The voices of the Forum
Session FT 3.28
Strategies and technologies for arsenic and fluoride mitigation from drinking water
U.S. Geological Survey
Universidad Autónoma de San Luis Potosí
The natural occurrence of arsenic and/or fluoride in sources water used for drinking is globally widespread. The WHO has established water standards of 0.01 mg arsenic/liter and 1.5 mg fluoride/liter (US EPA fluoride standard is 4 mg/liter), yet millions of people worldwide are subjected to chemical concentrations above these levels through their drinking water or through food irrigated with water containing high concentrations of these chemical constituents. Many factors affect the occurrence and bioavailability of these toxic chemicals. Among these are their geologic and hydrologic distribution, chemical speciation, the presence of microbial and other activating constituents. Efficacy of mitigating the bioavailability of these toxicants includes mapping their occurrence and understanding the geohydrologic, geochemical, and microbiological processes which affect their release to the water supplies, and applying adequate controls. Regardless, withdrawn water must be monitored for chemical constituents in water used for drinking, cooking, and bathing, and for irrigating food crops.
- Develop a cohesive strategy for identifying the occurrence of toxic concentrations constituents, monitoring toxic concentrations for bioavailability, and applying appropriate mitigation technologies;
- Adopt general principles on water quality and safety for enhancing safe water coverage to meet MGD 1 (food security and safety) and MDG7, Target 10;
- Plan and implement a credible strategic response at the country/regional level;
- Develop a well-designed information management system, including use of GIS, on water quality surveillance at national and district levels that can provide the platform for affected counties to share and learn from successes and experiences;
- Develop and promote appropriate water technologies to realize the communicated information at effective levels;
- Create an enabling environment for access to safe water by the poor;
- Recognize and build the capacity of women, the main managers and users responsible for drinking water, through effective programs;
- Educate and train technicians and farmers to operate communal mitigation systems;
- Consider environmental impacts of mitigation, such as optimal sludge disposal;
- Address potential risk of exposure to arsenic through food crops grown on soils contaminated by arsenic-laden irrigation waters. For example, rice is a staple crop for the Asian region and is consumed in large quantities (450g per day in Bangladesh) which could add to the body burden of arsenic if the rice is irrigated with arsenic-laden waters.
- Less well understood but potentially more serious to food security is the risk of arsenic accumulation in soils irrigated with arsenic-laden waters, thus exposing food crops to potential high arsenic uptake.
- Effectiveness of UNESCO-IHE technology for complete and consistent removal of arsenic irrespective of its speciation and concentration (within the range common for groundwater use) is demonstrated under laboratory and field conditions;
- UNESCO-IHE innovative arsenic removal technology is resulting in very limited production of waste in comparison to other commercially available arsenic removal technologies;
- Life cycle cost analysis that includes all investment, operation and maintenance costs, as well as handling and disposal of waste generated show that this innovative arsenic removal process is highly cost attractive;
- Family filters can be produced locally with UNESCO-IHE technological support; and
- Family filters are well accepted by the population as use and maintenance are easy. REGARDLESS,
- Appropriate effective, efficient, preferably low-cost, arsenic removal technologies are urgently required. Technologies should be properly developed, and then promoted to avoid confusion at the community level.
- Seek greater involvement of key stakeholders (especially women, responsible for domestic water retrieval and use) in surveillance and mitigation response;
- Children, with fragile developing physiologies, are most severely impacted by arsenic and fluoride toxicities. There is an urgent need to educate all stakeholders, at all levels, to the severity of the problems affecting children;
- Develop appropriate and affordable toxic constituent mitigation technologies, with sufficient capacity, to ensure safety of drinking and irrigation water (For example, despite all efforts to date, the Bangladeshi government has yet to approve use of a single technology for arsenic mitigation);
- Adopt rapid water quality assessment protocols that will effectively address water quality surveillance at the national and sub-national level, using techniques that provide reliable periodic assessments of the water quality situation at point-of-source and point-of-use;
- Many drinking water technologies are available on the market, though it is not easy to make a (good) choice; further, the scale of treatment for agricultural, primarily irrigation, purposes poses even greater difficulty. Some counties are already using tested procedures to accredit some of the technologies. As these procedures are under development, timely results are not always transparent. Further, it is clear that efficiency is lost if each country develops own procedures, often with similar technological results. This diverse approach contributes to delaying installations of filters in countries which need them, and it is not to the benefit of the people. Nonetheless, the differences in quality of water at the local levels should not be ignored – standards of water quality need to be established and implemented;
- To expedite the implementation process, as best practices can lead to appropriate actions, the organizations involved in the Session should contribute to developing a common testing procedure to be used as a basic document which all counties could use to define and remedy their own mitigation procedures. The organizations involved in the Session should contribute to developing such a procedure in preparation for acceptance by international organizations;
- Arsenic has not only health implications from use of drinking water, but also poses additional risks from consumption of crops irrigated with arsenic-contaminated waters;
- It is important to assess current and future risks derived from arsenic in the food chain in agricultural areas where high arsenic concentrations have been reported. Risks, using standard technologies, still need to be quantified;
- Expand R&D to understand the bioavailability of arsenic, the safe level of arsenic in irrigation waters, soils and crops under prevailing cropping systems – in terms also of crop yield and quality;
- Adequate mitigation options and arsenic management technologies need to be developed and refined to meet varying environmental conditions.
