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.