Environmental Science 12th Edition by William Cunningham,Mary Ann Cunningham

تمرين 14

Understanding the origins of pollution is the first step toward considering policies for reducing it. The chapter you have just read includes several graphs displaying pollution data. The following questions ask you to think more about the sources of this pollution:
The graph in figure 18.11 results from a reconnaissance study done by the U.S. Geological Survey. The researchers wanted to assess whether a list of 95 contaminants could be detected at all in public waterways. If you wanted to design a study like this, what sorts of sites would you select for sampling How might your results and your conclusions differ if you did a random sample