Phytoremediation Capability and Copper Uptake of Maize (Zea mays L.) in Copper Contaminated Soils

Abstract

Copper is a frequently used heavy metal worldwide and known to be an essential micronutrient for most living organisms including plants. However, excessive levels of copper in soil may adversely affect plant growth and survival. The continuing introduction of copper to soil, e.g., through excessive utilization of agrochemicals has raised serious environmental concerns throughout the world. A variety of plants have the capability to eliminate pollutants from soil through different mechanisms; however, limited information is reported on phytoremediation potential of maize (Zea mays L.) and its uptake and the accumulation potential in copper-containing soils. The effects of additions of 0, 50, 100, 200 and 300 mg kg−1 of copper to soil on growth parameters of Z. mays, copper uptake from soil and accumulation in roots and shoots, and phytoremediation potential of Z. mays were investigated in this research. Copper content in soil and plant samples were determined using atomic absorption spectrophotometry. The addition of 50 mg kg−1 Cu stimulated Z. mays growth parameters, while higher content of Cu exhibited inhibitory effects of plant growth. Results indicated that roots accumulated significantly higher levels of Cu than shoots in all treatments, suggesting dominancy of phytostabilization mechanism in remediation of Cu-polluted soil by Z. mays. However, translocation of Cu from the roots to the aerial parts enhanced to some extent with copper level in soil. The greatest Cu accumulation capacity of 5210 µg per pot was gained in Z. mays cultivated in soil treated with 200 mg kg−1 copper. Results demonstrated that Z. mays can promisingly remediate low to moderately copper-contaminated soils.