[ B a k k e r , J . – 1 0 0 2 1 2 2 1 ; B u r e r , K . – 6 3 2 9 7 1 3 ; K a m p s , M . – 1 0 0 8 3 1 0 3 ; K e r v e r s , A . – 1 0 2 6 3 4 1 1 ; T u t o r – R o t h u i z e n J . V . M S c ; E x p e r t
s u p e r v i s o r – D r . C . R a m m e l t ; W o r d c o u n t -‐ 9 8 6 4 ]
Combating world’s largest mass
poisoning in history
Guidelines for arsenic mitigation in Bangladesh
[Abstract -‐ Arsenic contamination of drinking water is a major public health issue in Bangladesh. Since the identification of the problem of arsenic contamination, several mitigation options have been used to provide safe drinking water. However, they have not had the intended effect yet, since policy makers have not taken the local characteristics thoroughly into account. Due to the complex nature of the problem, and that no discipline has come up with a solution an interdisciplinary approach has been chosen for this research. This research focuses on creating an integrative tool that policy makers may use as a guideline to choose the most feasible mitigation option when arsenic concentrations exceed the Bangladesh National Standard (BNS) in groundwater. Based on literature research a tool is designed that incorporates the key considerations and local conditions for developing arsenic mitigation policy in Bangladesh. While assumptions had to be made when creating the tool it is supposed that the tool represents reality to an extent that it can provide an answer to the question of arsenic mitigation.]
December
2013
20
Foreword ... 4
1.0 Introduction ... 4
1.1 Problem definition ... 4
1.1.1 Study area: Arsenic contamination in Bangladesh ... 5
1.1.2 Chemical properties of Arsenic ... 6
1.1.3 Problem with mitigation options ... 6
1.2.0 Relevance ... 7
1.2.1 Social relevance ... 7
1.2.2 Scientific relevance ... 7
1.3 Research question ... 9
1.4 Research approach - Towards an integrative assessment tool ... 9
2.0 The integrative assessment tool ... 10
2.1 Schematic overview of the tool ... 10
2.2 Justification of the integrated assessment tool ... 12
2.2.1 Step 1: Identification of the problem ... 12
2.2.2 Step 2: Characteristics of location ... 12
2.2.3 Step 3: Identification of mitigation options ... 13
2.2.4 Step 4: Integration disciplinary research ... 19
2.2.5 Step 5: Project feasibility ... 23
3.0 Discussion ... 24
3.1 Common ground ... 24
3.2 Assumptions and limitations of design ... 26
3.3 Reflection on the tool ... 28
4.0 Conclusion ... 29
5.0 Acknowledgement ... 29
Foreword
This research is commissioned by the Institute of Interdisciplinary Studies at the University of Amsterdam. It is the final course of the Bachelor track Future Planet Studies. In the course of this research we have obtained helpful insights in interdisciplinary research and gained knowledge on an interdisciplinary research process and teamwork that is involved in tackling complex problems. This course integrates previously obtained interdisciplinary skills and provides a clear and helpful contribution to the problem that is addressed within this research.
1.0 Introduction
The introduction consists of the problem definition, relevance, research question and approach. First, a short overview on the arsenic contamination problem in Bangladesh is given, followed by a description of the study area. Subsequently, a more in depth analysis of arsenic and its chemical properties is provided. Then, while outlining the problems with current arsenic mitigation methods, the extent of the arsenic problem in Bangladesh is illustrated. Finally, the tool is presented and discussed.
1.1 Problem definition
Arsenic contamination of drinking water is a major public health issue in Bangladesh (Ng et al., 2003). The World Health Organisation (WHO) recognizes this threat and has set a standard of 10 µg/L arsenic concentrations in drinking water. Yet, many developing countries allow higher concentrations of arsenic. In Bangladesh the arsenic concentration that is allowed in drinking water sources is set out in the Bangladesh National Standard (BNS) at a value of 50 µg/L. In Bangladesh, arsenic concentrations in groundwater can vary from < 1 up to 4700 µg/L. In the past the Worldbank and UNICEF supported and funded the instalment of groundwater tube wells to reduce shortages of safe drinking water. Thereby, the use of groundwater increased tremendously and currently provides 95% of the drinking water. However at the time no measurements were taken to check for arsenic contamination of the groundwater. Since the groundwater is the major source of drinking water in Bangladesh and this water is heavily contaminated with arsenic, it is the cause of a mass poisoning involving approximately 50 million people (Ahmad, 2001; Ng et al., 2003). Long-term exposure to arsenic through the consumption of contaminated groundwater can cause various cancers and skin conditions for both animals and humans (Howard, 2003). There is a great need for accessible, arsenic free and safe water. The next section provides a short overview on the study area.
1.1.1 Study area: Arsenic contamination in Bangladesh
The study area of this research covers Bangladesh. Bangladesh lies in the northeastern part of the Indian subcontinent (Alam et al, 2002). It borders India to the west, north and east, Myanmar to the southeast, and in the south lays the Bay of Bengal. The country lies in the largest delta of the world, the Ganges Delta. At the Ganges Delta three large rivers (Ganges, Brahmaputra and Meghna) empty in the Bay of Bengal. Most of the delta lies less than 15 meters above sea level, which makes it vulnerable to flooding and climate change (Alam et al, 2002). The country also has many other water related issues, such as a lack of clean water and unequal water access, pollution and contamination causing diseases and health problems (Figure 1).
Bangladesh is a developing nation in Asia and is one of the poorest countries of the world with a Gross Domestic Product per capita of US $899 (IMF, 2013). Since its independence in 1971 Bangladesh has become a democracy. The country faced many challenges, among them a pollution problem of the surface drinking water sources. The solution was to install and use groundwater tube wells, to create access to groundwater sources that were free from diseases and were not poisoned by waste and chemicals. This solution had already proven itself successful in other countries. Since then the Worldbank and UNICEF funded and supported the instalment of approximately 10 million groundwater tube wells. The first high levels of arsenic in groundwater were identified in West Bengal, India in 1983 (Alam et al., 2002). Because of the geological similarity of Bangladesh and West Bengal it made researchers interested whether cases of arsenic contamination would be present in Bangladesh. The first cases were found in 1986, however due to the limited scope of the research the magnitude and urgency of the problem was not made visible. More research conducted in the 1990’s by the British Geological Survey (BGS) and the Department of Health and Environment (DPHE, 1989) showed that this was possibly the largest mass poisoning in history. Since then the government and several non-governmental organizations (NGO’s) have taken action to identify contaminated tube wells and the amount of people suffering from health related issues. Furthermore, they inform the people about arsenic contamination and try to mitigate the effect by using other options that provide arsenic free water (Hossain, 2006). To be able to use a mitigation option sufficiently, first the chemical properties of arsenic need to be understood. The next section provides information on the chemical properties of arsenic.
