Cigarette smokers absorb significant levels of ----- from tobacco smoke.

Options

A. Cd
B. Zn
C. Hg
D. Cu

Answer

A

Explanation

Cadmium is a toxic element that is present in our foodstuffs and is normally ingested at levels that are close to the maximum safe leve. The kidney is the orange most susceptible to cadmium, about 200 ppm cause severe damage. Among trace essential elements, Zn is second only to iron in importance. Around teh world a lack of Zn is the most common soil deficiency. Beans, cirtus fruit, coffee, and rice are the crops most susceptible to Zn deficiency. Zn is an essential element for animal. Over 200 Zn enzymes have been identified in living oranisms and their roles determined. Zn enzymes that perform almost every possible type of enzyme function are known, but the most common function is hydrolysis. Hg is hazardous because of its relatively high vapor pressure. The Hg vapor is absorbed in the lungs, dissolves in the blood, and is then carried to the brain, where irreversible damage to the control nevous system results. The metal is also slightly soluble in water, again a result of its very weak metallic bonding. Inorganic compounds of Hg are usually less of a problem because they are not very soluble. However, organomercury compounds pose the greatest danger, as these compounds (such as the methylmercury cation, `HgCH_(3)^(+)`) are readily absorbed and are retaiuned by the body much more strongly than the simple Hg compounds. Chemically, Zn and Cd are rather simple and mercury is somewhat distinct. The compounds of these elements are characterised by the `d^(10)` configuration in which [with the excepetion of `Hg_(2)^(2+)` ion, which formally involves Hg `(+1)`] they almost exclusively involve `M(+2)` .