APPROPRIATE ARSENIC MITIGATION WATER SUPPLY AND INTERNATIONAL COOPERATION: BANGLADESH EXPERIENCE

Transcription

1 APPROPRIATE ARSENIC MITIGATION WATER SUPPLY AND INTERNATIONAL COOPERATION: BANGLADESH EXPERIENCE BILQIS AMIN HOQUE Environment and Population Research Center Dhaka, NAHID A. ALI Bangladesh Consultants Limited Dhaka, Bangladesh SHORIFUL ISLAM Environment and Population Research Center Dhaka, Bangladesh Access to safe drinking water is United Nation s assigned priority agenda for Effective access to safe drinking includes both quality and quantity aspects of water. About 30 to 50 millions people in Bangladesh are exposed to the risk of drinking arsenic contaminated water. Here arsenic mitigation water supply challenges and its implications for international cooperation are discussed based on literature and Kalia, Bangladesh, field data.. The national and international development partners have been undertaking appreciable efforts to address the problem. An appropriate arsenic technology is yet to be developed. So the Government of Bangladesh is promoting alternative options, such as, rainwater, surface water and safe groundwater based options. There are 100 villages where >80% hand pumps are contaminated in Kalia.. Alternative water options and village piped water have been installed there. Rainwater options do not provide water for the full year. The rivers are recently affected by salinity. Ponds and tanks dry out during summer. Dug wells are contaminated with bacteria. Almost all rivers in Bangladesh start from neighboring countries. Salinity intrusion, drying out of surface water and/or lowering of groundwater have occurred in Kalia and many areas due to withdrawal of water from Ganges river by the neighboring country. Climate variability induced changes are also experienced in Bangladesh and complicated the situations. Overall, international cooperation towards development of arsenic removal technology and appropriate management of international and national water resources towards sustainable drinking water solutions is urgently needed. INTRODUCTION Although water is the most widely occurring substance on earth, only 2.53 percent is freshwater while the remainder is salt water. There are huge differences in its availability in different parts of the world and wide variations in seasonal and annual precipitation in 1

2 many places. Humankind s control of runoff is now global and we are significant players in the hydrological cycle. The control of runoff may be a national issue or complicated national and international issue in international river basins. Per capita use is increasing and population is growing. Freshwater resources are challenged by pollution from human, industrial, and other wastes. Furthermore, the precise impact of climate change on water is uncertain. Water resources management spread over domestic, agriculture, industrial, transportation and other sectors, but domestic water- in particular the drinking water is the priority. Drinking water is life but, it has been also the cause of deaths and sufferings of people. Water is to be both available and safe in quality to meet the public health and other development needs of people. It is high time that appropriate management of water is looked into properly by the researchers, policy makers and implementers. This paper presents the arsenic mitigation drinking water supply scopes in Bangladesh in international cooperation perspectives. It is a discussion paper. Bangladesh is one of the highest populous countries in the world and located in Asia. According to a global overview the water availability versus the population stresses pressure is the highest in Asia. It is estimated that million of the approximately 138 million people of Bangladesh are at risk of drinking arsenic contaminated water [1]. Drinking of arsenic contaminated water has been reportedly associated with skin problems and its cancer, hypertension, cardiovascular diseases, diarrhea, and/or cancer in the liver, bladder, kidneys, lungs and other internal organs [2, 3, 4]. Drinking of arsenic safe water is the principle mode of prevention and treatment of health the problems [4]. Unfortunately, most of the people in the arsenic contaminated area do not have access to the safe drinking water. The arsenic contamination of drinking water has challenged the very basic human necessity and water security in the region. Arsenic contamination has been reported from India, Nepal, Pakistan, Vietnam, Myanmar, China and other countries of Asia and in other parts of the world. The potentials of the international community and cooperation in addressing the situation have been discussed here based on literatures [1-9, 11, 12] and an action research experience [10]. BANGLADESH AND ARSENIC CONTAMINATION Bangladesh is one of the most natural as well as built environmental disaster burdened countries of the world. It got independence in December 16, 1971 through a bloody civil war after several hundred years of colonial rules. It started with damaged infrastructures, food deficient and millions of mostly poor population. The country and its development partners have helped the country to achieve one of the noticeable family planning program, food self-sufficiency and reasonable level of communication system in the region. However, 38% of the population live below $ 1/day, and GDP/capita (PPPUS$) is 1610 and the Human Development Index is at the 139 th in 175 countries [5]. In Bangladesh, arsenic was first detected in groundwater/tubewell water in Chapai Nawabganj in A recent sampled survey of well water (n=3534) from most of 2

