As a result of a review by the Illinois Effluent Standards Advisory Group (IESAG) of the Illinois water pollution regulations, several modifications of pollutant levels were recommended. As part of R76-21, the effluent levels of hexavalent, trivalent, and total chromium were proposed. The basis of the proposed change is the presumption that the standard can be attained by using 'good conventional technology at no significant incremental increase in treatment costs.' The change in the chromium effluent standard will result in more stringent levels of control which would reduce the quantity of chromium discharged to the environment.