An oil-storage area was abandoned 18 years ago. Oil spilled on the ground had saturated the soil at a concentration of 400mg/Kg of soil. A fast food chain now wants to build a restaurant at the site, and samples the soil for contaminant, only to discover that the soil still contains oil residue. You are consulted as the expert environmental engineer on biodegradation of oil spill to give advice. Having identified the microorganism involved the biodegradation and discovered that its mode of action is first-order reaction with a reaction rate constant of 0.25 year-1, .
a) What is the calculated concentration on the site?.
b) How long will it take for the soil concentration to be below the acceptable EPA Maximum Contamination Level (MCL) of oil is 1 mg/kg of soil?
c. A 1.5 million gallon water reservoir in Avila Beach in California was contaminated by oxygenated gasoline containing 0.5% by weight of MBTE when the pipeline busted. If the estimated volume of gasoline released into the reservoir was 5000 gallons and the specific gravity of gasoline is 0.870. Density of water is 1000kg/m3. Calculate in ppb the concentrations of
i. Gasoline in the reservoir
ii. MBTE in the reservoir