Deep wells in Glastonbury have more uranium: study
Jun. 22—GLASTONBURY — Seventy percent of the private wells in town that have been found to produce water containing more uranium than the federal government considers safe for drinking are more than 400 feet deep.
That is among the more surprising findings in an initial report by a team of scientists that has been looking at the uranium pollution problem in town.
In the report, to be presented to the Town Council this evening, the scientists call the tendency for deeper wells to have higher uranium concentrations "somewhat counterintuitive, as shallower groundwater in most systems is usually more oxygenated, which would lead us to expect higher concentrations of uranium."
But they also say most Glastonbury wells are connected to a fractured rock aquifer.
"Water movement in fractured aquifers is very complex, which presents significant challenges in predicting water quality and quantity," they write. "Since the amount and quality of water transmitted by fractures can vary significantly over a small geographic area, wells situated close to each other are not necessarily connected to the same fractures. As a result, uranium concentrations can vary between wells."
They give some dramatic examples of this.
One 520-foot-deep well produced water containing 48 micrograms of uranium per liter, which is above the federal drinking-water limit of 30 micrograms per liter but well under the 900-microgram level considered unsafe for bathing.
Just 330 feet away, the length of a football field and one end zone, a 750-foot-deep well had 22,300 micrograms of uranium per liter, a concentration far above any usable level.
This phenomenon of wide variations in uranium levels in a small area has caused political conflict in town. People who want public water mains extended to their neighborhoods have run into disagreement from neighbors who don't want to pay for water service when their well water is fine.
The scientists also cite examples in which uranium concentrations have varied widely in different samples taken from the same well. They cite one well in which the lowest and highest uranium concentrations were 105 and 4,050 micrograms per liter, respectively.
"The data implies that there can be large fluctuations in uranium concentrations over time, which homeowners should be mindful of," the scientists write in the report.
The authors of the report include two town officials — Health Director Wendy Mis and Sanitarian Don Kendrick — and three scientists from other parts of the country recruited by the Washington, D.C.-based Thriving Earth Exchange, which is associated with the American Geophysical Union.
The most senior of the outside scientists is Assistant Professor Hari Kandel of the School of Natural Resources and the Environment at Lake Superior State University in Sault Sainte Marie, Michigan.
Also working on the project are two scientists who have received their doctorates within the last two years, Rachel Coyte of the Nicholas School of the Environment at Duke University in North Carolina and Caitlyn Hall of Arizona State University.
The health hazards presented by the naturally occurring uranium stem from its chemical nature rather than radioactivity. The study cites evidence that uranium can have toxic effects on the kidneys, bones, reproductive system, liver, and nervous system.
An illustration in the scientists' report shows that many of the polluted wells in town are in the Glastonbury Gneiss bedrock formation, which the scientists say illustrates "the potential" that uranium-rich minerals in this formation "are the possible primary source of uranium in groundwater and surface water in the area."
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