Spatial distribution of cadmium and lead in wheat grains and their environmental driving factors in major grain-producing areas, China

Cadmium and lead can enter the human body through the food chain, posing a threat to human health and food safety. Knowledge of the spatial distribution pattern of Cd and Pb in wheat grains in the major grain producing areas and identification of the main driving factors can provide scientific references for development of precise pollution remediation and management measures to ensure food security and sustainable agricultural development. The study adopted multi-method collaboration, and integrated multi-source environment data to comprehensively analyze the spatial distribution pattern and their environmental driving factors of cadmium and lead concentrations in wheat grains in a typical major wheat producing area in China. Results showed that the mean concentrations of cadmium and lead in wheat grains were lower than the Chinese standard limits, with the exceedance rates of 11.69 % and 8.83 %, respectively. The spatial distribution characteristics of cadmium and lead was similar, and had obvious spatial aggregation characteristics, i.e., the northwestern and southern parts were the agglomeration of high-value areas. The livestock and manure application had the most significant effect on the spatial distribution of cadmium and lead, with q values of 0.105 and 0.187, respectively, followed by fertilizer application and population density. The distribution of cadmium was more influenced by livestock and manure application, fertilizer application, etc. in the eastern region than in the western region, whereas for lead, it was higher in the southeast than in the northwest. The comprehensive analysis of geodetector and geographically weighted regression indicated that the livestock and manure application, fertilizer application, population density, and industrial activities were the main driving factors for the spatial distribution of Cd and Pb. The findings enhance our understanding of the spatial distribution pattern and environmental driving factors of cadmium and lead in wheat grains, offering a new perspective on the safe production of wheat.