Cadmium concentrations in German soybeans are elevated in conurbations and in regions dominated by mining and the metal industry

Publication Type

Journal contribution (peer reviewed)

Authors

Franzaring, J., Fangmeier, A., Schlosser, S., Hahn, V.

Year of publication

2018

Published in

Journal of the Science of Food and Agriculture

Page (from - to)

accepted

Background: Cadmium (Cd) is a mobile heavy metal and soybeans accumulate more of the element than other grain crops. Since vegan and vegetarian lifestyles are increasingly popular, plant-based diets should be free from contaminants. Cd minimization has recently been identified as a breeding aim in addition to protein and oil levels. It is also important to consider the regional variability of Cd in crops.

Results: A large sample collection (n=602) was subjected to Cd analyses. Soybeans were grown using a standard protocol by private gardeners in a citizen science program. 12.5% of the samples exceeded the EU limits, but Cd concentrations and exceedances showed regional variation around the national mean (0.13 mg/kg). Contamination was higher in densely populated regions, possibly due to long-term emissions of heavy metal loaded dusts from industry, traffic and energy production. Cd concentrations were also elevated in regions once characterized by mining and heavy industry. Values were overall low in rural areas and agricultural regions despite potential inputs via P-fertilizers.

Conclusion: Grain Cd levels are highly variable across Germany. Soybean farming may be problematic in regions with a long history of mining and heavy metal deposition.