Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Water treatments alone not enough to combat fluorosis in Ethiopia

27.04.2012
Increased intake of dietary calcium may be key to addressing widespread dental health problems faced by millions of rural residents in Ethiopia's remote, poverty-stricken Main Rift Valley, according to a new Duke University-led study.

As many as 8 million people living in the valley are estimated to be at risk of dental and skeletal fluorosis as a result of their long-term exposure to high levels of naturally occurring fluoride in the region's groundwater.

Fluoride is essential for healthy tooth enamel development, but consuming too much of it can damage enamel and bones, particularly in children between the ages of 3 months and 8 years.

Mild to moderate fluorosis typically results in permanent discoloring and disfiguration of tooth enamel. Severe fluorosis can cause chronic pain and lead to tooth and bone loss.

Most efforts to combat fluorosis in the region have focused primarily on treating drinking water to reduce its fluoride content.

The new Duke-led study, published online in the journal Environment International (www.sciencedirect.com/science/article/pii/S0160412012000530), finds that these efforts "may not be sufficient on their own, because of the region's geology and the low threshold of exposure at which we found fluorosis was likely to occur," said Avner Vengosh, professor of geochemistry and water quality at Duke's Nicholas School of the Environment.

Increasing the amount of calcium in villagers' diets, or finding alternative sources of drinking water may be necessary in addition to these fluoride-reducing treatments.

By systematically analyzing groundwater quality in the valley, Vengosh and his colleagues found that as water flows from the surrounding mountains into the rift, it interacts with volcanic rock, which contributes fluoride to the water while also removing most of its calcium. That's important, he explained, because "calcium is essential for mineral formation that can capture fluoride in a groundwater system."

Water samples from 48 of 50 wells tested in the valley contained fluoride levels above World Health Organization safe guidelines. The average daily fluoride intake of people drinking from the wells was six times higher than the current no-observed-adverse-effects-level (NOAEL) – the highest known level of exposure that can occur before adverse biological effects are detected.

The researchers also conducted clinical examinations of 200 villagers' teeth to see if differences in fluoride levels in drinking water supplies affected the severity and prevalence of fluorosis in a community's population.

"The idea was to test the hypothesis that higher fluoride in the water correlates to more common and severe cases of fluorosis in the people who drink it. But we found no linear correlation above a certain point," said Tewodros Rango, a postdoctoral researcher at Duke's Nicholas School of the Environment who was lead author of the study. "Essentially, our examinations showed that once you reach a low threshold of fluoride exposure, fluorosis is likely to happen."

In some of the communities, the fluoride levels in well water were so high you could treat the water to cut the fluoride content by half and it still wouldn't drop below the critical threshold, he said.

In villages where people had access to milk, severe fluorosis was about 10 percent less likely to occur, Rango's clinical examinations found. Further research is needed to explain this anomaly, he said, but it may be possible that by drinking milk -- which is not a common staple in the rural Ethiopian diet -- these people take in enough calcium to retard fluorosis development.

"Future mitigation strategies may want to include increased calcium intake in diets, particularly for children," he said.

The research team's tests also found high levels of naturally occurring toxic elements, including arsenic and uranium, in the groundwater samples.

"The combined impact of these elements on human health may be higher than the sum of the effects from each specific contaminant," said study co-author Dr. Julia Kravchenko, a researcher at the Duke Cancer Institute. "For example, it could result in aggravated toxicity of fluoride as well as increased risk of damaged kidney function. This phenomenon is very important for evaluating region-specific safety limits for water contaminants."

Increased numbers of fluorosis cases have been reported in recent years in many parts of the world, including Mexico, Brazil, China, Vietnam and Thailand. Devising mitigation strategies that take into account each region's geology and water quality is critical, the researchers noted, because global warming could worsen the quality of drinking water in these regions in coming years.

Other co-authors on the study were Marc Jeuland of Duke's Sanford School of Public Policy; Nicholas School PhD student Brittany Merola; Behailu Atlaw of Jimma University in Ethiopia, and Peter G. McCornick of the International Water Management Institute in Sri Lanka. Support came from the Duke Global Health Institute and Duke's Nicholas Institute for Environmental Policy Solutions.

Tim Lucas | EurekAlert!
Further information:
http://www.duke.edu

More articles from Ecology, The Environment and Conservation:

nachricht Five-point plan to integrate recreational fishers into fisheries and nature conservation policy
20.03.2019 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

nachricht Rain is important for how carbon dioxide affects grasslands
06.03.2019 | University of Gothenburg

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The taming of the light screw

DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.

The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...

Im Focus: Magnetic micro-boats

Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.

The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Solving the efficiency of Gram-negative bacteria

22.03.2019 | Life Sciences

Bacteria bide their time when antibiotics attack

22.03.2019 | Life Sciences

Open source software helps researchers extract key insights from huge sensor datasets

22.03.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>