CADMIUM LEVELS IN FERTILIZER: PRESENT AND LIKELY FUTURE POLICIES IN NORTH AMERICA
W.C. Herz^1
1The Fertilizer Institute, 820 First Street

Risk assessment is a widely used and accepted scientific approach that serves as a sound basis for setting health protective standards (i.e., safe limits) as part of the risk management process. Three stakeholders including the United States Environmental Protection Agency (U.S.EPA), the California Department of Food and Agriculture (CDFA) and The Weinberg Group (TWG) for The Fertilizer Institute (TFI) commissioned fertilizer risk assessments in response to a need for determination of safe levels of trace elements in fertilizers. U.S. EPA's risk assessment entitled Estimating Risk from Contaminants Contained in Agricultural Fertilizers appeared as a draft report dated August 1999. U.S. EPA evaluated 9 metals in 13 fertilizer product categories used widely across the U.S. and concluded 'based on the data available, hazardous constituents in fertilizers generally do not pose harm to human health or the environment.' The Agency did not recommend standards or limits for metals in fertilizers but has finalized a regulation governing the use of zinc wastes as a recycled source of essential zinc nutrient in inorganic fertilizer.

CDFA's risk assessment, entitled Development of Risk-Based Concentrations for Arsenic, Cadmium and Lead in Inorganic Commercial Fertilizers, was issued in March 1998. Risk-based acceptable concentrations (RBC) are calculated maximum levels (in parts per million - ppm) of a specific metal in a fertilizer product that do not pose an unacceptable health risk following its use and exposure over a sensitive person's lifetime. TWG's risk assessment, entitled Health Risk Evaluation of Select Metals in Inorganic Fertilizers Post Application, derived RBCs for 12 metals and compared to concentrations of these metals in NPK and micronutrient fertilizer products as reported by the U.S. EPA, numerous states monitoring programs and fertilizer manufacturers. TWG risk assessment summary is slated to be published in an American Chemistry Society book due out in December, 2003. Through collaboration of the risk assessment teams, and peer review comments, the RBC values have undergone some modifications and were finalized in July 2001.

As fertilizer is regulated primarily at the state level in the U.S., the development of TWG RBC values were incorporated into a model bill by Association of American Plant Food Control Officials (AAPFCO), a consortium of state officials that meet to address fertilizer regulatory issues and promote uniformity in state laws. A model bill was formally adopted at the August 6, 2003 meeting and metal regulations have been adopted in various forms in several states, including California, Oregon, Texas, and Florida. The model bill for metals regulation is useful to states either intact or modified to fit state - specific conditions.