On September 9, 2013, the U.S. Environmental Protection Agency (EPA) approved the revisions to Florida’s criteria for Dissolved Oxygen (DO) as part of the recent Triennial Review of surface water quality standards. As noted in EPA’s approval letter, EPA approved the DO related provisions in Chapters 62-302 and 62-303, Florida Administrative Code, and nutrient related water quality standards for the Tidal Peace River. The remaining revisions adopted as part of Triennial Review are still under review by EPA and will be addressed under separate cover at a later date. The approval letter and EPA’s Decision Document for their approval have been posted to the Department’s website at http://www.dep.state.fl.us/water/wqssp/dissoxy.htm. In addition, the final Technical Support Document for DO has also been posted. The revised DO criteria are now in effect and apply to both fresh and marine waters.