字幕表 動画を再生する 英語字幕をプリント Should you be worried about microbeads? Pick up a bottle of facial scrub and there's a chance it'll contain these really small beads of plastic. They're designed to gently strip away the outer dead layers of your skin, and leave you feeling tingly fresh. Since the nineteen nineties, these beads have been used in thousands of products: foundations, facial scrubs, shampoos, exfoliants, soaps, face polish ... whatever that is, and even toothpaste. They're typically around a millimeter or less in diameter, so similar in size of a grain of sugar. Unfortunately, while they seem to be effective, they may be creating problems. In 2013, researchers discovered that these microbeads were appearing in the environment, and they raised the alarm over possible adverse impacts. Since then, ten states in the US have restricted sales of microbead-containing products, and similar legislation is pending in six more. There are also proposals on the table for a federal ban on the use of microbeads in the US. But how concerned should you really be? Polyethylene - the plastic most microbeads are made of - is pretty non-toxic. It doesn't cause cancer, it doesn't seem to be a problem if you eat it, and it doesn't irritate your skin. In fact it doesn't do much of anything, including dissolve, or decompose. And this is where things get tricky. Microbeads in personal care products eventually end up being washed down the drain. And because they're so small, they escape capture in wastewater treatment plants, eventually ending up in rivers, lakes, and oceans. Once there, because they don't degrade or sink, they stick around. For a long, long time. This is an environmental red flag in itself. But there is another problem. Microbeads suck up toxic chemicals, and then potentially release them elsewhere, including into mussels, crabs, fish, and other organisms, that may ultimately end up on your dinner plate. Of course, how dangerous this is depends on how large the resulting exposures are. Professor Sherri Mason at the State University of New York at Fredonia is one scientist working on the problem. Sherri and her colleagues have measured up to a million microbeads per square kilometre at the surface of Lake Ontario. This is roughly equivalent to a polyethylene concentration of six parts per billion. This may not sound a lot. And it wouldn't be if the plastic was the only problem. But even at this low concentration, toxins absorbed to the microbeads could be an issue. To make matters worse, organisms that do take up beads, concentrate them into a smaller volume, potentially leading to higher exposures. And this isn't an issue confined to microbeads. Micro plastics, millimeter-sized fragments of the plastic rubbish we're continually dumping into the environment, also suck up toxins, and pass them up the food chain. But microbeads certainly add to the problem. At this point we don't know how big of a challenge we're facing, but without a doubt, microbead raise some serious red flags. On top of this though there is another issue with microbeads, even before they disappear down the drain. And that's their use in toothpaste. Some toothpastes include microbeads to, you guessed it, leave you with that tingly fresh feeling after brushing. The trouble is, some of those beads can end up lodged between your gums and your teeth. No one's sure yet whether this is a problem. The American Dental Association for instance doesn't think that microbeads are unsafe. But they are monitoring the situation. That said, some dental professionals are worried that, because microbeads stick around for so long, getting them lodged in your guns could potentially increase the chances of developing diseases like gingivitis. In the meantime some companies are phasing out the use of microbeads in toothpaste, though mainly because they'd prefer to play it safe with their customers. The bottom line is there's a lot we still don't know about the potential risks of microbeads. But given their size, persistence, and propensity to soak up toxic chemicals, there's a pretty good chance that they'll end up causing harm somewhere. So next time you reach for the facial scrub, or the microbeads soap, you might just spare a thought to future generations, who are going to have to clean up the mess, that you may just be contributing to. For more information on microbeads, do check out the links in the blurb below. And as always, stay safe.