Each day about 100 million people are being
poisoned with one of the deadliest substances known. In India and
Bangladesh, China and Southeast Asia, even in countries such as
Australia, the silent tragedy of arsenic poisoning continues to
unfold.
Arsenic is not merely a favourite resort of
medieval or Victorian murderers and crime novelists. It causes
cancer of the skin, lung, bladder, kidney, liver and uterus, is
implicated in several skin diseases, nerve disorders, diabetes,
lung disease and heart disease, and is suspected of causing birth
defects, liver and blood disorders. In South Asia, women and girls
who contract the symptoms are often expelled from their families,
inflicting social and personal tragedy as well.
Arsenic poisoning for the most part results from
human activity and is therefore preventable. In the case of
Bangladesh and West Bengal, the source is chiefly the millions of
household tube wells that aid agencies caused to be dug, so
families could avoid polluted surface water by obtaining ostensibly
clean well water.
This arsenic is geogenic: silt eroded from the
Himalayas is high in arsenic which, through the millenniums, has
accumulated in the sediments of the Gangetic Delta from which these
wells supply household water for drinking, cooking and growing
vegetables.
An estimated 70 million people are exposed to
arsenic in India and Bangladesh alone, part of what must surely
rate as the worst case of mass poisoning in history. Other
countries with similar geologies, such as Burma, Cambodia, Laos and
Vietnam, are also affected, though global awareness about these is
lower.
The human toll of death and sickness from
arsenic is unknown but certainly runs into the millions. The US
National Research Council estimates that drinking a litre of water
containing 50 micrograms of arsenic a day will cause 13 deaths out
of every 1000 people. Often household wells have many times this
level.
In countries such as Australia, New Zealand,
South Africa and Argentina the main sources of arsenic are
anthropogenic: the hundreds of thousands of century-old livestock
dips scattered across the landscape and the residues from former
goldmining tailings that leach arsenic into surface and
groundwater. Old railway lines, treated timber plants, cotton farms
and certain factory sites also contribute a toxic legacy on which
suburbia often innocently sprawls.
Many Australian scientists have worked on
different aspects of the arsenic problem and AusAID has run
programs to provide safer water in several countries. In some cases
the answer may be as simple as a rainwater tank. But for all the
efforts of Australians and international agencies the problem
remains intractable, only pecked away at the edges.
A recent development with some promise is the
discovery by Megharaj Mallavarapu of the Co-operative Research
Centre for Contamination Assessment and Remediation of the
Environment and University of South Australia of a naturally
occurring soil bacterium that oxidises the highly toxic arsenite to
much less toxic arsenate. Megh says the microbe can be used not
only to remediate badly contaminated soils but possibly also
incorporated into a filter to cleanse household water from affected
wells.
Other researchers, such as Ging Khoe at the
Australian Nuclear Science and Technology Organisation, have
devised different kinds of water filters using physical or chemical
techniques. The CRC CARE team has also mapped the spread of arsenic
through the Bangladeshi food chain.
Another important approach to the problem is one
in which Australians are experienced and well qualified: catchment
management. By planning and managing surface water better, there is
scope to clean up contaminated surface water, which would reduce
household dependency on toxic wells. There is also scope to reduce
the arsenic content of the food supply by not irrigating with
groundwater.
From these examples it is abundantly clear that
Australians have the ideas and scientific capability to overcome
this human crisis. What is missing is the large-scale vision to
pull all these elements into a cohesive program. When Howard Florey
developed penicillin as a useable drug, when Frank Fenner took on
the task of banishing smallpox from the world and when Fred Hollows
tackled eye disease in Australia and Africa, it required
vision.
In the case of the world's worst poisoning
episode, the vision to tackle and terminate it through a
comprehensive scientific and aid program so far has not been
forthcoming.
If Australia aspires to show leadership and to
put its scientific skills to work to benefit humanity on the large
scale, this is a task worthy of our mettle and within our
capabilities and resources.
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