Traffic and industrial activities around Riyadh cause the accumulation of heavy metals in legumes: A case study

The objective of this study was to analyse the effect of the continuously increasing anthropogenic activities around Riyadh, Saudi Arabia on the accumulation of heavy metals in leguminous crops. This study determined whether four legume crops, Pisum sativum L., Vicia faba L., Glycine max and Vigna sinensis, could accumulate the heavy metals Cu, Mn, Pb and Zn in their leaves, pods and grains during the summer when grown under conditions with ambient air pollution from heavy traffic and industrial activities in Riyadh, Saudi Arabia. The effect of the air pollution was examined by quantifying the protein and trace element Cu, Mn, Pb and Zn concentrations in the leaves, pods and grains of the four plant species. Analysis of the results indicated that air pollution significantly increased the heavy metal concentrations in the leaves, pods and grains. Toxic concentrations of the heavy metals were found in the plants grown at L3, L4 and L5. In conclusion, the air pollution increases as the traffic, industrial activities and population density increase.