Phytoremediation of Potential Toxic Elements by Native Tree Species in Mined- Spoiled Soils in Mátraszentimre, Hungary

Abstract

Potential toxic elements, such as Arsenic (As), Cadmium (Cd), Copper (Cu), Lead (Pb), and Zinc (Zn) are commonly left behind after mining operation. Being non-biodegradable, these elements serve as source of contamination for the soil and water ecosystems and create hazards to human health. This research work evaluated the phyto extracting ability for potential toxic elements by four endemic tree species, such as Betula pendula (Birch), Carpinus betulus (Hornbean), Fagus sylvatica (Beech), and Salix caprea (Goat willow). These tree species are predominantly growing in an abandoned mining spoil sites in Mátra Mountains, Hungary. Plant and soil samples were collected in the field and analyzed using inductively coupled plasma-atomic emission spectrometry (ICP-OES) method. The soil was highly contaminated with heavy metals, such as Pb, As, and Zn which were 10 to 60 times more than the typical non-contaminated Hungarian soil. Among the trees evaluated, Carpinus betulus showed the highest potential for Pb dendroremediation, with a mean concentration value of 4071.67±45.71 mg kgˉ¹ dry weight in roots, 439.05±1.06 mg kgˉ¹ dry weight in stems and 92.53±0.73 mg kgˉ¹ dry weight in leaves. Betula pendula and Salix caprea bioaccumulated 475.575±2.219 and 395.97±1.43 mg kgˉ¹ dry weight of Zn in their leaf biomass. Both trees had a Bio-concentration Factor (BCF) value of greater than 1.0 but less than 10 which classified them as potential phytoextractors of Zn. Salix caprea gave the highest Translocation Factor (Tf) for Cd while Betula pendula gave the highest Tf for Zn.