Bringing running Water to HousesThe Importance of MeasurementsConclusionStrict adherence to sanitary standards as discussed for example by WHOAcknowledgmentsONE SOLUTION TO THE ARSENIC PROBLEM:A RETURN TO SURFACE (IMPROVED DUG) WELLSSakila Afroz Joya, Bivash Chandra Barmon, Ariful Islam, Golam Mostofa, Altab Elahi, JabedYousuf , Golam Mahiuddin, Mahmuder Rahman, Quazi Quamruzzaman Dhaka Community HospitalRichard WilsonDepartment of Physics Harvard UniversityA brief history of Worldwide Arsenic Use Arsenic has been used since 3000 BC 1. In the United Kingdom, for example, it was usedto extract iron from iron ore. It has long been known that arsenic is acutely toxic. Anyone whodrinks arsenic in water at 60 parts per million (ppm) will soon die. Miners took particularprecautions to avoid exposure. Arsenic was also used for criminal purposes to poison a rival andmay, for example, have been used to poison Napoleon in his exile. However, chemicals and substances are often only dangerous at high doses. Indeed atlower doses beneficial effects can often occur. Arsenic has been used for about 2 centuries formedicinal purposes. At fairly high doses it was successfully used as a cure for syphilis beforeantibiotics entered the pharmacopoeia 70 years ago. Arsenic in moderately high doses repeatedover a month has been shown to assist in curing some leukemia2. In a 1% solution of arsenite3 itwas introduced in 1785 by Dr. Fowler, of Edinburgh, (UK) and was an imitation of a popularremedy known as "Tasteless Ague and Fever Drops." It was used as a “mild tonic for digestivedisorders”.. That arsenic at low levels is safe seemed to be reinforced by animal studies thatseemed to show that arsenic is beneficial (to animals) at low doses. Indeed, the fact thatlaboratory animals (mice, rats, cats, and dogs) could not be persuaded to develop cancer misledtoxicologists throughout the world and greatly contributed to the present catastrophe inBangldesh. One of the present autors (RW) contributed to this misunderstanding by arguing thatthe observed carcinogencity of arsenic was probeably due to inhlation exposure.4 Others havewritten about other possible beneficial effects at very low levels.5 Thus a myth developed that while the acute effects of a large single dose are lethal, thechronic effects of a small repeated dose were either small or beneficial. But we now know thatthis perception is wrong.Another myth is pervasive throughout society and across cultures. That the effect of aningested or inhaled substance is either adverse or beneficial but not both. We now know that itcan be both simultaneously, even at the same dose, with one medical outcome being beneficialand another adverse. For chronic exposures, the adverse effects of arsenic dominate.1A brief history of water use in BangladeshWater is life. Water for human consumption should be potable, which should be: - Easily accessible - Adequate in quantity throughout the year - Free from contamination - Clear - Pleasant to taste - Odorless - Arsenic free - Germ free - Toxin free - Acceptable- Affordable - Convenient - User friendly- Sustainable People of Bangladesh in the past 40 to 50 years, have been abstracting this water fromground water by sinking hand/shallow tube wells and deep tube wells for drinking and domesticwater and also for irrigation. The water available in the saturation zone (pores completely filledwith water) is known as ground water. Physically ground water is generally clear, colorless withlittle or no suspended solids. The water is also free from diseases producing microorganisms,which causes high prevalence of diarrheal diseases in Bangladesh. The only disadvantagesseemed to be due to high iron content (the iron makes cooked food blackish in color) and hard.Ground water is available in large quantities in shallow depths. The amount of groundwater that can be obtained from an area depends on the characteristics of the underlying aquiferand the extent and frequency of recharge. Betweeen 1980 and 2000, Bangladesh achieved aremarkable success by providing 97% of the rural population with bacteriologically safe tubewell water. This success led simultaenously to a disaster. Rural people were made aware of theimportance of drinking bacteriologically safe water and rapidly developed their habit of drinkingTube Well water. Unfortunately arsenic in shallow ground water aquifers is at an unacceptablelevel. Data from the Brtish Geological Survey (BGS) were used to estimate that 30 millionpeople in Bangladesh are living with arsenic at levels greater than 50 g/l 6 but 50 million peoplein Bangladesh are living with arsenic at levels greater than 10 g/l and are therefore under thethreat of arsenic poisoning. However scientists at Dhaka Community Hospital estimate an evenhigher number - possibly 80 million people are at risk of arsenic poisoning in Bangladesh. Ofthese a large fraction – between 200,000 and 1,000,000 will develop skin lesions or internalcancers as estimated, for example by Harvey et al.7 2Today possibly more than 3 million affected shallow tube wells are used for drinkingwater. Out of the total 64 districts of Bangladesh, in 50 districts arsenic has been found above 50µg/l (the recommended level of arsenic in drinking water of Bangladesh) and in 60 districtsabove 10 µg/l (which is the World Health Organization (WHO) recommended maximum level ofarsenic in drinking water). Soon after the arsenic problem was discuvered, it was widely suggested that a simpleoption is to drill te wells deeper – to below a clay layer where the water is relatively arsenic free.But in some areas the deep tube wells are found to be already contaminated with arsenic so thatthis is not a solution. Moreover it is feared that the deep aquifer may become contamitated withuse. In some villages 100% tube wells are contaminated with high level of arsenic. DCH andDipankar Chakraborti, Jadovpur University, Kolkata, India, jointly surveyed on arsenic affectedareas of Bangladesh and prepared the following maps (Fig. 1&2). Similar maps have beenprepared by others such as the British Geological Survey8. A listing of tube wells and theirmeasurement is available at NAMIC.9Figure-1 Figure-2Moreover in Bangladesh the water demand is increasing rapidly. 82% of the water supplysystem depends (in 2005) on ground water of which 95%goes for