The arsenic poisoning in Bangladesh
and West Bengal
Arsenic is the twentieth most common element in nature. Arsenic in drinking water has been observed in: Argentina, Australia, Canada, Chile, China, Greece, Hungary, India, Japan, Mexico, Mongolia, New Zealand, South Africa, The Philippines, Taiwan, Thailand, USA and USSR. As awareness of the menace spreads, new sources are discovered. The frightening Arsenic poisoning in the Ganges Delta is only the most spectacular example.
"Bangladesh is grappling with the largest mass poisoning of a population in history because groundwater used for drinking has been contaminated with naturally occurring inorganic arsenic”, the United Nations World Health Organization (WHO) reported in September 2000.
Allan H. Smith, professor of epidemiology at the University of California at Berkeley has said that between 33 and 77 million of Bangladesh's 125 million population are at risk.
Whereas the WHO recommendation, which in 2002, after a long debate, also was adopted by the United States Environmental Protection Agency, is 10 micrograms per liter, concentrations in many areas in Bangladesh are above 3000 micrograms per liter even up to 10 000. Some experts warn that it is a matter of time before contaminated water seeps through the entire country.
Remedies have been suggested from a large number of companies and
international aid agencies. None of them has yet been proven viable
and people are alarmed, even in areas that are not (yet) afflicted.
Also in large areas of the Indian state of West Bengal, groundwater contains Arsenic several hundred times the level recommended by WHO. Some 45 million people live in the inflicted area, and there are villages where as many as 40% of the people have visible symptoms of arsenic poisoning.
The World Bank has recognised the problem
The World Bank has allocated $ 44.4 M to find a remedy In Bangladesh. The cost for the remedy itself may run into billions of dollars, independent experts say.
There are ways to avoid the contaminated water – by transporting well water from non-afflicted sources, by drilling new wells that, hopefully, do not go into the Arsenic carrying sediment, by using purified surface water and by supplying bottled water for drinking. Considering the continuing spread of Arsenic, purifying the water is the best long run options. However, another report from WHO, Arsenic in Drinking Water, May 2001, states that: “There are no proven technologies for the removal of arsenic at water collections points such as wells, hand-pumps and springs.”
Characteristics of Arsenic
Organic Arsenic compounds that are found in foods pass through the body quickly and are therefore quite harmless. Inorganic Arsenic is deposited in the body and concentrated over time and therefore causes long-term damage.
Arsenic is difficult to detect. It is tasteless, odorless and colorless, and a person can absorb significant doses without immediate harm. A well-nourished and otherwise healthy person will withstand the poison for a long time while an undernourished will perish quickly. Babies and children are especially sensitive.
Inorganic Arsenic forms ions, which are trivalent or pentavalent. Trivalent Arsenic As+3 is considered up to 60 times more toxic than pentavalent As+5. As+3 is also much more difficult to detect and few Arsenic detection instruments can distinguish between As+3 and As+5.
Most of the technologies that have been recommended this far for combating Arsenic do a good job at removing As+5 but not As+3.
Sources of arsenic in water
Arsenic is and has been used in many activities throughout human history, as medicine, as poison, and in industry. Ever since industrialization, thousands of tons of arsenic have been poured out as waste from industrial processing, from livestock farming, from cotton and wool processing, from wood preservation and from mining and metal industry.
Arsenic is also used for killing weeds, insects and rats. Runoff from such activities has contaminated surface- and groundwater in many parts of the world, like lake Yangebup in Australia, or the Ogallala aquifer in Texas, USA.
In West Bengal and Bangladesh, as in many other areas, the Arsenic is from natural sources in the ground.
There is debate on how much arsenic the human body can handle without being harmed. A common figure is 12 micrograms per day. A generally agreed maximum contaminant level for safe drinking water has earlier been 50 micrograms per liter. This is obviously too high compared to the 12 micrograms per day assumption.
In the 1960’s, a large poisoning in Taiwan, involving 20,000 people, allowed detailed study, the analysis of which eventually led the WHO to lower the recommended maximum level to 10 micrograms per liter. Although WHO found that for health reasons a level of 2 would have been preferable, difficulties in measuring at those levels at that time prevented such ruling.
Diseases caused by arsenic poisoning
The following diseases are suspected to be caused or aggravated by Arsenic in drinking water according to EPA in Arsenic Rule Benefit Analysis, August 9, 2001: Cancer of the Lung, Bladder, Skin, Prostate, Kidney, Nose and Liver, Stillbirths, Postneonatal mortality, Ischemic heart disease (heart attack), Diabetes mellitus, Nephritis (chronic inflammation of the kidneys), Nephrosis (degenerative kidney diseases), Hypertension, Hypertensive heart disease, Emphysema, Bronchitis, Chronic airway obstruction, Lymphoma (tumors in the lymph), Black-foot disease and Developmental deficits.
