Widespread arsenic contamination of shallow (<150 m) and some deep tubewells was first identified in 2000 (BGS/DPHE, 2001). Of the total population of 125 million in Bangladesh, it was estimated that 57 million were exposed to arsenic concentrations above the WHO provisional guideline value of 10 µg/L, while 35 million were consuming water with concentrations above the Bangladesh Drinking Water Standard of 50 µg/L. Early mitigation efforts focused on technologies such as pond sand filters and hand-dug wells, but these options are more vulnerable to faecal contamination. It was estimated that in comparison to shallow tubewells, deep tubewells were predicted to cause a much lower burden of disease (Howard el., 2006). Deep tubewells were not prioritised in the 2004 national policy and implementation plan because of concerns that deep tubewells might not be free of arsenic in some regions, or that abstraction of deep groundwater could induce downward transport of arsenic from contaminated shallow aquifers. While deep groundwater in certain regions (notably parts of Jessore, Satkhira and the Sylhet Basin) can contain arsenic under specific geological conditions, the last decade has shown that deep tubewells are geochemically stable and that the feared draw-down does not occur as long as large volumes of water for irrigation purposes are not abstracted from deep aquifers. These results have given impetus to the already preferred deep tubewell mitigation option. As the capital costs of drilling deep tubewells are high, subventions were necessary. Government programmes contribute 90% of the installation costs.
A second national survey in 2009 found that exposure to 10 µg/L may have been reduced by roughly a quarter (although this just keeps up with population growth) and that exposure to higher concentrations (>200 µg/L) may have been reduced even further (UNICEF/BBS, 2011). As tubewells have a limited lifetime, new wells are continually being drilled, though arsenic is not always monitored (van Geen et al, 2014).
Ensuring that tens of millions of people exposed to arsenic have access to and use safe water is an extremely complex and expensive task, and though progress has been made, there is still a long way to go. The work presented here is based on Johnston et al. (2014).
The aim of the project was to learn from the experience gained in Bangladesh. Specifically, the aims were:
The studies were carried out during the same time period, between spring 2005 and autumn 2011, at sites that were most appropriate for individual investigations.
The institutional study required preparation to obtain an overview of the institutional setting. Problem scoping and site selection were carried out in the following steps:
Two structured face-to-face questionnaire surveys were developed and conducted to obtain the opinions at the institutional and household levels on various aspects of arsenic mitigation in Bangladesh. Institutional stakeholder surveys were performed in Munshiganj, Comilla and Pabna districts. A stakeholder survey was conducted targeting officials from central and local government, NGOs, and donors involved in arsenic mitigation (Khan and Yang, 2014). The background to the questionnaires and the type of questions asked is outlined below and are also given in Schmeer (1999) and GTZ (2007).
Institutional survey of stakeholders who can affect actions and outcomes
Structured or semi-structured face-to-face interviews should be held with representatives from:
The information to be sought through the interviews should include the following:
Understanding the institutional setup at different levels and the interaction between these levels:
Understanding the available means of execution and enforcement of laws, rules and regulations:
Understanding the forms of governance:
Understanding the reality of implementing and enforcing the laws, rules and regulations:
A householder survey was carried out to determine preferences and willingness to pay for arsenic-free drinking water, as these are critical factors for the success of any mitigation option. The survey was conducted in 13 arsenic-affected rural villages from Sirajdikhan, Sujanagar, Ishwardi and Laksham upazilas (sub-districts). Six hundred and fifty household respondents were asked about their current and preferred water sources and usage practices, awareness of arsenic contamination and medical costs related to arsenicosis, as well as their willingness to pay for or contribute to a new alternative water source, namely, deep tubewells (Khan et al., 2014; Khan and Yang, 2014). This is an important issue, because the financing and successful implementation of a mitigation measure may be dependent on the financial contribution of the users. There are a number of approaches for eliciting willingness to pay. The Contingent Valuation Method (CVM) is one of these. This method emerged in the 1960s and has become widely used since the 1990s. More details on conducting willingness-to-pay surveys can be found, for example, in Wedgwood and Sansom, 2003. An outline of the background to the questionnaires and the type of questions asked is given below.
Local community and household surveys (primary stakeholders)
A structured or semi-structured survey eliciting detailed information relating to:
The questionnaire needs to be pre-tested on pilot sites before a full-scale field survey is conducted. The sample size for the full-scale household survey should be over 300 to allow robust statistical analysis of the data. The following example questionnaire is an abbreviated version of a questionnaire used for interviewing households on arsenic mitigation strategies in Bangladesh.
