condition that has lasted less than three
months and has involved either a physician visit (medical attention) or