Question

The Louisiana Department of Environmental Quality (LDEQ) has determined that toluene concentrations in soil that exceed 20 mg/kg can pose a threat to the underlying groundwater. (a) if a 50-g sample of soil contains 5.4x10^3 ug of toluene, what will be the concentration expressed as mg/kg? (b) Does this soil pose a threat to the groundwater according to the criteria specified here?

Answer 1

a)
toluene mass = 5.4x10^3 ug

                    = 5.4 x 10^3 x 10^-6 g

                   = 5.4 x 10^-3 g

                   = 5.4 mg

soil mass = 50 g = 0.05 kg

concentration = toluene mass / soil mass

                     = 5.4 / 0.05

                    = 108 mg / kg

b)

yes , it is threat to the ground water because it is more than 20 mg / kg .