Pollutants entering and leaving natural water treatment systems such as constructed wetlands can be evaluated by considering the concentration entering and leaving, or the mass entering and leaving. mass of the pollutant can be calculated by multiplying concentration (dimensional units of concentration - m/l) by inflow or outflow (dimensional units of volume - l). consider nitrogen enters a 10,000 m2 (1 ha) constructed wetland at 10.0 mg/l. outflow concentration of the nitrogen is 2.35 mg/l. inflow volume is 1000 m/d and outflow volume is 900 m3/d. a. what is the % reduction in concentration? (hint: % concentration reduction = (in-out)/in) * 100%) b. what is the mass of nitrogen in kilograms (kg) removed by the wetland per day (hint: mass reduction = mass in - mass out) c. what is the % reduction in nitrogen on a mass basis? d. state which calculation (concentration decrease or mass removal) you think is the best way to determine the magnitude the wetland is treating the water, and briefly explain your answer.