Saturday, May 27, 2006
A good friend passed this along to us
A good friend passed this along to us…
Abstract
High levels of fluoride in drinking water are responsible for fluorosis, a crippling disease that affects many parts of rural India and Africa. I spent almost a year in India, primarily at the M. S. Swaminathan Research Foundation studying the problem of fluoride-affected drinking water and methods of natural product defluordation. Current chemical methods of defluoridation have been well explored. Despite their efficiency and low price, they have not been adopted for widespread use in fluoride affected rural areas. Natural products were explored another method for water defluoridation. As an alternative to defluoridation, a strategy for avoiding fluoride-affected water sources was explored. In a final analysis of the situation, the role of further scientific experimentation seems limited. Rather than developing new strategies for providing fluoride-free water to rural communities, scientists should help to facilitate implementation of existing strategies.
The M. S. Swaminathan Research Foundation
During the 2000-01 academic year I spent nine months in India on a Fulbright Foundation student research grant. After a year at Los Alamos National Laboratory working on bioremediation, I was eager to study hands-on approaches to environmental problems. The majority of my time in India was spent at the M. S. Swaminathan Research Foundation. MSSRF was established in the early 1990s as a center for scientific research on sustainable agriculture and rural development. It has an excellent reputation for doing cutting-edge science while focusing on areas where the science can make an immediate contribution to society and the environment. MSSRF hopes to do work that is "pro-poor, pro-woman, and pro-environment."
While this rhetoric is common among organizations working in India, it is striking to see this philosophy in action. Of the total staff of MSSRF, almost half are working in field offices. Staff working at the central institution are encouraged to take positions in field stations vice versa. Field work is an integral part of every research project. The time-scale of projects is also geared towards immediate impact. Projects are typically taken from the research phase to implementation within a few years. The procedure at MSSRF is in marked contrast to American institutions where it is difficult to do field work and there is no clear plan for testing and implementing research in real situations.
At MSSRF, I studied the problems of fluoride-affected drinking water in Tamil Nadu. I began my research in the search for natural products which could serve to remove the fluoride from drinking water. At the end of my program, I began to explore alternatives to water defluoridation, such as the identification of alternative water sources.
The problem of fluorosis
The United Nations declared the 1980’s to be the Water Decade. With the goal of providing a safe and continuous water supply to rural populations, bore-wells were dug across India. Water from these wells is reliably free from disease-causing bacteria and is available throughout the year. Unfortunately, a side-effect of this has been an increase in drinking water with dangerously high levels of fluoride (>1 ppm) and an associated increase in the incidence of skeletal fluorosis.
In areas where the bedrock contains high levels of toxic metals or minerals, water coming from bore-wells may be dangerously contaminated. The most well-known incidence of this problem has been the occurrence of arsenic in West Bengal and Bangladesh. Wells installed to alleviate a major public health problem by providing disease-free drinking water to rural areas have inadvertently created a new public health disaster.
A similar problem has been experienced in Tamil Nadu (as well as many other parts of India and Africa) with the occurrence of fluoride in the drinking water. Wells drilled into fluoride-rich bedrock often have elevated fluoride concentrations in the drinking water. High levels of fluoride in the drinking water are known to cause severe skeletal and dental disorders. High fluoride intake is suspected in causing goiter and has even been linked to higher incidences of cancer. In areas of Tamil Nadu where fluoride intake is particularly high, fluorosis can affect as much as 30% of the population. In many villages severe crippling is common.
Current methods of defluoridation
The most efficient and practical method currently available for water defluoridation uses aluminum sulphate (alum) and lime. The technique was first developed in the Indian village of Nalgonda and is still referred to as the "Nalgonda technique." Defluoridation kits based on this technique have been produced and distributed to many rural areas. Alum is inexpensive and easy to use, store and transport, and remarkably effective at removing fluoride from water.
Using a similar chemical process, activated alumina can also be used for defluoridation. The difference is that alum is added to water as a powder while activated alumina can be used in a solid form. As water is filtered through granular activated alumina, the fluoride is adsorbed out. This makes activated alumina ideal for community water source defluoridation.
The drawbacks of activated alumina technology are the cost of installation and the necessity of frequent maintenance. Trial filtration apparatus have been installed. The filtration system designed at Gandhi Gram University requires 100 kilograms of activated alumina. At a price of approximately Rs. 100 per kilogram, this means an investment of Rs. 10,000. The filter must be regularly treated with acid and base in order to regenerate the alumina.
