Accumulation of toxic elements in soil and date palm (Phoenix dactylifera L.) through fertilizer application

Abstract

Dates are the staple food for Arabs as well as the major export crop in the Middle East. In this work, we analyzed the concentration of toxic elements in commonly used fertilizers and evaluated metal accumulation in soil and date palm. Different types of fertilizers randomly selected from fertilizer dealers in the UAE were investigated for their toxic metals. Soil and plant samples collected from continuously fertilized date plantations were analyzed. Sandy loam soil (0–30 cm) samples were collected from date palm plantations continuously fertilized for more than 10 years (11 samples) and unfertilized date palm plantations (11 samples). A significant increase in chromium (Cr) and cadmium (Cd) was observed in the leaves of the fertilized date palms, whereas, in date palm fruits, the concentration of copper (Cu) was higher. A distinct correlation was observed between the total and the available metal concentrations in the soil for Cd and Cu. The average concentrations of toxic metals, however, remained within the limits of those used worldwide. It is important to encourage manufacturers to indicate the concentrations of toxic elements on the fertilizer labels due to environmental and health implications.

Keywords:

• dates
• ammonium phosphate
• copper
• arsenic

Acknowledgments

The authors are grateful to Dr. Hakim Saibi, Associate Professor, Department of Geology, College of Science, the UAEU for his contribution to refining the manuscript with additional geophysical information. The authors acknowledge the laboratory specialists Mr. Saad Khalil Ismail and Mr. Felix T. Labata for their help with the chemical analysis of fertilizer, soil, and plant samples.

Conflict of interest

The authors declare no conflict of interest.

Funding

This research was funded by the College of Food and Agriculture, the United Arab Emirates University (UAEU).

Author contributions

Mohsin Sulaiman and Shyam S. Kurup conceived and designed the research. Mohsin Sulaiman and Fayas Thayale Purayil conducted the research. Sonu Krishnakumar contributed to the field work and data tabulation. Mohsin Sulaiman and Shyam S. Kurup prepared the manuscript. Mohammad Pessarakli contributed to manuscript preparation and its improvement.