Toxin vs toxic

[Michael Gochfeld]

In the message below, Chris has explored the relationship between 
"toxin" and "toxic".  It would be reasonable to assume that the 
adjective "toxic" would have the same meaning as the noun "toxin", but 
that is not the case (and probably has never been the case). 

"Toxin" refers specifically to substances produced by organisms. Toxins 
are "toxic" but the adjective toxic has a much broader application to 
poisonous substances, both natural and synthetic. Indeed, there is a 
field of "toxinology" (which would be a subset of toxicology, and 
journals with different names---such as "Toxicon", devoted to the 
publication of papers on plant, animal, and micro "toxins".  

One frequently hears toxic chemicals referred to as "toxins", but that 
is an incorrect use of the word. Unfortunately, there doesn't seem to be 
a happy choice for a single word to refer to "toxic substances" or 
"toxic chemicals".  "Poisons" might suffice, I suppose. The word 
"toxics" has been coined to fill this void, but although I use it 
frequently in lectures, I don't think I've ever tried to use it in 
print. 

Another neologism is the word "noxin" which some people tried to 
popularize as a hybrid of "noxious" and "toxic". But it never took off 
(nor should it have, in my humble view).

Now there are some interesting challenges.  For example, methylmercury 
is produced in sediments by anerobic bacteria capable of attaching a 
methyl (CH3) group to inorganic mercury. But although this highly 
"toxic" chemical is of microbial origin, I don't think I've ever heard 
anyone call it a toxin. 

Perhaps the reason is that "toxin" usually refers to a poisonous 
substance generated by the organism for a particular purpose (to deter 
predation or capture food), while the methylation of mercury seems to be 
a detoxification product. 


M. Gochfeld

=====================================================================
  The first part of the dictionary definition was an eye-opener to me! I 
and obviously a lot of other educated people seem to use toxic as a 
synonym 
for poisonous. The definition states: "any of a group of poisonous, 
usually 
unstable compounds generated by microorganisms or plants or of animal 
origin. Certain toxins are produced  by specific pathogenic 
microorganisms  and are the causative agents in various diseases, as 
tetanus, diptheria etc.;". This means that most of the references to 
"toxic" waste, "toxic" spills made by the media are a wrong use of the 
word, or that the usage has changed in recent time to include inorganic 
poisons.
    Perhaps common usage has broadened the definition of the word at the 
same time that technical usage has narrowed it - a real dilemma for 
communication.

 
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