Scientists can measure drinking water age using atomic bomb fallout

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Scientists can measure drinking water age using atomic bomb fallout

A university research team has discovered a way to measure the age of treated drinking water by testing for residual radioactive fallout from atomic bomb testing

James Waples, a scientist at the University of Wisconsin-Milwaukee, says that measuring the decay of strontium-90, a radioactive byproduct of nuclear fission, can help determine how long drinking water spends in a municipal or private building system before it reaches a customer's tap.

The interdisciplinary research team at the university's School of Freshwater Sciences published their findings in the Environmental Science and Technology journal.

"We can go anywhere in a system at any time, grab a bucket of water and look at the ratio of radioactive yttrium to strontium," Waples said. "Based on the ratio at the source, we can then calculate how old that water is."

Yttrium-90 is a "daughter" element of strontium-90. It's what strontium becomes as it decays over time; a process Waples calls "natural alchemy." Atomic level variants of each, which have different numbers of neutrons, are called isotopes.

Strontium-90 is a radioactive isotope with a half-life about 30 years. In the 1940s, 50s and 60s, when the United States and Russia were testing atomic weapons, concerning levels were released into the atmosphere as nuclear fallout.

Waples stressed that, while still measurable, strontium-90 fallout does not remain in the environment at dangerous levels.

"Over time, it has essentially dropped to zero," he said. All water, whether in the Great Lakes or the oceans, has some small measurable levels.

Why is knowing the age of drinking water important? Well, municipal plants treat water with disinfectants like chlorine to prevent harmful microbial growth and keep people from getting sick. However, over time, those disinfectants react with organic material in the water and create toxic byproducts themselves.

Minimizing water's time in the pipes maintains quality. But water can travel for days in municipal mains through large cities. In Flint, which has been grappling with a leaded water criss, it took three weeks to clear corrosive river water from city pipes before Lake Huron water from Detroit was able to flow throughout the entire system again.

Source: Mlive

Taxonomy