You have been hired as a consultant to assess the impact of aspill of 10 kg of chlorobenzene in a river adjacent
to a small town. The average width is 20m, average depth is 2.4m,and has a discharge of 8.7 m3/s. The
average water temperature is 22 °C, the average air temperature is27 °C, and the average wind speed is
4.25 m/s. The suspended solids concentration has been measured at 7mg/L, Kd for chlorobenzene is 4.27 cm3/g,
and the average sedimentation velocity is 0.8 m/d.
(a) Assess the impact of the spill on the town’s water supplyintake 1 km downstream of the spill location.
Please compare this value with the EPA’s MCL forchlorobenzene.
(b) Investigate the relative importance of volatilization andsedimentation on the expected concentration of
chlorobenzene at the water-supply intake.
(c) If the city engineer decides to shut down the water-supplyintake when the river water at the intake
exceeds the drinking water standard, for approximately how longwill the intake be shut down?
