Objective To determine the level of chromium pollution in rural farmland soil in Shijiazhuang, China from 2016 to 2022 and evaluate the potential health risks to the population.

Methods Six project counties/districts including Wuji county, Zanhuang county, Luquan district, Luancheng district, Gaocheng district, and Zhengding county were selected, and 20 samples were collected each year from each county. The chromium content in the soil was evaluated using the geoaccumulation index, potential ecological risk index, and health risk assessment model.

Results The mean chromium content in the soil of each project county in Shijiazhuang did not exceed the standard limit. The overall mean chromium content in the soil significantly increased from 29.94 mg/kg in 2016 to 51.45 mg/kg in 2022, with a total increase of 40.66 mg/kg (Z=2.28, P=0.023). The pollution levels indicated by the geoaccumulation index from high to low were Wuji county>Zanhuang county>Luquan district>Luancheng district. The potential ecological risk was much lower than the risk value, indicating that the ecological risk was negligible. The result of non-carcinogenic risk analysis showed that the non-carcinogenic risk in children was significantly higher than that in adults (P < 0.001); the route of exposure at the higher risk was oral intake, followed by skin contact and respiratory inhalation, and the difference in the three routes of exposure was statistically significant between children and adults (P < 0.001). The carcinogenic risk analysis result showed that the carcinogenic risk of inhalation of heavy metal chromium by breathing in adults was significantly greater than that in children (P < 0.01).

Conclusion Among the six project counties, the chromium content in farmland soil in Zhengding county, Zanhuang county, and Luquan district is increasing year by year, but the overall pollution level is relatively low; the non-carcinogenic risk to the human body exceeds the threshold, and the carcinogenic risk is within the acceptable range.