Distribution and Assessment of Heavy Metals in Trifolium dubium (Little Hop Clover) and the Impact of Soil Quality

Abstract

Trifolium dubium is an edible plant that is utilized in traditional medicine for its anti-inflammatory and wound-healing properties. In this study, T. dubium was assessed to determine the elemental uptake by the plant as a function of soil characteristics. Across 10 geographic locations in KwaZulu-Natal, South Africa, the concentration of elements in T. dubium were found to be (descending order) Ca > Mg > Fe > Zn > Mn > Se > Ni > Cr > Cu > Co > Pb > Cd > As. The site had an influence on elemental uptake by the plant; however, accumulation or exclusion of elements from soil was controlled to meet physiological requirements. Soil chemical characteristics showed T. dubium grew in slightly acidic soils (pH – 6.15 to 6.68). The findings of this study show T. dubium to contain adequate concentrations of essential elements with undetectable levels of toxic metals, making the herb safe for human consumption and for use in traditional medicine. The plant can also contribute to poor communities by ameliorating food insecurity.

Keywords:

• Accumulation
• availability
• bioaccumulation factor
• cation-exchange capacity
• elemental uptake
• physiological
• soil organic matter
• traditional medicine
• Trifolium dubium

Acknowledgment

The authors are thankful to the School of Chemistry and Physics, University of KwaZulu-Natal for the research facilities.

Additional information

Funding

This study was supported by National Research Foundation, South Africa.