Figure 1: Arsenic groundwater contamination in Bangladesh (IIBB, 2013)
1.1.2 Chemical properties of Arsenic
Arsenic is a metal that originates from both anthropogenic and natural sources. In Bangladesh arsenic is mostly of natural origin, which originates from the erosion of natural deposits that occur in groundwater systems of Bangladesh (Ng et al., 2003). Arsenic is the 53rd most abundant element of the earth crust of which it makes up approximately 1,5 parts per million (ppm). In groundwater and aquatic ecosystems arsenic is mainly derived from rocks such as arsenic trioxide (As2O3), arsenic trisulfide (As2S3), arsinidyne (thioxo) iron (AsFeS) and alacranite (As4S4), which weather down and release As(III) and As(V) into the environment (Ng et al., 2003). Concentrations of arsenic are often higher in groundwater compared to surface water since groundwater flows through the bedrock very slowly, thus allowing arsenic levels to build up (Ahmad, 2001). Due to the large use of pumping groundwater through tube wells since the 1970’s, arsenic concentrations in groundwater have been steadily increasing. This is the result of fluctuating groundwater levels around the tube wells, which cause rapid oxidation processes and bedrock weathering (Alam et al., 2002). In addition, the use of tube wells has the effect that a larger part of the population has been exposed to arsenic contaminated water that otherwise would have stayed unaffected from the contamination. The concentrations of arsenic in groundwater have reached alarming levels in Bangladesh and require immediate attention to mitigate further public health effects (Ahmad, 2001; Ng et al., 2003). The next section provides information on the problems with existing mitigation options.
1.1.3 Problem with mitigation options
Since the identification of the problem of arsenic contaminated water in the 1990’s mitigation options have been devised to provide the people with arsenic free water. However, the mitigation options have not had the intended effect yet (Worldbank, 2005). In some parts of Bangladesh they are still non-existent, while in other parts they are often ineffective because they do not sufficiently consider the local conditions, such as the environment, demography, and political or economic situation (Worldbank, 2005). The large variety of mitigation options makes it more difficult to properly assess which option is the most feasible to use in certain conditions. Several mitigation options exist that could provide arsenic free water and they are classified into two groups: mitigation options that use groundwater sources and mitigation options that use alternative water sources (Ahmad, 2001). Arsenic contaminated groundwater could be treated through various large-scale water treatment methods or by small portable filters that can be attached to a tube well. Another option could be to use deep tube wells to pump up arsenic free groundwater from deeper aquifers, where there might be no arsenic contamination. The second group of mitigation options uses alternative water sources. Surface water could be collected and treated through sand filtration in a pond. Another option might be to collect rainwater in storage tanks (Worldbank, 2005). Further elaboration on mitigation methods is provided in paragraph 2.2.3.
Not only technical problems regarding the implementation exist, but also pressures created by the socio-political situation hold back the effective use of mitigation options. Since
the identification of the problem of arsenic contamination in Bangladesh, the government has failed to address it sufficiently. The government effectiveness is low due to the dysfunctional nature of national and local government. The main issues involve bureaucracy, corruption, patronage, clientelism, widespread intimidation, inadequate funds and a limited administrative capacity (Atikins et al, 2007a; Atikins et al, 2007b; Hossain, 2006). Central coordination failed and there is a lack of clear strategic plans (Alam et al, 2002). Policymaking is slow and implementation even slower (Atikins et al, 2007b). There is a lack of reform due to lobbying of small powerful rich groups, such as the landowners. This issues caused stalled development. There are weaknesses within and between governmental bodies (Rammelt & Boes, 2004). National parliament fails to find common agreements within a reasonable time. The Department of Public Health Engineering has responsibility to improve the public health but has little funds (Atkins et al, 2007b). At the local level there is an absence of devolved power. The state is incapable and reluctant to address problems; this leads to effective absence of the state, with NGO's taking over the role of the government in many areas of Bangladesh (Atkins et al, 2007b). However actions of NGO's have also not been effective in providing arsenic free water for all users.
1.2.0 Relevance
The magnitude of the problem and the technical and socio-political problems encountered when trying to solve the problem, imply there is a strong social and scientific relevance.
1.2.1 Social relevance
Arsenic poisoning in Bangladesh is the largest mass poisoning of a human population in history (Smith, Lingas & Rahman, 2000). The consequences of long-term exposure to arsenic are severe. First, arsenic contamination causes several health problems that include various cancers and skin conditions (Howard, 2003). It is estimated by the Worldbank (2005) that every year around 2.5 million people suffer from arsenicosis cases in Bangladesh. Second, health problems from arsenic contamination lead to a decreased labour force with lower efficiency, that has less welfare capabilities and chances to improve (Worldbank, 2005). Third, the lack of improvement of the arsenic contamination problem results in decreased trust and confidence in the capacity to solve the problem by the government and NGO’s (Rammelt, 2009). It is clear that there is a strong social importance to find adaptive solutions for the problems relating arsenic contamination in Bangladesh. At the same time there is a strong scientific relevance to conduct this research.
1.2.2 Scientific relevance
Despite the availability of more than 50 techniques to mitigate arsenic contamination, mass poisoning continues (Alam, 2002; Hossain, 2006). There is no single technique that is in every situation and under every circumstance applicable. Therefore, for each location an assessment
should be made of the existing mitigation options to identify which option or combination of options would be the most feasible. However, there are still many knowledge gaps about how to select mitigation technologies for decision-making purposes (Hossain, 2006). While previous research has mainly focused on improving existing mitigation methods, this research instead focuses on identifying criteria on which existing mitigation methods could be assessed most effectively. Developing an integrated tool has not been done before, while at the same time it provides an opportunity to find common ground between disciplines that otherwise might not have occurred.
1.2.2.1 Justification of research
From literature studies it appears that the usual approach to the problem of arsenic contamination is improvement of one of the several available techniques. This research adds to the existing literature because it makes the essential distinction that every contaminated site should be evaluated individually to assess which mitigation method is the most feasible. Furthermore the interdisciplinarity of this research contributes to the usefulness for other research.
