15. Determine the time required for the concentration of Dieldrin (a VOC) spilled in a shallow lake to be reduced to one-fifth of its initial value. Assume the temperature of

the water is 22°C, the average lake depth is 2.3 m, and the only loss of Dieldrin is due to volatilization.(Use Tchobanoglous and Schroeder, Table 7.1, for K value. See class example section of this packet).