Arsenic in Connecticut wells linked to former fruit orchards • Earth.com

Wells in Connecticut are contaminated with arsenic from pesticide use more than half a century ago, a new study suggests.

Much of the land that was once dedicated to fruit orchards has been converted to residential and commercial properties. Either way, researchers from the University of Connecticut and Eastern Connecticut State University have now found a strong correlation between arsenic contamination and proximity to historic orchards.

In the 1930s, the state was home to approximately 47,000 orchards which were heavily treated with arsenate of lead pesticides in the 1950s.

The study found that the closer a well is to where fruit trees once grew, the greater the likelihood of finding arsenic.

Study co-author Professor Gary Robbins explained that the research project began with a request from the Department of Energy and Environmental Protection (DEEP) in 2013. Since then, the team investigated groundwater contamination to trace the source of the contaminants.

Researchers were asked to study arsenic wells in eastern Connecticut starting with Lebanon. The project was led by Dr. Meredith Metcalf, who collected water samples from hundreds of homes in the eastern half of the state.

In total, the experts analyzed more than 100 wells and 189 orchards, using soil samples to check for the presence of lead and arsenic.

“After sampling, we looked at the distribution and possible sources of arsenic causing groundwater contamination, as a significant percentage of the wells were contaminated and many were above the norm. of drinking water from the EPA,” Professor Robbins said. “The problem that arose is: where does all this come from? »

He explained that initially it was suspected that arsenic-rich geological formations could be the culprits. But when researchers investigated the historical uses of arsenic, they found that arsenic pesticides were widely used from the late 1800s until the 1950s, when DDT became popular.

During that time, tens of millions of pounds of arsenic pesticides were applied each year in the United States, according to the study authors. Arsenate of lead pesticides were only completely banned in the country in 1988.

The study’s lead author, Dr. Mark Higgins, a hydrogeologist with Haley & Aldrich, Inc. who maintains a research affiliation with UConn, found a report listing all registered farms and farmlands in Connecticut in 1935. He are over 47,000 documented individual orchards, including peach, pear and apple.

“These pesticides would be sprayed on all fruit trees to kill pests like gypsy moths up to six times a year in some cases,” Dr Higgins said. He explained that the high application rates, coupled with the fact that lead and arsenic can move quite slowly through the ecosystem, is a combination that creates long-lasting remnants of the poisons.

When the researchers analyzed soil cores up to three feet deep at the orchard sites, they found persistently high levels of arsenic. They said that was more than you would expect for 50 to 60 plus years after applying these pesticides. “They are unlikely to migrate any lower in the water and are likely to be immobile.”

Dr. Higgins pointed to recent studies that show that certain compounds (like phosphate-containing fertilizers) can alter environmental conditions and begin to mobilize contaminants that were previously immobile in the soil.

In other areas of the state, domestic wells are near historic orchards and arsenic-rich geological formations, posing additional challenges in determining the source of contamination, Dr. Higgins said.

“How can you definitively say that the contamination came from one or the other or from both? We need this additional evidence.

With this article, we have a solid data set when it comes to the number of orchards. With additional funding and data from a wider area, I think that will tell if it’s coming from orchards or not, and how it’s getting into wells.

“It’s important for people in these areas to know because arsenic at these concentrations is not something that will make you sick tomorrow or 10 years from now. But if you’ve been drinking this low-level arsenic for 30 years, there are likely health risks associated with chronic exposure to this known carcinogen.

The study is published in The Environmental Quality Journal.

By Chrissy Sexon, Terre.com Personal editor

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