Image credit: A dirty word?
Chemophobia is rampant on the internet. It seems to range from a reasonable concern over the potential adverse effects of synthetic chemicals to an irrational fear of these substances because of misconceptions about their potential for harm. Often it is accompanied by a complete misunderstanding of risk and an unrealistic understanding of the role of concentration in toxicity.
The Soapbox Science blog article, The presence of a chemical is not the same as presence of risk, from a few years back, describes both these problems.
All substances are chemicals
“Chemical” is not a dirty word. Nor is it a synonym for “poison” or “toxin.” Chemicals are the basic building blocks of all matter and classifying them as “safe” or “dangerous” is inappropriate. But of course there are safe or dangerous ways of using chemicals. In any case, chemicals are not to be feared or worshipped, they are to be understood. And perhaps the most important point to understand is that the presence of a chemical does not equate to the presence of a risk.
I would add to this the confusion many people have about “natural” substances and “synthetic” chemicals. All substances are chemicals and the properties of a specific chemical are completely independent from whether it occurs “naturally” or has been manufactured or synthesised. Yet, again and again, I get comments from people who declare that fluoride in fluoridated tap water is bad – because the fluoridating agent is a manufacture chemical or by-product of a chemical industry.
Similarly, commenters will argue that the “natural” fluoride in our water is good because it is derived from the naturally occurring fluoride mineral fluorite or calcium fluoride. The chemical species in the water, whatever its origin, is the hydrated fluoride anion. Its origin has absolutely no influence on its properties, its reactions in our body or on its toxicity.
The actual concentration is relevant
Thanks to our analytical capabilities, we can now routinely detect substances down to the part per trillion (ppt) level. That’s not finding a needle in a haystack; it’s finding a needle in a world full of haystacks. At that level, we can detect a myriad of chemicals should we choose to look for them! And by selectively referencing the scientific literature, the spectra of risk can be readily raised.
Practically any element and most chemicals can be detected in all of our foods and beverages. But in most cases they are only present in incredibly small concentrations. Modern analytical techniques are capable of identifying chemicals at incredibly low concentrations – so low they are just not relevant to concerns about safety or toxicity.
This means that regulations controlling the presence of contaminants in our foods and beverages must define the maximum allowable or acceptable concentrations – otherwise, all foods would be rejected no matter how “natural” or “chemical-free” they are.
The problem is that chemophobic people react to analytical evidence of a contaminant chemical without considering the concentration. The very fact that it may have been detected in a sample (or even not detected at the analytical sensitivity available) is enough to raise concerns.
For example, I have seen opponents of community water fluoridation wave around certificates of analysis of fluoridating chemicals as if they proved these chemicals a loaded with toxic heavy metals.
But look at this example of data from a certificate of analysis for fluorosilicic acid purchased by Hamilton City Council at the time anti-fluoride campaigners were using the heavy metal argument in their campaign against fluoridation.
The use of the “less than” indicator (<) shows that the concentration of several of these heavy metals was below the detection limit for the recommended analytical method (in this case antimony, mercury, molybdenum and selenium).
All the other heavy metals have concentrations well below the regulated maximum for this concentrated fluoridating chemical. Check this out – the regulated maxima (mg/kg) are 132 for arsenic, 40 for cadmium, 660 for chromium, 132 for lead and 132 for selenium. (Remember, this data are for the concentrated chemical which must is diluted millions of times before consumption). In fact, in many the contribution to drinking of heavy metals from water treatment chemicals like fluorosilicic acid may be less than from natural sources (see Fluoridation: putting chemical contamination in context and Another defeat for anti-fuoridation claims about arsenic).
So these campaigners may scare chemophobic people by waving around a certificate containing analytical data – but a calm reading of the data and comparison with the regulated maxima shows there is absolutely no risk.
The risk of chicken soup
The article illustrates the silliness of chemophobia by considering a bowl of soup:
“For example, eat a bowl of chicken soup and hundreds of chemicals will flood your bloodstream, including many (benzene, methanol, etc.) that are potentially “highly toxic.” Although they are not toxic in the dose found in the soup, if you look for them in the urine, you will find them. Nobody bothers to look, because these chemicals are not deemed important; after all they are “natural,” and nobody has a political interest in banning chicken soup.”
The author says:
” I’m a big proponent of eating fresh, unprocessed foods. However, remember that chicken soup made with fresh vegetables and organic, free range chicken can still flood the urine with plenty of compounds that could be vilified the same way as BPA or phthalates, if only one cared to make the effort.”
And that is the problem. Chemicals get vilified – even when they are harmless or at extremely low concentrations – because propagandists and activists make that effort.