Arsenic in groundwater
Arsenic in groundwater is a natural occurrence, that become a public health problem in recent decades due largely to international development programs installing deep wells. This has occurred mainly in Bengal, India, and Bangladesh. For more background, see Wikipedia:Arsenic contamination of groundwater.
Inappropriate technologies and wasted aid
The deep wells installed over many years appeared to be doing a great job, and may have done in other locations. However the context of arsenic-tainted deep aquifers turned a life-saving technology into a deadly one.
Development consultant and arsenic whisteblower Dipankar Chakraborti claims that arsenic removal plants (ARPs) installed in Bangladesh by UNDP and WHO were a colossal waste of funds due to breakdowns, inconvenient placements and lack of quality control.
Effective removal methods arsenic from groundwater
Coagulation with ﬁltration is the most common method, including oxidation if arsenite is present.
Hi tech methods include commercially produced synthetic resins and activated alumina granules, removing arsenic through ion exchange; membrane methods are also available (reverse osmosis and nanoﬁltration).
These methods create a sludge which is rich in arsenic which needs disposal, and these technologies need proper maintenance.
Small-scale arsenic-contaminated-water purification technologies
Small-scale arsenic-contaminated water purification technologies in Pakistan --A complete review of the viability of small-scale arsenic-contaminated-water purification technologies is here.
Testing for arsenic?
Is there an affordable and practical way of testing water for arsenic levels, suitable for poor and remote areas? This is important for knowing when to treat, and also checking whether a Sono filter is currently working. If so, please add information or link from here. If not, this could be an important project.
It can be argued that the contaminated wells saved and extended lives overall, because while arsenicosis can kill in decades, the use of untreated surface water can lead to cholera and other diseases which kill in days. While this is an important perspective, it does not mean that the deep wells were a good decision - there may have been other more appropriate technologies, such as storage tanks and simple filters for surface water, that would have saved lives in the short term, without exposure to arsenic.
- Comments on arsenic crisis in Bangladesh, Amitava Mukherjee and Dipankar Chakraborti, 2004