Purified Water – Not So Pure

Posted in: Featured, Ground Water News, United States Water News, Water Contamination, Water Strategies
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Orange County’s Wastewater Reclamation Plant (Photo credit: Stephen)

By Seren Nurgun, Staff Writer for Save The Water™ | October 21, 2015

As effective and safe water storage becomes increasingly important around the world, especially in drought-ridden California, more scientists are conducting research on how current methods are enduring. A study, recently published online in the Environmental Science & Technology journal, details the results of data compiled from the Orange County Water District (OCWD) in Fountain Valley, CA. The issue arose when officials from the OCWD began to observe unusual spikes “in arsenic after it percolated into soils and sediments from surface basins into underground storage aquifers” (Than). What was specifically unusual was that the water that absorbed this excess arsenic had “undergone a rigorous purification process” (Than). Logically, a rigorous purification process, by definition, means that the water that comes out of this process is clean and safe to consume.

It is well known by the scientific community that water contaminated with abnormal amounts of hazardous chemicals can more often than not cause physical harm in animals and humans. More specifically, arsenic-contaminated water has been tied to causing skin damage, problems with the circulatory system, and an increased cancer risks (Basic). According to Chen et al., “arsenic exposure from drinking water has been associated with heart disease; however, underlying mechanisms are uncertain.” This study, completed in 2013 and published in the journal of Environmental Health Perspectives, tested how “a history of arsenic exposure” (Chen) affected the results of the electrocardiogram of the same group of women and men over a period of 5.9 years. A separate study completed by Dauphine et al. mentions how drinking water with high levels of arsenic can cause lung cancer.

The health risks of arsenic contamination were therefore serious enough to warrant immediate review of the system in Orange County, CA. Although the OCWD maintains a very high quality water purification process, known as the Groundwater Replenishment System (GWRS), workers found spiked levels of arsenic near a section of the system known as the groundwater monitoring wells. A few of these increases were slightly higher than the acceptable U.S. drinking water maximum of 10 micrograms per liter. Even though these spike levels were not particularly dangerous, officials still wanted to investigate the phenomenon. They reasoned that, because the arriving water was clear of any arsenic contamination, the arsenic must have contaminated the water by seepage underground. The investigative OCWD team also concluded “only the purified recycled water triggered the arsenic spike” (Than).

Following this discovery, a team from Stanford University’s School of Earth, Energy & Environmental Sciences found that there were in fact traceable amounts of arsenic directly above the aquifers. However, scientists were still puzzled as to how this arsenic was making its way into the water. After conducting multiple experiments, the team came to a conclusion. The post-purification water was so clean and lacking in calcium and magnesium that “this deficiency caused calcium and magnesium atoms in the sediments to migrate into the water and off of charged clay particles that harbored the arsenic” (Than). “With the calcium and magnesium ions leaving the clay surface, the arsenic ions were repelled from the clay surface and entered the water” (Than).

The team at OCWD began to explore possible remediation methods on how to avoid arsenic spikes in the future. They concluded their search by deciding “to add more calcium to the water during the treatment process” (Than). They figured that this was the best solution after consulting their own specialists as well as the team from Stanford University.

After finding a new way in which arsenic can contaminate an advanced water purification system, scientists and water management officials can begin to brainstorm more creative and effective ideas in order to solve future arsenic contaminations as well as additional water-related contaminations elsewhere.


“Basic Information about Arsenic in Drinking Water.” United States Environmental Protection Agency. EPA, 17 Sept. 2013. Web. 18 Sept. 2015.

Chen, Yu, Fen Wu, Faruque Parvez, Alauddin Ahmed, Mahbub Eunus, Tyler R. Mcclintock, Tazul Islam Patwary, Tariqul Islam, Anajan Kumar Ghosal, Shahidul Islam, Rabiul Hasan, Diane Levy, Golam Sarwar, Vesna Slavkovich, Alexander Van Geen, Joseph H. Graziano, and Habibul Ahsan. “Arsenic Exposure from Drinking Water and QT-Interval Prolongation: Results from the Health Effects of Arsenic Longitudinal Study.” Environ Health Perspect Environmental Health Perspectives (2013): n. pag. Web. 18 Sept. 2015.

Dauphiné, David, Allan Smith, Yan Yuan, John Balmes, Michael Bates, and Craig Steinmaus. “Case-Control Study of Arsenic in Drinking Water and Lung Cancer in California and Nevada.” International Journal of Environmental Research and Public Health IJERPH 10.8 (2013): 3310-324. Web. 18 Sept. 2015.

Stephen, and Rob. “The Best Architecture of the Decade – Mammoth // Building Nothing out of Something.” The Best Architecture of the Decade. Mammoth, 25 Jan. 2010. Web. 18 Sept. 2015.

Than, Ker. “Stanford Soil Sleuths Solve Mystery of Arsenic-contaminated Water.” Stanford News. Stanford Report, 2 Sept. 2015. Web. 17 Sept. 2015.

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