chemicals

Alcoa's Davenport Works wants to increase the amount of pollutants it can discharge into the Mississippi River by 24 percent to accommodate higher quantities of oil/grease, chromium, zinc, cyanide and other suspended solids generated by expansion of the Riverdale plant to serve the automotive aluminum market.

The company is seeking modification of its National Pollutant Discharge Elimination System (NPDES) permit issued by the Iowa Department of Natural Resources (IDNR). The permit revisions, if approved, would allow the plant to discharge a combined average of 548 pounds of pollutants each day into the river. That's an average of 106 pounds per day more than the plant's current permitted discharge.

Based on the plant's 312 production days each year, the change would permit the plant to dispose of an additional 33,000 pounds of those pollutants into the river annually.