A lake maintains a constant volume $V = 10^6$ m$^3$. Polluted water enters the lake at a rate of $Q_{in} = 1000$ m$^3$/day with a pollutant concentration of $C_{in} = 5$ g/m$^3$. Pure water evaporates from the lake at a rate of $Q_{evap} = 200$ m$^3$/day, and the remaining water drains out of the lake at a rate of $Q_{out} = 800$ m$^3$/day (keeping volume constant). What is the steady-state concentration of the pollutant in the lake?