Williamson Tea Award for Social Progress
Contaminated water is the world's commonest cause of sickness, but many developing countries have no national programme for testing its physical, chemical and microbiological safety, and little money to create one. Malawi, though most of its people live in rural areas, was able to do so using motorcycles and the Paqualab made by ELE International of Hemel Hempstead.
With a Paqualab, staff can test water on the spot, however remote. They do not need to send samples to a distant laboratory and they can get results in only l6 hours.
For microbiological tests, Paqualab - originally developed at Surrey University- uses a membrane to capture coliform bacteria from a water sample. 0n the membrane these are cultivated on lauryl sulphate in incubators powered by the local electricity supply, a car battery or their own rechargeable battery. Bacteria then appear as yellow colonies on the membrane.
If the incubator is run at 44 degrees centigrade, any yellow colonies will be faecal coliform, indicating that the water has been contaminated with sewage and could contain dysentery or diarrhoea-causing organisms. An incubator run at 37 degrees will give a total coliform count, which could warn of other contamination. Also in the Paqualab are handheld, battery-operated meters to check the water for turbidity, temperature, acidity/alkalinity, chlorine, nitrites, nitrates and ammonia. Using the photometer, tests for 22 further substances are also available. All can be used easily and with little training.
A Paqualab system with two incubators costs £4,500 and with a single incubator £3,900. lt comes cheaper with fewer tests. There is also a lightweight version in a shoulder bag at £2,136; but users tend to prefer the robustness of the boxed models. Last year's British Hovercraft Expedition to China took a Paqualab and manhandled it in and out of hovercraft, jeeps and lorries; but it suffered no damage. Paqualabs are used in over 60 countries by health departments, water boards, the World Health Organisation, UNICEF, the UN refugee service and Zimbabwe's army medical corps. Oliver Cumberlege, technical adviser for Christian Community Services, has been using one to test water from wells and dams in Nakuru diocese, Kenya. Apart from bacterial pollution, he has found high levels of fluoride in some supplies, which could cause bone disease if not removed.
ELE, which supplies a wide range of water, soil and air testing equipment, has introduced a small camera-sized microscope to accompany the Paqualab. This can, for instance, detect the cyclops water fleas which carry guinea worm, an irritating and painful parasite which attacks rural people in parts of Ghana, Nigeria and India.
See also Nigeria Resources