1.2.2.2 Justification of interdisciplinary
To date no single discipline has been able to provide an effective way to make a water treatment assessment that includes and integrates a wide variety of local conditions. Furthermore, due to the complex nature of the arsenic contamination and the multiple stakeholders involved, interdisciplinary integrated research is not only desirable but also necessary (Repko, 2012; Hossain, 2006). The disciplines that are involved to create the tool and evaluate the most feasible mitigation option are Earth Science, Economics and Political Science. These disciplines are required to assess the problem of arsenic contamination with a broad perspective and come up with an integrated solution. Earth Science is required to understand the natural processes and dispersion involved in arsenic contamination. Furthermore, the technical aspect of Earth Science is needed to understand the various biogeochemical reactions that are part of the water treatment methods. Economics is required to make a quantitative and qualitative valuation of the key-criteria used to assess the water treatment methods. Subsequently, the qualitative and quantitative data is aggregated to form a Cost Benefit Analysis (CBA) for the water treatment methods. Political Science will provide an understanding of governmental processes and institutional actors such as the WHO, UNICEF and Worldbank. Governmental processes and national policies about water availability and quality are focused on a wide range of users concerning different national interests, from the public health to the economic development of industries and ensuring food security. Knowledge from economics will provide the bridge between what is technically possible and politically feasible.
1.3 Research question
In order to obtain what is technically, economically and politically feasible this research focusses on finding key-criteria for policy makers in Bangladesh to address the right questions to make arsenic mitigation policy. The research question is as follows:
What key-criteria are required to provide a guideline in arsenic mitigation policy making in Bangladesh?
Key-criteria are the most important aspects that need to be taken into consideration by policy makers when assessing the most feasible method at a specific location in Bangladesh. Combining the key-criteria and local conditions a guideline can be provided. The guideline is a step-by-step approach in the form of a tool, that provides policy makers with steady and comprehensible guidance. Arsenic mitigation is the reduction of arsenic concentrations in groundwater to provide safe drinking water according to the Bangladesh National Standard. Policy making describes the decision-making processes that policy makers go through, to result in implementation of a certain water treatment method.
1.4 Research approach - Towards an integrative assessment tool
There is a great need for clarity and comprehensibility about arsenic mitigation in Bangladesh (Worldbank, 2005). To answer the research question and provide clarity about this problem an interdisciplinary approach is used. Based on extensive literature studies key-criteria are identified in the three associated disciplines. The key-criteria are criteria that are absolutely necessary to take into account when assessing what treatment method is most feasible on a specific location. After identifying the key-criteria they are matched and connected depending on their cohesion and logical succession. With logical succession is meant that some criteria must be assessed prior to other criteria. The tool is the final product of interconnecting all key-criteria. However, the key-criteria are chosen based on the literature research of this report. It might be the case that important key-criteria are missing due to subjective and incomplete use of literature. Besides this, the tool is a representation of reality and therefore subject to assumptions. In this case 3 assumptions are made. It is assumed that the tool represents reality to such an extent that it can improve reality. The second assumption, on the CBA, states that all values can be quantified. The last one assumes that a Willingness to Pay (WTP) study can indicate social support for a certain mitigation method.
2.0 The integrative assessment tool
Policy makers may use this tool in the case of a situation in which As(III) and As(V) concentrations exceed BNS. The tool functions as a guideline to assess a specific arsenic mitigation method in a specific location or region of the country through an integrated approach. The integrated approach considers many aspects as will be discussed in the next sections. In this paragraph first a schematic overview of the tool is presented, with a description of the tool from step 1 to step 5. Step 1 specifies identification of the problem. Step 2 integrates characteristics of the location. Step 3 specifies a mitigation option that brings arsenic concentration levels down to BNS. Step 4 integrates environmental impacts, financial capabilities and the socio-political situation in order to find common ground for the mitigation method and determine whether it is feasible. Before the next step can begin, it is needed to evaluate whether the chosen mitigation option is a feasible method. If the mitigation method does not appear feasible the tool loops back to criteria that may be responsible for failure of the mitigation option or loops back to step 3 in which a different mitigation option could be chosen. Step 5 presents the project outcome. If the project appears to be feasible from step 4 it is ready for implementation, which is represented by step 5. The tool is based on a theoretical framework that focuses on the theories of location characteristics, CBA, stakeholder analysis and WTP. These theories are explained in the justification part of the tool. The focus on these theories is determined after an extensive literature review for which numerous scientific articles and books are consulted. Biased interpretations are avoided by consulting different authors and referring to all disciplines equally. While reading the literature the central focus kept in mind are the key-criteria needed for the guidelines. This has been the point of departure for our literature review.
2.1 Schematic overview of the tool
A schematic overview of the tool is provided in figure 2. The tool should be read by starting at the top at step 1 and continuing until step 5, indicated by the uninterrupted line. The tool provides the order in which all the key-criteria should be considered. While the tool generally should be read from top to bottom, there are several feedback mechanisms in place that allow the user to make evaluations when necessary. These feedback mechanisms are indicated by the interrupted lines. On the right side of the tool the associated paragraphs are indicated, referencing to the appropriate paragraphs in the text. The key-criteria that are displayed in this tool are the requirements for the guideline in arsenic mitigation policy in Bangladesh.
2.2 Justification of the integrated assessment tool
This section elaborates on step 1 to step 5 and provides a justification of options, aspects and decisions made, which the tool is founded upon (figure 2). Furthermore, this section will elaborate on all key-concepts that were identified and used in the tool.
2.2.1 Step 1: Identification of the problem
Policy makers may decide to use this tool if As(III) and As(V) concentrations exceed BSN of 50 µg/l. From a population density measurement in 1998 it appeared that 21 million people were exposed to arsenic concentrations above 50 µg/l. However, if the measurement were adapted to the WHO standards of 10 µg the number of people exposed would approximately double (Smith, Lingas & Rahman, 2000). Opposed to WHO standards (10 µg [As]/l) BNS is chosen since this standard seems more feasible to realize in Bangladesh. While BNS might not be entirely protective of human health (Morales et al., 2000), reaching BNS concentrations will greatly increase the quality of life in Bangladesh. However, when enough capital is available the WHO standard could be applied to improve upon the BNS, reducing arsenic poisoning even more. Once the threshold of 50 µg [As] is reached step 2-5 identify essential aspects that need consideration for project success.
2.2.2 Step 2: Characteristics of location
After the problem is identified and the arsenic concentration indeed exceeds BNS, further specification is required on the location. Location is split into three characteristics; geography, physical soil characteristics and demography. These characteristics provide a sufficient and comprehensive coverage the location (Howard 2003).
