12.5 Groundwater is contaminated with 300 µg/L (300 ppb) of toluene. Assume that the aquifer solids contain 1.5% organic carbon and that sorption is ade- quately described by a linear model. Estimate the mass of toluene sorbed to the solid material.

Please ans a and b

A wetland with a volume of 103m3 drains into pond with a volume of 106 m3. The concentration methylmercury (CH3Hg) in the wetland is 4 × 10-3 ng/L. The wetland is flowing into the pond at a rate of 103 m3 /day. Microbial processes are causing methylmercury to be generated within the pond at a rate of 100 ng/day. The pond has a concentration of 6 × 10-4 ng/L CH3 Methylmercury decays within the pond at a rate of 100 ng/day. The pond has an outflow of 103 m3/day.  Is methylmercury mass increasing or decreasing in the pond? Show all mass balance calculations?

What is the retardation factor of a pulse of dissolved benzene move through organic-rich wetland soil (organic carbon fraction of soil, foc=50%) if the effective porosity is 0.4 and the bulk density of the soil is 1.5 g/cm3.   Hint: organic carbon partition coefficient for Benzene Koc = 1.50  Use K oc = K d / f oc to   calculate Kd.   Select the range which includes your calculated answer.   a) 300 to 400   b) 2.0 to 2.5 mg/l c) 2.0 to 2.5 d) 2.6 to 4.8 e) 0.5 to 1.0.   f) 2.6 to 4.8 mg/l            None of these ranges include my answe

Measurement of a 25 ºC groundwater sample isolated from the atmosphere indicates that pH = 6.35 and total ALK of 1 meq/L. b) What will the new alkalinity be if 0.5 mM hydrated lime (formula Ca(OH)2) is added to the source water?