An accidental discharge of black liquor on 9th of August, 2011by Temple-Inland papermillinto the Pearl River in Bogalusa, Louisiana, USA, resulted in the death of more than38,000 fishes. The river water turned black and the effects were seen for over 100kmdownstream. There was a drastic drop in the dissolved oxygencontent, whichled tothe fishkill. Following the incident, the Louisiana Department of Environmental Quality investigatedthe accident scene and collected water quality parameters, which included dissolvedoxygencontent, salinity, temperature, and pHat different location mainly downstream to thedischarge point. This study aims to understand the route and concentration of pollutants overa period of time along the river with the help of GIS using the technique of interpolation. Thegenerated maps showed the level of dissolved oxygen with respect to the fish kill locationsfrom 13th of August 2011 to 25th of August 2011 after the accidental discharge. The resultsshowed a virtual aspect of the chronology in dissolved oxygen level and improved waterquality after an upstream reservoir was opened, which flushed the black liquor to the Gulf ofMexico.