A jar containing 3.1 kg of mercury is dropped into a lake that is 43,000 ft^3 and has an average depth of 4.2 fr. Water flows into and out of the lake at 1.6ft^3/s maintaining constant volume. Assuming the mercury completely dissolves and the lake is completely mixed, what is the mercury concentration in the lake immediately after exposure, and (b) 5 days later, (c) how long would it take for the lake to meet the water quality criteri of 0.77*10^-6 g/L.