Chose any one topic

13. Cadmium accumulates in the kidneys of humans, and over time the concentration can increase to dangerous levels. This metal is concentrated in shellfish as well as in plants, and also occurs as an impurity in coal. What are some of the pathways through which cadmium can enter the human body?

14. Suppose it were possible to operate automobiles using batteries that had to be recharged every 350 miles. How would this alter the character of urban pollution? Would it reduce it, increase it, or merely change the composition? Explain your answer.

15. Suppose you are analyzing the data from a study to determine the incidence of lung cancer among uranium miners. One of your conclusions is that there appear to be two distinct groups. One group has a high mortality rate after a cumulative exposure of D units and the other group has a high mortality rate after a cumulative exposure of D+D* units. There are no differences in age distribution or ethnic background between these two groups. Can you explain what might cause this difference in mortality rates?

16. The incidence of both breast cancer and prostate cancer has increased significantly in the industrialized countries over the past three decades. Can you think what non-environmental factors might account for a portion of these increases?