|Bangladesh Chemical and Biological Society of North America|
Chairman, BCBSNA Bangladesh Affairs Subcommittee, Vice President (South).
A press release / white paper from Bangladesh Chemical & Biological Society of North America. (BCBSNA).
Subject: Technical deficiency of the arsenic detection method used in Bangladesh.
For any comment and communication, please contact: Dr. S.S.Newaz, Phone:
713-743-2729. e-mail: firstname.lastname@example.org.
Date: November 15,1999.
Technical deficiency of the arsenic detection method used in Bangladesh.
The presence of high level of arsenic in drinking water in rural Bangladesh, and West Bengal of India, is well documented and the arsenic poisoning has become a serious threat to public health. Soluble form of arsenic comes from underground water table and pumped by shallow and deep tube wells. The water may be pathogen free at this stage. However, the cumulative effect of drinking arsenic contaminated water over long time is irreversible and is demonstrated in the worst form of skin lesions, to cancer and eventually lead to slow and painful death of the victims.
Arsenic contamination cumulates in human body and therefore even trace quantities would build up to a lethal stage over a period of time. The WHO (World Health Organization) has set the maximum permissible limit (MPL) of arsenic in drinking water at 10 ppb (10 parts per billion or 10 micrograms per liter). But Bangladesh government has adopted an MPL at 50 ppb, 5 times higher the internationally recommended limit! A great many of the tube wells in Bangladesh cannot meet any of these safety regulations. Arsenic salts are soluble in water and there is no way to know its presence by simple observation, taste or smell. Arsenic acts as an invisible killer. Accurate detection of arsenic at this extremely low level (10-50 ppb) requires very sensitive instrumental test procedures.
Unfortunately, the very first step towards prevention and arsenic testing is in great chaos in Bangladesh. Detection of arsenic even at 50 ppb level is not easy. E.Mark (EM) sells a simple reagent paper strip for arsenic detection. The absolute lowest level of detection by this paper is 100 ppb. At this 100ppb level, the test paper would gradually turn from white to a very faint yellowish tinge and it requires very close examination to detect this slight change of color. This makes this test unreliable, inconsistent and irreproducible at the 100 ppb level. Of course, detection at a lower than 100ppb level is impossible by this test paper. The only way to know for sure about the safe level of arsenic is by sophisticated instrumental tests done by trained chemists. At present, reliable analysis can only be done by a limited few laboratories in Bangladesh.
It is quite apparent that use of this arsenic test paper is convenient but not accurate. If a water sample is found to be arsenic free by this paper, that only means it may have less than 100 ppb arsenic. But the level very well could be anywhere between zero to 99 ppb-- and if it is higher than 10 ppb (or 50ppb for Bangladesh), then it is not safe for drinking. As a result, exclusive use of this test is creating an alarmingly false sense of security.
Government organizations in Bangladesh, even UNICEF (United Nations International Children's education Fund) agencies have been using and recommending this simple field test method in Bangladesh, to certify the water source to be designated as safe or unsafe. More dangerously, business enterprises are promoting arsenic-filter devices based exclusively on this test. Government and Non-government agencies (NGO's) in Bangladesh have completely ignored the advice from technical authorities based on basic science and as a result are squandering away tremendous amount of monetary resources and making the situation miserably confusing.
We, the members of Bangladesh Chemical & Biological Society of North
America. (BCBSNA), a non-profit organization of professionals, feel that
we have the technical understanding of and a great deal of concern for
this problem. We feel strongly that in order to mitigate this situation,
WHO , UNICEF, Bangladesh Government and the NGO's should stop recommending
the use of this simple test procedure as the exclusive method
of testing for arsenic contamination in public water supply. We feel strongly
that unless clear, precise and technically reliable methods are adopted
as protocols by the Bangladesh Government, non-Government and international
agencies , unscrupulous business people would exploit the situations to
add more miseries to the common population.
1) The present test kit method results may be reliable only for the detection of higher than 100 ppb level of arsenic and therefore, whenever a water source (usually a tube well) shows high level of arsenic by this method using EM reagent paper, the tube well should be properly marked as unsafe.
2) When the water samples show no detectable color change (a negative test), by this arsenic test paper method , then those selected water samples should be further tested by instrumental laboratory procedures using approved protocol in order to know the exact level of arsenic, before those are certified to be safe.
3) For certifying any commercial water filter system for public use,
the filtered water must be tested for arsenic, inorganics, organics, and
bacterial contamination by approved protocol and meet WHO and Bangladesh