In other literature, the following additional conditions suspected to be caused by Arsenic in drinking water are cited: Bowen’s disease, Basal cell carcinoma, Squamous cell carcinoma, Enlargement of liver, Jaundice, Cirrhosis, Non-cirrhotic portal hypertension, Hearing loss, Acrocyanosis, Raynaud’s Phenomenon, Megablastosis, Goiter and it is suspected to contribute to various other cardiovascular, pulmonary, immunological, neurological, peripheral vascular and endocrine diseases.
However, the epidemiological study of diseases caused by Arsenic poisoning is only in its infancy. For instance, a report from the United States National Academy of Sciences (NAS) from September 12, 2001, says EPA has this far greatly underestimated the cancer risks of Arsenic in drinking water. In April 19, 2001, a team of EPA scientists at EPA’s Office of Research and Development laboratory in North Carolina also reported that arsenic may cause genetic damage.
Technologies for arsenic removal
In large-scale applications, such as municipal or industrial treatment plants, there are established technologies for achieving reliable separation of Arsenic. To remove As+3 in a large plant, it is first oxidized into As+5. This oxidation is usually accomplished with chlorine or hydrogen peroxide. The second step is precipitation with lime or coagulation/flocculation with some salt while controlling water’s pH. Then follows filtration. Activated alumina is often recommended as a complementary adsorptive media in the filtration process.
EPA’s report from December 2000, mentioned above, shows that As+3 no doubt is the most difficult substance ever encountered in the water purification business. When I first heard of the Arsenic disaster in 1996 as a request for information on behalf of an Indian Development Bank in West Bengal, my immediate advise was to try reverse osmosis, RO, which, as far as I knew then, removes all ions to a high degree.
When it was reported back that RO did not accomplish desired results I was full of disbelief. Later I have seen results from tests made for EPA in 1998 where the RO equipment tested removes 96% of As+5, but, surprisingly enough, only 5% of As+3.
It is however possible to achieve good removal with RO, if combined with pre-oxidation and then some form of after-treatment such as anion exchange or activated alumina adsorption/filtration. The large number of steps may make operation complicated. To this are added the difficulties in monitoring the result.
Lately, several different absorption and adsorption technologies have been proposed. Arsenic will simply stick in a certain media when the arsenic containing water is poured through. These are attractive systems since capital costs are generally very low – a simple container and a first batch of the appropriate media. Long term costs are however high since media will have to be replaced at intervals. Disposal of used media may also present a problem since it must be classified as hazardous waste.
Holistic and sustainable approaches
The Swedish Sustainability Foundation (SSF) will promote holistic and sustainable approaches to the arsenic problem.
Short term measures
Analysis of arsenic is a difficult task. It is common to use field equipment which is not entirely reliable. The result is that some people continue using contaminated water while others avoid non-contaminated water.
Methods and logistics for reliable laboratory testing have been developed in West Bengal. SSF will support the establishment of a competence center in Calcutta which can assist in setting up correct testing procedures in other places of the world. SSF will also provide funds for disseminating such know-how as well as for necessary logistics.
It has been shown that deeper wells may solve the problem at least temporarily. SSF will support geological research to evaluate the effects, costs and benefits of deeper wells and will assist in the dissemination of these findings.
For the people already afflicted it is urgent to find the right palliatives. Know-how in these matters is limited. SSF will finance a survey of cures for arsenic poisoning, including traditional and so called alternative, and finance programs in spreading the know-how in appropriate ways to relevant clinics, NGO’s etc.
Poor nutrition is a co-factor in many illnesses, also in arsenic poisoning. SSF will finance a meta study on critical nutritional factors as regards arsenic poisoning and set up a panel of nutritionists to work out recommendations. These findings will be disseminated.
Poverty is of course a very important co-factor in many ways. This can not be dealt with in a short term program, but has to be addressed by designing and promoting a long term program that is economically, ecologically and socially sustainable.
Sustainable utility structures
There are many technologies for removing arsenic from contaminated wells. However, spending large open ended recurring costs for just removing arsenic will make any community poor. Even in rich countries, the authorities have concluded that the cost of adding arsenic removal technology to existing technology may be possible in large water utilities, but unfeasible in small water utilities.
Not only arsenic, but many other water borne diseases kill and debilitate millions of people of the world every year - probably more than any other single cause. Improving drinking water supply is therefore probably the most cost efficient measure to increase welfare.
SSF will finance evaluation of proposed technologies, demonstration plants for sustainable solutions, and dissemination of appropriate solutions. SSF will also design financial vehicles for implementation of the solutions.
Swedish Sustainability Foundation September 2006
The Swedish Sustainability Foundation (SSF) promotes high-tech projects that develop welfare in holistic and sustainable ways.