This article provides an analytical solution for the multi-species pollutant transport model in the presence of additional source/sink term in one-dimensional semi-infinite medium. The contaminant concentration of reactive species is assumed in liquid and solid phases, both. Model is formulated for constant dispersion coefficient and velocity profile. The effect of average porosity and bulk density of the porous formation is included with the retardation factor and distinct value of retardation factor is considered with each reactive species. Analytical solution is derived for three-species reactive system with first order decay rate by using Laplace transform technique along with different transformation processes and graphs are plotted for concentration variation by using MATLAB software.