2.2.2.1 Location and geography
Geography describes the accessibility of the site, entailing available infrastructure and remoteness of the site and how suitable the land is for specific mitigation techniques. Poor infrastructure and remoteness may increase project cost considerably. In addition, mountainous or swampy land may result in harsh conditions, which raise operational cost. Finally, the available land in square meters should be known. Different treatment methods require a different amount of space. If there is not enough space for a certain treatment method initially, it might be a viable option to deforest an area. However this will increase the economic and environmental costs.
2.2.2.2 Location and physical soil properties
Physical soil properties incorporate arsenic concentration in the soils where water is being extracted. The exact arsenic concentration is required to distinguish between treatment methods. Arsenic concentrations up to 200 µg/l can be purified with precipitation or mitigation methods such as slow sand filtration or pond filtration. Higher concentrations require membrane, oxidation or adsorption processes.
pH is of significance for the efficiency of precipitation, adsorption and oxidation treatment processes, which require pH conditions ranging between 1 and 7.5 for optimal removal efficiency (§2.2.3.1-3; Kartinen & Martin, 1995). However, even when the pH is not optimal chloride can be added to the water to decrease the pH. This leads to higher removal efficiency, but also to increased costs due to chemical requirements and waste production and treatment.
Furthermore, other chemicals being present in the soil that may induce (other) health effects (Howard, 2003). While this research focuses on providing a tool, which determines which method is most feasible to remove arsenic, other chemicals in the water might also be harmful, thereby negating the removal of arsenic. Therefore, it is important to screen and examine the source water initially. The considered treatment methods can all remove most heavy metals. However, the removal efficiency of membranes decreases with the presence of other metals.
2.2.2.3 Location and demography
The demographic aspect represents how much water is needed in water demand [m3/day] and how large the area is that needs to be provided with the treated water in population density. Water demand has strong implications about what treatment method to use, since the discharge of each treatment method differs. Depending on the community size, different methods might be most feasible. Population density has implications about whether a method has to be found for a rural or an urban area. For a rural area more scattered small-scale treatment plants are required, as opposed to an urban area where water demand and population density are high. Together the geographical, physical and demographic aspects of the site form the initial conditions that need to be considered for choosing an arsenic mitigation method at a specific site.
2.2.3 Step 3: Identification of mitigation options
Once initial conditions are identified a mitigation method needs to be defined. §2.2.3.1-8 presents descriptions of eight most applied arsenic mitigation methods. These methods have been identified through extensive literature review (Han et al., 2002; Jain & Ali, 2000; Kartinen & Martin, 1995; Khan et al., 2000). According to Ngai et al. (2008) more than 50 treatment technologies exist worldwide. In general, these methods are capable of providing sufficient and acceptable services under the correct circumstances. The challenge for Bangladesh and other countries dealing with arsenic contamination is to determine which method is most suitable for their specific set of circumstances (Kartinen & Martin, 1995). Four overarching and seemingly most mitigation theories have been identified. The overarching theories that will be studied in this research are precipitation, reversed osmosis, adsorption and oxidation. Following, eight important mitigation methods are discussed; precipitation, adsorption, oxidation, membrane filtration, slow sand filtration, tube well, pond sand filtration and rainwater harvesting.
2.2.3.1 precipitation
Precipitation is a natural process. Precipitation is the formation of a solid by adding a precipitant to a solution, causing a chemical reaction. Specific precipitants can bind to arsenic and then the
conglomerate can then be removed by centrifuging the solution, since the precipitate will descend to the bottom (Han et al., 2002).
Present-day precipitation is still used as a water treatment method. Four precipitants are commonly used to remove arsenic from water: aluminium, iron, lime, and manganese. These precipitants are most effective based on the pH of water and should be used accordingly. Aluminium can best be used if the pH of the water is lower than 6,5, iron if the pH is between 6 and 8, manganese for a pH higher than 7 and lime softening for a pH larger than 10,5 (Kartinen & Martin, 1995). Moreover, with the addition of chloride, the removal of arsenic can be increased even further. Precipitation with these four precipitants leads to the formation of insoluble arsenic, most commonly in the form of Al(AsO4), Fe(AsO4) or Mn(AsO4). Due to the insoluble nature and density of these chemicals they can easily be removed from the water.
The addition of iron (Fe2+) can also lead to co-precipitation, which is the incorporation of soluble arsenic (As3+ and As5+) into the metal hydroxide flock. Co-precipitation actually combines both precipitation and oxidation, since the Fe2+ oxidizes to Fe3+ and eventually forms ferric hydroxide (Fe(OH)3). Because both iron and arsenic precipitate in this reaction it is called co-precipitation (Johnston & Heijnen, 2001). Co-precipitation often occurs by the following chemical reactions:
2 H3AsO3 + H2O > 2 H3AsO4- + H2 2 Fe2+ - 2e- > 2 Fe3+
2 Fe3+ + 6 H2O > 2 Fe(OH)3+ H2
2 FeOH3 + 2 H3AsO4- > 2 FeAsO4 + 6 H2O
The FeAsO4 that is created during these reactions is actually a solid and can easily be removed from the solution by centrifuging (Johnston & Heijnen, 2001).
2.2.3.2 adsorption
Adsorption is a sorption process in which an adsorbate is selectively transferred from a fluid phase to the surface of insoluble, rigid particles suspended in a vessel or packed in a column (Essington, 2003). Activated alumina is an adsorbent that can remove arsenic and has also been used to reduce undesirably high fluoride concentrations. It is made of aluminum oxide (Al2O3), a highly porous material with a surface area over 200 m2/g. Nowadays it is used as a desiccant and as a filter of fluoride, arsenic and selenium in drinking water. Activated alumina is a water purification technique that has already been effectively put into operation in Bangladesh for several years. Most remarkably is that through the efforts of community-elected water committees taxes have been raised for funding operations and maintenance. Hence, long-term performance has been possible. The technique has proven itself to effectively remove As(III)as well as As(V) (Kartinen & Martin, 1995). However, with activated alumina toxic arsenic waste or ‘sludge’ is produced, which has to be dealt with.
2.2.3.3 oxidation
Recently, a new technique has been developed by a consortium of European & Indian scientists led by Dr. Bhaskar Sen Gupta, OBE from Queen’s University Belfast, which is based on in situ treatment. This Subterranean Arsenic Removal (SAR) method does not use any chemicals and produces little waste. SAR uses the concepts of oxidation and filtration of conventional surface treatment plants for removal of iron and manganese from water but also uses enzymatic oxidation of As(III) to insoluble As(V). Iron, manganese and arsenic compounds are rendered inactive in the aquifer itself.