A series of surveys of the inhabitants of six arsenic-affected districts – Munshiganj, Comilla, Satkhira, Khulna, Bagerhat and Brahmanbaria – was conducted. In all study locations, the people had access to one (or two) of eight arsenic-safe options: dug wells, pond sand filters, piped water supply, household arsenic removal filters, community arsenic removal filters, household rainwater harvesting, deep tubewells or the possibility of the sharing of safe shallow wells. All mitigation options had been installed by the DPHE, UNICEF or local governments. The purpose was to investigate the acceptance and use of available arsenic-safe water options (Inauen et al., 2013a), including the psychological factors leading to their use (Inauen et al., 2013b; Mosler et al., 2012), and to test behaviour change interventions intended to increase their use (Inauen and Mosler, 2013; Inauen et al., 2013c).
The aim of the technical study was to determine at what depth the water was safe to drink and what measures could be taken to ensure that the right depth had been reached during drilling (Hug et al., 2011). The study site, Munshiganj district near Sreenagar town (a 2.5 by 2.5 km2 area), which lies 30 km south of Dhaka and 5 km north of the Ganges River, was selected because over 85% of shallow tubewells in the Mushiganj district are affected by arsenic concentrations >50 mg/L.
In 3 surveys from 2005 to 2010, samples were collected from existing shallow and deep tubewells, monitoring wells (5–210 m depth) and newly installed deep tubewells. Electrical conductivity (EC), pH and dissolved O2 were measured in freshly pumped water with a multi-parameter sensor. Filtered (0.2 mm, nylon) and unfiltered samples were collected into pre-acidified (0.15 mL 2M HCl) polypropylene vials (4 mL) for the analysis of cations (major ions (charges omitted): Na, K, Mg and Ca; minor ions: Mn(II), Fe(II), Astot etc.). For the determination of total organic carbon (TOC), unfiltered samples were collected in pre-acidified (0.2 mL 5M HCl) polypropylene vials (30 mL). For Cl, SO4, NH4 (charges omitted) and alkalinity measurements, samples were collected untreated in 50 mL or 100 mL polypropylene bottles. The samples were placed in a refrigerator on the day of sampling and cooled to 4–8 °C until analysis. A survey involving around 200 deep wells was conducted by Eawag in collaboration with UNICEF and the University of Dhaka in the sub-district of Monoharganj (Comilla). The purpose of the survey was to assess the water quality with regard to salinity and to arsenic, manganese and other elements, and to find the best depth for the installation of new deep tubewells. The preliminary results were used as a basis for the installation of deep tubewells in this region by UNICEF and by private donors (e.g. Rotary). Surveys were also conducted on taste and odour, with the purpose of determining acceptable limits for salinity and the concentrations of metal(loid) ions.
The results presented here are based on Khan and Yang (2014) and Khan et al. (2014). Stakeholders from all different types of organisations stated that their major roles were to provide arsenic-safe water and to increase awareness of arsenic contamination and exposure among the rural population. The majority (63%) felt that one of their major achievements had been to increase awareness of arsenic contamination among the rural population, and that as a result of increased awareness, demand for deep tubewells and other alternative arsenic-safe water options had increased. Other major achievements revealed by the stakeholders included the provision of assistance for health-care services related to arsenicosis problems (32%) and introducing and ensuring safe water options (27%). Surveys at both the institutional and household levels clearly identified deep tubewells and piped water systems as the most preferred options for avoiding arsenic exposure through drinking water. Institutional stakeholders rated deep tubewells as being “highly suitable” (89%) as a long-term safe water option, followed by piped water systems (68%). Rainwater harvesting was also identified as a popular and suitable option in coastal areas of Bangladesh, where groundwater salinity restricts water supply through either deep tubewells or piped water systems. However, household arsenic removal filters were identified as being a “not suitable” option by a majority of institutional stakeholders (63%), and the household-level survey found that less than 10% of households interviewed expressed their preferences for household filters as a safe water option. None of the other water options (pond sand filters, dug wells, rainwater harvesting) were significantly favoured by institutional stakeholders, and overall, 50% of the respondents considered other water options as being “not at all suitable” and only 10% considered any other water options as “highly suitable”. Last but not least, the majority of the institutional stakeholders (68%) strongly preferred a community-based safe water option over individual household options. On average, institutional stakeholders estimated that 50 BDT/month (range 10–250 BDT/month) until full recovery of installation cost was made would be reasonable. These estimates matched well with household responses: Overall, three quarters of the household respondents were willing to pay 25 (32%) or 50 (42%) BDT for monthly operation and maintenance costs. Household survey results indicated that study households were generally willing to pay up to 5% of their disposable average annual household income for a one-time investment (capital cost) towards construction of a deep tubewell to receive arsenic-free drinking water (Khan et al., 2014). This low value reflects the fact that in the rural villages in Bangladesh, the concept of “paying for water” has not been completely developed, because households can still obtain water without payment. Stakeholders stressed that regular awareness programs would help to develop the concept of “paying for water” in the rural community. The great majority of the institutional stakeholders (90%) agreed that end-users should be willing to walk (WTW) a certain distance for water, while only 10% believed