Uranium (U) element was discovered by a German chemist, Heinrich Klaproth, in 1789. Uranium is a radioactive element with an atomic weight of 238.02891 and an atomic number of 92. The uranium element initially discovered by Heinrich was an oxide, uranium oxide. A French chemist, Eugène-Melchoir Péligot, was the first person to produce pure uranium by reacting it with potassium in a heated platinum crucible. The element’s radioactive properties were established in 1896 by a French physicist known as Antoine Henri Becquerel. Currently, uranium can be extracted from various ores such as carnotite (K2(UO2)2VO4·1-3H2O), pitchblende, uraninite (UO2), and autunite (Ca(UO2)2(PO4)2·10H2O). Other sources include phosphate rock (Ca3(PO4)2), monazite sand ((Ce, La, Th, Nd, Y)PO4), and lignite (brown coal) (Gagnon par.1). Uranium is normally used as a fuel in nuclear reactors to generate electricity. However, its presence in rocks found in water bodies can contaminated water sources. Contamination of water sources by uranium can cause health issues and render such water undrinkable.
In the Unites States, several water sources are contaminated by uranium. To avoid exposure to contaminated water by unsuspecting individuals, uranium extraction is regulated by the Environmental Protection Agency (EPA). Operators of water sources contaminated with uranium are required by law to put up signs warning people of the contamination and the danger of drinking such water, such as the likelihood of developing cancer. EPA, in a bid to regulate and curb uranium contamination, defined the contamination levels that can be allowed in a water source. As such, EPA has set the maximum allowable maximum drinking water contamination level, referred to as maximum contaminant level (MCL). The EPA MCL for uranium and its waste products is 0.03mg/L. However, EPA has a maximum contaminant level goal (MCLG) of zero mg/L (How EPA Regulates Drinking Water Contaminants par.8). MCLG is also defined as the maximum concentration of a contaminant in drinking water which cannot pose any known or anticipated health effects. As such, the water is considered safe for drinking.
Uranium contamination of water sources occur when ores in uphill locations are eroded by rain and melting ice and carried downstream to low lying water bodies. In the Flagstaff City of Arizona, the MCL and MCLG levels for uranium are 30 and 0 ppb respectively. As such, no violation has been committed as this does not exceed the MCL limit of 0.03mg/L. The highest level of uranium detected in water bodies is 1.5ppb while the lowest detected level is less than 1ppb (Knickmeyer & Scott par.7). The Water production Division supplies water to the residents of Flagstaff. The water is drawn from the springs emerging from the inner basin of the San Francisco Peaks and Lake Mary. Also, Flagstaff receives water from groundwater sources such as the Woody Mountain well field, Lake Mary well field, and the Inner Basin well.
In flagstaff, tap water is safe for drinking. In the United States, the safe drinking water act (SDWA), which is a federal regulation, protects utility water supplies. EPA, under the SDWA sets standards for water utility suppliers. Also, EPA, in collaboration with its regulatory partners, ensures that drinking water is safe by implementing various financial and technical programs. The city of Flagstaff has met the statutory requirements of the Safe Drinking Water Agency with regard to the level of contaminants and the safety of drinking water. Also, the city has never been in violation of any SDWA regulation (Knickmeyer & Scott par.9). Therefore, it can be conclude that the utility water supply in Flagstaff is safe for drinking.
Drinking water contaminated with uranium can be treated through two techniques, ion exchange with anion resin and through reverse osmosis. Ion exchange resin is an organic polymer in the form of beads arranged in the form a matrix. The polymer is porous thereby providing a large surface area for ion exchange. The ions exchange occurs when ions from the contaminant, such as uranium, are absorbed into the polymer with the release of other ions into the water, hence the ion exchange process. Through the ion exchange process, uranium is absorbed from the water into the resin. On the other hand, the reverse osmosis process filters minerals, including uranium, from water by passing water through a porous membrane (Removing Uranium from Drinking Water Using Reverse Osmosis par.5). The minerals are trapped behind the membrane and the water that flows to the opposite side is free of contaminants.
Exposure to uranium can be deleterious to human health. Some of the health issues associated with drinking water contaminated with uranium include heart attacks, skin cancer, and kidney toxicity which can lead to kidney failure and eventually death. Uranium is introduced to water sources by storm water runoff and melt-water that passes over areas with uranium ore deposits. Drinking water is tested for uranium contamination using a method coded as ID-170SG. The process requires a sample volume of 240 liters with a sampling rate of 2.0 L per minute. During the analysis for uranium, a FWS-B extract is obtained using an electrolyte solution. An aliquout is then taken from the sample and analysed for uranium using the Differential Pulse Stripping (DPS) or the Differential Pulse Cathodic Stripping Polarography (DPCSP) technique (How EPA Regulates Drinking Water Contaminants par.9). This approach requires a minimum concetration of 0.2 µg per 10ml sample for uranium to be detected.
Uranium is a heavy radioactive metal that occurs naturally. The metal is usually use as a fuel in nuclear power plants. When the metal is washed into surface and ground water sources, the water sources become contaminated and harmful to human health. Ingestion of uranium contaminated water can cause skin cancer, kidney failure, and heart failure. To lower the concentration of uranium in drinking water, reverse osmosis and ion exchange with anion resin processes are used. EPA regulates the concentration of uranium in water under the safe drinking water act. The Flagstaff city of Arizona has low but acceptable MCLG of uranium contamination although EPA targets zero uranium MCLG values.
Works Cited
Gagnon, Steve. “The Element Uranium.” Jefferson Lab. Jefferson Lab, n.d. Web. 23 April 2015.
“How EPA Regulates Drinking Water Contaminants” Environmental Protection Agency. EPA, 2 Oct. 2015. Web. 23 April 2015.
Knickmeyer, Ellen & Scott Smith. “5 things to know about uranium found in drinking water.” Associated Press. Associated Press, 8 Dec. 2015. Web. 23 April 2015.
“Removing Uranium From Drinking Water Using Reverse Osmosis.” NAVASCOTIA CANADA. Government of Nava Scotia. 31 March 2014. Web. 23 April 2015.
