Toxic Metals

Question 1

Toxic metals of greatest concern

Answer 1

Be, Cd, Cr, Pb, Hg, Te, As (Metalloid but has similar effects to metals)

Question 2

Heavy Metal

Answer 2

Ill defined term that means a metal of high relative density (>5.0 g/cm3)
eg. 
Pb: 11.4 g/cm3
Hg: 13.5
Cd: 8.7
As: 5.8 (metalloid)

Question 3

Why are most heavy metals an issue?

Answer 3

• derive toxicity from strong affinity to sulphur
• React w/ sulphydryl (-SH) groups which are present in the acitve sites of many enzymes eg amino acid: Cycteine
• Hg2+ Bonds to 2 enzymes SH (active sites), rendering both enzymes inactive

Question 4

Mercury

Answer 4

Answer to follow