that end-users should not walk at all for water. Most believed that 0–250 m and 10–30 min per trip were a reasonable distance and time for water collection, without unduly impairing the ability of women (traditionally responsible for water collection in Bangladesh) to manage efficiently their other household work. However, stakeholders also mentioned that religious and cultural issues are also principal factors restricting people's WTW for water. As for cultural factors, in some areas of rural Bangladesh, the women and girls are not encouraged to travel far outside the family home (bari). This can pose a barrier to the collection of water from public sources. When asked the reasons for the relatively slow progress in arsenic mitigation, the most common response identified by 32% of institutional stakeholders was the lack of responsibility and accountability. Insufficient funding, lack of coordination and shortage of skilled manpower were all considered as major limiting factors by about 25% of the stakeholders. They particularly mentioned the locally elected upazila parishad (sub-district councils), whose responsibility it is to identify and mitigate arsenic contamination in drinking water. The stakeholders were of the opinion that greater decision-making power (37%) along with increased funding and the allocation and retention of trained manpower (74%) would strengthen capacity at the local government level and hence result in better performance. Most institutional stakeholders also believed that lack of accountability (32%) and commitment (11%) from both providers and end-users, as well as a lack of coordination between organisations (26%), were the key factors resulting in unsustainable arsenic mitigation. Stakeholders were of the opinion that for sustainable, effective arsenic mitigation by the upazila parishad, the effectiveness of existing arsenic coordination committees was crucial and that this could be enhanced by organising regular meetings and involving experienced people regardless of their political affiliation. Stakeholders also agreed that arsenic mitigation should use a combination of different options suitable to different parts of Bangladesh, and therefore a single blanket mitigation option for the whole country would not be sustainable.
The study of eight arsenic-safe water options showed that overall, only 62% of households with access to a safe water option (N = 1268) actually use it (Inauen et al., 2013a). The study also revealed great discrepancies between user rates for the different water options. The most used options were piped water, followed by community arsenic-removal filters, well-sharing, deep tubewells, dug wells, pond sand filters and rainwater harvesting systems (Fig. 9.7). Clearly, if more people would use the options which are accessible to them, the public health burden would be reduced. Psychological factors determined from the RANAS model of behaviour change (risk, attitudes, norms, abilities, self-regulation) (Mosler, 2012) are an aid to better understanding the reasons why some options are preferred over others (Inauen et al., 2013a). A piped water supply was most popular in terms of taste and temperature preferences, followed by strong social norms (i.e. that many relatives and friends are in favour of using arsenic-safe water sources, and that they are also using them), high confidence in their ability to obtain as much arsenic-safe water as needed (i.e., self-efficacy, Bandura, 1997) and high commitment (i.e. a personal desire, Inauen et al., 2013c) to consuming piped water. Interestingly, deep tubewells also enjoy a high degree of acceptance, despite only moderate user rates. This may be due to the fact that collecting water from deep tubewells has been reported as time-consuming, which may have led to lower commitment (Inauen et al., 2013c). Households with access to neighbours’ tubewells only reported below average social norms for using them and low commitment, perhaps also because users are dependent on their neighbours' consent. At the other end of the spectrum, dug wells were perceived as time-consuming and were associated with taste and odour issues. The next step was to analyse the survey data to forecast the most promising promotion campaigns. Self-efficacy and the descriptive norm (i.e. how many other people use arsenic-safe water options, Cialdini, 2003), emerged as the most important factors to explain the use of arsenic-safe tubewells (Inauen et al., 2013b). Further important factors were instrumental attitudes (i.e. the perception of water collection as time-consuming and hard work) and the injunctive norm (i.e. what one thinks that others think should be done, Schultz et al., 2007). This was applicable to all arsenic-safe water options included in the study. Summarising, these studies indicated that more committed persons, who perceive safe water collection as “normal” and have higher confidence in their abilities to collect safe water, find safe water collection less time-consuming and less of an effort, and those who feel they have more approval from others when they collect arsenic-safe water are more likely to use arsenic-safe water options. Given their general acceptance, deep tubewells were chosen for promotional campaigns to overcome the issues of distance and lack of commitment. To increase commitment, the most promising factor of deep tubewell use, they developed reminders, implementation intentions (simple plans of when, where and how to obtain arsenic-free water, Gollwitzer, 1999) and public commitment (sometimes termed “pledging”, Fig. 8.8), and combined them with risk information (Fig. 9.8, Inauen et al., 2013c, Gollwitzer, 1999). The results of a randomised controlled trial revealed that evidence-based behaviour change techniques increased the behaviour change effect by 50% compared to simple information provision (Inauen et al., 2013c). But also less “spontaneously” accepted and used arsenic-safe water options can be promoted by targeting any of the psychological factors identified above. For well-sharing, for example, the commitment-enhancing behaviour change techniques described above increased the number of users by up to 66% (Inauen and Mosler, 2013).
