The Current - Heard black plastic is toxic? Listen to this before you throw it away

Episode Date: December 4, 2024

A recent report sparked widespread concern about black plastic leaching toxic compounds into food, via plastic utensils and containers. But scientist Joe Schwarcz says the research needs another look — and you might not need to dump all your black plastic spatulas and spoons.

In 2017, it felt like drugs were everywhere in the news, so I started a podcast called On Drugs. We covered a lot of ground over two seasons, but there are still so many more stories to tell. I'm Jeff Turner, and I'm back with Season 3 of On Drugs. And this time, it's going to get personal. I don't know who Sober Jeff is. I don't even know if I like that guy.

On Drugs is available now wherever you get your podcasts. This is a CBC Podcast. Hello, I'm Matt Galloway, and this is The Current Podcast. If you rummage around your home, maybe look around the kitchen right now, do you see a lot of black plastic nearby? Things like black plastic spatulas, takeout containers, toys? If you do, you might have felt alarmed about a study that came out this fall around the potential dangers of this material. Researchers studied 203 black plastic consumer

products and found flame retardant chemicals in 85% of them. These are toxic chemicals that can cause serious health issues like cancer. Joe Schwartz is director of McGill University's Office of Science and Society. And we spoke earlier this week about this study. Here's our conversation. This study created, I don't want to say panic, but certainly a lot of attention and people kind of wondering whether they should toss all the black plastic that might be around them. Tell us a bit more about what the researchers found in the study. Well, certainly, as you mentioned, it did create some panic. But when we talk about toxicity, it's very important to refer to numbers. It isn't enough

to say that something is toxic or not. And this is indeed an issue with black plastic. Now, black plastics are sort of fascinating. The industry likes black plastics for several reasons. One is that when you add carbon black, which is the pigment that we're talking about here, to plastic, it makes the plastic more heat resistant. It increases its strength and rigidity. And very importantly, it blocks ultraviolet light. and very importantly it blocks ultraviolet light ultraviolet light is really poison to plastics that causes them to break down so there is a reason to to use carbon black but then there are aesthetic considerations also because consumers tend to evaluate black items as being more luxurious and producers also like that leakage from foods packaged in black containers is less visible.

Now, the question that arises here is about things like sushi containers and black spatulas that you may have in your kitchen. The study was carried out by a non-profit organization called Toxin-Free Future and published in a very reputable journal. The journal is Chemosphere, and they investigated a number of plastics, including toys and kitchen appliances that are made of black plastic, and found that there were residues of flame retardants. Now, these are all items that do not have flame retardants purposely added to them, because let's face it, you know, there's no risk of the kitchen spatula that you're using spontaneously bursting into flame, even when you are turning over your pancake or your scrambled eggs. So, there's no need for these. So how come this is happening? Because black plastic is notoriously difficult to recycle.

In a recycling facility, the plastic items kind of scoot by on a conveyor belt. And the machine detects the recyclable ones. And this is done by infrared radiation. Depending on reflection, the instrument can determine what sort of plastic it is. But black plastic does not reflect infrared light, so it is not sorted. It goes straight through on the conveyor belt and ends up in a bin that goes into landfill. But because there's a big demand for black plastic and it's not available from recycling facilities, then producers look elsewhere. So you can either produce it from raw materials or they can reach out to some of these Asian countries where electronic equipment is dismantled

in order to get precious metals out of it. But then they are left with a lot of black plastic, which is found in our computers, our television sets, our cell phones. And some companies will buy this and melt it all down and reformulate it into appliances. And that's how the fire retardants, which, of course course in TVs and computers are necessary. You sure don't want your TV bursting into flame. But then they end up in this plastic, which is all mixed together and melted down and reassembled into the items that we're talking about. So how much of that is leaching out? How much of that flame retardant is leaching out from the toys and the spatulas?

That's indeed the question to ask because toxicology revolves around numbers. Paracelsus, the great sage of the Renaissance, told us only the dose makes the poison, and that is critical to understand. So researchers at the University of Birmingham investigated exactly what amount transfers, and they discovered that just by handling the black plastic, there is no transference. So children playing with toys, that is not an issue. However,

when they immersed bits of black plastic in olive oil at 160 degrees for 15 minutes, they did find some of this transfer to the oil. Now, the fact is that this is not really a mimic of how one would use spatula in a fry pan. You know, it's not exposed to 160 degrees for 15 minutes. And of course, we don't eat all of the oil that we use for frying. But nevertheless, based on this study, scientists at Toxin-Free Future estimated a daily intake of 34,700 nanograms of the most toxic flame retardant. Is that a lot? I mean, that's a big number, but is that a lot?

