Geology for Global Development

Geology for Global Development

Water Series (2): Fluoride Contamination in Drinking Water

This week, as part of our ‘water series’ we will focus on fluoride contamination in drinking water. In some parts of the UK we add fluoride to our drinking water, because small amounts can help to protect your teeth. However, too much fluoride (>1.5mg/L) can lead to a serious medical condition called fluorosis, affecting the development of teeth and bones. This strong dosage dependency can lead to real battles in science communication. Even in the UK, where our fluoride levels are carefully controlled and maintained at a level that benefits us, there are public concerns and conspiracy theories about fluoride.

In places where water is not regulated at a centralised plant, many people have to drink from wells that have dangerously high levels of fluoride.  The main source of fluoride is contaminated groundwater, but other sources should also be taken into account when assessing safe concentrations. In the UK, toothpaste provides an extra source of fluoride, whereas in Ethiopia, the tea people drink is high in fluoride. Fluoride poisoning affects two hundred million people worldwide, and is a particular problem in Ethiopia.

The underlying control on fluoride concentration is geological. Fluorine appears in almost every kind of rock. The highest concentrations of fluoride occur in connection with intercontinental hot spots and along rift zones. In geologically unstable regions fluoride enriched fluids rise from the Earth’s crust or mantle up towards the surface sediments.

Rifting breaks apart continents and forms new oceans, often beginning with a 3-armed structure, such as the one in the Middle East/East Africa highlighted by the red lines. Normally the rift axis is underwater, but here one rift occurs on land, through the centre of Ethiopia. Source: Google Earth

The great rift valley cuts across the centre of Ethiopia with a NE-SW strike, pulling the country in two. The rift is an important geological site as this process normally occurs on the seafloor, and can rarely be observed above ground. Rocks in the valley are mostly young volcanics. Samples of drinking water from along the length of the valley have been analysed for their elemental concentrations using  ion chromatography and an ICP-MS and (a mass spectrometer that is common in most Earth Science departments, used for measuring the concentration of a whole range of elements in a liquid sample). Seventy eight per cent of the samples would fail EU drinking water regulations, and this is predominantly due to high fluoride levels. The contamination is a result of the water passing through the volcanic rocks in the rift valley.

To remove fluoride, water can be passed through a cleaning system at the point of access or within the home. One cost effective and widely available method for removing fluoride is to filter the water through charred animal bones. Fish bones or eucalyptus wood work just as well for communities that have an ethical objection to the use of animal products. Crushing and heating the bones increases the surface area, and so improves the absorbance capacity. The temperature that the bones are heated to is critical, and the ideal lies between 400 and 500 degrees centigrade. In Ethiopia large kilns are already in place, so most people have access to the necessary technology to remove fluoride from their water. The temperature can be monitored with waxed candles, as the fuse breaks when the temperature is too high, and can be controlled by altering the balance between extra fuel and air supply. The addition of simple ligands can double the Fluoride uptake, so if possible the charred material is treated with Aluminium oxides or sulphate to improve the efficiency.

The technology to remove fluoride from people’s water supply is well developed and easily accessible. However, the science alone is not enough. Collaborations between geologists, engineers, anthropologists, sociologists and entrepreneurs is needed to make a project a success. Social surveys and group discussions are used within communities to determine the best way to deliver the water purification treatment. In some cases it makes sense to treat the water centrally as this is more cost effective. However, in some communities it is more beneficial for families to treat their own water at home. A family can be issued with equipment the size of a bucket and can last up to 6 months. Entrepreneurs can also be involved in financing the scheme, aiming to transform it into a business that can continue to fund itself. This is a truly multi-disciplinary issue.

Friday Photo (55): Photos from Industry – Man Operating Machinery at a Mine in China

Man Operating Machinery at a Mine in Anhui Province, China

There are many large mining operations covering Anhui Province, China. They tend to have limited safety regulations. The mines can ruin the landscape, cause pollution and can be dangerous places for people to work. However, this primary industry is fuelling China’s rapid growth and development.

Our Friday Photo series will be focused on ‘industry’ for the following few weeks. If you have any photos from time spent working in industry, that do not breach company copyright regulations, then please get in touch and we will publish them on our blog!

(c) Geology for Global Development 2012

Introducing the GfGD National Committee (2)

We have advertised a range of positions on our national committee over the past month. The positions have been filled by enthusiastic, dedicated people and the team will be working together for the year ahead. Having a national committee will increase both the capacity of GfGD to produce resources and support University groups, and also the number of opportunities for you to become involved with our work. Last week we introduced the communications team, myself (Rosalie Tostevin) and Jane Robb, and this week we are pleased to announce the rest of the committee.


Joel Gill is the Founder and Director of GfGD. Joel studied Natural Sciences at the University of Cambridge, followed by a Master’s degree in Engineering Geology at Leeds University. Joel is now researching multi-hazard models for small urban areas as part of his PhD at King’s College London.  Joel established Geology for Global Development in 2011, and is currently responsible for the overall leadership and strategic development of our work. Joel will be continuing to direct the organisation, working closely with and receiving support from our new secretary, Ellie Murtagh.

