Outside the city of Five Points, a small illegal dump is found containing old computer monitors. The concentration of lead in the soil is 200 ppm in a primary area, a circular region with a radius of 7 meters centered at the dump. A secondary area with an additional width of 7 meters has a concentration of 20 ppm.

Lead can be treated at a cost of $9/m^2 with phytoremediation with sunflowers or $45/m^3 with removal of soil by excavation.

Show your work in each calculation below.

a. What is the range of lead concentrations in mg/kg?

b. What is the area of the primary area? What is the area of the secondary area?

c. Evaluate the cost of remediation through phytoremediation and excavation to 1

meter for the primary and secondary area.