[ASC-media] Media release: Arsenic - a global menace
jca.media at starclass.com.au
Wed Sep 27 01:57:19 CEST 2006
CRC for Contamination Assessment and Remediation of the Environment
Media Release 06/11
September 27, 2006
ARSENIC: A GLOBAL MENACE
Millions of people worldwide face the risk of cancer and poisoning due to arsenic in their water, food or from living near contaminated sites.
A new scientific book published in Australia explores the magnitude of the arsenic threat to humanity - and explains what can be done about it.
Managing Arsenic in the Environment looks at the wide range of ways arsenic - both naturally-occurring and resulting from human activity - can reach and affect people.
"Arsenic is unique," says the book's editor-in-chief, Professor Ravi Naidu, the managing director of the Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE). "It is the only known carcinogen which places people at risk from both inhalation and ingestion."
Arsenic is released into the environment naturally by volcanoes and dust from arsenic-rich soils, but the greatest exposure of people is from industrial sources. Twenty countries worldwide have reported groundwater contaminated by arsenic.
The most severe threat to human health is in Bangladesh, India (West Bengal), Inner Mongolia and Taiwan, where tens of millions are exposed. Millions more are at risk in Vietnam, Laos, Cambodia, Myanmar, Pakistan, Iran, Mexico and Argentina.
Arsenic can contaminate both water and soil, and enter the food chain through crops and vegetables grown or cooked in contaminated water.
"Arsenic gets its sinister reputation from its historical use as a poison, but its modern impact - including the calamity on the Indian subcontinent - is from unintended contamination either from soils naturally rich in it or from places where it was formerly produced as a mining byproduct, an unintended ingredient of fertiliser, or used as a pesticide - such as in sheep-dips."
The good news, says Professor Naidu, is that there is now quite a lot that can be done to reduce the risk to humans of arsenic poisoning or cancer. This includes:
" managing soils to reduce levels of arsenic contamination
" growing special plants (such as brake fern) which extract it from the soil
" using special bacteria to transform it into less toxic forms in the soil
" locking it up chemically
" soil-washing with chemicals
" using electrical currents in the soil to concentrate arsenic ions for removal
" cleansing of groundwater using adsorbents or ultraviolet treatment.
"The most important thing is to understand the extent of the risk," says Professor Naidu. "Sometimes the arsenic is not very toxic. Sometimes it is not available to be taken up by living organisms, including people. Sometimes it moves around or combines with other things in the soil. Every site is different - and requires a different solution.
"The important thing is that irrespective of the nature of arsenic, we can now devise ways to manage arsenic contamination.
Arsenic is common throughout the Australian environment. Most of this arsenic is naturally present in soils and rocks, but mining can release and concentrate it. This has been reported in Victoria.
Arsenic was also widely used in farming from the 1880s-1960s as a pesticide in orchards and vineyards and in thousands of sheep and cattle-dips. It was used to poison weeds along thousands of kilometres of railway lines and is a byproduct of gold and titanium extraction.
Prof. Naidu says that there have been few studies of arsenic levels on Australian groundwater, but this is not regarded as a widespread hazard by authorities, as groundwater is rarely used for drinking. Arsenic has been found in fish from polluted water and in vegetables, but investigations have been limited.
"More needs to be done in Australia about arsenic, given the extent of its use in the livestock and railways industries over many years," he says.
"Unquestionably arsenic represents a global threat to human health where it is present in water used for drinking and cooking and soils used to grow leafy vegetables. Besides cancer and poisoning the social and economic consequences of arsenic can be very severe on those affected," Prof Naidu says.
Managing Arsenic in the Environment is published by CSIRO Publishing and contains contributions from 120 leading international scientists. It summarises arsenic contamination incidents worldwide, explores the human health and food issues, looks at the latest technologies for reducing the threat and reviews the situation in almost 40 countries.
Professor Ravi Naidu, CRC CARE, 08 8302 5041 or 0407 720 257
Kim Sinclair, CRC CARE communication, ph 08 8302 3933 or 0429 779 228
Kim.sinclair at crccare.com
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