Pyrite contained in wasted ore dumps induces a strong acid environment when it contacts oxygenated rainfall. Present research was designed to evaluate the pollution of an area that is supposedly contaminated by pyrite of ore wasted dumps form in Chonju Il Mine. Measured are the pH and selected heavy metal elements in the supposedly polluted hydrologic system. The samples include three types those collected from the stream waters; those from the stream sediments; and those from the rice field soil scattered over the area. The dispersion path of the pollution source was also traced. The pH of the hydrologic system ranged from 3.44 to 5.46, which clearly indicates that the area is on the acid environment. The pH tends to rise as the distance from the minehead increases. The content of heavy metal elements dissolved in the stream water varies as follows; Mn=69.73∼1.99ppm, Cd=0.02∼0.03ppm, Zn=0.77∼1.18ppm, Cu=0.04∼0.13ppm, Pb=0.22∼0.32ppm. The stream water in this state may induce serious heavy metal pollution to the agricultural land and the water for human life especially in the villages down the stream. The content of heavy metal elements dissolved in the stream sediment varies as follows; Mn=245.0∼4685.0ppm, Cd=10.0∼15.0ppm, Zn=105.0∼210.0ppm, Cu=65.0∼155.0ppm, Pb=90.0∼150.0ppm. The content of heavy metal elements dissolved in the rice field soil varies as follows; Mn=185.0∼260.0ppm, Cd=10.0∼15.0ppm, Zn=135.0∼180.0ppm, Cu=65.0∼90.0ppm, Pb=100.0∼130.0ppm. The pollution index in the stream sediment and the rice field soil is 1.36∼2.03, which shows that pollution had already begun all over the area where the samples were collected.