Getting to the Bottom of the World's Biggest Mass Poisoning Case (UPDATED)
Image from vm2827
Every year, over 70 million Indians and Bangladeshi are exposed to arsenic when they consume rice, the region's primary food staple, and water. Often portrayed as the world's worst case of mass poisoning, this chronic exposure has been linked to increasing cancer rates and is believed to impact 6 out of every 100 people in the Bengal Delta -- at least one of which will suffer from near-death symptoms. The situation is so critical that the WHO has described it as being "beyond the accidents of Bhopal, India, in 1984 and Chernobyl, Ukraine, in 1986," in scope. Arsenic, a semi-metallic compound that has typically been deposited in silt on riverbanks, has steadily begun leaching into the groundwater over the past 3 - 4 decades as intensive farming and fertilizer use have become more common. Once underground, the arsenic, bound to minerals found in the silt, is used by bacteria as a source of oxygen -- causing it to become dissolved.
As has so often been the case in the past, efforts by the U.N., the World Bank and other international organizations have proved insufficient in tackling this festering problem. Instead, the credit for a new, potentially breakthrough solution -- a low-cost treatment system -- must go to a team of scientists from the UK's Queen's University Belfast.
Led by Bhaskar Sen Gupta, the scientists developed a system of 80 - 100 ft deep tube-wells that pump the contaminated groundwater above ground, exposing the arsenic to oxygen and causing it to precipitate. Once the arsenic levels have dropped below the hazardous level (a few hours later), the water is pumped back down into the wells. While it may not sound particularly impressive on its face, this technology, unlike other innovative all-purpose filters, could be deployed on a large scale.
The project, part of the EU-funded TiPOT (Treatment of Water for Irrigation and POTable Use) program, could provide millions of villagers with a source of potable water for their farming and drinking needs; the treatment plants would be set up and maintained by local technicians.
Gupta and his colleagues have received a $200,000 grant from the World Bank to expand the technology to other areas in Southeast Asia, including Bengal and Bangladesh.
NOTE: As my colleague John just pointed out in an e-mail (and as some of you have remarked in the comments), it looks like I "missed the boat completely" on describing the root cause of this arsenic crisis. John explains:
Beginning years ago the World Bank paid for drilling irrigation wells into deep Bangladeshi groundwater aquifers that are by nature arsenic contaminated and anoxic.
Ironically, that effort was amplified by the George Harrison sponsored Concert for Bangladesh, which was naively targeting the rampant starvation in Bangladesh during the 1970's.
By overdrafting the deep groundwater with those WB funded deep wells, farmers brought up ancient and natural arsenic contamination which recharged the surface aquifers, which in turn discharged to local rivers - contaminating sediments. This results in the processes you cited (which are secondary and not really the causative factor).
At the root, the WB and Norman Borlog's Green Revolution are collectively responsible for this mass poisoning. Even Concert for Bangladesh had a role.
Incidentally, rusty nails and a pH shift will take almost every bit of arsenic out of the water faster than you can say "safe". It is a very old treatment technology. Do a Google on Best Practicable Treatment, EPA and arsenic.
More about arsenic and water treatment
::What Evil Genius Fed Arsenic To The Chickens?
::All-Purpose Water Filters For Humanitarian Projects
::'Nanorust' Removes Arsenic From Polluted Water