What goes into a landfill should stay there, but a new study finds that toxic, so-called forever chemicals are leaking from waste into the air. Per- and polyfluoroalkyl substances, or PFAS, have been detected in gas emitted by some Florida landfills in quantities comparable to or even greater than the amount of liquid leaking from the waste, researchers report. These chemicals have been linked to cancer, a weakened immune system, developmental problems in children, and a variety of other harmful health effects.
Landfills are everywhere and their danger, it turns out, has been underestimated. Image: Wikipedia
What substances do landfills emit
The study was published in Environmental Science & Technology Letters. The difference between liquid and gas in a landfill is significant. That's because, compared to systems that collect effluent or leachate, systems that collect gas are less efficient, says environmental engineer Ashley Lin of the University of Florida in Gainesville. Moreover, the portion of the gas that is collected on site is usually not treated to destroy harmful contaminants.
PFAS molecules contain strong bonds between carbon and fluorine atoms, which contributes to their resistance to high temperatures, grease and water. This substance is used in the production of consumer products such as raincoats, cosmetics and non-stick cookware. But these connections also cause PFAS to linger in the environment, withsome forms take more than 1,000 years to decompose.
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Are there safe landfills
It is natural that these eternal chemicals accumulate in most, if not all, landfills and their leachates. For example, a 2023 EPA report indicated that leachates frommore than 95 percent of the 200 landfills inspectedin the US contain PFAS, and 63 different types of this compound have been identified. But few have studied what types and amounts of PFAS end up in landfill gas.
In the new study, Lin and her colleagues sampled and analyzed gas from three municipal solid waste landfills. Of the 27 types of PFAS they tested, 13 were detected, with totalconcentrations ranging from 210 to 940 parts per trillion, which is quite a lot. One class of PFAS that typically exists in a gaseous state, called fluorotelemer alcohols, dominated the samples, reaching concentrations somewhat comparable to those in vapor from soil near the PFAS production facility, the researchers noted.
Near the landfill there is always a smell of something similar to natural gas. These are the same bubbles that break out. Image: RIA Real Estate — RIA Novosti
The team also took leachate samples from each landfill. But because these samples contained other types of substances, the researchers compared the total amount of fluoride that was contained in the leachate and gas samples. They found that comparable amounts of fluorine were released from the waste into leachate and gas, and at one landfill three times as much fluorine was released into the gas. And after all, few people have thought about this before.
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Does the time of year affect the danger of landfills
Landfill location, time of year and different detection methods can influence the amount of PFAS in gas and leachate samples, says environmental chemist Florentino De la Cruz of the University of North Florida in Jacksonville. According to him, to get a complete picture on a national scale, more data needs to be collected, and a national sampling campaign funded by the U.S. Environmental Protection Agency is currently underway.
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Lin says they remain questions about the fate of discarded PFAS. Captured landfill gas is often burned in gas flares, but it remains unknown whether this process destroys PFAS.
To get an idea of the scale of the garbage, think about how many bags you throw away per day and multiply that by the millions and billions of people on the planet. And even then, the figure will be greatly understated. Image: russiarecycling
Civil engineer and environmentalist Morton Barlaz calms the public a little, saying that the gas that comes out of the landfill very quickly dissolves in the atmosphere. He believes that its concentration levels are so low that they are unlikely to have an impact on health. However, according to him, it is too early to say for sure, because the gas can accumulate, emitted from all the landfills of the world.
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Research shows that household products can also emit PFAS, which are concentrated in indoor dust, says Barlaz of North Carolina State University in Raleigh. In any home located within a radius of several kilometers from the landfill, dust, furniture or old carpet can contain a huge concentration of harmful substances, which is definitely not a good sign. But such features of accumulation in homes have not yet been studied.