How plants could help us detect, and even destroy, dangerous ‘forever chemicals’ – Grist
The vision
“I think many people are now aware of the PFAs, or who care about this, or want to know if they are present in their water, their food. The purpose of what we are trying to do is to develop something simple and profitable to answer this question for them. ”
– Bryan Berger, professor of chemical engineering at the University of Virginia
The spotlights
Last fall, we wrote a story about how a group of researchers, as well as the Mi’kmaq nation in Maine, worked to combat the contamination of APF – substances by and polyfluoroalkyle, a group of pernicious and human chemical compounds sometimes called “chemicals forever”. Substances, which have been increasingly linked to health problems, are a common problem for farmers and other landowners in the Maine State. The group had experienced early success using hemp plants to shoot APFs from the soil, on a plot of land that the tribe had acquired in an old Air Force base. But many questions have remained – for them and for others working on this question – on the way chemicals move and accumulate, what safe uses for contaminated land could be and how to decompose these chemicals forever.
“I think everyone is struggling with this question, trying to understand, what does” forever “mean? How long will he persist in the ground? How will he transport in the environment? ” Bryan Berger, one of the researchers, told me at the time. In addition to the work with the hemp experience of the Mi’kmaq nation, his laboratory has examined a range of ways that the plant kingdom could help us to follow and perhaps even eliminate the contamination of PFAS.
I can’t wait to follow up with Berger, a chemical engineer at the University of Virginia, about what he and his collaborators have learned so far to try to answer these questions. At the time, the group had just received a four -year subsidy from the Environmental Protection Agency to continue to study the sanitation potential for hemp factories, as well as other activities, such as the way of giving farmers better test tools to know when their land is contaminated. But in the past two months, as for so many research projects, the group has faced setbacks. Their subsidy (already approved by the congress) was interrupted unexpectedly in May, as well as a list of other subsidies focused on PFAS research – previously considered a fairly non -partisan problem.
The group appealed and the EPA restored its subsidy at the end of June, without any other explanation.
“Because of this whole situation, I do not feel so completely sure of [the funding] As I did when we got the subsidy for the first time, “the Maine Morning Stanley, co-founder of an environmental organization told The Maine Morning Stan, told The Maine Morning Star.” But of course, we are just going to go ahead and do all our work. “
As Berger shared with me, this work is still in its infancy, but gave exciting results for the team.
One of the first questions of the battle to try to contain APFs is whether chemicals are present in a given area – let’s say, a farm or a field – and if so, where they could come from. The growing proof that PFAs can be dangerous for human health have led chemicals to be prohibited in many places. “We expect you to see a reduction in PFAS levels accumulating in the soil and crops,” said Berger, “but that did not happen.” There are still unregulated sources causing the propagation of substances.
Give land and water managers better test tools to follow the PFASs on which his laboratory had been working for a long time. PFAS tests are currently being done with a mass spectrometer, sophisticated laboratory equipment. This provides high quality data, but it is very expensive and timed, said Berger – with around $ 400 per sample, with an execution period of one to two weeks. “There is just a huge shortage of infrastructure to carry out tests on a necessary scale,” he said. The terrestrial stewards need a simple test similar to a pH strip which can measure the PFA – and shepherd and his team have developed something close: a biocapper, in the form of a fluorescent microbe that shines when exposed to PFA.
Thanks to the collaboration with the Mi’kmaq nation, Berger and its collaborators tested the biocappters on water samples taken from the earth of the tribe in the old Air Force base – and in a report published in October, they found that the sensors could effectively detect the high levels of chemicals, even in samples that contain other contaminants.
“So we have a direct test method that could be used, it’s a kind of fast and cheap detection point,” said Berger. It will not replace the most sophisticated laboratory tests, but offers an option to farmers who wish to test, for example, on hundreds of acres.
To rely on this work, Berger hopes to develop a way to incorporate the same technology within a plant – which he calls “a new turn on an old idea”. The old idea refers to the concept of sentinel plants: traditionally, a plant sensitive to certain diseases or pests that farmers were monitoring to see when these pests were present, then the measures to control adaptations accordingly. “And if we are then going further and engineer to indicate a signal to tell you that there are PFAs present – you know, maybe you apply a pesticide and then it turns on,” said Berger. As with the microbes that his team has tested, this signal could be a fluorescence – which means that plants literally shine when PFAs are present. A warning panel like this one would mean that farmers would not need to take an additional step of regular tests, even with simple microbe kits; They could simply look at the sentinel plant to see when the PFAs arise. “Then you get real -time data,” said Berger.
Another thing that he and the Maine team have worked is to understand if the food cultivated in a soil contaminated by the PFAS or supplied by water contaminated by the PFAS is also contaminated, and therefore dangerous to eat. The obvious answer seems to be yes – but it depends on how substances move, where they accumulate and if certain plants could be resistant to take them.
“If there are PFA resistant cultivars, it could be another tool in the arsenal for producers,” said Berger. Likewise, if farmers understood that the PFAs met only in a part of the plant that was not codible, they can still be able to cultivate certain crops in complete safety while working simultaneously on sanitation. Most recently, the team had a discovery of a breakthrough on this front.
“We have done a study where we examined the accumulation of PFA in potatoes, which are a kind of significant part of the agricultural heritage of Maine,” said Berger. “They are very proud of their Maine potatoes.” This study, published by the Central Aroostook Soil and Water Conservation District of Maine, one of the subsidy partners, revealed that the PFAS did not accumulate in the edible root of the potato – the chemicals were only stored in the green leafy parts.
“So you could cultivate potatoes even if there were PFAs present in irrigation water, which they found,” said Berger. The team plans to continue to test other common crops such as broccoli, Brussels cabbage and kale, as well as culturally important plants for the Mi’kmaq nation, such as violin heads and ashes.
Although it is comforting conclusions of the first months of the grant, one of the biggest questions that remains for anyone working on the PFAS is what, if necessary, can be done to get rid of chemicals. According to Berger and his collaborators, there is currently no evolutionary and profitable means of destroying the PFA. “This is a million dollars,” said Berger.
But his laboratory has tested a possible approach, essentially imitating photosynthesis in a specially designed microbe and using the energy of this process to break down the PFA that the microbe had absorbed. “Thus, the kind of manufacture of plants or other microorganisms diverts part of this energy or electrons in the destruction of PFAS,” said Berger. The initial trials in the start -up phase turned out to be promising, although there is even more research to do before the approach can be attempted in a real application. “It is not a perfect solution ready to leave or anything, but these are promising things that we do that are different from what currently exists,” said Burger. In fact, the decomposition of PFAs in a contaminated plant or microbe would mean that substances would propagate no further – unlike other elimination methods, such as incineration, which can release chemicals in the air.
“If it works, it is the most benign way in the environment that we can do things because it is almost all biological,” said Berger.
– Claire Elise Thompson
No more exhibition
A separation stroke
In this 2019 photo, dairy producer Fred Stone held a small press conference on his land in Arundel, Maine, calling on civil servants to take action to avoid future contamination of APFs on farms. He closed his farm after discovering the PFAS levels in the milk of his cows and became a leading defender of the action. Many state farms, such as stones, have been exposed to chemicals by applying sludge or biosolids – a product of wastewater treated for a long time as fertilizer.
