Radioactive Waste 236 - New Hand-Held Device Can Cheaply And Quickly Measure Trace Amounts Of Uranium In Water
It is important to be able to monitor the level of uranium in bodies of water. Unfortunately, current methods of testing water for uranium are expensive and complicated.
Gary C. Tepper, the chair of Virginia Commonwealth University’s Department of Mechanical and Nuclear Engineering, and a graduate student have invented and patented a new device that will make it easier, faster and cheaper to monitor the amount of uranium in water. The new device is more sensitive than previous monitoring equipment and is able to detect lower levels of uranium pollution.
Uranium is common in many different minerals. It can enter surface and ground water in many different ways. These include uranium mining, the production of nuclear weapons, leakage from nuclear fuel storage canisters, the illegal dumping of nuclear waste and agriculture. Fertilizer runoff can result in chemical reactions that release uranium from minerals in the ground.
The U.S. Environmental Protection Agency’s Safe Drinking Water Act provides the standards for what is considered a safe level of uranium in drinking water. The problem is that testing is expensive and takes time which lowers the actual monitoring and compliance with the standards from the EPA. Tepper says that "Right now, you test for uranium by taking water a single sample [of water] and sending it out to a lab. This is impractical. You need a device that takes measurements in real time. It should also be easily used across various regions of the water source because concentrations vary from place to place."
The new device that Tepper and his graduate student invented uses a nanoporous material that collects and concentrates particles of uranium in water and then employs an ultraviolet light which makes the collected particles visible. When uranium compounds are dissolved in water, they are fluorescent. Because of this effect, ultraviolet light can be used to create a measurable signal in the form of visible light. Tepper says "But water quenches that reaction and makes it difficult to detect and quantify uranium at very low concentrations."
The device that Tepper invented uses tiny beads of silica get that are commonly used as a desiccant. Tepper explains that “The uranium compounds attach to silica gel and accumulate inside the small pores. This enhances the signal and minimizes the quenching effect of water, so now if uranium is present, it lights up and can been seen in the visible spectrum.”
Combining the silica gel and an ultraviolet light source results in a cheap portable hand-held device that can reliably read low concentrations of waterborne uranium. An early version of the device required an hour to read uranium concentration after being dipped in water. An improved model added a pump to move the water through the device. This resulted in the ability to read uranium concentration is a matter of seconds.
Tepper and his graduate student have provisional U.S. and international patents for their device. They are working with Virginia Commonwealth University’s Innovations Gateway to bring their device to market.
