Thank you. I'll direct your attention to the screen, please. Don't look at me; look there.
I direct McGill University's Office for Science and Society. Our mandate is to inform the public on scientific matters and to demystify these for them, because we like to think that the moment our students leave our gates is not the moment their education stops.
As a university, we have a responsibility to the public to provide information, and I thought it would be interesting to share with you some of the methodologies we use in the context you're interested in, because there is massive confusion out there in the public. I know this because I do a weekly radio show and do public lectures and I'm very closely connected to the pulse of the public.
The public fears all kinds of things. They're told one day to eat as many fish as they can because of the omega-3 fats, and then they find out that they may be contaminated with PCBs. We tell them to eat as many fruits as possible, but then there are concerns about the pesticide residues. Some people then tell them to wash these toxins out of their bodies by drinking lots of water, and then they learn that the water has trihalomethanes in it, so they filter the water with these filter jugs. Then they discover that the plastic is made of polycarbonate, which leaches bisphenol A into the water, and they get all concerned because they've heard that this is an environmental estrogen and may be responsible for precocious puberty in young girls, so they can't even drink the water.
They really start to sweat things, but then they find out they can't even use an antiperspirant because it is contaminated with parabens, which are used as a preservative. If they can't make themselves smell good like that, well, then they think maybe they can use a perfume or a cologne and discover that there are phthalates in there. At this point they really get concerned because they've heard stories that phthalates interfere with the anal-genital distance in rats, and that of course is a concern to everyone.
There is real worry out there. There is virtual panic, especially about the chemicals that are used in everyday life. These days, of course, we have learned a great deal about how these chemicals appear in our blood, but just because something is found in our blood doesn't mean it is necessarily harmful; it just means that the analytical chemists are extremely good at detecting things down to the level of parts per trillion.
Sometimes, of course, there is a need to take action because of links that have been made between these contaminants and health. For example, 1,4-dichlorobenzene is very commonly found in mothballs and in some air fresheners. It turns out that about 95% of the public has detectable traces of these, and we also know that they have been linked to impaired lung function. There may be a reason here to take action, but that's quite different from some of the other issues out there.
An example is phthalates, which of course you have heard a great deal about. These substances are used as plastifiers to soften plastics, particularly PVC. Well, there are a great many phthalates out there. This is not just one compound, it's a family of compounds, and you can't look at them as if they were all identical.
For example, diethylhexyl phthalate has received a lot of adverse publicity, much of it justified, because in this case we do have issues. This is where this anal-genital distance business comes in. It has been shown in test animals. It has been shown in male rats, for example, that the distance is altered. This is because it blocks the synthesis of testosterone, and this effect has been scientifically shown.
What does it mean to us as humans? Well, I think it does mean that we have to be very careful about the kinds of plastics we use with very young children and premature babies, because some of the phthalates may be leaching out into the body. There I think it is a cause for action, and perhaps even in the case of toys, because children put these into their mouths. There may be an issue, but the industry has looked at that and has replaced the DEHP with diisononyl phthalate, a different phthalate that does not have those issues associated with it, and yet the public does not make that kind of distinction, does not realize that these chemicals can be dramatically different.
Also dramatically different is the butyl phthalate used in nail polish or the phthalates used in shower curtains, for example--but again, people start fearing their shower curtains, because they've heard stories about what may happen in rats from DEHP, which is a completely different story.
Dr. Shanna Swan at the University of Rochester has done some human experiments and has discovered in fact that in male babies there is an anal-genital distance difference that depends on how many phthalates there are in the mother's blood. However, it is important to realize that there have been no health consequences noted other than that measurement.
Parabens, another set of chemicals that have been in the news a great deal, are used at a very small concentration as preservatives in a variety of cosmetics products. Again, it's a whole class of molecules, depending on just what kind of substitution pattern we have. But once more, the public doesn't look at it like that; everything is all dumped into one category.
Eyebrows have been raised about this issue, particularly because of the work of Dr. Philippa Darbre at the University of Reading. She measured levels of phthalates in breast cancer tissue, discovered their presence, and linked this to various kinds of products, especially deodorants. The fact is that in this study, which got a lot of publicity, she had no controls at all, so she didn't know whether or not healthy tissue also had parabens--which is very likely, because it's a ubiquitous substance--and she never determined whether there was any connection to antiperspirants. She never even asked her patients if they used antiperspirants.
Furthermore, these particular compounds are far less estrogenic than many others that occur in the environment, including things that are found in soybeans or tofu, so again it has to be looked at in the proper perspective.
As for the parabens we are so concerned about in deodorants, the truth is that very few antiperspirants or deodorants even use these things. They're just not in there. Of course, we need to do testing, absolutely, but we also need to have public education so that people can understand the results of these tests, because if they don't, it leads to all kinds of unnecessary worries and to quackery. Products are sold on the Internet and elsewhere that claim to remove toxins from the body: you just put your feet in there and your toxins are sucked out. People are paying $700 for this, and they have visual evidence, because 30 seconds after putting their feet in there, it turns dark; supposedly the toxins have come out. It is a totally quack device based on an iron electrode that forms iron oxide or rust, but people are buying this for $700 because they're convinced of the toxins in their bodies.
The word “chemical”, of course, should not equate to toxic. Chemicals are not good or bad. They have no morality; it's people who do.
The effects of these things depend on the molecular structure of the specific substance, not on whether it's synthetic or natural. High-dose animal studies do not necessarily reflect human risk, and there are some very good examples of animals reacting very differently. We love chocolate and eat it a great deal, but of course you cannot feed it to dogs, so the dog would not be a good model to test toxicity of chocolate.
Paracelsus told us 500 years ago, “sola dosis facit venenum”, meaning “only the dose makes the poison”. That is the fundamental tenet of toxicology. Vitamin A in small doses is very beneficial, but eaten in large doses--as Arctic explorers have done when they consumed the livers of polar bears--it is fatal. Vitamin A: is it good or bad? It all depends on the amount, and so it is with a large variety of substances that you are interested in.
What we really need is data, but it's not enough. We also need to communicate the data and interpret it to the public. Allaying public fears, which I think is one of the responsibilities of the government, has to go hand in hand with legislation like CEPA and the proper communication of what that legislation means to the public. I think the government has done a great thing in moving to evaluate some of the 23,000 consumer products out there, but it's also very important to communicate to the public that the government knows what it is doing--that all of this is being done in a scientific way--so that we can regain the confidence of the public, not only by adhering to CEPA but also by communicating what CEPA is to the public.
Thanks very much for giving me the chance to inform you of our efforts at the McGill Office for Science and Society.