Mystery of Bangladesh's mass arsenic poisoning solved

[bujhee kom]

Hey, check it out guys!!!!!

Mystery of Bangladesh's mass arsenic poisoning solved

2 hrs 51 mins ago
PARIS (AFP) – Researchers have pinpointed the source of what is probably the worst mass poisoning in history, according to a study published Sunday.

For nearly three decades scientists have struggled to figure out exactly how arsenic was getting into the drinking water of millions of people in rural Bangladesh.

The culprit, says the new study, are tens of thousands of man-made ponds excavated to provide soil for flood protection.

An estimated two million people in Bangladesh suffer from arsenic poisoning, and health experts suspect the toxic, metal-like element has caused -- and will continue to cause -- many deaths as well.


A Bangladeshi woman collecting drinking water from a local made "sono filter" at Alampara village in the western Bangladeshi town of Kushtia in 2007. Researchers have pinpointed the source of what is probably the worst mass poisoning in history, according to a study published Sunday.
(AFP/File)

Symptoms include violent stomach pains and vomiting, diarrhoea, convulsions and cramps. A large dose can kill outright, while chronic ingestion of small doses has been linked to a large range of cancers.

It has long been known that the arsenic comes from water drawn from millions of low-tech "tube wells" scattered across the country.

Ironically the wells were dug -- often with the help of international aid agencies -- to protect villages from unclean and disease-ridden surface water.

Tragically, millions of people continue to knowingly poison themselves for lack of an alternative source of water.

Earlier studies succeeded in filling in a few pieces of the deadly puzzle.

They showed that water with the highest concentrations of arsenic is roughly 50 years old, and that the organic carbon which, once metabolised by microbes causes the poison to leach from sediment, does not take long to filter down from the surface.

But the source of both the contaminated water and the organic carbon remained unknown until a team of researchers led by Charles Harvey of MIT in Boston, Massachusetts cracked the secret.

Working in the Munshiganj district of Bangladesh, the researchers analysed the flow patterns of surface and underground water in a six square-mile (15.5 square-kilometre) area.

They used natural tracers and a 3-D computer model to track water from rice fields and ponds, and tested the capacity of organic carbon in both settings to free up arsenic from soil and sediments.

"We saw that water with high arsenic content originates from the human-built ponds, and water with lower arsenic content originates from the rice fields," said Rebecca Neumann, a co-author and postdoctoral associate at Harvard.

Chemical analysis showed that the organic compound that unleashes the poison first settles on the bottom of the ponds and then slowly seeps into the ground.

The findings, published in Nature Geoscience, "suggest that the problem could be alleviated by digging deeper drinking water wells below the influence of the ponds, or by locating shallow drinking wells under rice fields," Neumann said in a communique.

The same team of researchers plan to dig such wells in different region to see whether it leads to improved health for villages.

Scott Fendorf, a professor at Stanford University who studies arsenic content in soils and sediments along the Mekong River in Cambodia, said the new study was clearly a breakthrough.

"It shows that human modifications are impacting the arsenic content in the groundwater," he said in a statement. "The ponds ... are having a negative impact on the release of arsenic."

Yahoo, Link: http://news.yahoo.com/s/afp/20091115...shwaterarsenic

[Akib]

Good to hear that they found the source. Hopefully someone can do something about it.

[ialbd]

yes good job, now please do sth about it.....

[billah]

Originally Posted by Akib
Good to hear that they found the source. Hopefully someone can do something about it.

The study is suggesting that deeply dug ponds become collecting basin for arsenic. This arsenic then seeps down and quickly finds it's way to groundwater sources.

Where does it come from? The study does not address. It also does not say why we were not affected a thousand years ago. We have been digging ponds for a very long time in this region.

I don't buy this study. We are a monsoon country with average rainfall of about 100 inches a year. Having man-made lakes is our first line of defense against India's water manipulation hegemony. No amount of upstream dams can stop us from harvesting our own rain water. This study indirectly discourages us from storing water.

I have issues with these findings.

[Icysteel]

I totally agree with you. Every village stead has a pond on every corner of the country. Its is a integral part of our land scape. this study seems to be a load of bull. we don't need these mofos teaching us how to manage our lands

[Akib]

Originally Posted by billah
The study is suggesting that deeply dug ponds become collecting basin for arsenic. This arsenic then seeps down and quickly finds it's way to groundwater sources.

Where does it come from? The study does not address. It also does not say why we were not affected a thousand years ago. We have been digging ponds for a very long time in this region.

I don't buy this study. We are a monsoon country with average rainfall of about 100 inches a year. Having man-made lakes is our first line of defense against India's water manipulation hegemony. No amount of upstream dams can stop us from harvesting our own rain water. This study indirectly discourages us from storing water.

I have issues with these findings.

Arsenic is a naturally occuring substance. Its also used in many chemicals.
http://www.who.int/mediacentre/factsheets/fs210/en/
Source

• Arsenic is widely distributed throughout the earth's crust.
• Arsenic is introduced into water through the dissolution of minerals and ores, and concentrations in groundwater in some areas are elevated as a result of erosion from local rocks.
• Industrial effluents also contribute arsenic to water in some areas.
• Arsenic is also used commercially e.g. in alloying agents and wood preservatives.
• Combustion of fossil fuels is a source of arsenic in the environment through disperse atmospheric deposition.
• Inorganic arsenic can occur in the environment in several forms but in natural waters, and thus in drinking-water, it is mostly found as trivalent arsenite (As(III)) or pentavalent arsenate (As (V)). Organic arsenic species, abundant in seafood, are very much less harmful to health, and are readily eliminated by the body.
• Drinking-water poses the greatest threat to public health from arsenic. Exposure at work and mining and industrial emissions may also be significant locally

Also I don't see where they mention anything about building upstream dams? They suggest building deeper wells to bypass the ponds.

And its not telling you to stop storing water. Its just suggesting that may be the reason for all the arsenic poisoning, and that they should do something about it.

[revolver]

good thing

[cricket_pagol]

Originally Posted by billah
The study is suggesting that deeply dug ponds become collecting basin for arsenic. This arsenic then seeps down and quickly finds it's way to groundwater sources.

Where does it come from? The study does not address. It also does not say why we were not affected a thousand years ago. We have been digging ponds for a very long time in this region.

I don't buy this study. We are a monsoon country with average rainfall of about 100 inches a year. Having man-made lakes is our first line of defense against India's water manipulation hegemony. No amount of upstream dams can stop us from harvesting our own rain water. This study indirectly discourages us from storing water.

I have issues with these findings.

I was also initially skeptical of this study... but a cursory reading of the original research paper convinced me this theory should be taken seriously.

Here is a link to the paper...
http://www.megaupload.com/?d=GZ5XH69G