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Human Rights Day: How Nuclear Techniques Help Madagascar Villagers Access Clean Drinking Water


Josiane Ranorosoa, a member of the village council, draws water from a communal well that – isotopic techniques have revealed – accesses groundwater potentially contaminated from a landfill next to the village. This water can be used for washing and cleaning only. (Photo: M. Gaspar/IAEA)

Ambaniala, Madagascar – Amidst the penetrating smells of rotting and burning garbage and constantly chased by thousands of flies live the 4000 residents of Ambaniala, a village built right on the edge of the Andralanitra municipal waste dump of Antananarivo, the country’s capital. But – thanks to the use of nuclear and isotopic techniques – at least villagers now know which wells in the settlement can be used for getting drinking water and which are contaminated from effluent from the open-air landfill, which provides their livelihood.

“It is much easier now and nobody gets sick,” said Josiane Ranorosoa, a member of the village council. “Some of us need to walk further for water, but it is at least drinkable.” A few of the wells in the contaminated area are used to draw water for washing and cleaning, she added.

While access to clean drinking water is recognized as a universal human right, over 2 billion people around the world struggle to find clean water. Madagascar is one of the countries that uses nuclear techniques as one of the tools to ensure that the water people drink is clean. The theme of this year’s Human Rights Day is the involvement of youth in human rights and sustainable development – an issue dear to the heart of Ranorosoa, 23, who has been an outspoken advocate for clean water on the village council for years.

Whether the water in a well is clean or contaminated can be determined with the use of conventional chemical analysis – but such an analysis cannot reveal whether it is going to remain safe and would therefore need to be repeated constantly to provide reassurance. Understanding the flow and dynamics of the groundwater, and knowledge of whether it could contain surface water that is potentially contaminated, is only possible with the help of isotopes.

Isotopes are versions of “ordinary” atoms, containing the same amount of protons and electrons, but one or more additional neutrons. Chemically they exhibit the same behavior, but they have a different atomic weight and some of them are unstable, emitting a tiny amount of radiation, which can be measured. This way the isotopes are used as tracers by scientists known as isotope hydrologists.

A communal well whose water is too polluted for consumption has been locked down. (Photo: M. Gaspar/IAEA)

“We determined that a 300-meter wide strip of the ground underneath the settlement contains contaminated or potentially contaminated groundwater, while the effluent from the garbage disposal site does not reach the rest of the water under ground in the area,” said Joël Rajaobelison, an isotope hydrologist and Director General of the National Institute of Nuclear Science and Technology (INSTN Madagascar), which has received both equipment and training for its staff from the IAEA, through its technical cooperation programme, to use isotopic techniques for water analysis. “It is therefore safe to use.”

This is important for the villagers not only in the short term but for the coming years: they have petitioned the government to get electricity and running water, and while the construction of electricity poles has begun, there are no immediate plans for piped water reaching the village, Ranorosa said.

While the concentration of isotopes of hydrogen and oxygen – the two elements that make up water – in any water is extremely low, surface water tends to be relatively richer in isotopes 2H – known also as deuterium – and 18O. The sensitive equipment that Rajaobelison’s team uses, and which was donated by the IAEA through its technical cooperation programme, is able to detect the difference and therefore any infiltration of surface water. “If it contains surface water, the groundwater may easily get polluted from the affluent even if it is clean now,” he explained.

Deuterium and 18O are stable isotopes, the kind that do not decay and emit radiation, so they cannot be used to trace the direction and speed of water flow – crucial information in order to be able to identify potentially polluted areas. Enter 3H – known as tritium – which is even rarer and was mostly introduced into the atmosphere as a harmless byproduct of nuclear weapons tests in the 1950s and 60s. Through rain it entered surface water and the water cycle. When found in groundwater, it indicates that the reservoir has been recharged in the last 60 years. The small amounts of radiation tritium molecules emit when decaying is used to trace the direction and speed of water. “Therefore we can tell whether any body of water is coming from the landfill site or flowing towards it,” Rajaobelison said.

When last year his office was alerted to the problem of Ambaniala by a private citizen, who heard about the use of isotopic techniques through a national outreach campaign, his staff knew right away that INSTN can help. “For us it is a simple, routine analysis performed over a number of weeks, Rajaobelison said. “For them it is a life saver.”

The main street of Ambaniala, with Madagascar’s largest landfill at the end of the street. Groundwater contamination from the landfill is polluting some of the village’s wells. Scientists using isotopic techniques helped to show the villagers which well is safe to use. (Photo: M. Gaspar/IAEA)

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