ENVIRONMENTAL HEALTH 357
lack of pH control, expose the unprotected surfaces to pos-
sible infl ammation, irritation, and infection. Contraction of
the skin on immersion in water may make possible the direct
entrance of contaminated water into the nose and eyes.
Stevenson^26 reported that “an appreciably higher overall
illness incidence may be expected in the swimming group
over that in the nonswimming group regardless of the bath-
ing water quality.” It was further stated that “eye, ear, nose,
and throat ailments may be expected to represent more than
half of the over-all illness incidence, gastrointestinal distur-
bances up to one-fi fth, and skins irritations and other illnesses
the balance.” Although based on limited data, swimming in
a lake water with an average coliform content of 2300 per
100 ml caused “a signifi cant increase in illness incidence.. .”
and swimming in a river “water having a median coliform
density of 2700 per 100 ml appears to have caused a signifi -
cant increase in such (gastro-intestinal) illness.” The study
also showed the greatest amount of swimming was done by
persons 5 to 19 years of age.
Diesch and McCulloch^27 summarized incidences of lep-
tospirosis in persons swimming in waters contaminated by
discharges of domestic and wild animals including cattle,
swine, foxes, racoons, muskrats, and mice. Pathogenic
leptospires were isolated from natural waters, confi rming
the inadvisability of swimming in streams and farm ponds
receiving drainage from cattle or swine pastures.
Joyce and Weiser report that enteroviruses which are
found in human or animal excreta, if introduced into a farm
pond by drainage or direct fl ow, can constitute a serious
public health hazard if used for recreation, drinking or other
domestic purposes.^28
Many other studies 29 – 30 have been made to relate bathing
water bacterial quality to disease transmission with incon-
clusive or negative results.
British investigators^29 have drawn the following general
conclusions:1) That bathing in sewage-polluted sea water carries
only a negligible risk to health, even on beaches
that are aesthetically very unsatisfactory.
2) That the minimal risk attending such bathing is
probably associated with chance contact with
intact aggregates of faecal material that happen to
have come from infected persons.
3) That the isolation of pathogenic organisms from
sewage-contaminated sea water is more important
as evidence of an existing hazard in the popula-
tions from which the sewage is derived than as
evidence of a further risk of infection in bathers.
4) That, since a serious risk of contracting disease
through bathing in sewage-polluted sea water is
probably not incurred unless the water is so fouled
as to be aesthetically revolting, public health
requirements would seem to be reasonably met by
a general policy of improving grossly insanitary
bathing waters and of preventing so far as possible
the pollution of bathing beaches with undisinte-
grated fecal matter during the bathing season.The fi ndings of the Public Health Activities Committee
of the ASCE Sanitary Engineering Division^31 are summa-
rized in the following abstract:
“Coliform standards are a major public health factor in
judging the sanitary quality of recreational waters. There
is little, if any, conclusive proof that disease hazards are
directly associated with large numbers of coliform organisms.
Comprehensive research is recommended to provide data
for establishing sanitary standards for recreational waters on
a more rational or sound public health basis. British investi-
gations show that even fi nding typhoid organisms and other
pathogens in recreational waters is not indicative of a health
hazard to bathers but is only indicative of the presence of
these diseases in the population producing the sewage. The
Committee recommends that beaches not be closed and other
decisive action not be taken because current microbiological
standards are not met except when evidence of fresh sewage
or epidemiological data would support such action.”
In view of the available information, emphasis should be
placed on elimination of sources of pollution (sewage, storm
water, land drainage), effective disinfection of treated waste-
waters, and on the proper interpretation of bacterial exami-
nations of samples collected from representative locations.
In swimming pools there is a possibility of direct trans-
mission of infection from one bather to another if the water
does not have an active disinfectant such as free available
chlorine. Proper operation and treatment therefore are of
prime importance.FOOD PROTECTIONSite Location and PlanningIt is extremely important that a preliminary investigation
be made of a site proposed for a new plant to determine the
suitability of a site for a given purpose. This should include
restrictions related to zoning, sewage, and wastewater dis-
posal, solid wastes disposal, air pollution control, and noise.
Time and money spent in study, before a property is pur-
chased, is a good investment and sound planning. For exam-
ple, a factory that requires millions of gallons of cooling or
processing water would not be located too distant from a lake
or clear stream, unless it was demonstrated that an unlimited
supply of satisfactory well water or public water was avail-
able at a reasonable cost. An industry having as an integral
part of its process a liquid, solid, or gaseous waste would not
locate where adequate dilustion or disposal area was not avail-
able, unless an economical waste treatment process could be
devised.
Such factors as topography, drainage, highways, rail-
roads, watercourses, exposure, swamps, prevailing winds,
dust, odors, insect and rodent prevalence, type of rock and
soil, availability and adequacy of public utilities, the need
for a separate power plant, and water-, sewage-, or waste-
treatment works and special air pollution control equipment
should all be considered and evaluated before selecting a site
for a particular use.C005_009_r03.indd 357C005_009_r03.indd 357 11/18/2005 10:24:53 AM11/18/2005 10:24:53 AM