Arsenic in geomedia contaminates an aquifer by naturally occurring geological processes. The aquifer has a bulk density of 1.55 g/cm3 and a particle density of 2.63 g/cm3. The distribution coefficient, Kd value is 0.0370 L/kg. The initial concentration at the source is 40.0 ƒÝg/L. The groundwater velocity is 9.50 x 10^1 m/yr and the dispersion coefficient is 0.500 m^2/day. Assume a half-life of 6.00 x 10^4 years. Estimate the concentration at 11.0 m distance from the source 0.120, 0.125, 0.130, 0.140, 0.150, and 1.00 years after the process begins. Also, estimate the time needed for the arsenic concentration to exceed 0.0100 ƒÝg/L at 25.0 m from the source.