Antidotes against metals

Dimercaprol (BAL, British Anti-Lewisite) was developed in World War 11 as an antidote against vesicant organic arsenicals (B). It is able to chelate various metal ions. Dimercaprol forms a liquid, rapidly decomposing substance that is given intramuscularly in an oily vehicle. A related compound, both in terms of structure and activity, is di-mercaptopropanesulfonic acid, whose sodium salt is suitable for oral administration. Shivering, fever, and skin reactions are potential adverse effects. 

Of histidine and cysteine (see Problem 6.34 for structures), which would be a better antidote against heavy metals ... 

The structures of serine and cysteine are shown below. Which of these amino acids would be the better antidote against heavy metals Briefly rationalize your... 

SOOg of milk (which still perceived to have antidotal qualities against poisoning from esposuie to metal fiunes, in addition to nutrition properties it has) is also given to the above wodkeis. 

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