3 Bangladesh by British Geological survey and Bangladesh [1] has shown that arsenic content in water samples from 27% of the tubewells which are less than 150 meter deep, exceeded the Bangladesh standard for arsenic in drinking water (0.05 mg/l), 46% exceeded the WHO guideline value of 0.01 mg/l. In water samples from wells lower than 150 meter the same figures were 1% and 5 % respectively. There is a distinct regional pattern of arsenic contamination with the greatest contamination in the south and southeast of the country and the least contamination in the north-west and in the uplifted areas of north central-bangladesh. In arsenic-contaminated areas, the large degree of well-towell variation within a village means that it is difficult to predict whether a given well will be contaminated from tests carried out on neighboring wells. The arsenic is of natural origin and is believed to be released to groundwater as a result of a number of mechanisms which are poorly understood. WATER SUPPLY Until the recent observation of arsenic in groundwater, the country was recognized as one of the few developing countries that had achieved remarkable success in the supply of safe drinking water through tubewells. About 95% of the people drink hand tubewell water. Surface water is abundantly available in Bangladesh, but it is heavily polluted with fecal and other matters. Extensive technical, social, financial and other efforts by national and international partners over last 2-3 decades were involved to motivate the people to change drinking water practice (and supply) to groundwater from surface water. There are about 11 million hand tubewells. Most of the tubewells are private. It is an irony that the people have to once again change their water practice within 2/3 decades. It is interesting to note that the people of the capital city or big or most towns of the country who drink piped water are mostly not exposed to the risks of drinking arsenic contaminated water. The people in those areas are supplied with piped water from deep wells and/or surface water sources. Arsenic contamination has been observed in groundwater, in general, in the top few 100 meters. Arsenic Mitigation Water Supply Program Testing of almost all tubewell water and creation of mass awareness about the contamination as well as its impacts have been completed in most of the arsenic affected areas. It has been done by Bangladesh Arsenic Mitigation Water Supply Program funded by Government of Bangladesh and various donors. The tested tubewells have been marked (painted) green or red based on absence or presence of arsenic content above Bangladesh standard in the water sample, respectively. Very limited areas of the affected areas are being provided with the improved water options as demonstration. Most of the affected people do not have access to arsenic safe water. 3

4 Arsenic Mitigation Water Supply options Safe water options may be grouped based on sources of water, types of treatment required to make water drinkable, types of service and other characteristics of the options. One of the common practiced methods is to group it by whether or not it requires arsenic removal treatment, such as, (i) options based on arsenic-safe water which will not require arsenic treatment and may or may not require other treatments; alternative options and (ii) options which require arsenic removal treatment and may or may not require other treatments. There are several arsenic removal options. The options are mainly after: oxidation/reduction, precipitation, adsorption and ion exchange and passive sedimentation processes. The details about the technological designs and processes may be found in literatures. Nine household options were assessed as a part of a Rapid assessment of Household Level Arsenic Mitigation Technologies under a technical assistance program [6]. The options included: Alcan Enhanced Activated Alumina (AL), Adarsha Filter (AR), BUET Activated Alumina (BUET), DPHE/Danida 2-bucket System, Passive Sedimentation, GANET Home-made Emergency Filter, Sono-3-kolshi Filter, Stevens Institute Method (Stevens) and Tetrahedron. Many different aspects related to the performance, use and sustainability of the options were assessed under different water quality conditions of the country. Cost and environmentally safe disposal of sludges were included in support service. Support service was recognized important but not considered in the assessment. The options were tested under two conditions: (i) according to the strict operating instruction in a controlled set-up by the project team, and (ii) normal operating conditions by the householders over a thirty day period. The reported most appropriate technologies were: Alcan, Tetrahedron, Sono and Stevens. However, none of the above-recommended nine options have been yet observed performing satisfactorily and/or generally accepted in the field areas after several months of the promotion [7,8]. The main observed concerns were one or more of the following: lack of consistent arsenic removal efficiency, bacterial and other chemical contamination, amount of work needed on the part of users to operate and maintain the technology and the volume of water that was available on a daily basis. As the Government of Bangladesh was not convinced about its performance, it has stopped promoting the arsenic removal options and is further studying the options. It is promoting alternative options. The alternative options include all three sources of water; surface water, groundwater and rain water which are arsenic safe. The surface water based common technologies/techniques are: pond sand filters, Balir kolshi filters, local ceramic filters, and boiling of water. Pond sand filter is after slow sand filtration principles. Here pond water is fed to a pre-treatment chamber and then to the sand bed using a hand tube well. Balir Kolshi filters are pitchers filled with sand and stacked one over another. Surface water is poured on the top pitcher and filtered by gravity through the other pitchers. Ceramic filters are commercially prepared to filter surface water. 4

