[Assam] [WaterWatch] Experiences on mitigating arsenic contamination in groundwater

[mc mahant]

Dear Gunnar,
 
At the end of all this, please do :
Review all you know/have learnt  on Arsenic-Groundwater-effects ---that show up on health  of humans/livestock/biosphere. And what main routes   may be pursued to eject Arsenic from  drinking water.
And post all that in WaterWatch .How best to avoid this ejected Arsenic returning to the drinkinking water circuit at a future date.
 
We will  be gratefully enlightened.
 
Mukul Mahant


To: WaterWatch at yahoogroups.com; rohit.pathania at gmail.comFrom: gjacks at abo.fiDate: Fri, 14 Mar 2008 17:43:30 +0200Subject: Re: [WaterWatch] Experiences on mitigating arsenic contamination in groundwater




Dear All,There is actually no overdraft of water in general where the arsenic pollution occurs. A lot of groundwater monitoring data show stable levels over time. Overdraft and oxidation of sulhides was believed to be the reason in the beginning but later the ferric hydroxide reduction has been proven as the major cause.The specific about arsenic is that the amount in the sediments really does not matter, it is just the redox conditions. If they happen to be within the Fe2+ satge then even low contents of arsenic in the sediments may result in polluted groundwater.Best regards!Gunnar JacksKTHSE-100 44 StockholmSwedenCiterar rohit pathania <rohit.pathania at gmail.com>:> the problem is actually due to overdrwawing of groundwater and also, as per> my own belief, due to industrial pollution of surface waters. arsenic has> even entered the food chain, with rice impregnated with arsenic being> reported now.>> On 3/12/08, Tom Spalding <geotomspaldi at yahoo.com> wrote:>>>> I am so sorry to read about this problem. Sufficient study of the>> aquifer system seems to have been done. Deep wells might be an answer. Or>> it looks like millions of people need safe surface water supplies. It is a>> huge problem.>>>> Here is a link to an article about the source of the pollutant.>>>> http://www.unesco.org/courier/2001_01/uk/planet.htm>>>> in part it says:>>>> *"Where does the arsenic come from?*>>>> The arsenic probably originates in the Himalayan headwaters of the Ganges>> and Brahmaputra rivers, and has lain undisturbed beneath the surface of the>> region's deltas for thousands of years in thick layers of fine alluvial mud>> smeared across the area by the rivers.>> According to David Kinniburgh of the British Geological Survey, who has>> recently completed a detailed study of the arsenic's route into millions of>> tubewells, the arsenic concentration in the mud is not extraordinary. Time>> is the culprit. The mud in Bangladesh lies thicker, wider and flatter than>> almost anywhere on Earth. It can take hundreds or thousands of years for>> underground water to percolate through the mud before reaching the sea. All>> the while it is absorbing arsenic.>> This, says Kinniburgh, helps explain the diverse pattern of arsenic>> concentrations in tubewell waters. The contaminated wells almost all take>> water from a depth of 20 to 100 metres. Shallower wells are clean because>> they contain mostly recent rainwater or water flowing swiftly through the>> sediments. Deeper wells tap water in older sediments which have by now been>> flushed clean of arsenic. It will take thousands of years, says Kinniburgh,>> before the rest of the arsenic will wash away into the Indian Ocean.>> Many underground water sources around the world contain arsenic. Parts of>> Taiwan, Argentina, Chile and China have all suffered epidemics of skin>> diseases, gangrene and cancer as a result. Smith's analysis of the Taiwan>> epidemic in particular helped set the WHO arsenic standards for water and is>> the basis for his current predictions. Bangladesh, he says, is quite>> unprecedented.">>>>>> As an alternative water source, I offer the following. In Kentucky, there>> has been study of cisterns as a farm water supply. This link is fairly>> comprehensive on the topic.>>>> http://www.ca.uky.edu/agc/pubs/ip/ip4/ip4.htm>>>>>> Kindest Regards>>>> Tom Spalding>>>> --- On *Tue, 3/4/08, gautam jayprakash <gautam.jayprakash at gmail.com>*wrote:>>>> From: gautam jayprakash <gautam.jayprakash at gmail.com>>> Subject: Re: [WaterWatch] Experiences on mitigating arsenic contamination>> in groundwater>> To: WaterWatch at yahoogroups.com>> Date: Tuesday, March 4, 2008, 7:32 AM>>>> Sir,>>>> Would you be kind enough to throw some light on how this arsenic>> contamination works. I think it has got to do something with the excessive>> exploitation of ground water. Your inputs will surely help spreading>> awareness to areas that are next in line.>>>> Gautam>>>>>>>>>>>> __________________________________________________>> Do You Yahoo!?>> Tired of spam? Yahoo! Mail has the best spam protection around>> http://mail.yahoo.com>>>>>__._,_.___ 
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