Objective To evaluate the levels and dynamics change of health hazards in farmland soil in Jiangyin City, and to provide theoretical basis for the government and other relevant departments to policy formulation.

Methods From 2011 to 2022, five towns (streets) were randomly selected in non-urban areas of Jiangyin each year.In each town (or street), four administrative villages were randomly chosen as monitoring sites. One farmland soil sample was collected from each monitoring site. A total of 240 soil samples were collected and analyzed for lead (Pb) and cadmium (Cd) contents. Additionally, from 2020 to 2022, the contents of chromium (Cr), mercury (Hg), and arsenic (As) were analyzed in 60 samples. From 2012 to 2020, 180 samples were tested for the presence of Ascaris eggs. Fisher′s exact test was employed for comparing rates. Soil heavy metal content was characterized using the median and interquartile range. Mann-Kendall method was used for trend analysis. Soil heavy metal pollution was assessed using the single-factor pollution index method and the Nemerow comprehensive pollution index method.

Results The detection rate of ascaris eggs in farmland soil of Jiangyin City was stable (χ²=5.91, P>0.05) and remained at a low level. Specifically, the overall detection rate of ascaris eggs was 5.00% (9/180) and that of viable ascaris eggs was 3.89% (7/180). The concentrations of Pb, Cd, Cr, Hg and As in all soil samples were below the risk control thresholds for soil heavy metal pollution. The single-factor pollution indices (P_i) for Pb, Cr, Hg, and As were all less than 1. Slight, mild or moderate cadmium (Cd) pollution was detected in 9.58% (23/240) of the soil samples. The Cd exceedance rate was 40.00%(8/20) in 2020 and 35.00%(7/20) in 2021. Additionally, there was a significant increasing trend in soil Cd content (S=39, Z=2.63, P=0.009).The Nemerow comprehensive pollution index for heavy metals in soil was from 0.16 to 2.78.

Conclusion The hygienic condition of farmland soil in Jiangyin City is generally good. However, there is a certain risk of soil cadmium pollution. Therefore, it is necessary to continuously monitor soil cadmium levels and conduct joint monitoring with agricultural products. Additionally, efforts should be made to strengthen the regulation of industrial waste emissions (solid, liquid, and gaseous) and promote the rational use of chemical fertilizers and pesticides.