1.a - Calculate the flow rate in the shallow sandstone groundwater aquifer (use highest hydraulic conductivity of sandstone in Table 9.1) with porosity 0.35 and hydraulic head measured at three locations below. Location A is 22 m, Location B is 33 m, and Location C is 25.6 m 1.b - An instantaneous, illegal dump of 1 kg of perfluorooctanoic acid (PFOA) occurs in the aquifer from Problem 1 1000 m up-gradient from a drinking water well. What is the maximum concentration of PFOA that could be expected in the drinking water well (assume no retardation or reaction)? 1.c - Calculate the maximum concentration and the time at which the maximum concentration is expected with retardation and no reaction (PFOA is a “forever chemical” with a half-life >90 years in groundwater). KOC = 130 L/kg, foc = 0.5%, porosity = 0.35, bulk density of soil = 2.5 kg/L.
Leave a comment