In water treatment, oxidation processes refer to a set of chemical treatment procedures, developed to remove (in)organic materials in water and wastewater through reaction with hydroxyl radicals (OH-). Oxidation reactions entail chlorination, ozonation, UV irradiation, electrochemical treatment and processes based on OH. An acidic pH improves the oxidation process (Rashed et al., 2005). However, excessive oxidation processes may result in arsenic and iron precipitation rather than adsorption. In addition, abrupt changes in redox potential may disturb existing bacterial populations, which may have uncontemplated effects.
2.2.3.4 membrane filtration
Reverse osmosis and electro dialysis are the most commonly used filtration methods and considered the most effective processes to reduce arsenic concentrations in drinking water (Han et al., 2002; Jain & Ali, 2000). In 1987 reverse osmosis and electro-dialysis were used for municipal water treatment (Khan et al., 2000). These techniques are still being used present-day.
Reverse osmosis and electro-dialysis are based on the theory of membrane separation, and osmosis. For reverse osmosis pressure is used to force the water through the membrane, leaving the dissolved chemicals on one side of the membrane and purified water on the other side. Electro-dialysis uses an electric current to draw the dissolved solids through the membrane. A negatively charged electrode attracts the positively charged arsenic. Reverse Osmosis can be divided into nano-filtration and hyper filtration. Nano filtration is a reverse osmosis process, which requires relatively low pressure, whereas hyper-filtration requires high pressure (Kartinen & Martin, 1995). Nano-filtration removes primarily the larger dissolved solids compared to hyper-filtration. Reversed osmosis is more effective at removing As(V) than As(III). 97% of As(V) can be removed with reversed osmosis, whereas only 40 to 80% of As(III) can be removed (Han et al., 2002). An oxidizing agent can be used to convert As(III) to As(V), this way a substantially larger amount of arsenic can be removed (Kartinen & Martin, 1995). However these oxidizing agents, such as chloride, are harmful to the membranes used in Reverse Osmosis. Moreover, post-treatment is necessary to provide safe drinking water, since reverse osmosis generally removes too much nutrients and other particles from the water (Han et al., 2002). As with the reversed osmosis, electro-dialysis also removes more As(V) than As(III) and post-treatment is required to meet drinking water standards. However, with the addition of chloride, arsenic reductions of more than 95% have been achieved in tests (Kartinen & Martin, 1995). For a conceptual overview of both water treatment methods see figures 3 and 4.
Figure 3 (left): The process of reverse osmosis requires that the water be forced through a semi-permeable membrane (APT, 2013)
Figure 4 (right): Schematic view of the flow within the process of reverse osmosis (Prato & Gallagher, 2013)
In the following paragraphs (2.1.4.4 to 2.1.4.7) descriptions are given of several mitigations options instead of treatment methods. These mitigation options are usually a lot cheaper than the water treatment methods, but can only be used on a small scale. For instance a pond may be household based, and a single tube well can be used for a small community.
2.2.3.5 slow sand filtration
Slow sand filtration is a physical and biological mitigation option that uses a complex biological film that grows on the sand layer naturally. The sand layer itself acts as a substrate for bacteria and fungi and performs a filtration function (Huisman, 1994). Slow sand filters are non-pressurized systems and do not require any electricity or chemicals to operate. However, slow sand filters need low turbidity to efficiently operate (Howard, 2003). A slow sand filtration system normally consists of a tank with a layer of sand on top of a layer of gravel. Water is filtered through the sand and gravel and the contamination can be adsorbed or chemically altered by microorganisms residing in the sand. At the bottom of the tank an outlet valve is located through which purified water comes through (Huisman, 1994; Howard, 2003). See figure 5 for a schematic overview of slow sand filtration.
Figure 5: Schematic overview of slow sand filtration (NESC, 2013)
Slow sand filtration was first used as a municipal water treatment method in 1829 in London (Howard, 2003). Typically, a slow sand filtration tank is 1 to 2 meters deep and is primarily used to purify surface water. However, using pumps or tube wells, groundwater can be inserted in the tank and treated by slow sand filtration (Huisman, 1994). Slow sand filtration usually produces 0.1 to 0.2 cubic meters per square meter per hour. While, slow sand filtration does not produce water on demand, like other water filtration technologies it rather produces a slow, constant flow of water (Howard, 2003). The slow flow rate is required for the healthy development and degradation of the biological processes in the water filter (Huisman, 1994). Moreover, a storage tank can be used to store water when demand is low and this water can then be used when demand is high (Howard, 2003).
Slow sand filtration can be an appropriate technology in isolated and poor areas, because it requires no mechanical power or chemicals. It makes good use of local materials and skills that are available in many developing countries. In addition, it requires only periodic maintenance. However, due to the low filtration rate, extensive area is required and it might be difficult to provide a large community with enough clean water (Howard, 2003).
2.2.3.6 tube well
Figure 6: Overview of several different tube wells (Feroze, 2013)
Tube wells are the source of arsenic contamination in Bangladesh. However, geologists can easily identify areas without arsenic and then tube wells are a viable option. In Bangladesh the tube wells typically have a diameter of approximately 5 cm and are inserted into the ground to a depth of less than 200 meters (figure 6). Via a cast iron or a hand pump the water can be accessed (Smith, Lingas and Rahman, 2000). Before digging a tube well it is important to screen the source water and determine if the aquifers are easily accessible. Tube wells can be attractive to farmers because of low required investments and suitability for small scale operations (Asian Development Bank, 2004).
A distinction can be made between different types of tube wells. Typically the different types are divided in the following categories: shallow tube well, medium tube well, deep tube well and dug well. Shallow tube wells are drilled into the ground to a maximum depth of 30 meters. The typical capacity of a shallow tube well is 20 to 30 m3/h. Medium tube wells are usually 45 meters in depth. However, depending on the capacity needed and the depth of the aquifer they may be dug deeper. Medium tube wells usually have capacities of about 30 to 40 m3/h. Deep tube wells can reach depths of 400 meters. The capacity of a deep tube well varies between 150 m3/h and 300 m3/h. A dug well is identified as a shallow well where the water from surrounding aquifers accumulates. These wells typically have very limited discharge rates (Alberts, 1998).
2.2.3.7 pond sand filtration
Ponds are similar to slow sand filtration as they both use physical and biological mechanisms for water treatment. Pond sand filters are usually built around artificially constructed ponds (DPHE, 1989). These ponds are replenished during the monsoon by rainwater. Using hand-pumps, water from the pond is pressurized through a pre-filter. The pre-filter can be created from coconut fibres. Outflow from the pre-filter flows to the main filter, which consists of a layered sand bed. This sand bed removes contamination, impurities and bacteria the same way as in slow sand filtration (DPHE, 1989).
