Trace element composition of fertilizers and soil amendments

The use of fertilizers and soil amendments has raised concern regarding the toxic accumulation of their trace components in the environment. The objective of this research was to evaluate the trace element and heavy metal composition of a wide variety of fertilizers and soil amendments. Thirty-five elements, including priority pollutants, were determined in 24 materials. A microwave HNO3-HF-H2O2-H3BO3, digestion procedure was used to dissolve the samples. Selected solid samples were directly analyzed by neutron activation analysis, while atomic absorption and inductively-coupled plasma atomic emission spectrometric determinations were carried out on the digests. The trace element and heavy metal concentrations generally decreased in the following sample order: rock phosphate > sewage sludge > phosphorus fertilizer > organic amendments and liming materials > K fertilizers > N fertilizers. Relatively high concentrations of toxic elements in the sewage sludge, rock phosphate, and phosphorus fertilizer samples suggest that these materials should be the primary target materials for environmental evaluations.