The effect of cadmium contained in fertilizers on the cadmium content of vegetables

Authors

• Antti Jaakkola Agricultural Research Centre, Department of Agricultural Chemistry and Physics, 01300 Vantaa 30
• Johan Korkman Kemira Oy, Malminkatu 30, 00100 Helsinki 10
• Tuomo Juvankoski Kemira Oy, Malminkatu 30, 00100 Helsinki 10

DOI: https://doi.org/10.23986/afsci.71995

Abstract

The aim of the study was to find out to what extent the cadmium contained in fertilizer influences the cadmium content of vegetables. For this purpose, highly cadmium-bearing batches of fertilizer were prepared from selected quantities of raw material with an exceptionally high cadmium content. To one such batch of fertilizer, an extra amount of cadmium was added at the mixing stage. In a two-year field experiment carried out in soil consisting of clayey fine sand and begun in 1977, 1000 kg/ha of NPK fertilizer with a cadmium content of either 57 or 81 mg/kg brought about a clear increase in the cadmium content of radish tops. The cadmium content of radish roots, spinach and lettuce appeared likewise to rise, but the differences registered were not, owing to the unevenness of the field, significant. The cadmium content of the dry matter of rye grass was lower than that of the other experimental plants, and it appeared to rise less with an increase in the cadmium content of the fertilizer. Owing to the wide range of variation, the cadmium uptake of the experimental plants could not be determined reliably, The spinach, however, appeared to have taken up the largest amount of cadmium, and the rye grass the least amount. The increase in the cadmium content of the spinach harvested in 1978 corresponded to 1.5‰ of the cadmium introduced into the ground during the two-year period through application of the fertilizer with the highest content of the metallic element.