Identifying sources of contamination of groundwater may help POU water treatment system development

Stable isotope (O-18) can help to assess the sources and processes governing fluoride and nitrate contamination of groundwater

References: 1. P.S. Datta et al, Journal of Contaminant Hydrology 24 (1996) 85-96.

2. P.S. Datta et al, Journal of Contaminant Hydrology 27 (1997) 249-262

In developing and under-developed regions of the world, issues related to environment protection, water consumption scarcity of safe drinking water, increasing water contamination, and growing awareness about the benefits of clean drinking water are matters of great concern for water resources managers. The market is however driven mainly by the waste management and water management in some countries. Due to the increasing need for ground water protection, to address such issues, the demand in the point-of-use water treatment systems and the geo-membranes market is increasing and will rise in the future, as these are the most commonly used solutions.

The market has been segmented on the basis of technology into reverse osmosis systems, distillation systems, disinfection methods, filtration methods, and others. The applications of such water treatment systems include both residential and non-residential with residential segment accounted for the highest market share of the total such water treatment systems market in 2014. The market for RO systems is projected to witness the highest growth based on technology during 2015-2020. However, high equipment cost acts as a restraint to the market. One of the main strategies adopted by such water treatment systems manufacturer companies is new product development, adhering to the standards set by governments for water treatment systems by continually investment in research and development activities for innovative solutions.

Undoubtedly, RO+UV (with pre-treatment) Systems have a very high effectiveness in removing protozoa, bacteria, viruses; and common chemical contaminants (metal ions, aqueous salts), including sodium, chloride, copper, chromium, and lead. It is not clear however, what specific treatments are available for removal of fluoride, arsenic and nitrates, if found in excess of the WHO prescribed MPL. Ordinary candle filters and UV treatment systems will not remove fluoride, arsenic or nitrates. In general, a reverse osmosis plant associated with Ion exchange systems can only lower the level of fluoride, but will not eliminate. A reverse osmosis filter has a pore size of approximately 0.0001 micron, which is much larger than the size of fluorides, arsenic and nitrate ions. Those who think RO+UV can solve the problem; they may please also educate all how, not simply mention that it will be a viable solution.

In many parts of the globe, human health problems are endemic and are associated with high concentrations of contaminants ions in drinking water. Since large percentage of population is almost totally dependent on groundwater for its raw water requirement and nearly 70% of the area under irrigation is irrigated by groundwater, contamination in groundwater is a matter of concern for the planners and managers of water resources. Knowledge gaps and limited understanding of the factors controlling water quality (particularly for fluoride and nitrate) are unable to assess the probable changes in natural resources water quality in tropical regions. The fundamental challenges have always been monitoring and measurements uniformity across systems, which are known to have wide variability. 

In this background, the stable isotope (18O) signatures in groundwater in integration with contaminants concentrations have been discussed in the above-mentioned papers to determine clearly the sources of contamination in groundwater and the processes governing it, which otherwise becomes difficult to ascertain from ion-concentration data alone. For judicious effective application of economic principles to water, development effort must have the competent & capable individuals and transparent organizations/institutions to address the aforementioned aspects. Influence of corrupt and unscrupulous practices, working hand-in-hand with greedy investors, should not put private gain before the welfare of citizens.