The main advantages of pond sand filtration are that its cheap, requires low maintenance and is culturally accepted in Bangladesh. Pond sand filtration can be used to serve a large community and induces community cooperation in the provision of safe drinking water. A major disadvantage is the raw water storage. Because water replenishment only occurs in the monsoon period, the pond must be large enough to ensure it will not dry out in the dry season (DPHE, 1989).
2.2.3.8 rainwater harvesting
Rainwater harvesting can be an efficient and suitable mitigation option to provide clean drinking water in Bangladesh. Rainwater harvesting is a technique practiced since the Neolithic (1000 years ago) all over the world (Boers & Ben-Asher, 1982). Depending on local climate characteristics rainwater harvesting can be a very cheap and effective mitigation option. The only requirements for rainwater harvesting are a collection surface and a water storage tank. Precipitation is simply intercepted by the collection surface and then funneled to the storage tank (Thomas, 1998).
Rainwater harvesting is a good option when rainwater is well distributed throughout the year, when surface water is absent, when groundwater is contaminated or when tube wells are too expensive (Thomas, 1998). The capacity of rainwater harvesting depends on the rainfall intensity and temporal distribution of precipitation in the area. Because Bangladesh is a country affected by the monsoon and otherwise relatively dry periods, rainwater harvesting may not be a year-round suitable option. However, the instalment of large storage tanks may provide clean water for a suspended amount of time.
2.2.4 Step 4: Integration disciplinary research
In this step an evaluation starts, which helps to decide if the chosen mitigation option is likely to be a feasible method for the specific initial conditions. It has been chosen to do a cost benefit analysis prior to the stakeholder analysis and determining socio-political support. This is since stakeholders support a certain treatment method, because they want clean drinking water. However, if the environmental impact is too high, it might not be a feasible method. Therefore, to determine if a mitigation method is feasible in the first place, a cost benefit analysis is done. If the costs exceed the benefits in the CBA the mitigation option does not appear feasible and the tool loops back to step 3 requiring another mitigation method to be evaluated. Every mitigation
option needs to be split into five aspects; efficiency, construction, maintenance, waste production and chemicals. If in reality other aspects appear important, the tool should be used flexible enough to incorporate them. Together, these aspects form the foundation and the input for a CBA.
2.2.4.1 Input for CBA
Five aspects are identified which function as an input for a CBA. Efficiency of the method to remove arsenic is of crucial importance. High arsenic concentrations need a high removal efficiency, to reduce arsenic concentrations to BNS (Kartinen et al. 1995). All water treatment methods have different removal efficiencies, making them useful depending on the initial concentrations of arsenic in the groundwater. However, with efficiency comes costs. The most effective and efficient treatment methods are the most expensive.
Construction of the plant or technical implementation of the method requires financial input, available materials, time and labour. Infrastructure is required for importing required materials and in addition skilled workers are needed to build the plant. This aspect is considered a one-off investment. Construction costs also relate to initial conditions wherein geographical conditions may influence them.
Maintenance contributes to the long-term investment. It considers labour, time, costs and parts of the construction that may need replacement as costs of operation per year.
Waste production and use of chemicals are closely related to each other and together they cover environmental impact. Relative waste production varies with every method and is also influenced by chemicals that some methods need as input for arsenic removal. Together, waste production and chemicals require waste treatment. Together mitigation efficiency, construction, maintenance, chemical input and waste treatment costs are input for a CBA.
2.2.4.2 Cost benefit analysis (CBA)
A CBA determines whether a treatment method improves social welfare (Hanley, Shogren & White, 2001). Social welfare is determined by quantifying the social advantages and disadvantages of the treatment method in terms of a common monetary unit. The discounted difference between the benefits and the costs shows in what degree social welfare is improved (Hanley, Shogren & White, 2001). Besides social welfare, environmental impact should influence the CB, which is not often included. First the valuation of costs and benefits is described. Next the structure of a CBA is explained according to Hanley & Splash (1993).
2.2.4.2.1 Valuation of costs and benefits
After having decided for a specific mitigation method it is essential to perform a cost benefit analysis on this method. Only if benefits exceed costs, next steps can be undertaken. The total costs of implementing a water treatment method consist of two types of costs (Abelson, 1979). First, the costs of resources: The value that could have been produced with any other way of depleting the resources (Hanley, Shogren & White, 2001). Second, the external costs: the indirect costs imposed by the project, like waste or land degradation (Abelson, 1979). The costs
that do not vary between different methods should not be taken into account. The costs of the resources are described by the opportunity costs and the external costs are valued at the minimum amount of compensation required for households to accept the imposition of the cost (Hanley & Splash, 1993).
Usually domestic market prices form the basis of the CBA. Correcting for the divergence between market prices and shadow prices, and establishing the correct prices is a very important part of the method of CBA. Correct prices are called shadow prices and defined by Senante et al. (2010) as a quantification of unwanted output without market value but with negative environmental impact. Also non-market goods have to be quantified for the CBA. In the next section the structure of a CBA is described.
2.2.4.2.2 Structure of a CBA
A CBA is constructed according to a universal structure divided into stages (table 1).
Table 1: Universal structure of CBA
Universal structure CBA
Stage 1 Definition of the project. Stage one includes the reallocation of resources being proposed and an indication of the population of gainers and losers.
Stage 2 Identification of project impacts. In this stage the effects of the implementation of the project are identified.
Stage 3 Which impacts are economically relevant? The aim of a CBA is to find out whether the mitigation options increase society’s utility. It is assumed that these utilities depend on consumption of market goods and non-market good. Therefor the relevant goods should be taken into account.
Stage 4 Physical quantification of relevant impacts. In this stage the physical amount of cost and benefit is determined and identified when in time they will occur.
Stage 5 Monetary valuation of Relevant Effects. In order to be able to compare the impacts of the implementation one unit of account is needed. A CBA’s common unit is money. The prices have to be accounted for social costs and benefits.
Stage 6 Discounting of cost and benefit flows. When performing a CBA costs and benefits occur at different
times, therefore it is necessary to discount the cost and benefits to present value (PV) terms. This is due to time preference: one prefers to receive 100 euro today rather than tomorrow. Time preference is true even if inflation is zero. Choosing the discount rate is one of the decisions that have to be made (Abelson, 1979). Discounting can be done with the discount rate (Abelson, 1979). Most of the time the interest rate is used for discounting. However, the interest rate only covers the demand and supply of money of this generation. If a CBA is made of a project with long-term effects, the discount rate also needs to capture the supply and demand of money of future generations. (Hanley, Shogren & White, 2001).