5 The rain water based options are mostly tanks or containers to harvest and store water from roofs. Ground water alternative options include wells which are not arsenic contaminated, it could be shallow or existing deep wells. The shallow wells are tube wells and dug wells. Dug wells are about 7 meter to 15 meter deep wells which are wide enough to allow withdrawal of water, usually by manual methods, using buckets and other containers. However, installation of new manual or mechanical deep tube well based options is not encouraged. There is a debate and concern on the possibility of deep aquifer contamination from the top contaminated shallow aquifer depending on the characteristics of the aquifers. As there is limited hydrological data, the installation of new deep tube well option is rarely allowed under special conditions. In arsenic affected coastal areas deep tubewells are promoted. ARSENIC MITIGATION WATER SUPPLY ACTION RESEARCH IN KALIA Arsenic mitigation action research is ongoing in Kalia following the Government strategies [10]. The objective of arsenic mitigation water supply action research in Kalia is to provide safe drinking water to about 0.3 million people. The project is funded by UNICEF and Department of Public Health Engineering and conducted by Environment and Population Research Center. There are approximately drinking hand pumps. Madhumita and Nawaganga rivers and a few canals flow through the sub-district. Both the rivers are linked to Ganges river, an international river. About 67% of the hand pumps were found contaminated above Bangladesh standard (WHO standard =0.1 mg/l and Bangladesh standard=0.5mg/l). There are 100 villages where >80% hand pumps are contaminated. There the people are being motivated to choose one of the following options: dugwell, rainwater harvester or pond sand filter. Sharing of green tubewells is strongly encouraged. The people are to share 20% of the installation cost and 100% of the operation and maintenance costs. Of the promoted alternative options sharing of the existing safe tube wells were most widely used. However, serious concerns expressed widely about the physical and social problems in transporting water from long distance shared tube wells. Dug wells have been so far one of the most commonly accepted new option. But the fecal coliform bacteriological quality of dugwell water varies between a few times to many tens of times higher than the Bangladesh water quality standard (10). The project chlorinates the dugwells before handing over the option to the caretakers. Chlorination or further development have been trained and strongly suggested as the quality of water improves significantly after chlorination [9, 10]). But people do not practice it as they do not like the odour of chlorinated water. Also dugwells cannot be installed in all areas. Ponds or surface water based technologies require that there is enough water through out the year. But availability of year round pond or surface water is not easy Kalia or in many areas in Bangladesh (10). Pond water is heavily contaminated. Various designs of pond sand filters are promoted. But the acceptance is low [8, 9, 10]. Chlorination and 5

6 other methods of disinfection showed improved results (9), but people did not practice it. Boiling, filtration or combination of the two methods for surface water is not appreciated by the people. Boiling is not affordable by common people. People preferred the river and flowing water over that of pond water (10). According to them flowing water was not that polluted. But the river and its connected water bodies are increasingly drying out during summer season. River and groundwater also become saline during dry season (10). The drought and salinity problems increased after the construction of Ganges barrage in India. The harvested rainwater is more or less accepted. The quality is reasonably good [9, 10]. But as rainwater is available over a few months of a season and the options are not designed for year round use many people do not accept it. A deep well based village piped water system is being tested. The original plan was to test river based piped water system but it was abandoned due to increasing salinity problem. A recent paper suggested that rural cluster based piped water systems are in high demand, particularly by the women [8]. They found it convenient and an indicator of well being. Overall, providing cost effective safe water to the affected people has become a complex challenge. WATER RESOURCES AND INTERNATIONAL The water ecosystem of Bangladesh comprises the tributaries and distributaries of three major river systems: the Ganges-Padma, the Brahmaputra-Jamuna, and the Mehna. All the three major river systems originate outside the country. Preliminary estimates indicate that cross-border flows into the country amount to around 1010 billion cubic meters (BCM), and an additional amount of 340 BCM is generated from local rainfall. Eighty percent of this huge flow of water is concentrated in the five-month monsoon period of June to October. Bangladesh often experiences droughts for prolonged periods during pre-monsoon and monsoon due to erratic and delayed rainfall. Over the last three decades the dry-season flows of the transboundary rivers passing through Bangladesh have been facing gradual reductions from the normal historic flows (11). India started large-scale diversions of the dry-season flows to the Ganges by unilaterally constructing the Farakka Barrage in Due to frequent droughts and periods of water scarcity, natural water bodies like ponds, beels, rivers and rivulets dry up. The ground water table goes down to alarming levels. Drying up of sources puts serious stress on the supply of water for drinking and domestic, municipal, industrial and agricultural uses. The Ganges basin inside Bangladesh includes most of the South and South-east areas which is also the most arsenic affected area. Since the late seventies, the southwest region has been facing the critical problem of salinity intrusion from the Bay of Bengal as a result of the drastic reduction of fresh water flows in the Gorai-river-the major distributory of the Ganges. 6

