Environmental Engineering Reference
In-Depth Information
The number selected should be based on skin type and expected exposure time.
Individuals with light skin are especially vulnerable.
Tap Water Scalds
Residential hot-water heaters with temperature settings above 120
◦
F (48.9
◦
C)
are the principal cause of tap water scalds. Young children, the elderly, and the
handicapped are most frequently involved. Showers are another potential hazard
if capable of discharging water above 120
◦
F. Hot-water heater thermostats should
be lowered to 120
◦
F to prevent scalding accidents.
Sporotrichosis
Conifer seedlings packed in sphagnum moss can cause papules or skin ulcers and
inflammation on the hands and arms, which can then spread to other parts of the
body. This disease is caused by a fungus,
Sporothrix schenckii
, found in moss,
hay, soil, and decaying vegetation. Protective clothing, including gloves and
long-sleeved shirts, should be worn when handling sphagnum moss or seedlings.
DEFINITIONS
Certain terms with which one should become familiar are frequently used in the
discussion of communicable and noninfectious or noncommunicable diseases.
Some common definitions are given here.
Antigen(s)
Foreign substance(s) inducing the formation of antibodies. In some
vaccines, the antigen is highly defined (e.g., pneumococcal polysaccharide,
hepatitis B surface antigen, tetanus, or diphtheria toxoids); in others, it
is complex or incompletely defined (e.g., killed pertussis bacteria; live,
attenuated viruses).
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Antibodies are specific substances formed by the body
in response to stimulation by antigens.
Body burden
The total effect on the body from ingestion or exposure to a
toxic chemical in the air, water, or food. Can be determined by examination
of samples of human hair, tissue, blood, urine, and milk, also by measure-
ment of the amount in air, water, and food, and then the intake from these
sources, including contact.
Contact
A person or animal that has been in an association with an infected
person or animal or a contaminated environment that might provide an
opportunity to acquire the infective agent.
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Contamination
The presence of an infectious agent on a body surface; also
on or in clothes, bedding, toys, surgical instruments or dressings, or other
inanimate articles or substances, including water and food.
Pollution
is
distinct from contamination and implies the presence of offensive, but not
necessarily infectious, matter in the environment. Contamination on a body
surface does not imply a carrier state.
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