Orientation for action
- Identify major national, regional and sub-regional water quality problems in the country situation analysis;
- Address the specific physiologic needs of children with regard to toxicity abatement;
- Work with global national counterparts on selection of basic parameters for community-based water quality mitigation and monitoring;
- Provide technical assistance for establishment of national standards on water quality, if not yet in place;
- Provide support to educate technicians, women (responsible for domestic water retrieval and use), and farmers within communities to test and monitor for toxic constituents in municipal, domestic, and rural water supplies;
- Support projects or activities aimed at building community capacity in water quality surveillance, e.g., water testing and problem reporting mechanisms;
- Facilitate collection of water quality information and sharing of mitigation experiences among countries with similar problems;
- Provide support for R&D of appropriate technologies; for example, it is clear that continued research is needed to understand pathways of arsenic/fluoride from the environment to the human being: geohydrolgy and chemistry of drinking water and irrigation water, and the food chain pathways, that is, water, plants and animals, to the human consumer. Understanding the pathways will allow researchers to devise means to find ways to prevent the movement of the contaminant to the humans. For example, rice strains that will not uptake arsenic or means to pump groundwater that will avoid the dissolution of fluoride. ;
- Resource mobilization is needed, in the multidisciplinary context, for the agricultural sector in assessing and mitigating arsenic-related risks;
- Study details of vertical variation of arsenic and fluoride concentrations to identify aquifers with less fluoride concentrations so that aquifers with high toxic constituent concentrations can be restricted from use;
- Recharge, where possible, aquifers with high concentrations of toxic constituents with high quality surface waters to facilitate dilution;
Investigate alternative sources of drinking water, including harvesting rainwater and treatment of surface waters;
- Educate to link arsenic and fluoride issues with the promotion of health and sanitation; and
- Develop and maintain a global database containing information on geohydrologic occurrence and bioavailability of arsenic and fluoride, contaminant standards to meet health objectives, and appropriate mitigation technologies (Problem: The abundant information developed to date on arsenic and fluoride toxicity and mitigation is confusing. A central database identifying technologies, where they used, and by whom, will greatly facilitate government accreditation and implementation of effective technologies).
- Arsenic/Fluoride Removal Technology validation. There are many criteria that have to be met in order to successfully design, test, validate and introduce removal technology in any particular country. Since the legal responsibility for any adverse affects of the technology ultimately reside in the country, it is important that the individual country satisfy itself concerning the efficacy of the technology. On the other hand, international testing through organizations such as UNICEF and WHO may help to speed the process of introducing the technology.
- Arsenic/Fluoride Removal Technology. There are competing methods that have been developed. A critical look at the methods is needed. If it hasn’t already been done, a standard should be developed including a consideration of human safety and environmental disposal of any waste products. Such an international standard would become the minimum acceptable standard for manufacturers to meet in the design of technology.
- Strategies for efficiently introducing effective technologies to enable local actions. There will be a huge investment needed to introduce either household based or community based arsenic or fluoride removal systems. For example it has taken Bangladesh more than 6 years to screen 11000000 tube wells. This was a massive undertaking!!! After a mitigation technology is devised, it will take another huge investment to introduce the technology and to train people and communities to use it properly.
- Focus efforts. Design an international effort with a time line and milestones perhaps led by UNICEF and WHO to systematically assess the state of the art understanding of arsenic and fluoride pathways, technological methods to treat the waters and strategies to efficiently introduce such methods in the household or community.
- Do not neglect use of the volunteer youth sector to promote strategies for arsenic and fluoride mitigation. These people are intelligent and enthusiastic about protecting their future.
Local Actions presented
Applications of the Knowledge of the Presence of Fluorides and/or Arsenic in Drinking Water and Its Health Effects
An Extraction Regime for Handling Underground Water with High Fluoride in the San Luis Potosi Basin
Fluoride Contamination and Treatment in the East African Rift Valley
Government of Ethiopia
Geohydrology and Mitigation of Arsenic from Drinking Water