Despite many advantages, the chemical defluoridation techniques has not achieved widespread use in fluoride-affected areas. Social and political factors are as much responsible for this as any technological deficiency. While these techniques require only a few minutes of work each day, a strong community education effort must be put forth to convince villagers to practice the technique. Even the small effort required to defluoridate water will not be put forth unless people clearly understand the dangers of fluorosis. There are no great logistical barriers to production and distribution of Nalgonda kits in India. The problem lies more with politicians who prefer more "impressive" solutions such as pumping water from a reservoir.
The other hurdle in defluoridation technologies is the neccessity for community education. This was made clear to me when I visited a village with a newly installed activated alumina defluoridation apparatus. The graduate student who had installed it claimed to have spent a month visiting every day to educate the community about the dangers of fluoridated water. For monitoring purposes, the defluoridation apparatus has an outlet for water before it is filtered through the activated alumina. As we were watching, a young boy came up and began to drink the fluoride-affected water directly from the tap meant only for monitoring. Of course, we need not have worried too much about the danger of highly fluoridated water…the village rarely used water from the hand-pump because sweet water from a reservoir was available from the screw taps on the other side of the street!
Natural product defluoridation
Despite the efficiency of the Nalgonda technique and new research into activated alumina defluoridation, a natural-product alternative for water defluoridation is being sought. There are many advantages to defluoridation using natural products. Because they can often be locally grown, production and transportation costs could be reduced. Natural-product defluoridation might also achieve widespread acceptance more easily. The use of natural products in water purification is already common practice among many communities in India and Africa. Natural-product defluoridation could become more popular among the rural populations than chemical methods. Although the use of alum in water purification has never been proved dangerous, aluminum is toxic to humans in large amounts and use of natural-products might be healthier.
No natural products tested provide a promising alternative to chemical defluoridation methods. Research yielded two intriguing candidates with significant defluoridation capacity, but neither seems well suited for village-scale or community-scale water defluoridation.
The seeds of the drumstick tree (Moringa oleifera) were the first tested. The tree is common throughout India and Africa and grows well in arid conditions. Drumstick seeds act as a coagulant. They have long been a traditional method for purification of turbid water in both India and Africa. A previous researcher at MSSRF had shown drumstick seeds to have remarkable defluoridation efficiency, higher than that of activated alumina. Unfortunately, these results proved irreproducible.
The roots of vetiver grass (Vetiveria zizanoides) are another product that has traditionally been used for water purification. Water filtered through the roots is supposed to have a sweeter taste, probably due partly to a taste imparted by the roots and partly to a decreased salt content in the water. The roots were effective at defluoridation and could remove as much as 70% of the fluoride from a sample. The defluordation efficiency was higher than activated alumina, and the price was comparable. Unfortunately, back-of-the-envelope calculation indicate that a family would need to raise acres of vetiver grass every year in order to provide enough material for defluoridation.
An alternative strategy: Fluoride avoidance
Given the inherent drawbacks of defluoridation, perhaps an entirely different approach should be considered. Except for a few districts where extremely high fluoride levels have already crippled much of the population, nothing is being done to address the problem of fluoride contamination.
In most areas, a source of fluoride-free water already exists! There is no district in Tamil Nadu where more than 20% of the wells are affected by fluoride. Even within the same village, there are often some wells affected by high fluoride levels while other wells are not affected. It may be possible to avert the spread of fluorosis simply by closing down taps with high fluoride content, or encouraging people to not to use this water for drinking.
The advantage of this monitoring work is that could make an immediate impact. As you read this report, thousands of people across Tamil Nadu are drinking water with dangerously high levels of fluoride. Within weeks or months they could be told where to obtain safer sources of drinking water. This is not a perfect solution, the search should continue for better defluoridation methods. In the meantime, however, many villagers have no alternative to putting themselves at risk of a crippling disease. It seems that the benefits of instituting such a program will easily outweigh the costs of implementation.
Conclusions
The efforts to provide fluoride-safe drinking water to rural Tamil Nadu are an case study in the challenges of structuring scientific research to meet the needs of rural populations. Cost-effective, simple, and effective procedures for water defluoridation are already known. The task is not just to experiment with more efficient methods of defluoridation, it is to develop workable strategies to provide fluoride-safe drinking water to rural communities as quickly as possible.
The role of scientific research in halting the spread of fluorosis in rural areas seems limited. Methods for water defluoridation have been well developed, as have the hydrological techniques necessary to find fluoride-safe alternative sources. Lacking is the funding, organizational capability, community education, and the desire to implement solutions that have already been developed. Scientists should advocate these courses of action and may play an advisory role in these processes. Implementation will require collaboration with organizations who have the political clout and experience to work effectively in rural communities.
# posted by Middle Child @ Saturday, May 27, 2006 
