Researchers report rapid removal of BPA from water using green chemistry
As water treatment plants struggle to keep up with the chemical cocktail heading into our pipes, researchers say they've come up with a solution to remove one of the most ubiquitous contaminants—BPA.
Chemists were able to remove about 99 percent of bisphenol A (BPA) from water using a mixture of hydrogen peroxide and engineered catalysts, according to a study released today in the journal Green Chemistry.
Changing the game
The findings are a potential game-changer. Water treatment plants were not designed to deal with chemicals such as BPA, which is used to produce polycarbonate, epoxy and phenolic resins and largely used to make plastic hard and shatterproof, but also used in thermal receipt paper and food packaging.
The chemical gets into waterways from leaching out of landfills and industrial emissions. In a study of 19 U.S. landfills the U.S. Geological Survey found BPA in 95 percent of the tested leachate, which is the water that passes through landfills.
It's not totally clear how much people are exposed to BPA from water, said Chris Kassotis, a postdoctoral research scholar at Duke University who studies endocrine disrupting chemicals.
"But it's [BPA] widely occurring in water—it's been found in everything from effluent, surface water, ground water, and drinking water," added Kassotis, who was not involved in the new study.
A cost-effective solution
Researchers combined small molecules that act as oxidizing catalysts with hydrogen peroxide and found that the mixture breaks down chemicals in water. When the mix was added to water contaminated with a high amount of BPA, 99 percent of the contaminant was gone within a half hour.
"If what we found in lab water transfers to these much messier solutions at landfills, we'd have a really great, cost effective solution," said senior author of the study, Terrence Collins, a chemist from Carnegie Mellon University.
The mixture works by binding BPA together into larger clumps, which then precipitate out of the water and could be filtered out at a treatment facility. "When we add the catalyst (molecules) and the hydrogen peroxide, it's almost immediate— a white cloud forms," Collins said.
This cloud of clumps also won't revert to BPA, making it harmless. When the researchers put zebrafish embyros in the water with the clumps, there wasn't any hormone activity, as you would see with regular BPA exposure.
A health priority
BPA is a popular chemical—about 15 billion pounds are produced annually and people are consistently exposed. Scientists have expressed alarm for years over this exposure, as BPA is a known endocrine disruptor, meaning it alters the functioning of hormones.
Properly functioning hormones are crucial to reproduction, as well as development, brain function and immune systems. BPA exposure has been linked to certain cancers, obesity, behavior issues in children, fertility problems, low birth weights and birth defects and other health problems.
In the new study Collins and colleagues outline the ubiquity and toxicity, saying that the removal of BPA should be a health priority. "There isn't a living thing on this planet that can escape BPA," Collins said.
Landfills are especially a concern as they are full of products with BPA, which can escape over time.
"Think of your DVDs, or CDs, for examples, those are polycarbonate, so if they're sent to the landfill, they break down in water over time, leaching out BPA," Collins said.
Studies of Japan landfills found untreated leachate had about 17,200 parts per billion of BPA, and even treated leachate had about 5.1 parts per billion.
Work in progress
Kassotis said waters that receive industrial discharge have higher levels as well.
A review of US studies by the U.S. Environmental Protection Agency found that BPA was found in about 80 percent of 1,068 surface water samples. The concentrations, however, are usually very low, averaging less than 1 part per billion.
BPA has also been found in some drinking water, however, those levels have been small concentrations too, Kassotis said. "Researchers are still working out exactly which are the most significant pathways for exposure," he said.
Collins said his team has been working on this process for about 15 years. While this method targets BPA he said it could work on other similar endocrine disrupting pollutants. "We can get most of the active pharmaceuticals and many, if not all, pesticides," he said.
The next step is getting the technology out of the lab.
"I expect this will happen," Collins said, "I'm quite optimistic this will work in real world scenarios."