Use and validation of magnetic properties for differentiating nickel hyperaccumulators and non-nickel hyperaccumulators in ultramafic regions

Abstract

Nickel hyperaccumulators are plants that can absorb a large amount of Ni in their tissues. Nickel hyperaccumulators have a strong potential to be used as bioindicators in mineral explorations. Previous studies show that analysis of magnetic susceptibility has a potential to accelerate the screening of Ni hyperaccumulators. In this study, we investigated the use magnetic characterizations for screening directly Ni hyperaccumulators and non-Ni hyperaccumulators from ultramafic regions. For comparison, the characterization of Ni hyperaccumulators was also performed on Alyssum murale and Alyssum corsicum, which were cultivated on lateritic soils. The metals concentrations in the tissues were determined via inductively coupled plasma optical emission spectroscopy analysis, atomic absorption spectroscopy analysis, and X-ray fluorescence analysis. The magnetic characterizations were conducted by magnetic susceptibility measurement, acquisition of hysteresis curves, and analysis of the thermomagnetic properties. The results showed that the concentration of Ni in A. murale and A. corsicum were correlated to the magnetic susceptibility values. Concurrently, all samples had negative magnetic susceptibility values were non-Ni hyperaccumulators. Two new species of Ni hyperaccumulators were found in Halmahera and Sulawesi and have high potential for use in phytoremediation, phytomining or mineral exploration.