Stage 7 Applying the Net Present Value test. This stage determines whether the sum of the discounted benefits
exceeds the sum of the costs. If this is the case the project can be said to represent an efficient shift in resource allocation. This method is originating from Hanley & Splash (1993).
If costs exceed benefits the tool loops back to step 3 and a new mitigation method needs to be evaluated. However, if benefits exceed costs the mitigation method is with a high probability desirable. Before an investment plan is set up a stakeholder analysis is required to identify the stakes in arsenic mitigation at the specific site. A stakeholder analysis is helpful because it puts power relationships and a realistic social cohesion situation into perspective. Stakeholders play an important role in the implementation of the mitigation method.
2.2.4.3 Stakeholder analysis
If the CBA turns out to be positive a stakeholder analysis should be done. To assess whether a mitigation option is feasible to use, certain questions arise. Who are involved, what are their interests, and what are their capabilities? These questions could be answered through a stakeholder analysis. A stakeholder analysis is an approach to understand a system by identifying the stakeholders in the system and assessing their respective interests in that system (Grumble et al., 1995). A stakeholder analysis in itself cannot provide answers to problems or guarantee representation (Grimble & Wellard, 1997), therefore it should be used as an integrated part of the overall approach of this tool. There are several reasons to use a stakeholder analysis (Ramirez, 1999): (1) Empirically to discover patterns of interaction, (2) As a management tool in policy-making, and (3) as a tool to predict conflict.
In the tool three main stakeholders have already been identified: government, NGO and community. In reality each of these stakeholders consist of multiple parts, and the specifics of each stakeholder may vary per site. Besides these three main stakeholders there might be other non- or semi-governmental stakeholders, such as research institutes that might need to be taken into account. The stakeholder analysis should be carried out with some flexibility to incorporate such unexpected results. Three main stakeholders are identified; government, NGO’s and communities.
Government
The government consist of different levels. On the highest level there is the national government, parliament and the ministries. Next is the regional government with its subdivisions. Then there are the local government levels and finally there may be government representatives within some village councils (Hossain, 2006). The structure of the parts of the government should be identified. What are the capabilities and responsibilities of each part, who is involved in the decision making process, how have the stakeholders performed in the past, what could be expected of them in the future?
NGO’s
NGO’s also consist of different types. There are large, well-funded international operated NGO’s with large networks that might have more experience with arsenic mitigation options, such as Worldbank, UNICEF or WHO (Hossain, 2006). While there are also other smaller, more local NGO’s with fewer funds, but which might have more expertise about the local conditions. The structure of the NGO’s also needs to be identified.
Government and NGO’s influence create the political support
For this tool it is argued that the identification of the structure of both the government and NGO’s lead to an identification of the overall political support, because when these two main stakeholders have the financial and political capabilities, they are able to implement a mitigation option.
Community
A community is made up of the local people. It holds a number of households and often has a village council. A willingness to pay (WTP) survey could identify what the financial capabilities are of the community, and their willingness to have a certain mitigation option and use it (Ahmad, 2001). Furthermore, it could identify if and how the community is able to help with the construction and maintenance of the technology, through potential village committees. However a WTP does not sufficiently cover the social dynamics and power relations within the community. If it proves necessary the tool should be extended to includes these aspects as well. Still, the extent of the social support can be estimated through a WTP, because the capabilities of a community represent the willingness to have a mitigation option.
2.2.4.4 Investment
Social and political support define the amount of investment capital, capital aggregation and investment distribution. Investment is the total amount of capital that stakeholders are willing to pay for the implementation of a certain mitigation method. While the CBA proved that the benefits are higher than the costs, investment proves that enough money is actually available to implement the mitigation option. Investment is provided by the involved stakeholders and is therefore include after the stakeholder analysis.
2.2.4.5 Economic, political and social feasibility require evaluation
The feasibility of a mitigation method is based on an evaluation of economic, political and social feasibility assessment. The mitigation method only has a chance of success if all three feasibility
pillars are positive; sufficient funding to pay for the technique of arsenic mitigation, sufficient
and effective political support to guide project implementation and acceptance of (local) communities so that the technique will be used effectively and accordingly. Evaluation of the three feasibility pillars enhances project outcome reliability. If one of the pillars is not feasible, certain aspects should be re-evaluated. If it appears that a mitigation method scores positive on the CBA, political support and social support, but there just is not enough capital available for implementation, investment should be re-evaluated. Maybe more stakeholders can be involved that are willing to pay, or maybe foreign NGO’s are willing to invest. However, if it is not possible to gather enough investment for a particular expensive mitigation method, it might be feasible to re-evaluate the chosen mitigation option and choose another less expensive method. However, then it is important to redo the CBA and research political and social support. If it appears that the CBA is positive but socio-political social support is lacking, these can be re-evaluated, and when necessary choose another mitigation option with more preferable support.
2.2.5 Step 5: Project feasibility
The last step is the project outcome. After extensive evaluation on the feasibility pillars estimation on the success of the project implementation can be given. When all three pillars appear to be positive, in other words, when there is enough capital available and there is socio-political support and acceptance, the project is feasible and ready for implementation.
3.0 Discussion
The tool should be used with an open mind, with the acknowledgement that the tool is a simplification of reality that causes various limitations. The tool itself should be viewed as an ongoing process, whereby the use of the tool could lead to new insights. Such new insights should be included accordingly. In this section three main subjects are discussed. First common ground within the tool and this research is discussed. The limitations and restrictions of the tool are connected with finding common ground, and because it doesn't only cover the methodological aspect but also transcends the multidisciplinarity of the problem it is reviewed in the discussion. Subsequently, the assumptions and limitations of design are discussed, and finally there is a reflection of the tool.
3.1 Common ground
In order to integrate the three disciplines and ultimately create an interdisciplinary research, common ground has been found in several ways. A common goal was found by creating a research question that reflects the aim, scope and research area but also its interdisciplinary nature. This common goal leads to communality in purpose, which prevents conflict afterwards. Choosing to build a policy making guideline tool that encompasses a variety of subjects, in itself creates the opportunity to provide common ground. Starting the research, it proved necessary to set off with a common knowledge base, which was accomplished through extensive literature research. To prevent conflict and unclarity, a common scientific language was needed for understanding. Terminology and disciplinary concepts are explained carefully to avoid ambiguity. Thereafter, the disciplinary research was carried out in which common ground was further sought through the acknowledgements of the disciplinary biases, assumptions and research limitations. The disciplinary research provides the information on which integration has been done. During the whole process of creating a policy-making tool, communication has been a key point. The communication and close interaction during the process led to mutual understanding, which avoided conflicts, identified the limitations and in turn has made finding common ground possible. Another key point that was carried out simultaneously with proper communication was the recurrent evaluation of the process and the goal of the research. Evaluation increases finding common ground, because it checks if the process and goal still happens correctly. However, searching for common ground should not be a goal on its own, it facilitates the integration of the disciplines and should not try to force common ground in places where there is none. During the process of creating the tool, the disciplinary results show that the benefits of the disciplines are that they can identify certain aspects that other disciplines cannot. For example, a CBA is able to value environmental impacts in monetary terms, while other disciplines might contest the idea of valuing the environment.
