This work presents the development of a tool to study the water contamination problem. This tool involves the utilization of stabilization methods and the utilization of the Conjugate Gradient method. The stabilization methods aims at overcoming the limitations imposed by the grid Peclet number. The Conjugate Gradient method aims at providing an eficient method to solve the system of equations which arises from the application of the finite element method in the solution of the contamination problem. As part of this work a chemical model was developed to simulate the interaction among chemical species involved in the transport process. These species sometimes have different physical properties that have to be taken under consideration by the chemical model. Taking advantage of the Object Oriented paradigm, we proposed a class hierarchy (OOP) to support the development of a chemical model. Finally the developed program was used to study a contamination problem with HCH at Cidade dos Meninos city in Duque de Caxias township, Rio de Janeiro, and to evaluate the reactive barrier design as a remediation method.