Organic Farming, Cadmium and Other Trace Metal Content of Plant Foods

Background and methodology:

The increasing consumer interest in ecologically produced foodstuffs has resulted in a steady growth of organic farming in recent years. As a result of the claims used in marketing of organic foodstuffs, many consumers take it for granted that ecologically produced foods have lower levels of environmental contaminants such as cadmium (Cd) compared with conventionally grown products. The aim of this study was to investigate if there is any significant difference in Cd levels between organically and conventionally grown crops. 

The levels of Cd in the wheat did not correlate with the cultivation system or the Cd in the soil. Conventionally grown wheat from one field trial showed a significantly higher Cd level compared with ecologically grown wheat, while in the other field trail significantly lower Cd levels were detected in the conventionally grown wheat. No statistically significant differences in the concentrations of Cd, Pb, Cr, or Zn in rye, carrots and potatoes were detected between the cultivation systems. The results indicated that organic farming, at least in the short term, does not necessarily result in reduced levels of Cd and other potentially harmful metal in food of vegetable origin.

Jorhem, L. & Slanina, P. (2000). Does organic farming reduce the content of Cd and certain other trace metals in plant foods? A pilot study. Journal of the Science of Food and Agriculture. 80:43-48.