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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 wilI 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.
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