Heavy Metal Residues in Soil and Accumulation in Maize at Long-Term Wastewater Irrigation Area in Tongliao, China

Abstract

Soil and plant samples were collected from Tongliao, China, during the maize growth cycle between May and October 2010. Heavy metals, such as Cr, Pb, Ni, and Zn, were analyzed. The concentrations of Cr, Pb, Ni, and Zn in the wastewater-irrigated area were higher than those in the topsoil from the groundwater-irrigated area. The concentrations of metals in the maize increased as follows: Pb < Ni < Zn < Cr. In addition, Cr, Pb, and Ni mainly accumulated in the maize roots, and Zn mainly accumulated in the maize fruit. The results of translocation factors (TF) and bioconcentration factors (BCF) of maize for heavy metals revealed that maize is an excluder plant and a potential accumulator plant and can serve as an ideal slope remediation plant. In addition, the increasing heavy metal contents in soils that have been polluted by wastewater irrigation must result in the accumulation of Cr, Pb, Ni, and Zn in maize. Thus, the pollution level can be decreased by harvesting and disposing of and recovering the plant material.

Bioaccumulation of Potentially Toxic Elements in Cereal and Legume Crops: A Review

“…The PTEs contents in maize ( Zea mays L.) increased as follows: Pb < Ni < Zn < Cr. In addition, Cr, Pb, and Ni mainly accumulated in the maize roots, and Zn mainly accumulated in the maize fruit …”

“…In addition, Cr, Pb, and Ni mainly accumulated in the maize roots, and Zn mainly accumulated in the maize fruit. [62] Improving seed mineral concentration is the focus of many research groups in a variety of food crops such as wheat, rice, www.advancedsciencenews.com www.clean-journal.com maize, and beans. [63] Among legumes, soybeans are the highly sensitive species to PTEs present in the soil, representing their ability potentially to absorb higher amounts of PTEs than other plants.…”

“…Cereals are considered as excluder and generally non-hyperaccumulator plants with translocation factor <1 and bioconcentration factor !0.2. [16] In contrast to cereals, legumes produce a higher biomass and hence have a greater ability of PTEs accumulation. Legume plants increase the exchangeable pool of metals and metalloids in soil through occurrence of low molecular weight organic acids that develop soluble complexes with PTEs, thus releasing metal ions from the contaminated soil.…”

Interactions between plant hormones and heavy metals responses

“…In developing countries, this problem has arisen from long-term use of untreated wastewater for irrigation, leading to increased concentrations of heavy metals in soils (Arora et al , 2008; Lu et al , 2015). This prevents plants from reaching their maximum genetic potential for growth, development and reproduction.…”

Efficiency Assessment of bioremediated water and soil on cultivation of maize plant.

“…T he addition of Ni i n nutrient s olution als o i ncreas ed Ni concentration in roots and shoots. Lu et al (2015) report ed that t he great er Ni cont ent in the soil r esult ed in the acc umul ation of Ni in the maiz e organs. Tickoo et al (2003) s howed that there is t he signific ant diff erenc e i n the cas e of root lengt h, s hoot l engt h, fres h weight and dr y w eight betw een Cd and Ni treatments .…”