Answers
1. Lead was once widely used in the United
States as a gasoline additive but it was banned due to health risk.
2. Radon is a radioactive gaseous decay
product of uranium that is found in rocks, soil and water.
3. Radon is a leading cause of lung
cancer in the United States because the by-product of this can get trapped in
the lungs.
4. Mercury poses a health risk to humans
who eat large quantities of marine fish such a tuna and swordfish.
