The Register Citizen (Torrington, CT)
ARSENIC AND OLD ORCHARDS?
Scientists eye link to contaminated state’s drinking water
In 2013, drinking water at an elementary school in Lebanon was found to contain traces of arsenic.
The source, three local researchers are suggesting, may have been a century-old apple orchard. And the issue might be far more widespread than that one location.
Researchers from UConn and Eastern Connecticut State University pieced together a puzzle, mapping high levels of arsenic in wells in search of a common source.
“Basically, what we found is that there is in fact a spatial correlation between wells that are contaminated with arsenic and old orchards,” said Gary Robbins, professor of geosciences and natural resources at the University of Connecticut.
From the late 1800s until the 1950s, orchards in Connecticut were sprayed with a lead-arsenic compound. There were, Mark Higgins said, 47,000 orchards registered in Connecticut in 1935.
“We don't want to sound the alarms here,” he said. “We're not saying that we found absolute proof that you’re drinking poison if you live near an orchard. Right now, what we’re saying is, up until recently, no one's really considered the fact or paid much attention to the fact that they were spraying lead-arsenate all over the place for 60, 70 years.”
Higgins, a senior hydrogeologist at engineering firm Haley & Aldrich and a research affiliate at UConn’s Department of Geosciences, has been working with Robbins to confirm the relationship between apple orchards that pre-date 1950 — when leadarsenate was exchanged for DDT as a pesticide — and high arsenic levels in local wells.
While they are confident of a correlation, they have not yet confirmed causation. There are still questions to answer.
“What we don't know is whether or not those houses that are seeing arsenic today are seeing arsenic that’s emanating from those orchards now, as opposed to arsenic that started to emanate when they were spraying, and it just took this long to get there,” Robbins said.
But they have found a strong enough location correlation to suggest a relationship. If a well is situated near or down-slope from an orchard that predates 1950, if the wells have what Robbins said was “shallow depth to groundwater” and if it’s a bedrock well, then it’s likely to have elevated arsenic levels.
“I think there’s enough cause to say, someone should be looking more into this and providing more funding to collect more data on the ground so that we can definitively understand,” Higgins said, “is it coming from the orchards?”
The levels of arsenic are not insignificant. The U.S. Environmental Protection Agency has said that arsenic concentrations in drinking
water of 10 parts per billion is safe for human consumption, but Higgins and Robbins said they found concentrations as high as 200 parts per billion in local wells.
“I can't tell you how many wells, but, nonetheless, we’ve seen concentrations up to 200-plus,” Robbins said.
Rock formations
Arsenic is a naturally occurring substance. It is found, among other places, in local rock formations.
A 2017 report from the U.S. Geological Survey, updated in April 2021, found that about 3.9 percent of private wells across Connecticut contain water with arsenic that exceeds EPA standards.
“Arsenic and uranium are naturally occurring metals in bedrock around the world,” said the report, written after a study conducted along with the state Department of Public Health. “Sometimes wells drilled into bedrock aquifers can produce water containing arsenic
or uranium.”
Robbins confirmed that there is arsenic in local rock, more specifically: “We have formations that have arsenopyrite. This is an iron, arsenic sulfide mineral, and naturally occurring.”
“People have known about arsenic in the water for quite some time,” Robbins said. But while “the assumption was it’s coming from the rock,” he added, “we have never seen definitive evidence demonstrating that.”
Arsenic-laden rock formations do not explain the correlation between contaminated wells and orchards.
That work began with Meredith Metcalf, a professor in the Earth Science department at Eastern Connecticut State University.
“We started looking into arsenic in groundwater after the Lebanon Elementary School tested positive for arsenic in 2013,” she said in an email. “Given the observed distribution here and in other towns and our results with respect to the underlying geology, we started to investigate the likelihood that the distribution may be attributed to
historic land use which was primarily agricultural (i.e., orchards).”
Patrick McCormack, director of the Uncas Health District, which covers the town of Lebanon, said there have been no indications of arsenic-related illness. At least not yet.
“The impact of high arsenic can take years and years for somebody to have an effect from it,” he said. “There’s the potential for having health impacts down the road.”
After Metcalf ’s initial work in Lebanon, Robbins and Higgins moved on to Weston, where the U.S. Geological survey had found high concentrations of arsenic.
“They cited Weston as the town that had the highest levels of arsenic contamination,” Robbins said. “That's why we focused our attention to look, is there a correlation between the geology and that arsenic, or is there a correlation between the orchards and arsenic? And, basically, the evidence to date points to the orchards.”
Higgins and Robbins examined water quality data from 480 wells in the town and found that 34 percent
were contaminated with arsenic.
“About half of those exceeded EPA standards,” Robbins said.
‘No reason to panic’
Many of the wells in both Weston and Lebanon that were found to have high levels of arsenic have been fitted with filters, either in the well itself or at the faucets.
“It's really up to the homeowner to test their wells, and to determine what remedial efforts are necessary or when they are desired,” Robbins said.
Mark Cooper, director of the Westport-Weston Health District, said no arsenic-related illness has been identified in the town, and that “there is no reason to panic.”
Low levels of arsenic are found in many common foods, he said, and “the body regulates arsenic to a certain degree.”
“Levels that we’re seeing are higher than people want them to be, but there is treatment equipment,” he said. “It’s not a hazard for bathing and washing, and there are solutions to having elevated arsenic in one’s drinking water.”
The next step for Robbins and Higgins is to date the groundwater, which they said will help establish causation. They’re also hoping to sample the soil in the orchards themselves. The lead in the leadarsenate is not as mobile, so if a higher proportion of lead is found closer to the orchards themselves it would be another strong indication of causation.
They’re also hoping to dig their own wells.
“I would love to put some shallow water wells in some of these properties, just to see what's going on,” Robbins said. “That would be the ultimate in the end, the most definitive test.”
And while they don’t want to raise concern, Higgins and Robbins do suggest that homeowners get their wells tested for arsenic.
“We're saying if you are either on an old orchard or your property’s on what was a former orchard or a current orchard or, in fact, you’re downgradient of an orchard that was there during this period of time, then you might have a higher risk,” Robbins said, “and you should get your well tested.”