Figure 3.1. Potential microbial hazards in pools and similar environments
Microorganisms that are used to assess the microbial quality of swimming pool and similar environments
include heterotrophic plate count – HPC (a general measure of non-specific microbial levels),
faecal indicators (such as thermotolerant coliforms, E. coli), Pseudomonas aeruginosa, Staphylococcus
aureus and Legionella spp. HPC, thermotolerant coliforms and E. coli are indicators in the strict sense
of the definition.
As health risks in pools and similar environments may be faecal or non-faecal in origin, both faecal
indicators and non-faecally-derived microorganisms (e.g. P. aeruginosa, S. aureus and Legionella
spp.) should be examined. Faecal indicators are used to monitor for the possible presence of faecal
contamination; HPC, Pseudomonas aeruginosa and Legionella spp. can be used to examine growth, and
Staphylococcus aureus can be used to determine non-faecal shedding. The absence of these organisms,
however, does not guarantee safety, as some pathogens are more resistant to treatment than the
indicators, and there is no perfect indicator organism.
CHAPTER 3. MICROBIAL HAZARDS
1. Risk assessment
Papillomavirus is a double-stranded DNA virus in the family Papovaviridae. The virions
are spherical and approximately 55 nm in diameter. The virus causes benign cutaneous
tumours in humans. An infection that occurs on the sole (or plantar surface) of the
foot is referred to as a verruca plantaris or plantar wart. Papillomaviruses are extremely
resistant to desiccation and thus can remain infectious for many years. The incubation
period of the virus remains unknown, but it is estimated to be 1–20 weeks. The infection
is extremely common among children and young adults between the ages of 12
and 16 who frequent public pools and hot tubs. It is less common among adults, suggesting
that they acquire immunity to the infection. At facilities such as public swimming
pools, plantar warts are usually acquired via direct physical contact with shower
and changing room floors contaminated with infected skin fragments (Conklin, 1990;
Johnson, 1995). Papillomavirus is not transmitted via pool or hot tub waters.
World Health Organization (WHO) Microorganism Pool Water Hazard Chart
Why do you think the WHO would believe these are only indicator organisms and don't cause
deadly diseases in humans?
Why do you think the WHO risk assessment for Papillomavirus claims the virus only causes plantar
warts from direct contact with the floor?
Could it really be, that the WHO doesn't know all of these microorganisms are in sewage effluent
(reclaimed water) and sewage sludge (biosolids)?
Could the USEPA and its partners be their advisor?