Distribution, accumulation, migration and risk assessment of trace elements in peanut-soil system

Trace elements contamination is mainly originated from industrial emission, sewage irrigation and pesticides, and poses a threat to the environment and human health. This study analyzed the trace element pollutants in peanut-soil systems, the enrichment and translocation capacity of peanut to trace elements, and the potential risk of trace elements to environment and human health. The results indicated that Cd and Ni in peanut kernels exceeded the standard limits in 2019, and the exceeding rate were 9% and 31%, respectively. Cd in 8% of soil samples and As in 98% of soil samples exceeded the risk screening value of trace elements. The concentration of trace elements in peanuts was related to varieties and planting regions. In addition, there was a significant positive correlation between the concentration of Cd in peanut kernel and its concentration in soil. Compared with other trace elements, peanut kernels had stronger ability to enrich and transport Cd, Cu, and Zn, the BFs were 0.45, 0.51 and 0.47, respectively. After oil extraction, trace elements were mainly concentrated in peanut meal, and only 0.25% of Cd was in oil. The RI of trace elements was less than 150, indicating that the study area was under low degree of ecological risk. However, As and Cd might pose moderate risk to environment. Trace elements in soil and peanut could not cause non-carcinogenic and carcinogenic risks to human, but the HI and CR value of As (0.59 and 9.54 × 10⁻⁵) in soil and CRᵢₙg value of Cd (9.25 × 10⁻⁷) in peanut were close to the critical value. We conclude that Cd pollution in peanut kernel, and Cd and As pollution in soil should be monitored to enter into the food chain or environment and to avoid the possible health hazards and environment risks.