The systematic exploration of cadmium-accumulation characteristics of maize kernel in acidic soil with different pollution levels in China.

Cadmium is a toxic element with a half-life of more than a few decades that can be absorbed by crops and threaten human health. The problem of food security caused by cadmium through soil-crop systems has received great attention in China. Maize is a staple food widely cultivated throughout the world. However, the lack of systematic study makes it difficult to draw an accurate conclusion on its exact characteristics of cadmium accumulation and the corresponding health risk assessment. The availability of cadmium increased with the decrease of soil pH in acidic soil, enhancing the uptake of cadmium by crops and thus posing a major threat to food safety. In this study, the performance of kernel cadmium accumulation in abundant maize inbred and important hybrid lines were analyzed on acidic fields with different pollution levels in China. It was found that the kernel cadmium concentration both in inbred and hybrid lines showed left skewed distribution and concentrated significantly in a low interval under different soil cadmium gradients with good correlation. The classification of cadmium risk level in maize germplasm and cultivars and the analysis of soil cadmium threshold for maize safe planting can provide references to utilize the crop more feasibly and effectively. Maize may be an important staple crop to reduce human exposure to cadmium in agricultural soil.