Is maize suitable for substitution planting in arsenic-contaminated farmlands?

Abstract

The efficacy of using maize (Zea mays L.) as a suitable substitute for other crops with high arsenic (As) accumulation in As-contaminated farmlands remains debated. Here, the As uptake capacity and the stability of accumulated As of different maize cultivars were studied using pot and field experiments, outdoor investigations and literature data analysis. When the total and available soil As levels were 238.8 and 8.1 mg/kg, respectively, grain As ranged from 0.03 to 0.07 mg/kg, significantly lower than the acceptable As limit (0.5 mg/kg) for maize in China. The results of field investigations and literature data analysis also supported this observation. Maize is a crop with low grain As, thus, making it suitable for substitution planting in As-contaminated farmlands. Further, grain As concentration varied among different maize cultivars. The planting of normal and waxy maize is prioritized over the sweet maize as the first one has lower available bio-concentration factor (aBCF) of 0.007 for grain and higher accumulated As stability among its cultivars (CV < 10%) than those for sweet maize (aBCF = 0.01 and CV = 35.5%). Arsenic compartmentalization in the roots and low As upward migration into the grain were responsible for the low grain As of maize.

Sweet Corn Research around the World 2015–2020

“…Sukiasyan [293] assessed the environmental risk factor of diverse heavy metals in various soil and climatic regions and concluded that standard protocols are needed for classifying heavy metals by hazard class according to the maximum allowable concentration. Cao et al [294] evaluated the efficacy of using maize for accumulating arsenic in contaminated soils in China and concluded that the concentration of arsenic in maize kernels was lower than for other crops, with waxy corn more appropriate than sweet corn based on their concentration levels specifically. He et al [295] suggested that oxidative proteins from Arabidopsis might be involved in stress tolerance and stress escape, such as Cadmium, explaining the possible mechanism and suggesting the candidate gene homologous of ZmOXS2b to engineer stress tolerance.…”

The Synergetic Effect of Soil Amendments on Reducing Bioavailable Heavy Metals and Greenhouse Gas Emissions from Upland Soil

“…Similar results were observed in our study, with 23.0-173.5, 32.0-78.0, and 10.5-38.2 times higher concentrations of As, Cd, and Pb observed in roots than in grains, respectively. The main reason for the higher accumulation of heavy metals in roots is that heavy metals are generally immobilized by complexation with iron oxide plaques or thiol ligands in roots, which inhibits heavy metal translocation to grain [40]. We therefore observed a markedly higher reduction efficiency of As and Pb in corn when FeO was combined with SM.…”

Seeking for an optimal strategy to avoid arsenic and cadmium over-accumulation in crops: Soil management vs cultivar selection in a case study with maize

“…The genetic variance of crops for heavy metals uptake and the intrinsic resistance to adverse growing environment are responsible for different accumulation risks of heavy metals (Clemens et al, 2016). Previous work indicated that As compartmentalization in roots and small amounts of upward-migration of As into the grain are responsible for low grain accumulation of As in maize (Cao et al, 2019). The underlying mechanism of As and Cd uptake by the root is thought to be strongly associated with P as well as Fe, Zn, Mg transporters at the cell membrane (Zhang et al, 2018b).…”

“…The aBCF was then calculated as: aBCF = [Cd or As] in grains/ available [Cd or As] in soil (Cao et al, 2019). Total As concentrations in maize samples were determined by ICP-MS after acid digestion using HNO3, HClO4 and H2SO4 in a ratio of 4:1:1.5 (Yu et al, 2016).…”

“…In field work, the available bio-concentration factor (aBCF) is encouraged to be introduced for the cultivar selection (Cao et al, 2019 for the subsequent statistical analysis. CATREG has been successfully employed to identify the association between lead (Pb) and mercury (Hg) exposures with certain genetic polymorphisms in human body (Gundacker et al, 2009(Gundacker et al, , 2010.…”