FDEP Issues Guidance on Non-Enforcement of Ammonia Groundwater Cleanup Target Level

New guidance to change how agency enforces the GCTL for ammonia in groundwater

The Florida groundwater cleanup target level (GCTL) for ammonia may soon become obsolete. At landfills and other waste management facilities, ammonia is frequently detected in groundwater at levels in excess of the GCTL set by the Florida Department of Environmental Protection (FDEP). FDEP has generally required waste management facility operators to monitor and report groundwater ammonia concentrations. FDEP has also required property owners undertaking site rehabilitation to take corrective actions to address groundwater concentrations of ammonia in excess of the GCTL.

A new guidance issued by FDEP changes the way the agency will enforce the GCTL for ammonia in groundwater at waste management facilities. In a memorandum issued on December 3, 2012 by the Director of the Division of Waste Management, FDEP indicated that it will no longer require such facilities to monitor ammonia where ammonia is the only contaminant of concern and groundwater is not expected to discharge to surface waters.

Similarly, facilities undergoing corrective actions solely to address ammonia exceedences in groundwater will not be required to continue such actions. In such cases, FDEP staff will evaluate whether related nitrogen-bearing compounds, such as nitrate and nitrite, exceed their respective GCTLs, as well as the potential for surface water quality impacts.

FDEP is basing its decision to stop enforcing the ammonia GCTL at solid waste management facilities on a new draft toxicological review of ammonia by the U.S. Environmental Protection Agency. The ammonia GCTL was originally based on an oral reference dose for ammonia published by the Agency for Toxic Substances and Disease Registry that has since been withdrawn.

FDEP requested that the University of Florida Center for Environment and Human Toxicology provide comments on the draft toxicological review. Based on these comments, FDEP concluded that there is no longer a toxicological basis for the ammonia GCTL. Once the Environmental Protection Agency completes its review, FDEP expects to conduct rulemaking to consider changes to both the ammonia cleanup target levels for both groundwater and soil.

To view the full memo, please click here.