Heavy metals mobility, sources, and risk assessment in soils and uptake by apple (Malus domestica Borkh.) leaves in urban apple orchards

ABSTRACT

The aim of the study was determine potential mobility, sources, and environmental impacts of heavy metals in soil of urban apple orchards using a sequential extraction procedure and multivariate analysis. The soil and apple (Malus domestica Borkh.) leaf samples were collected from apple orchards of urban areas in Çanakkale, Turkey. A sequential extraction procedure was employed to determine the binding forms of Cd, Cr, Cu, Ni, Pb, and Zn in soil samples. Sequential extraction procedure revealed that mobile fractions (acid soluble, reducible, and oxidizable) of Cd (60.2%) and Pb (56.8%) were higher than their immobile fractions. Such higher mobile fractions indicate the anthropogenic sources, and multivariate analysis results also supported the existence of such sources. The relationship between pH and mobile fractions of the metals (sum of acid soluble, reducible, and oxidizable) indicates that Cd and Pb become more mobile under decreasing pH conditions. Considering all metals, except for Cd, a strong relationship was observed between metal concentrations of apple leaves and mobile fractions, and plants were primarily able to uptake the metals in these fractions. Contamination factor and risk assessment code results together also revealed that Cd was highly mobile; retained less and had high risk for the environment.

KEYWORDS:

• Heavy metal mobility
• multivariate analysis
• risk assessment
• sequential extraction
• urban soils

Acknowledgements

The author thanks Associate Prof. Dr. Habib Kocabıyık for his support provided for the statistical analyses of the study.

Disclosure statement

No potential conflict of interest was reported by the author.