Time：2016-07-06| Author：Admin
Some businessmen and scientists in Austin, Texas, are trying to change the way consumers think about plastic.
They say it's not enough to buy a water bottle or sandwich bag that's free of BPA, the chemical consumer groups have criticized because, at least in animals, it acts like the hormone estrogen. They say BPA is only part of the problem, and they think they have a solution that involves a new approach to making plastic.
Mike Usey, the CEO of PlastiPure, says people need to stop focusing on BPA.
"If you're concerned about BPA, and you think that BPA-free is resolving the problem, then you should be aware that the majority, by and large, of these BPA-free products have high levels of estrogenic activity," he says.
In other words, they release other chemicals that also mimic estrogen.
Usey's claim is more than marketing hype. This week, scientists from PlastiPure and its sister company, CertiChem, published a study of more than 450 plastic products, including many labeled BPA-free. It found that more than 90 percent released chemicals that mimic estrogen.
Although it's still unclear whether any of these chemicals harm people, many consumers have shown that they are willing to pay more to be extra cautious.
Usey says he hopes these people will take note of the new research.
"The biggest challenge that we have is that we have solutions to problems that consumers are largely unaware of," he says.
Those solutions were funded in part by more than $1 million in small-business grants from the National Institutes of Health and the National Science Foundation. The result: baby bottles, water bottles and all sorts of plastic items that don't release any estrogen-like chemicals.
It all has to do with which raw materials are used and how they're processed.
Stuart Yaniger, a polymer expert at PlastiPure, points to a machine that extrudes plastic into a thin film.
"You can see we have pellets of the raw plastic resin; we have some pellets of the colorant material," Yaniger says.
He says even if these materials start out free of estrogen-like chemicals, they may not end up that way.
"It's very important to actually test plastic that has been through a manufacturing process, because things react chemically when you heat them, when you shear them, when they're exposed to oxygen," he says.
Yaniger says most plastic products contain many different materials, any one of which may be a problem.
"If we take a water bottle, for example, there is the bottle itself, the ink which is printed on the bottle, there are the antioxidants which are put into the bottle," he says. "You've got the lid ... you've got colorants. By the time you're done, you might have 20, 30, 40 different materials in what looks like a very simple bottle."
PlastiPure hopes to make money by showing manufacturers how to tweak each step in the manufacturing process so there won't be any unwanted chemicals in the plastic bottles coming off the line.
To find out whether a product measures up, manufacturers can hire CertiChem, which has its lab in the same building.
On one side of the room, a robotic arm squirts liquid into glass vials. On the other side, Matthew Stoner, senior research scientist at CertiChem, checks on some glass plates of human cells that were exposed to various plastic products, then left to grow.
"These are breast-cancer cells, which have a defined response to estrogen signaling," Stoner says.
The cell mixture in each plate ranges from light blue to navy.
"Darker blue means more cells, less blue means less cells, and we can then correlate this back to how much estrogenic activity was coming from the sample," Stoner says.
Already, the lab work has resulted in several products.
Some came from R&D Molders, a nearby company that makes all kinds of stuff out of plastic: fishing lures, medical containers, goose decoys and now a very special water bottle.
R&D's Greg Brown remembers when the folks from PlastiPure showed up.
"They came in and said, 'We want to make this particular bottle and we want to make it out of this resin,' " he says. "And it looked like it was blow-moldable, so it was no problem."
The bottles were easy to make, and tests showed they were free of estrogen-like chemicals.
The trick now is to find customers for those new bottles.
George Bittner, the biologist from the University of Texas who founded both PlastiPure and CertiChem, says if you make a better bottle, people will come —- especially if they are concerned about health.
"In this case, the solution to the potential health problem is very inexpensive," he says.
The history of BPA supports Bittner's optimism about his own ventures. Just a few years ago, BPA-free products were rare. Now they're an important part of the plastics market.
(THE NEWS COME FROM NPR, COLLECT BY JUNSHENG MOULD)
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