7 Bangladesh is universally acknowledged to be extremely vulnerable to climate change [12]. Bangladesh will face varying types and degrees of problems including reduced fresh water availability, increased bank erosion, disturbance of the balance between river sediment transport and deposition in river flood plains and coastal areas, increased intensity of floods, cyclones/storm surges, and droughts. The climate variability induced changes will make the water management problems further complex and difficult. A program on Interlinking of rivers (including a few international rivers) is being considered in India. The estimates of water availability in the international river basins which will form the basis of surplus and scarce basins are based on assumptions of gross and net irrigation requirements and non-irrigation requirements; return flows, etc. by India. Bangladesh is still not informed of the assumptions and the plans. But it is the lowest riparian country. The whole issue is extremely sensitive and related to the survival of the people in Bangladesh, the lowest riparian country. THE SCOPES There is no question that the primary responsibility for sustainable development and poverty reduction are on the countries. But the developing countries have severe social, technical and financial limitations. It is humankind that concerted and concrete measures at both national and international levels are undertaken to enable developing countries to meet the basic needs. International commitments towards making safe drinking water accessible to the people have been noted in most of the important meetings from the 1970s to the United Nations Millennium Declaration Goals. The MDG is to the halve of the people who do not have access to safe drinking water. The Government, national and international development partners have been making significant and appreciable efforts to supply safe water to people in the arsenic affected areas. Still there is no major project to supply safe water to the affected people. Piped water for rural people is being recently discussed by the policy makers. Accordingly, a few international development partners are suggesting privatized piped water systems. There is no doubt that water has an economic value. Privatization has many merits. The piped water system infrastructure started as public investment in most of the developed countries. The privatization of its expansion, upgrading and operation are recent concepts. The poor people installed millions of tubewells recently as promoted by the Government and its national and international partners. It is an irony that the poor people have to pay for the installation/ infrastructure costs of piped water option. The conjunctive use of the water sources is essential to solve the problem. For example, surface water do not have arsenic and so far treatment of bacteriological contamination has been better known than arsenic treatment. But drying out of surface water and salinity intrusion in rivers and ground water in significant part of Bangladesh (like in Kalia), has challenged the use of surface water. The conjunctive use of the water sources is hampered by transboundary water conflict and climate induced changes. Bangladesh is not responsible for the complication of the situation. Addressing the issues through 7

8 international development of the basins and/or water management from inside Bangladesh will require will require international technical, social and financial cooperation and support. Overall, the millions of the affected poor people in the arsenic affected areas in Bangladesh are at risks of one of the worst human disasters (4) to which they had no roles or have no control. International cooperation, coordination, consultation and assistance have immediate and long-term scopes towards survival of millions of people through access to safe drinking water as well as appropriate water management in Bangladesh and similar developing countries. ACKNOWLEGEMENT Dr Hoque is grateful to Disaster Prevention Research Institute (DPRI), Kyoto University, Japan. An earlier version of the paper was written during her Visiting Professor position there. REFERENCE [1] British Geological Survey, Department of International Development- UK,Government of the People's Republic of Bangladesh. Arsenic Contamination of groundwater in Bangladesh. Final Report [2] Rahman M. et al. Hypertension and arsenic exposure in Bangladesh. Hypertension [3] Department of Health and Human Services. Agency for Toxic Substance and Disease Registry. Toxicological profile for arsenic. Draft Report. March 2000 [4] Alan H. Smith, Ethna O. Lingas and Mahfuzur Rahman. Contamination of drinking water by arsenic in Bangladesh": a public health emergency. Bulletin of the World Health Organisation, 2000, 78 [5] Human Development report 2003 [6] Sutherland.D. kabir MA, Chowdhury NA. rapid Assessment of Technologies for Arsenic Removal at the [7] Zakaria M. The use of safe water options to mitigate the arsenic problem in Bangladesh. M.SC. Thesis. Dept. of geography. University of Cambridge. August [8] Bilqis A.Hoque,M.M. Hoque, Tofayel Ahmed, Shoriful Islam, Nahid Ali et. al (2004) Demand-based water options for arsenic mitigation: an experience from rural Bangladesh. J. of the Royal Institute of public Health. 118, [9] Bilqis Amin Hoque, A.A.Mahmood, et al. (2000) Recommendation for Arsenic Mitigation in Bangladesh. Journal of Public Health Medicine and Epidemiology. 114, UK. 8

9 [10] Bilqis A. hoque, S. Islam, S. Khnam, A, Bari et al. Safe water options in arsenic afected areas under the 15 upzilla arsenic mitigation project, Kalia. An annual report submitted to UNICEF [11] QK Ahmad. Bangladesh Water Vision Towards a sustainable water world BWP [12] World Bank. Dhaka. Bangladesh: Climate Change and Sustainable Development. Report No BD. July