Question

Pesticide is applied to a 10 ha (hectare) field at an average rate of 1 kg/ha every month. The soil is regarded as 20 cm deep and well-mixed. The pesticide evaporates at a rate of 2% of the amount present per day and it degrades microbially with a rate constant of 0.05 day-1. What will be the steady state concentration of pesticide in g/m3 and in unit of g/g, assuming the soil density as 2500 kg/m3.