By Ken Perrott 21/03/2016 10


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.

Hamilton CofA

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.

Image credit: A dirty word?


10 Responses to “The toxicity of chemophobia”

  • I’m reminded of an advertisement for body wash currently running on TV, showing a long list, presumably on the product label, of what is ‘not’ in the product, coupled with two young women chatting inanely about the product having ‘nothing’ in it! GAH! Who writes this stuff!

  • I wouldn’t consider a haystack 400 x 200 x 2 metres tall to be a “world full of haystacks”, and I’m dubious about describing chemicals as the “basic building blocks of all matter”. In order to denigrate others for their failure to unreservedly accept your reassurances, I suppose a little hyperbole could help.

  • Bruce, from your comments, I would say you are living proof of chemophobia.
    Can you name a substance that doesn’t have any chemicals in? (note that the primary definition of chemical in the Oxford dictionary is ” substance obtained or used in chemistry”, which is defined “as the study of elements and the compounds they form and the reactions they undergo”) If you can’t, then everything that exists must be a chemical. So Ken is correct in describing them as the basic building blocks of ALL matter.
    It is your denigration of him that has the hyperbole. Just like all those advertised “chemical free” organic products – That can only happen in a science free world.

    • Chris,

      I’m a product of 20th Century education, so in my view, the basic building blocks of all matter are atoms, not chemicals.
      Physicists would probably look with scorn at me, given their use of expensive toys to identify the building blocks of atoms.
      Atoms combine to make molecules, and common usage is that “chemicals” are molecules. I wonder how many students would get A+ for providing “Chemicals” answer to the exam question “What are the building blocks of all matter?”?.

      Ken quoted a soapbox science article containing the statements I objected to. Perpetuating obvious inaccurate “new science” definitions, whether from dictionaries or soapboxes, does not enhance credibility. It doesn’t take much imagination to realise that finding a small sewing needle at 1 ppt concentration only requires a 400 x 200 x 2 metre haystacks. My education about chemistry was based on the atomic theory, whereas yours is apparently some later theory where “chemicals” now reach into the atomic and subatomic regions of matter.

      • Bruce, you should not be so dogmatic in your criticisms as this backfires when it comes to your assertions.

        As a chemist from way back I have never understood “chemicals” as restricted to molecules. Most chemicals I have researched during a relatively long career actually have not been “molecules.” Mostly they have been atoms – usually the charged variety we call ions.

        Here is a simple definition from Wikipedia for your enlightenment:

        A molecule is an electrically neutral group of two or more atoms held together by chemical bonds. Molecules are distinguished from ions by their lack of electrical charge.

        One can argue the semantics of how to define the “building blocks” of all matter. But the fact remains that we are all composed of chemicals and that also goes for all our food.

        Chemophobia and the foolish advertising a “chemical-free” products is just plain stupid. This is what the article and my post was about.

  • I’m amazed, truly! Bruce Hamilton must be missing the point on purpose, how else can he be so pedantic in his comments. I suggest, Bruce, that Chris’s piece assumed his readers would exhibit some intelligence. We all know that atoms are the fundamental building blocks of matter (although modern physicists may have something to say about that) but Chris was reminding us that our whole world is made up of ‘chemicals’, whether natural (whatever that means in the minds of the ill-informed ) or synthetic (whatever that means in the minds of the ill-informed).

  • Thanks Anne you put it a lot politer than I would have.
    And Bruce, there is almost nothing used in elemental form and even then, a lot like oxygen are molecules. Atoms is elements, OK. The ions and molecules are the building blocks. Otherwise how does one differentiate between organic and metallic mercury with vastly different toxicities. The analogy of ppt is a very hard one to grasp. The one I use is a teaspoon in an Olympic swimming pool, but some people can’t grasp the concept of dilution.

  • Just in case some other unfortunates stumble on this discussion, a teaspoon ( 5 mL ) in a swimming pool ( Olympic = 2500000 L ) is indicative of ppb, not ppt. I don’t mind being called pedantic, and the other comments now dance around with concepts and names, but tellingly they no longer call “chemicals” the basic building blocks of all matter – which I still believe should not be accepted as the correct answer.

    • Bruce – for the vast majority of us chemcicals are the basic building blocks of everything, ouselves – what we eat, what we live in. These chemicals can be elemental (eg aluminium or copper wire), ionic (eg sodium choride – common salt) or covalently bound into molecular structures (eg water or alcohol).

      After all, not many of us are going to be dealing with black holes, neutron stars or what goes on in the LHC.

      But we are all subject to very msileading advertising and misinformation about the horror of “chemicals,” the advantages of “chemical-free” products, the desirablity of “natural” products and the evil of manufactured products.

      I am often aassured that the “naturally” occuring hydrated fluoride anion in water is very different, and much safer than, the hydrated fluoride anion in water derived from fluoridating chemicals. That is just ignorant.

      This is what the article and my post are about.

  • Bruce
    You are correct. ppt is a teaspoon in 1000 Olympic swimming pools – needle in a lot of haystacks stuff. Teach me not to check my mental maths when in a hurry.
    But no, you still aren’t correct or not even pedantic – just wrong. Molecules and elements are chemicals. If I add sodium to water, I get a good chemical reaction. What produces the chemical reaction? CHEMICALS.