Influence of electrical fields enhanced phytoremediation of multi-metal contaminated soil on soil parameters and plants uptake in different soil sections.

The influence of electrical fields on phytoremediation of multi-metal (Cd, Cu, and Zn) naturally contaminated soils has been investigated based on different soil sections. After ryegrass and hybrid penisetum were sowed for 30 d, electrical fields were applied during 30 days with the switching polarity every 30 min and continuing for 16 h d-1. After electrokinetic (EK) assisted phytoremediation process, soil electrical conductivity (EC) in anode section and available soil potassium (K) in cathode section were obviously elevated. Plants biomass in middle and cathode sections were increased in both plants, especially in middle section the overall biomass of hybrid penisetum increased by 68.8%. The influence of electrical field on the contents of heavy metals in plants was different depending on the species of plants, kind of heavy metals and soil section. For Cd, Cu, and Zn co-contaminated soils, shoot metals accumulation in middle section in both plants were improved at least about 20% (with the exception of Zn in ryegrass). Electrical fields had the most significant effect on copper absorption by ryegrass and shoot Cu accumulation were elevated 32.5% in all the section. The soil EC maybe an important factor that affected electrical fields enhanced plants growth, plant metals concentrations and remediation efficiency.