'Man-made' water may bring changes to the environment

Washington, June 22 : Duke University researchers say that the chemistry of "man-made" water - created by removing salt from seawater and brackish groundwater through reverse osmosis desalination - is different from that of natural water.

They believe that the introduction of "man-made", just in population explosion and climate change reduce the Earth's natural water supply, may bring changes to the environment.

"Water that's been desalted through reverse osmosis contains a unique composition which will induce changes in the chemistry and ecology of aquifers and natural water systems it enters," Science Daily quoted Avner Vengosh, associate professor of earth and ocean sciences at Duke University's Nicholas School of the Environment, as saying.

Vengosh says that a study he carried out with other scientists in France and Israel has provided them with tools to identify and trace man-made water as it mixes with natural water supplies, and over time replaces natural waters in areas entirely dependent on desalination.

Describing the study in the peer-reviewed journal Environmental Science and Technology, the researchers says that identifying unique isotope geochemistry (chemical fingerprints) of the elements boron, lithium, strontium, oxygen and hydrogen found in reverse osmosis-desalted seawater and brackish groundwater gives a new array of tools for tracing the presence and distribution of man-made fresh water in a region's soils, surface waters and ground waters.

"We studied the chemistry of water produced in several of the largest desalination plants on earth and found that that composition of the desalted water is totally different from those of natural waters. As this water leaks into the environment through poor infrastructure or enters it directly through irrigation, it will be possible to use our new tracers to track the water back to its origin," he says.

"It's sort of like a detective who collects fingerprints at the scene of the crime and matches them to the guilty suspect," he adds.

Vengosh believes that the ability to trace water back to a desalinated source through its isotopic and geochemical fingerprints may enable local governments and water utilities to zero in on the problem of valuable water loss, and correct it more quickly and efficiently.

Given that desalted wastewater can be recycled through the environment and reused as a drinking water source, the new tools may allow water authorities to trace the relative contribution of desalted water in their system, and to test the effectiveness of their water treatment processes.

"This will be especially beneficial in water-scarce regions like California or the Middle East, where natural water sources are diminishing and made-made waters are becoming the ultimate water sources. Given the complexity and variety of man-made fresh water sources being used to replace natural recharge in these regions, traditional tests alone, such as testing for water salinity, cannot provide a single solution," Vengosh says.

ANI