Mini-Science 2011 – Chemicals for better and for worse

Mini-Science logo At the conclusion of each Mini-Science lecture, audience members submit their questions to the evening’s presenter, who answers as many as possible on the spot. Three of the unanswered questions are sent to the presenter for posting here. Here are questions from Dr. Joe Schwarcz’s lecture “Chemicals for better and for worse” (March 16, 2011).

Q: What are the 10-12 most abundant elements in an “unpolluted” human body?

A: Elements in the human body:

Element Mass Atomic percent (calc.)
Oxygen 65% 25.6
Carbon 18% 9.5
Hydrogen 10% 63
Nitrogen 3% 1.3
Calcium 1.5% 0.24
Phosphorus 1.2% 0.24
Potassium 0.2% 0.03
Sulfur 0.2% 0.04
Chlorine 0.2% 0.04
Sodium 0.1% 0.03
Magnesium 0.05% 0.01
Iron 3.8g in men, 2.3g in women
Cobalt, Copper, Zinc, Iodine < 0.05% each
Selenium, Fluorine < 0.01% each

Q: How important is it to wash fruit before eating it?

A: It is very important to wash foods, not because of pesticide residues which are trivial, but because bacterial contamination is certainly possible.  And that can lead to some nasty results.

Q: Is bottle water better than tap water in terms of chemicals?

A:  Bottled water does in general have fewer contaminants but in my view the difference is insignificant.  I do not drink bottled water.  If the taste is troublesome, a Brita-type filter works well.

Q: What are the links to the websites and literature recommended during the lecture?

A: Here they are:

Please visit the Mini-Science website for more information about the lecture series.

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