In 1993 tragedy struck Bangladesh when it was confirmed that their main source of water - groundwater of the deltaic basin - was contaminated with arsenic. Coined the largest mass poisoning in history; the country needed to find a cost effective and sustainable solution to provide safe water for the country. In cooperation with the World Bank, the IAEA used the techniques of isotope hydrology to aide in the identification of safe drinking water, a milestone for the country and a hopeful instance for the rest of the world.
The groundwater wells which supply almost 97% of the population with groundwater was thought to be safe at the time of creation. The discovery of this new source of water resulted in an expansion of agriculture. The provision of groundwater had been credited with bringing down the incidence of diarrheal diseases and infant mortality caused by water bourne diseases in surface water, which was previously used as a primary source. For years, the groundwater was seen as a blessing.
The arsenic contamination was a highly publicized major public health crisis which had detrimental long-term health effects on the people. Health effects resulting from oral exposure ranged anywhere from skin lesions, hyper pigmentation, various cardiovascular effects, and the long-term possibility of skin cancer just to name a few. Although there were many agricultural and industrial developments from 1970s on, the arsenic contamination was found to be natural.
"Arsenic contamination comes by naturally because the water in those areas is moving slowly and does not have enough oxygen and therefore the arsenic from the sediments is desorbed into the water. There is no easy way of removing it naturally or stopping the pollution from occurring. What is needed is to know is where the arsenic is, how it´s getting there, and how old the water is." Explains Pradeep Aggarwal, Section Head of the IAEA Isotope Hydrology Section.
Through the World Bank´s Bangladesh Arsenic Mitigation Water Supply Project (BAMWSP) it had been concluded that there were two choices for eliminating arsenic contamination: treatment of the water, or identification of arsenic free aquifers. The latter proved to be the most sustainable and cost effective. In collaboration with the Bangladesh Atomic Commission, the Agency provided the scientific analysis to support the project.
Isotope hydrology can uncover the history of the water, how it flows and where it comes from. In brief, isotopes can be used to estimate the age of an underground reservoir of water in an aquifer system, determine how quickly the resource is replenished, and provide estimates to the degree of mixing and interconnection of groundwater in complex aquifer systems. By putting the pieces together with this technique the IAEA was able to identify arsenic free sources drinking water in the deltaic basin.
"Even though we did this work several years ago, this is the same type of work that continues, and provides direction and guidance for water quality studies related to aquifers and groundwater everywhere, the technique is not new - we have used it before" - Pradeep Aggarwal, Section Head of the IAEA Isotope Hydrology Section.
The project was completed in 2007, and demonstrated that isotope hydrology is an effective way to study the groundwater flow and to identify safe sources of water. In the future, using the technique at the beginning of water extraction projects can provide a general understanding and concrete basis to strategic planning for sustainable water sources which are free of contamination. The impacts of the technique are revolutionary, but to the IAEA Isotope Hydrology Section, and its multiple projects in South and East Asia, addressing hopes for clean water is just part of a days work.