Figure 7: Finding common ground with the research question (RQ)
Instead of focusing on the disciplinary results, common ground was created through identifying key criteria that were found within the disciplinary results. The common ground between the disciplines is shown in figure 7. Earth Science identifies the local characteristics, the different mitigation options and the environmental impact. The information about the mitigation options is necessary for Economics to perform a CBA on. Within Economics it further identifies what the investment need for each method is. Subsequently, based on the result from the CBA Political Science checks if stakeholder investment capacities are sufficient. Further political support is identified through the stakeholder analysis, which encompasses the stakeholders, their interests and their structure. A WTP identifies the social support. Finally, Political Science has the means to gather the information from Earth Science and based on this information implementation can start. The disciplinary results are based upon the disciplinary theories and concepts, such as CBA, stakeholder analysis and WTP. For this interdisciplinary research the integrative technique of organization was used through which the underlying commonality of the disciplinary concepts were defined and organized to bring out their relationships (Repko, 2012).
From the key criteria the interrelations between them were identified, which in turn led to a logical and meaningful order. By focusing on the clarity, purpose and overall usefulness of the tool, common ground was found simultaneously. In figure 7 common ground is presented between the economic costs and benefits of a mitigation method and the environmental effects
since they are intrinsically intertwined and should be valued similar in importance. Furthermore common ground can be found when benefits are greater than costs; in that case the CBA indicates which amount of money is needed. Subsequently, the stakeholders provide capital and have a say in how the money is spend. Here Economics and Political Science meet. Common ground made it possible to design a integrative tool encompassing all tree disciplines.
3.2 Assumptions and limitations of design
Several limitations of the design of the tool exist. A schematic overview, such as the tool, is intrinsically a simplified representation of reality and therefore subject to assumptions. It is assumed that the tool represents reality to an extent that it can provide an answer that might improve reality. The key-criteria that are considered relevant for covering the complete arsenic mitigation dilemma are chosen based on extensive literature research. However, the selected criteria remain an interpretation of reality as well as the succession and interconnection of these criteria. Within the tool, several assumptions have been made and limitations of design arise. These are discussed below.
In step 1 of the policy guideline tool a threshold is set at the BNS. This standard is considered to provide healthy levels of arsenic concentration within the drinking water in Bangladesh. However, according to Morales et al. (2000) this standard is not sufficient to protect public health. Therefore, a new standard of 10 µg/l has been set by the WHO. However, taking socio-political aspects of Bangladesh into account, the policy guideline tool proposes that this standard is not likely to be achievable in any near future, therefore the BNS is chosen. For achieving BNS the location characteristics is one of the important aspects.
The most important characteristics of the location have been identified, based on extensive literature research. While it is assumed that these characteristics provide a sufficient representation of the research a specific location, it should be noted that the research is an ongoing process, open to suggestions and users should be able to make adjustments to the characteristics. Such additional characteristics should be added if they provide additional accuracy and functionality to the tool. In addition, supplementary mitigation methods could also be added if proven useful.
Eight mitigation options have been identified as the most feasible methods to be used in Bangladesh. However, more than 50 methods are available worldwide. These methods are not included in this research, but might be more feasible than the included methods for a specific location. That being said, the included methods have been chosen to support a broad range of arsenic concentrations, locations, socio-political structures and financial costs and all eight mitigation methods together should be able to cover the arsenic contamination problem.
Several assumptions have to be made to include environmental effects. It is difficult to predict the exact environmental effects of a specific mitigation method on the surrounding area. This is because there is a strong relation to local hydrological regimes and geomorphology. Furthermore, especially referring to changes in redox-potential in the ground, a lot of environmental effects are still unknown.
Another assumption is made for the CBA. It is assumed that it is possible to quantify everything and express the quantified values in monetary terms. Also market goods price need to be revised for a CBA. Market prices would only work if the market price would represent the true value of the goods and services. This is only the case if the law of supply and demand operates freely, which is not the case due to taxes, subsidies and asymmetric information. Also external effects need to be integrated to cover the true price. The price system is distorted and does not represent true values of the products. To obtain the true social costs and benefits the market prices should be corrected. (Abelson, 1979).
Furthermore, it is assumed that through a stakeholder analysis a sufficiently representative group of stakeholders could be identified without neglecting the complexity of reality. There are several critics that have identified shortcoming and various limits of a stakeholder analysis. An overview of the literature by Fassin (2009) on stakeholder theory shows that the stakeholder concepts are referred to in confusing ways. First, the widening range of application of the stakeholder concept has raised confusion and ambiguity. Second, there are clear ambiguities in the literature on the basic stakeholder concepts: stakeholder theory, stakeholder approach, and stakeholder analysis. Third, there is a lack of clarity and consistency in the definition and identification of a stakeholder and its interest. However there has been a general consensus that the stakeholder concept has to possibility to be usefulness for management practices. In addition, the difference in the use of the concept ‘stakeholder’ also causes confusing (Fassin, 2009). The use of a broad view on stakeholders, in which any individual or group can affect or be affected, needs to take all stakeholders into account, which is not likely to be possible. Due to globalization and improved communications there is a great increase of the amount of stakeholders, because virtually everyone and everything, everywhere, can affect or be affected by the decisions and actions of a other stakeholders. However, the use of a smaller view such as the legal interpretation, that focuses only on claims of stakeholders might lead to leaving essential details out of the analysis. When the most important stakeholders have been identified, their willingness to support a mitigation method can be researched.
To research whether there is social support, it is suggested that for each mitigation option a WTP should be conducted. The assumption that is made is that a WTP is an indication for social support. However, a WTP does not sufficiently include the underlying power relations within a community. Some poor people might give socially desirable answers in a WTP. It should be noted that the power relations between the stakeholders are of importance, since they influence the effectiveness of an mitigation option. Therefore, another theory should be included to the tool to understand these power relations. For example, a theory from social geography might cover this knowledge cap.
