Pools can be bad for you

Press, 18 February 1984, Page 14

Pools can be bad for you

By OLIVER RIDDELL Swimming pools can endanger the health as well as give pleasure. They can transmit a variety of infectious diseases — from spa pool eruption to the often fatal amoebal meningitis (of which Matamata had several cases a few years ago). There should be no prospect of contracting a disease from a properly controlled swimming pool. The Department of Health has stringent standards for maintaining pool safety. Recently, the Local Authority Affairs Committee of the Board of Health considered a standard was needed for the physical, chemical, and bacterial aspects of running a swimming pool. Not only must the pool itself be handled sensibly, but both in and out of the water the disinfecting chemicals must be handled with extreme care.

In 1978, the Thames Valley hamlet of Kerepehi was stunned by the deaths of three children killed- in an explosion involving pool chemicals. The children were playing with matches in a shed where calcium hypochlorite was stored, and the chemical was a contributing factor to the explosion.

The Standards Association

is about to publish the first part of a Standard which will provide the format for a safe and healthy swimming pool. The first part to be published will be a detailed document on the control of pool water quality intended for use by swimming pool consultants and people managing pools.

The Standard will be in three stages — Park I, a reference document; Park 11, four plain-language codes for school, home, and home and commercial spa pools, intended for non-pro-fessionals; and Part 111, an operations manual for each type of pool. Because of the variations between pools, it has been found to be impossible to make recommendations that fit all pools exactly. Dr Craig Stephenson, head of the water testing section of the D.5.1.R., says the manual should come down to the level of colour coding of pipes and valves. It should include really simple basic instructions, such as: “Turn the red tap on in the morning... ” Opinions are divided about what acid-alkaline level is desirable for pools. This is called the “pH regimen” and in New Zealand there are two schools of thought. The Standard will

hold that “balance" is the essence of good pool water management. When a pool is balanced it is easier to sanitise and keep free of bacteria and algae. In assessing balance there are three factors to take into account — water hardness, total alkalinity, and the pH level indicating excess acid or alkaline substances in the water.

The pH is measured on a scale of 1-14; at 7 the water is neutral, below 7 it is acidic, and above 7 alkaline.

The “high” school is led by Mr S. J. Mills, of the Ministry of Works and Development Water Treatment Centre at Bulls, and believes that a level of about 8.3 is perfectly acceptable, and even desirable.

The “low” school is led by Dr J. M. Robertson of the D.S.I.R. in Christchurch, and believes pools should be operated at about 7.6 Dr Stephenson says it has been found impossible to make a recommendation which can totally prove a case. Experiments at the D.S.I.R. Chemistry Division Laboratories at Gracefield in Lower Hutt, if anything, tended to support the “high” case.

“In the laboratory, the problem is that you have to simulate bodily excretions by adding ammonia,” he

says. “What was obvious from our experiments is that some of the chlorine fractions which were thought to be simple were, in fact, not.” Experiments showed that pools performed very differently depending on the numbers of people using them. With school baths, there are so many people that it is very difficult to run them safely. The Standard contains detailed instructions about the use of chemicals — mainly chlorine, because it is the most popular. “Never, never mix dried or concentrated chemicals except with large amounts of water,” Dr Stephenson says. “Using tiny quantities of water can generate heat, gases, or acid. “Some reactions which can occur can be pretty violent. People have got into trouble because they failed to appreciate the dangers of handling these chemicals.” Part I of the Standard will include a section on the safe handling and storage of chemicals. Conditions applying to the three categories of geothermal pools are included in Part I:-

® Pools using ordinary water heated by a geothermal heat exchanger can be treated as normal.

® Geothermal pools in which the chlorine level is greater than two parts per million, and where the water draining has greater than one part per million, can be operated without special restrictions. Amoebae are extremely sensitive to chlorine and are most unlikely to survive in chlorinated water.

@ Untreated geothermal pools must have special provisions, which are laid out in the standard. Notices and barriers must be erected, and diving, sliding, and immersion of the head strictly forbidden. Spa pools are considered to constitute the biggest health problem, particularly when used by a lot of people. Dr Stephenson says: “It is like trying to keep the bath clean.”

Someone in a spa pool at 37 degrees Celsius for one hour will lose 2.5 litres of body fluid. When body fat, cosmetics, “organic matter,” and urine are added to the mixture, bacteria are likely to thrive. One result is “spa rash.” This is a recognised medical condition which occurs in spa pools not operated satisfactorily. The Standard recommends that the water be changed often, especially in public spa pools with large numbers of people.