Most people don’t think about arsenic from day to day, but Matt Ginder-Vogel says it’s more common than you’d think.
Ginder-Vogel, an assistant professor of civil and environmental engineering at the University of Wisconsin-Madison, has received a $560,000 CAREER award from the National Science Foundation to ponder that very topic. This prestigious grant for young faculty members funds a five-year study in which Ginder-Vogel will research the ways in which arsenic becomes “mobile,” and ends up in water sources that could pose threats to humans.
Given that the World Health Organization views access to safe drinking water a basic human right, it’s a question with global implications.
“Arsenic is everywhere,” Ginder-Vogel says. “You don’t think of it, but it really is everywhere in the environment. Having a little bit in the soil—that’s not bad as long as you don’t eat a lot of soil. To humans, a lot of the threat is when it’s in water.”
Known in some circles as the “poison of kings,” arsenic is famed for its properties as a potent, odorless and tasteless poison. When it’s present in the water we drink, arsenic can lead to conditions such as cancers, developmental effects, and cardiovascular, pulmonary and other diseases.
Ginder-Vogel’s study, which will consist of lab work, will focus on understanding how manganese oxides transform arsenic, and how mineral surface chemistry impacts arsenic transformations. His goal: learn how to prevent the poison from easily entering groundwater, which is among the sources of our drinking water.
In the environment arsenic (As) commonly exists in one of two oxidation states—arsenic(V) and III—depending on the number of electrons present. Arsenate (As(V)) is less mobile in the environment than arsenite (As(III)), and Ginder-Vogel says much of the research he’s been involved with over the last decade has focused on figuring out how arsenic transforms from +V to +III, and vice versa.
“If you have manganese oxides present, arsenic stays in the +V state and is less mobile,” he says. “Once you start losing your manganese oxide in the sediments or you don’t have a lot of manganese oxides in your sediments, you start seeing a lot of arsenic +III, which is more mobile—and by more mobile, I mean it ends up in the water.”
How arsenic ends up in groundwater is a question with health implications around the world. Ginder-Vogel says it’s important to figure out why that’s happening, especially as scientists have been encouraging communities around the world—and particularly in Asia—to move away from already contaminated surface water as a drinking source and tap into groundwater instead.
For example, in Vietnam, Cambodia and Bangladesh, groundwater arsenic levels were significantly higher than in the United States, despite similar concentrations in the sediment.
“The sediments aren’t much higher in arsenic than the sediments in the Mississippi River delta,” he says. “But for some reason the groundwater is much higher in arsenic. A real focus of environmental chemistry for the last 15 years has been trying to figure out what factors will result in higher concentrations in groundwater.”
Arsenic can get into the ground a number of ways. Ginder-Vogel says arsenic is common in sulfide minerals, and can usually be found near sulfide mineral mines like those in northern Minnesota and northern Wisconsin. Conversely, in southeast Asia, iron oxides wash down from mines in the Himalaya Mountains and can release arsenic.
The chemical has historically been used for hide tanning, in pressure-treating lumber, in fungicides and even for feeding chickens.
And once arsenic is in the ground it can linger for decades or more.
“The farm fields we looked at in Delaware hadn’t been orchards treated with fungicides for 50 years, and yet they were still enriched in arsenic,” Ginder-Vogel says.
As a part of the grant, Ginder-Vogel will conduct public outreach to increase awareness of his work. He plans to do some of that through two of his classes—intro to environmental engineering and water chemistry—and by making presentations and speaking at public-facing events.
He says he hopes the work may help people think more about arsenic in the environment.
“I think you know about it if it’s an issue in your area,” he says. “But it’s not necessarily something you think of when you’re drilling your well. I believe it should be.”
Author: Alex Holloway