1. An orchard worker sues his employer for not providing protective measures against exposure to DDT used in the orchard. a. Calculate the chronic daily intake of DDT for an adult from exposure at a level of 9 ppb for 40 hours a week over 30 years. b. Calculate the cancer risk sustained by the worker using the slope factor from Davis and Masten.

2. The SO2 emission from a fixed source is 25 g/s. The effective stack height is 60 m, the wind speed is 4 m/s at the top of the stack. Assuming class C stability, what is the expected ground level concentration 2 km downwind?

3. A sanitary landfill is being designed to handle solid waste at a rate of 75 Mg per day. It is expected that the waste will be delivered 5 days a week. The density as spread is 135 kg per m3. It will be spread in 0.5 m layers and compacted to 0.25 m. Assuming two lifts a day and a daily cover of 0.10 meters, determine the annual volume of landfill consumed in cubic meters and the daily horizontal area covered by the solid waste. Ignore the soil volume between stacks.

4. Ferric chloride (FeCl3·7H2O) is used at a water treatment plant. The FeCl3·7H2O is dosed at 40 mg/L. The flow rate of the treatment plant is 2,000 m3/d. a. Calculate the mass of sodium bicarbonate (NaHCO3) that would be required per day to replace the alkalinity consumed. (Hint: NaHCO3 dissociates to Na+ and HCO3 -) b. Calculate the total mass of sludge dry solids generated per day.