Insight of heavy metal contamination of soil in high background area: field investigation and laboratory test

This paper utilizes field sampling and laboratory testing to identify potential sources of heavy metals, including rock, dust, rainfall, surface water, and groundwater, employing Pearson Correlation Coefficient—Principal Component—Sources Factors Analysis. A total of 33 surface and 22 profile soil samples were collected to investigate the migration characteristics and spatial distribution of heavy metals in the study area. Additionally, the paper discusses the comparison of soil heavy metal concentrations between sunny and shady slopes. The findings reveal that soil heavy metals in the study area primarily originate from weathering and downward migration deposition of parent rock, indicative of a geological high background area. Moreover, this has led to arsenic contamination in the soil, with an excess rate of 74.5%. It was observed that heavy metals tend to accumulate more on shady slopes than sunny slopes, with mercury and arsenic showing the most significant differences at 69.70% and 49.33% higher levels, respectively. The comprehensive impact index of agricultural soil was calculated at 53.25, indicating a sub-pollution level. Additionally, the study notes that with the increase in crop enrichment coefficient, the variation values of soil heavy metal concentrations decrease, with a correlation coefficient of 0.6077 between the two variables.