The Hippo


Nov 16, 2019








Spill or emission?
How chemicals contaminating N.H. wells may have escaped a plastics factory

By Ryan Lessard

 There’s still plenty we don’t know about PFOAs — like whether they cause cancer in humans — but investigators are starting to figure out how they ended up in scores of private and public drinking water wells in Merrimack, Litchfield and Bedford.

Working backward
After tests of 107 wells found that 26 private wells had levels of perfluorooctanoic acid (PFOA, a chemical used in making Teflon coatings) at 100 parts per trillion or higher within a roughly one-mile radius of the Saint-Gobain Performance Plastics plant beside the Merrimack River, investigators have become certain about what they suspected from the start: that the chemicals came from the factory.
The wells with the highest concentrations were three wells in Merrimack fairly close to the plant. They were found to contain 830, 820 and 680 ppt. The remaining 23 wells with high levels were on the eastern side of the river in Litchfield. Most of those had between 100 and 350 ppt, but two wells had as much as 570 and 530 ppt. 
This confirmed that PFOAs were in the water table because multiple area wells, siphoning from the same source, were contaminated.
“A lot of wells basically are a hole in the ground that go deep enough so that the … lower end of the hole is below the water table. It’s kind of like if you put a straw … into the water,” said UNH chemistry professor Christopher Bauer.
One of the reasons the chemical has been able to make it as far as the water table is that it is designed to be resistant to most methods of chemical breakdown.
Bauer says PFOAs are made of a chain of carbons surrounded by fluorine atoms with an acid group on the end. 
“The structure of this molecule is very much like soap. … That stuff will dissolve to some extent with water and it will go wherever the water goes,” Bauer said.
Soap, however, is covered with hydrogen atoms where PFOA has fluorine. The fluorine atoms make the molecules much more resistant to chemical reactions with the environment.
“The fluorine effectively helps protect the structure, so microbes are not genetically engineered to break that stuff down very efficiently. They don’t have the biological mechanisms to turn that into food,” Bauer said.
And breakdown becomes more difficult once the chemical gets underground because of the scarcity of sunlight and oxygen, which promote geochemical and biological breakdown.
To make matters worse, the family of perfluorochemicals, or PFCs, of which PFOA is a member, is generally fire- and water-resistant. In fact, they have, until fairly recently, been key components in the creation of Teflon and Scotchgard, water resistant polymer coatings. 
Russ Foster, an environmental chemist with EnviroSystems in Hampton, says Teflon reacts to heat by softening instead of burning, which is one reason why it’s used in cooking equipment. Airport fire departments would use a foam with PFCs to put out fuel fires.
“The airport would practice with these and there’ll be a practice field and those fields may be contaminated,” Foster said. 
He said the molecule chain that composes the chemical has two ends. One end is the resilient “Teflon” end, and the other is the acid end, which can be dissolved in water. 
“So the compounds are half organic in nature and half inorganic,” Foster said. 
This makes them able to seep into the environment easily while also maintaining most of their chemical structure.
Foster says PFCs, while they are manmade, are already ubiquitous in our modern world. We likely consume trace amounts every day. 
“I’m my opinion, I’m guessing that we’ve all been drinking one part per trillion, five parts per trillion all our life, or ever since Scotchgard hit the market,” Foster said.
Foster said his lab isn’t equipped for it because the equipment costs as much as $200,000 and would require a super clean room.
The link to Saint-Gobain
One likely scenario, according to New Hampshire’s Department of Environmental Services, is that smoke emissions from the Saint-Gobain smokestacks may have resulted in the contamination.
“That is a reasonable pathway to explain [what may have happened],” said DES spokesman James Martin. “PFOA can be released to the air, it can be absorbed by other particles, it settles onto the ground [and] it gets into the soil and transported to groundwater, where it’s very resistant to degradation. That’s why it’s sort of persistent in the environment.”
In fact, Martin says DES is already aware of past emissions from 12-year-old monitoring data that led to corrective action. In 2004, the testing methods were improved and analysts found APFO (ammonium perfluorooctanoate) exceeding ambient air limits coming from the Saint-Gobain stacks. DES then ordered Saint-Gobain to phase out the use of that chemical, which it substantially reduced by 2007.
Saint-Gobain spokesperson Dina Pokedoff said PFOA was used to process a raw material known as PTFE, a fluorinated polyethylene, but that processing was done off-site and the PTFE was delivered to Merrimack with “very low levels” of PFOAs. 
“In 2006, the manufacturers of PTFE raw materials started to manufacture PTFE made with either reduced levels of PFOA or without PFOA. Saint-Gobain purchased, from suppliers, PTFE raw material made with reduced levels of PFOA or without PFOA as soon as they were available,” Pokedoff said in an email.
This, she said, resulted in significant reductions of PFOAs by 2009, and the company eliminated all PFOAs by 2014.
DES is also looking into the possibility of a direct spill.
“We’re investigating the use of the chemical and what [Saint Gobain’s] wastewater uses may be ... if there were any spills at the facility that got washed into a drain,” Martin said.
Martin says the department is awaiting data from Saint-Gobain and expects it to arrive any day now. If a “source point” exists, one possible cleanup method would be to pump water from that site to remove any chemicals actively leaching into the groundwater.
Investigators think that both emissions and direct discharge likely happened. Those contaminated wells getting water from the shallower sand and gravel level were likely affected by emissions, while chemicals in affected wells in the deeper bedrock level probably originated from a discharge. 
In the meantime, DES commissioner Tom Burack told Saint-Gobain in a letter that the company is expected to cover the cost of bottled water for affected homes, the cost of any water supply changes or filter installations, the cost of the state investigation thus far and moving forward and, ultimately, the cleanup of the site.
Experts say household charcoal filters may be effective in getting most of the chemicals out of drinking water, but wells with severe contaminations will probably tax ordinary home filters. 
Until a more permanent solution is set up to provide clean water to affected homes, bottled water will be provided. Permanent solutions may either involve the installation of heavy-duty water filters in basements or building a new water line from Pennichuck Corporation. 

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