Forum für Wissenschaft, Industrie und Wirtschaft

Hauptsponsoren:     3M 
Datenbankrecherche:

 

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 Malaysia's unique freshwater mussels in danger
27.09.2016 | The University of Nottingham Malaysia Campus

nachricht How to detect water contamination in situ?
22.09.2016 | Tomsk Polytechnic University (TPU)

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: Experimentalphysik - Protonenstrahlung nach explosiver Vorarbeit

LMU-Physiker haben mit Nanopartikeln und Laserlicht Protonenstrahlung produziert. Sie könnte künftig neue Wege in der Strahlungsmedizin eröffnen und bei der Tumorbekämpfung helfen.

Stark gebündeltes Licht entwickelt eine enorme Kraft. Ein Team um Professor Jörg Schreiber vom Lehrstuhl für Experimentalphysik - Medizinische Physik der LMU...

Im Focus: Der perfekte Sonnensturm

Ein geomagnetischer Sturm hat sich als Glücksfall für die Wissenschaft erwiesen. Jahrzehnte rätselte die Forschung, wie hoch energetische Partikel, die auf die Magnetosphäre der Erde treffen, wieder verschwinden. Jetzt hat Yuri Shprits vom Deutschen GeoForschungsZentrum GFZ und der Universität Potsdam mit einem internationalen Team eine Erklärung gefunden: Entscheidend für den Verlust an Teilchen ist, wie schnell die Partikel sind. Shprits: „Das hilft uns auch, Prozesse auf der Sonne, auf anderen Planeten und sogar in fernen Galaxien zu verstehen.“ Er fügt hinzu: „Die Studie wird uns überdies helfen, das ‚Weltraumwetter‘ besser vorherzusagen und damit wertvolle Satelliten zu schützen.“

Ein geomagnetischer Sturm am 17. Januar 2013 hat sich als Glücksfall für die Wissenschaft erwiesen. Der Sonnensturm ermöglichte einzigartige Beobachtungen, die...

Im Focus: New welding process joins dissimilar sheets better

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of light metals.
Scientists at the University of Stuttgart have now developed two new process variants that will considerably expand the areas of application for friction stir welding.
Technologie-Lizenz-Büro (TLB) GmbH supports the University of Stuttgart in patenting and marketing its innovations.

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of...

Im Focus: Neuer Schalter entscheidet zwischen Reparatur und Zelltod

Eine der wichtigsten Entscheidungen, die eine Zelle zu treffen hat, ist eine Frage von Leben und Tod: kann ein Schaden repariert werden oder ist es sinnvoller zellulären Selbstmord zu begehen um weitere Schädigung zu verhindern? In einer Kaskade eines bisher wenig verstandenen Signalweges konnten Forscher des Exzellenzclusters für Alternsforschung CECAD an der Universität zu Köln ein Protein identifizieren (UFD-2), das eine Schlüsselrolle in dem Prozess einnimmt. Die Ergebnisse wurden in der Fachzeitschrift Nature Structural & Molecular Biology veröffentlicht.

Die genetische Information einer jeden Zelle liegt in ihrer Sequenz der DNA-Doppelhelix. Doppelstrangbrüche der DNA, die durch Strahlung hervorgerufen werden...

Im Focus: Forscher entwickeln quantenphotonischen Schaltkreis mit elektrischer Lichtquelle

Optische Quantenrechner könnten die Computertechnologie revolutionieren. Forschern um Wolfram Pernice von der Westfälischen Wilhelms-Universität Münster sowie Ralph Krupke, Manfred Kappes und Carsten Rockstuhl vom Karlsruher Institut für Technologie ist es nun gelungen, einen quantenoptischen Versuchsaufbau auf einem Chip zu platzieren. Damit haben sie eine Voraussetzung erfüllt, um photonische Schaltkreise für optische Quantencomputer nutzbar machen zu können.

Ob für eine abhörsichere Datenverschlüsselung, die ultraschnelle Berechnung riesiger Datenmengen oder die sogenannte Quantensimulation, mit der hochkomplexe...

Alle Focus-News des Innovations-reports >>>

Anzeige

Anzeige

IHR
JOB & KARRIERE
SERVICE
im innovations-report
in Kooperation mit academics
Veranstaltungen

EEHE 2017 – Strom statt Benzin. Experten diskutieren die Umsetzung neuester Fahrzeugkonzepte. Call vor Papers endet am 31.10.2016!

28.09.2016 | Veranstaltungen

Folgenschwere Luftverschmutzung: Forum zur Chemie der Atmosphäre

28.09.2016 | Veranstaltungen

European Health Forum Gastein 2016 beginnt

28.09.2016 | Veranstaltungen

 
B2B-VideoLinks
Weitere VideoLinks >>>
Aktuelle Beiträge

3D-Food Printing an der Hochschule Rhein-Waal

29.09.2016 | Energie und Elektrotechnik

Schneller Energietransport zwischen ungleichen Partnern

29.09.2016 | Biowissenschaften Chemie

Das Ribosom als Kontrolleur

29.09.2016 | Biowissenschaften Chemie