NEW fears about the safety of school swimming pools have been sparked by the latest revelations about the health hazards of chlorinated water.

Academics and safety experts are concermed that the poor design and maintenance of many school pools could put pupils at risk.

Researchers from London’s Imperial College have found relatively high levels of potentially carcinogenic chemicals in public pools. Their report was issued five months after Belgian researchers suggested that weekly trips to indoor pools may be damaging children’s lungs (“Human bodies and toxic gases don’t mix”, TES, November 2).

The chemical compounds - measured by the London study published earlier this month - are formed when chlorine is added to water and reacts with organic matter such as skin cells, sweat and traces of shampoo and other body-care products.

The Imperial College researchers found that levels of chloroform - one of the most harmful of these by-products were 20 times as high in the eight indoor London swimming pools they tested as in tap water. The highest chloroform levels were recorded at times when pools were busy and water temperatures were relatively high.

Their findings attracted widespread publicity because some American studies indicate that chloroform and other trihalomethanes may cause miscarriages and birth defects.

The Imperial College researchers and Britain’s Pool Water Treatment Advisory Group emphasised this week that the link between pool water and still birth has not been proven. But neither is complacent.

Imperial’s Dr Mark Nieuwenhuijsen acknowledges that little research has been carried out on pool water. “You never know if it’s actually safe,” he says.

One of the main messages from his research is that swimmers should always shower properly before they enter a pool. “This is not always done - they are often allowed to run straight in,” Dr Nieuwenhuijsen says.

The pool water group endorses that message and fears that sloppy practices in many of Britain’s 2,300 school pools may lead to even higher chloroform levels than in public leisure centres.

If chlorine levels exceed 1.5 to 2 parts per million - the recommended limit for a pool not using ultra-violet or ozone to kill bacteria - the pool hall atmosphere may deteriorate. But water specialists say they have detected chlorine levels of up to 4ppm in some schools.

Ralph Riley, chairman of the pool water group, has been worried about school pools for some time. “Some are not built to the same standards as public ones, which are designed to ensure that by-products are minimised. It is also questionable whether they are being managed and operated with adequate competence, knowledge and understanding,” he says.

Mr Riley and other pool experts emphasise the need to reduce the potential risks of using chlorine, while ensuring that there is enough disinfectant to kill off infections. This means following guidelines on chlorine dosage levels, ventilation, regular addition of fresh water, control of numbers admitted, and monitoring of chemicals.

Noel Winter, facilities officer at the Amateur Swimming Association, echoes Mr Riley’s concerns. He says that inadequate training of staff who maintain school pools can lead to unduly high chlorine levels.

Maintenance staff should ideally attend the plant-operator course run by the Institute of Sport and Recreation Management, which deals with water chemistry and how to operate pools. But relatively few do.

Simon Whittingham of Thermelek Engineering Services - which designs, supplies and installs water-treatment plants - says he has seen school caretakers pouring chlorine straight into pools by hand, unmeasured, which can lead to overdosing.

He says that many school plants are designed incorrectly and not maintained thoroughly, sometimes breaching health and safety guidelines. “Many do not have automatic chemical dosing equipment, which is important for proper control of chlorine and pH levels,” he says.

More on pool maintenance at the World Health Organisation website: www.who.intwater_sanitation_healthWater_qualityrecreat.htm