Case Study

A petroleum refining facility located in a suburban, but relatively populated, area converts crude oil derived from subsurface deposits into various fuels (e.g., gasoline, kerosene, heating oil, diesel) and organic solvents (e.g., miscellaneous aromatic and aliphatic hydrocarbons, such as toluene and hexane, respectively). The refining operations and processes are diverse, but frequently involve distillation and combustion. Accordingly, some operations and processes are associated with discharge of potentially hazardous by-products and used materials (wastes?) into the environment. The petroleum refinery hired a team of environmental specialists to help proactively and reactively identify, explain, and prevent or minimize problems that could potentially contribute to adverse environmental impact. There was extra concern by the facility administrators that environmentally mismanaged refining operations and processes could ultimately contribute to excess human illness and premature death in the surrounding communities.

Question:

Just when facility administrators were feeling comfortable with their implemented efforts and demonstrated commitment to prevent or minimize adverse impact to the surface water, a report appeared one day suggesting that there was an excess number of fish dying immediately outside and downstream from the facility. The fish kills, however, did appear to be more localized in the area where a pipe was discharging used cooling water back into the environment. In addition, the concentration of dissolved oxygen was mysteriously low. Briefly discuss what the likely source and cause of the fish kill.