Trace Element Content of Selected Fertilizers and Micronutrient Source Materials*

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Abstract
Twenty‐eight fertilizer materials, including nine micronutrient sources and a slag, were analyzed for 10 elements of environmental concern: arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), molybdenum (Mo), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn). Also, we calculated the soil loads of these elements that would result from 50 annual applications using high application rates. Results were compared with published data contained in two risk assessments and with indigenous soil loads calculated from a database of elemental concentrations in South Carolina soils. Except for two micronutrient sources, elemental concentrations were below those considered to present minimal health risk associated with food‐chain transfer to humans. Generally, long‐term use of the conventional fertilizers we examined, including micronutrient sources, should not be cause for concern regarding metal loading of soils. However, several of the materials would result in doubling the soil concentration in 20 years or less if applied at the assumed rates, which are considered “high end.” Since some soils have an unusually high concentration of one or more elements of environmental concern, and since that cannot be predicted from a conventional soil test, a total elemental soil analysis should be obtained if unconventional materials such as slag and industrial by‐products are used as nutrient sources or soil amendments.