GENEVA — Users of point-of-entry (POE) and point-of-use (POU) water treatment equipment should be made aware of the changes the devices can make in the mineral composition of drinking water and the potential impact of those changes on nutrient intake and health, the World Health Organization (WHO) said in a recently released report.
Further, WHO said in the report, "Those who sell or install these devices may be encouraged to bring to the attention of the users of these devices the possibility of reduced mineral intake and alternative means for [the minerals'] replacement."
The report is the result of a scientific symposium in Baltimore in April that looked at the health effects of calcium and magnesium in drinking water, and a subsequent WHO Meeting of Experts in Washington that examined research and comments presented at the symposium in an attempt to come up with recommendations.
Representatives of the water treatment industry were among symposium speakers and had urged WHO to consider the benefits of treatment methods such as ion-exchange softening and reverse osmosis, which typically reduce levels of calcium and magnesium ions in water.
WHO suggested in its report that manufacturers of POU/POE devices provide bypass or remineralization technology to ensure that adequate calcium and magnesium levels are maintained in water used for drinking.
WHO noted the important roles played by calcium and magnesium in the human diet, primarily in maintaining the health of bones (in the case of calcium) and in reducing the risk of cardiovascular disease (magnesium); it added that "many people in most countries" fail to get enough of these minerals in their diets, although dietary need and consumption of the minerals can vary widely among individuals.
WHO also recommended that the public have access to information about the mineral content of bottled or packaged waters, saying there is "extreme variation" in mineral composition among bottled waters now on the market.
The agency said modification of calcium and magnesium levels in piped (typically public) water supplies should not compromise disinfection or technical requirements, such as pH balancing, required to make water suitable for distribution.
Water suppliers should ensure that stabilization of product water from desalination plants or wastewater reuse plants to reduce pipe corrosion also avoid reduction of calcium, magnesium or fluoride levels below recommended nutrient values, according to WHO.
In its report, WHO pointed out several gaps that need to be filled by additional research, recommending, among other things, well-designed epidemiological studies on the health effects of waterborne calcium and magnesium, and identification of population sub-groups who are most vulnerable to calcium and magnesium deficiencies, and
For related information on this story, click here.
To subscribe to Water Technology® magazine, click here.
To discuss this topic with other water and wastewater industry professionals, click here.
Every month in Water Technology Magazine, "Professor POU/POE" answers reader questions about point-of-use/point-of-entry water treatment.
If you have a question for the Professor (also known as David Bauman, Technical Editor), send an e-mail to rdipaolo@ntpmedia.com and we'll pass it along. With your question, please indicate your general location (region, state, province, etc.). Not all questions will be chosen for publication.
Write for WT
Water Technology welcomes and encourages editorial contributions from the world of residential water conditioning, bottled water delivery, and treatment for commercial or light industrial applications.
To place a classified ad online, e-mail your ad text to pharrington@ntpmedia.com or call Pat Harrington at 518-640-9173.
Bookstore
WaterTechBooks.com is an online bookseller for the water treatment industry. It has dozens of titles in stock, in a variety of categories. A simple e-commerce platform allows you to complete your transaction online and have your books shipped directly to your home or business.
Every month in 
