Heavy Metals Accumulation in Biomass of Some Crop Plants

1 College of Engineering Sciences, Technology & Agriculture, Florida A&M University, Tallahassee, Florida, USA 32307
2 Institute for Sustainable Development, BG - 1407 Sofia, Bulgaria


ANGUELOVA, I., G. ANGUELOV, I. ATANASSOV and N. BAILEY, 2004. Heavy metals accumulation in biomass of some crop plants, Bulg. J. Agric. Sci., 10: 107- 112

Field investigations were carried out with winter wheat, barley and alfalfa in order to examine the accumulation of Pb, Zn, Cd and Cu in plant tissues depending on the concentration of the metals in the soil. Elevent plots were chosen to grow experimental plants located at different distances from a local source of pollution: a Pb - Zn smelter. The soil in vicinity of the smelter was determined as Calcarious Fluvisol and the contents of the pollutants in the experimental plots vary as follows: for Pb - between 48.0 and 551.0 mg/kg; for Zn - 369.0 and 1808 mg/kg; for Cd - 0.4 and 16 mg/kg and Cu - 24.0 and 87.5 mg/kg.
The content of Pb, Zn, Cd an Cu in vegetative plant tissues vary between 5 - 115 mg/kg for Pb; 63 - 174 mg/kg for Zn; 1 -7 mg/kg for Cd and 4 - 14 mg/kg for Cu.
The transfer coefficients (Tc) vary depending on the content of the metals in soil, their bioavailability and plant species For winter wheat Tc vary between 0.1 - 0.7, for barley - 0.1- 0.8 and for alfalfa - between 0.07 -0.8. According to the Tc values, the bioavailability of the metal was in order: Cd> Cu > Zn > Pb. There is a good correlation between concentration of the Pb an Cd in soil and plants but no significant relationship between the Zn concentration in soils and plants was found.
There is relationship between mobile and water-soluble forms of Pb, Zn, Cd and Cu in soil and the concentration of these metals in plant tissue. On the base of these results it is possible to conclude that mobile (extraction with ammonium acetate buffered solution at pH 4.8) and water soluble forms of above mentioned metals in soil can be considered as indicative for assessment of their bioavilability.

Key words: heavy metal pollution of soil, uptake of Pb, Zn, Cd and Cu by winter wheat, barley and alfalfa, transfer coefficient