Poisonous and Toxic
Poisonous (adjective) describes any substance, natural or manufactured, that is harmful or deadly to living cells, even in small quantities.
Toxic (adjective) refers to poison that is produced naturally by living things, but it is often used to describe any substance that is harmful or not good for you e.g. ‘toxic fumes’. This is very common usage, especially in non-technical language.
Comment by lori
thx that was great!
Comment by Ethan
What about usage such as water toxicity?
Comment by admin
Interesting comment, Ethan. “Water toxicity” usually refers to the level of harmful substances (of any kind) in water. So water utility companies, for example, do water toxicity tests to make sure water is OK to drink. Why not water poisonousness tests? Maybe the word is just too long and awkward! It seems that the distinction between toxins and poisons is not maintained in longer words like ‘toxicity’ and ‘toxicology’ The alternative words, poisonousness and poisonology are rarely used.
‘Water toxicity’ is sometimes used erroneously to describe the harmful effects of drinking too much water. The correct term for this is ‘water intoxication’.
Comment by Holman
What is the difference between a toxin and a prion?
Comment by admin
The difference between a toxin and a prion:
A toxin is a substance that poisons or irritates whereas a prion is a type of infectious agent. But unlike infectious viruses and bacteria, prions are not cellular organisms. Prions are proteins that normally perform a beneficial function in animal tissue; but they can become abnormally shaped, leading to illness. According to the US Food and Drug Administration - http://www.fda.gov/Food/FoodSafety/FoodborneIllness/FoodborneIllnessFoodbornePathogensNaturalToxins/BadBugBook/ucm071397.htm - abnormal prions can be infectious when consumed by other animals. Prions are thought to be absorbed into the body during digestion where they begin the process of changing their normal protein counterparts into abnormal proteins; however infectious prions from one species of animal have less of a potential of causing the abnormal shape in the normally shaped prion proteins of another species (the “species barrier”).