Have You Wondered How Arsenic Enters a Well? You're Not Alone

Jun 24, 2014

A new project at Eastern Connecticut State University is looking at arsenic contamination in privately-owned wells. The question of where that arsenic is coming from has attracted surprisingly little attention, until now. 

Arsenic is tasteless, odorless, and poisonous if ingested. It was put in American pesticides prior to World War II, added to metals to make them stronger, and today, often turns up in landfills. It's also naturally occurring underground. "It can be common in several of the rock types in Connecticut as well as other areas of New England," said Meredith Metcalf, assistant professor at Eastern Connecticut State University.

Metcalf is working with undergraduate Laura Markley to address a surprisingly complicated question: when arsenic turns up in a private water well, where is it coming from? "We really don't know all that much. And the reason being is that we really don't know anything about groundwater flow in Connecticut as well as all of New England," Metcalf said. 

A diagram of a typical bedrock well in Connecticut. Well yields depend on characteristics of water contributing fractures (pictured above) that intersect the well. Unfortunately, Metcalf said, little is often known about those fractures or how water flows.
Credit Meredith Metcalf / Laura Markley / Eastern Connecticut State University

Metcalf and Markley are focusing on how water flows underneath one Connecticut town: Lebanon. Last October, traces of arsenic were found in the well water of a school there. Now, the team is now pulling drilling reports from wells all over town to see how the underground water flows and what type of rock it intersects with. They're also looking at water quality data and testing 100 wells to see if they contain arsenic. 

"The idea is to not only look at arsenic, but to look at groundwater flow and really have a good idea of where it's coming from and where it's going. And then determine its source," Metcalf said. "Can we really attribute it to something naturally occurring or do we have to attribute it to something that is anthropomorphic or man made?"

Currently, there's no state-mandated requirement that all of Connecticut's estimated 4000,000 private wells be tested regularly for arsenic, but the Department of Public Health recommends testing every five years.

Metcalf and Markley said they hope to present their findings next year.