The common antibiotic Sulfamethoxazole has been found in drinking water at conce
ID: 1712797 • Letter: T
Question
The common antibiotic Sulfamethoxazole has been found in drinking water at concentrations of 0.385 g/L The solubility is 610 mg/L and it has a very low vapor pressure. 7. Is soil/vapor extraction a good solution to remove this chemical? Explain your answer. You detect a plume of 0.385 g/L sulfamethoxazole in an aquifer over the following dimensions: 400 ft long, 20 ft wide and 20 ft deep. The aquifer has a hydraulic conductivity of 10 ft/day and a hydraulic gradient of 0.006, a porosity of 0.32. If the water is pumped at the rate of the flow of the aquifer, calculate the time required to remove all the sulfamethoxazole. Calculate the mass of sulfamethoxazole that would have to be released into this aquifer to reach the solubility limit above. Someone told you that drinking water containing 0.385 ug/L of sulfamethoxazole a. b. c. d. for 10 years would increase your cancer risk by 107. What is the oral potency factor that would make this statement true? Assume that you weigh 70 kg and drink 2 L/dayExplanation / Answer
A)
vapour pressure is very low hence at low pressure itself vapor will be thermodynamic equilibrium with its condensed phases. hence it's not a good idea.
b)
seepage velocity Vs = ki/n = 10*0.006/ 0.32=0.1875 ft/day
whatt is pumping capacity ?
c)
solubility limit = 610 mg/L
total volume = 400*20*20 = 16000 ft3 = 4530695.45 lit
concentration = 0.385 ug/L
require mass per lit = 610- 0.385*10-3 = 609.999615mg/L
Total mass = mass/L * Volume = 609.999615* 4530695.45= 27.637 kg
d)
ILCR = Exposure (g/kg/d) x Cancer Slope Factor (g/kg/day)-1
10-7 = (.385/(70*365*10)) CSF
CSF= 0.06636