by Dr Annette Johnson and Anja Bretzler, Swiss Federal Institute of Aquatic Science and Technology (Eawag) – www.wrq.eawag.ch
Researchers at Eawag have been involved in finding technological solutions for arsenic-contaminated drinking water over the last decades. When we also started looking at fluoride contamination in drinking water we soon came to realise how enormous the problem was and how that challenges to long-term mitigation were the same irrespective of contaminant.
On a global scale an estimated 300 million people are at risk of exposure to arsenic and fluoride. Ingestion of excess arsenic over prolonged periods of time can result in various internal cancers amongst other conditions, while high levels of fluoride are responsible for the development of dental and crippling skeletal fluorosis and yet contaminated regions were being identified on a piecemeal basis.
Our answer has been to develop contamination prediction maps based on measured data and geological and geochemical conditions. Although not an alternative to measurements these maps highlighted the regions with a contamination potential where measurements had not yet been made.
In poor urban and rural settings the provision of drinking water free of geogenic contamination is proving to be a real challenge. Indeed in many regions the problem has been recognised for decades and though efforts have been made to address this chemical contamination, nationwide efforts are limited to a few countries and many millions remain at risk. This is true despite the developments in technology.
Through our collaboration with the NGOs Oromo Self Help Organisation (Ethiopia) and the Nakuru Defluoridation Company (Kenya), who provide fluoride-free drinking water to communities in the Rift Valley, we have learnt how many factors come into play, from financing and the necessity of subventions, through to ownership by the local communities and a change in the habits of individuals. Indeed the long-term success of mitigation measures for contaminated drinking water depends on the integration of technical solutions with societal and economic aspects.
With this handbook we aim to provide a concise resource for approaching and handling geogenically (or naturally) contaminated water used for drinking and cooking. The handbook focuses on the requirements of the implementer; government officials, NGOs, planning agencies, consultants and engineers, confronted with the problem of arsenic and fluoride contamination in drinking water. It includes guidelines on water sampling, an outline of available treatment technologies and also highlights the necessity of considering the institutional setting and the financial viability of drinking water services. It also provides guidelines on behavioural change in affected communities, while case studies illustrate integrated mitigation approaches. The manual is available in digital format, including relevant weblinks and attached resources.
Eawag (2015) Geogenic Contamination Handbook – Addressing Arsenic and Fluoride in Drinking Water. C.A. Johnson, A. Bretzler (Eds.), Swiss Federal Institute of Aquatic Science and Technology (Eawag), Duebendorf, Switzerland
Download from www.wrq.eawag.ch