morphometric and hydrologic data for a lake in a metropolitan city is given as suspended solid concentration m=0.65 gm/m3 , suspended solid load, ws = 7.5x 10¹² g/yr, PCB load Wc= 6.5x10¹² ug/yr . toxicants have the following characteristics partition co-efficient , K_d =0.025m³/g the volatilization mass transfer co-efficient , V_v= 185m/yr. determine (a) the settling velocity of the solids (b) the flow concentration of the contaminant (c) the transfer coefficient and steady state concentration . Neglect the sediment feedback . The lake parameters are as follows volume V= 3700 x 10⁹m³ surface area A= 60,400 x10⁶ m² Depth H= 70 m, Outflow Q= 175 x10 ⁹ m³yr