A small lake is surrounded by agricultural land. The lake is 150 m long and 120 m wide. The average depth is 30 m. The lake is fed by a small pollution-free stream having an average flow rate of 1.5 m3 . s -1 . A herbicide, Greatcrop, is detected at a concentration of 45.2 µg . L1 in the lake. Greatcorp degrades biologically with a rate constant of 0.22 day-1 . Assuming that the lake is at steady-state conditions and completely mixed at the time of sampling, what would have been the mass input of herbicide? Assume that the stream is the only source of water to the lake and that the evaporation, precipitation, and seepage can be neglected.