Abstract: Objective To evaluate the pollution characteristics and the non-carcinogenic and carcinogenic risks associated with Pb, Cd and Cr in farmland soil across different areas of Chengdu. Methods From 2018 to 2021, a total of 200 soil samples were collected from Chengdu farmland. The single factor index, Nemerow index and human health risk assessment model were used to assess the contamination and risk of heavy metals in farmland soils. Results The exceedance rate of Cd content in the 200 soil samples was 24.00%, while Pb and Cr contents were within national standard limits. Among the three regions of Chengdu, the Cd exceedance rate followed the order：north>southwest>east. The average Nemerow comprehensive pollution index for the soil samples was 0.671, indicating an overall "no pollution" status. However, the soil in the north and southwest regions reached a "warning level" while the east region remained "no pollution" The non-carcinogenic health risk indices for Pb, Cd and Cr were all bellow 1. In contrast, the average value of the carcinogenic health risk index for children's oral intake of Cd and the maximum value of the carcinogenic health risk index for adults' oral intake of Cd both exceeded 1.0×10^-6. The total carcinogenic risk indices for Pb, Cd, and Cr across the three regions followed the order：north>southwest>east. Conclusions The overall pollution level of farmland soil in Chengdu was classified as "no pollution" and the non-carcinogenic health risks of the three heavy metals were within acceptable limits. However, the carcinogenic health risks associated with Cd pollution in certain regions require close monitoring.

Key words: Agricultural soil, Heavy metal pollution, Health risk assessment, Cadmium contamination, Carcinogenic risk, Regional variation