It sounds like a big number, and that's why we have to look at what is called the reference dose. That is the number that scientists have developed based on laboratory experiments, animal experiments, which is safe for our daily intake. And that turns out to be 7,000 nanograms per kilogram of body weight. So the researchers said, look, the average body weight is 60 kilograms. They multiplied 7,000 by 60, and they came out with 42,000 and said that the 34,700 that was detected is too close to that for comfort. But they made a mistake. They made a mathematical mistake in the paper,

because 7,000 times 60 is not 42,000, but 420,000. So the supposed exposure is not close to the reference dose. It is actually one-tenth of it. And this is what caused all of the panic. So are you suggesting, I mean, the math could scramble people's heads, but are you suggesting that perhaps we don't need to panic, that these things are not leaching as much of the harmful chemicals we might want to believe? Exactly. They were off by a factor of 10.

Exactly. They were off by a factor of 10. So, indeed, the amount that leaches out is not close to the reference level that tells us safety. I don't think anybody would want any of the leaching to come out. I mean, we assume that the spatula that you're using, sure, little bits and pieces of it fall off. But generally, you don't want, you know, to believe that that is going to help poison you or even in a small dose. Well, yes, this is true, but I mean, you know, we are surrounded by potential toxins, you know, in our life everywhere. The question is whether we are talking about, you know, a flea on the back of an elephant, flicking that off,

or talking something that is more significant. Well, in this case, because of this mathematical error, I think we're talking about a very small risk. But that being said, these flame retardants should never be in these items. Why don't we just stop using black plastics? Is there something else that we could use instead of those black plastics that have unnecessary flame retardants in them? Certainly stainless steel is the stuff that we should be using in the kitchen.

Very little leaches out of that. I mean, even there, if you investigate it, you will find some nickel and some chromium that leaches out. Because the problem is that today, with our analytical chemical techniques, we are adept at picking up substances even down to the part per trillion level. That's the width of a credit card compared to the distance between the Earth and the Moon. When we do a careful analysis of anything, we will always find some potentially toxic substance.

That's why numbers are so critical. And you have to make a distinction between things that are very minor risk and things that are very significant risk. And I think, when you have a scientific paper that gets so much attention, and that attention really is based on a tenfold error, is a significant mathematical error. So you are actually exposed to one-tenth of what they claim. But in this case, even a minor risk can be avoided because obviously we do have alternatives that do not have any remnants of flame retardants in there.

The Canadian government has tried to regulate plastic, including banning certain types of black plastic. The Supreme Court said that that was unconstitutional to ban those sorts of plastics. Can we regulate black plastic in Canada? Yes, it's certainly possible to regulate it. Of course, there will be vigorous opposition to that from manufacturers. But I think it is possible to put limits on the amount of residue that can leach out from plastics. But the issue isn't only black plastics. There are other plastics that have, you know, different problems. But banning plastic, obviously, is a non-starter. Our life relies on plastics. Our cars, our airplanes, our hospitals, pharmaceutical and food industries could not function without plastics. I mean,

a lot of the clothes we wear are based on synthetic fibers. So there certainly are very significant issues with plastics. And I'm sure you've heard of the concerns about nanoplastics. They're found in every organ in the body, because when plastics get into the environment, usually through improper discarding, they eventually break down, and they end up in our water, they end up in our food, and therefore they end up in our body. And these are real concerns. I mean, those are much bigger concerns than, you know, turning over your omelet with a black spatula. So just to end where we started, which was that panic that people felt when they heard about this study, a lot of people went into the kitchen

and if they could, cleared out all the black plastics. Should I be throwing out all the black plastic in my kitchen? No, I don't think so. And then, of course, there's the added problem of when you're throwing it out, what happens to it, right? Because many of the older landfills are not properly sealed and eventually everything in there starts to break down and it gets into the environment from there. So that the flame retardants that are found in the black plastic that you're throwing out

may eventually come back to haunt us through our water and through our food. And, you know, as is almost always the case in science, when you scratch the surface, things are always much, much more complicated than it first appears. And so I think the panic over black plastic is not warranted. But I think we do need to have regulation

so that electronic equipment waste does not end up in the plastics, which are food contact materials. Joe Schwartz, we'll leave it there. Thank you for speaking with us about this. Thank you very much. Joe Schwartz is director of McGill University's Office of Science and Society. We spoke earlier this week, and after our interview, we also checked the math, and we contacted the authors of the study to ask about that tenfold discrepancy that Joe was pointing out. The co-author of the study, Megan Liu, replied that yes, they had recently been made aware of the issue

and had submitted a correction to the journal. However, she goes on to say, it is important to note this does not impact our results. The levels of flame retardants that we found in black plastic household items are still of high concern.