Ellie Murtagh is an Irish American, who has recently graduated with a degree in Geology and Physical Geography from the University of Edinburgh. Ellie has experience working in a hospital in Vietnam and as a climate researcher in Tajikistan. She now works as a graduate geologist for a geophysical service provider for the oil, gas and mining industries. Ellie undertook our CAFOD placement earlier this year and proved to be an excellent test case for UK-based student placements, achieving an incredible amount in a short time.

Faith Taylor will be managing our University Groups. Faith is a PhD student at King’s College London, where she is developing a model to understand the probability of landslides impacting road networks.  Faith will be offering support, advice and resources to both new and existing GfGD University Groups. We are always looking to expand our network of University groups, and Faith would be happy to provide the necessary support if you would like to establish a new group at your university.

Tim Middleton will be our Advocacy Development officer. Tim is a first year PhD student in the Department of Earth Sciences at Oxford University. He spends his time studying active tectonics in central and eastern Asia, including some rather exciting fieldwork in Kazakhstan and China! Tim will be coordinating our advocacy programme and campaigns, engaging young geoscientists in effective advocacy work – including the scrutiny of government legislation, getting involved in major campaigns, and promoting good geoscience within development work. Tim has a strong background in science communication and will be able to help us put our message across in the right places.

Donald John MacAllister will be our Publications and Resources Officer. Donald has a BSc in Geophysics from the University of Edinburgh and an MSc in Water Management from Cranfield University. He has spent three years working as a hydrologist and water engineer, both in the UK and in the international development sector. Donald will be developing the resources and publications that we make available to NGOs, after careful consideration of the requirements of NGOs.

Marc Leach will be our dedicated Education & Careers Officer. Marc is a recent graduate of the University of Manchester with a BSc in Geology, who is planning on undertaking an MSc starting in 2013. His primary interests include Hydrogeology and Engineering Geology, and he has experience working with the mining industry as well as for charities. Marc will be working to develop our education and careers resources, including highlighting and advertising relevant Master’s courses, collating careers advice from those in the development sector and helping students to understand the various career pathways that exist.

 You can hear more from each of our committee members on the dedicated area of the GfGD website. If you want to be more involved with the work of GfGD, then please don’t hesitate to get in touch with one of us.

Water Series (1): The Quantity and Quality of Groundwater

The water available in or near your home can vary dramatically over short distances. In Manchester, there is a robust supply of fresh water from the Lake District, whereas in London (only 200 miles away) the water has passed through limestone, leaving it with a cloudy taste and causing limescale build-up. Signs up on the London underground at the moment are encouraging people to save water by taking the “4 minute shower challenge” and this summer we have had a series of localised droughts and floods. Food prices are expected to rise because there was too much rain this summer, leading to widespread crop failure. Even in the UK, where we have plenty of year-round rainfall, controlling the quantity and quality of water is an expensive and precarious business.

It was in London that the connection was first made between water and health. John Snow noticed that the cholera outbreak in Soho was being caused by a contaminated water supply from the broad street well. In the UK there is now a secure and safe water supply. However, the water available to people around the world is much more variable. Over two million deaths a year are caused by poor water hygiene – equivalent to AIDS or malaria.

The primary control on precipitation (water that falls as rainfall, sleet or snow) is the large-scale convection cells in the atmosphere, which vary systematically with latitude – are you in a tropical zone or a desert zone? Groundwater levels, however, follow more complex patterns. Groundwater maps of Africa produced by a team at UCL show surprising levels of groundwater in unexpected places, such as deep beneath the sahara desert. The primary control on the quality of water is often geological – what rock and sediment does the water pass through between the source and the point of access?

NASA’s landsat educational archives: Latitudinal bands of tropics and deserts across the globe are driven by large scale atmospheric circulation cells.

In developing countries projects often have to work on a local scale, because there is no centralised water supply. Lack of access to water often has a disproportionate impact on women, who are normally expected to walk long distances to collect water from uncontaminated wells. Babies and small children are then the most vulnerable to health problems if the water supply is contaminated. Provision of clean water  is the single most important factor in reducing infant mortality.

Clean groundwater is being extracted from a deep borehole in Ethiopia – giving local communities a better chance of staying healthy. (c) Geology for Global Development 2012

Surface water is more susceptible to contamination from bacteria, but groundwater is more susceptible to heavy metal contamination. Two of the most worrying contaminants are Fluoride and Arsenic, and we will discuss each of these in depth in future blog articles. GfGD has discussed problems relating to water supply in the past, such as our winning entry in last years blog competition, and Donald John MacAllister’s guest blog sharing his practical experience in Bangladesh. Look out for more on our ‘water series’ over the coming weeks.