Multi-Target Element-Based Screening of Maize Varieties with Low Accumulation of Heavy Metals (HMs) and Metalloids: Uptake, Transport, and Health Risks

Mitigating heavy metals (HMs) contamination and ensuring the safe production of crops is of paramount importance for sustainable agriculture development. The purpose of the current field plot study was to select maize varieties with low HMs and metalloids in their edible parts but high accumulation in other parts. The cadmium (Cd), arsenic (As), lead (Pb), and chromium (Cr) contents of 11 maize varieties were measured by atomic absorption spectrometry, and the plant growth and bioconcentration factors (BFs) were examined. Furthermore, the average daily intake (ADDi) of HMs in maize grains was calculated to assess the associated health risks. The results revealed that the growth of variety TZ23 was minimally impacted HMs and metalloids. The grains of all of the tested maize varieties contained Cr, As, and Pb contents in accordance with National Food Safety Standards (NFSSs, GB2762-2017, ≤0.1 mg·kg−1), while the Cd concentration in grains of varieties QJN1, LSCR, and JN20 were 0.084 mg·kg−1, 0.094 mg·kg−1, and 0.077 mg·kg−1, respectively, in accordance with NFSSs. The translocation factor (TF) of As, Pb and Cr in the grains of 11 maize varieties were found to be less than 1. However, the TF of grain Cd in varieties LYN9, JYN9, and QJN3 exceeded 1. For varieties HNY21, TZ23, and LYN9, the TF of Cd, As, Pb, and Cr in the stems/leaves was less than 1. Cluster analysis revealed that the grains of variety HNY21 had the lowest accumulation capacity of all four HMs. Importantly, the variety JN20 exhibited a high accumulation capacity for Pb and a low capacity for As, while both varieties SKN11 and QJN3 had high accumulation capacities for Cd and low capacities for As. Health risk (HR) indices of the different age groups displayed an overall trend of children > elderly > young adult. Among the HMs and metalloids, Cd and Cr pose the greatest health risks of maize intake. Variety QJN3 posed a significant HR due to chronic toxicity. This study provides a scientific basis for multi-element pollution control and screening of maize varieties suitable for cultivation in mining areas and the remediation of HMs-contaminated soils.