The analyses of water from shallow and deep tubewells in the tested area of Sreenagar, Munshiganj, identified three types of groundwater currently used for drinking:
Drillers have traditionally used the transition from grey to brown sediments as an indicator of the depth from which safe drinking water can be obtained. However, in most of the tubewells in the study area below 190 m, the Mn concentrations exceed the WHO limit of 0.4 mg Mn/L (WHO, 2011) by a factor of 2–5, and the water tastes noticeably saline. Based on these findings of this small survey of deep tubewells, a depth range of 150–180 m with light grey sediments is recommended for the construction of new wells. The finding of an “intermediate depth” at which water which is safe not only with regard to arsenic but also with regard to salinity and manganese is echoed by Hossain et al. (2012), who found good quality groundwater at 120 m in Chandpur, one of the most highly arsenic-affected areas in the country. Groundwater from this depth contained moderate levels of iron (2–4 mg/L), but iron in the region is also common in shallow groundwater (~10 mg/L), and locals are accustomed to the metallic taste. The surveys in Monoharganj have shown that the concentrations of arsenic, manganese and salinity as a function of depth are locally highly variable and that the best depth for water extraction should be determined in each community in which a larger number of deep tubewells are planned. Finding a depth with acceptable water can be difficult in some locations, and newly installed deep tubewells often deliver water that is too saline or that contains high manganese concentrations. Methods are being developed that allow drillers to test the water quality during the drilling process and to install well screens at the optimal depth. More generally, high salinity in deep tubewells is also common in parts of the coastal zone as well as in the Sylhet basin, and manganese concentrations frequently exceed both the government limit of 0.1 mg/L and the WHO health-based value (WHO, 2011) in central and northern Bangladesh (UNICEF/BBS, 2011). Owners have reported damaged pumps that apparently corroded more quickly due to high salinity.
These studies have shown that there is considerable agreement between the wishes of the institutional stakeholders and rural householders with respect to the preferred mitigation options, namely, piped water and deep tubewells. Further, there is agreement between institutional stakeholders and householders about cost. However, the institutional stakeholders were of the opinion that a distance of 0–250 m (or 10–30 min) per trip was acceptable, whereas householders perceived water collection as time-consuming and hard work. These studies also showed that there would be significant potential for reducing the number of people exposed to arsenic if householders used the safe-water options available to them. They also showed that information alone would not be enough to change people’s habits. Evidence-based behaviour change techniques to increase commitment would be required. With respect to deep tubewells in the Sreenagar district, it was found that, although free of arsenic, water taken at depth can be saline and contain unacceptably high manganese concentrations. Water taken from intermediate depths (140–180 m) fulfilled the quality requirements. Further, pumping tests showed that the deeper aquifer was to a large extent separated from the upper aquifer, so that the abstraction of small amounts of water for drinking using hand pumps can be deemed safe as long as wells are periodically tested.
The institutional stakeholders identified a lack of capacity at the level of the locally elected sub-district councils (upazila parishad). They also mentioned a lack of accountability and coordination between organisations. These appear to be good starting points to improve mitigation outcomes. The role of awareness creation appears to the institutional stakeholders to be an important factor in reducing exposure to arsenic, while the results of the behavioural change study indicate that the introduction of simple behaviour change techniques to “empower” the local population to make use of existing facilities, particularly well-sharing and deep tubewells, could make a significant difference to the number of people at risk. With respect to deep tubewells, it must be remembered that groundwater quality is spatially highly variable and that safe zones within the deep (or intermediate) aquifer are site-specific. It is therefore recommended that in areas where deep tubewells are to be installed, safe depth zones should be identified by surveying existing deep tubewells and, if possible, by the installing of a small number of monitoring wells, which could also serve as sources of drinking water. Maps can be very useful.
NOTE: Article from the Geogenic Contamination Handbook
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