The Identification of Soil Heavy Metal Sources and Environmental Risks in Industrial City Peri-Urban Areas: A Case Study from a Typical Peri-Urban Area in Western Laizhou, Shandong, China

Abstract

During the past several decades, soil heavy metal contamination has emerged as an environmental affliction and subject of study. Soil heavy metal contamination in peri-urban areas is more severe and intricate. The western region of Laizhou City, as a typical industrial city exhibiting vigorous factory, agricultural, and extraction activities, possesses substantial research merit and can offer a noteworthy example for the analysis of heavy metal contamination in the peri-urban areas of industrial cities. We procured 271 surface soil samples (0–20 cm) from the western peri-urban areas of Laizhou City. Through statistical scrutiny, it was discerned that the concentrations of As, Cd, Hg, and Pb surpassed the local baseline concentrations, with the ranking of the coefficient of variation being Hg > 1 > Cd > 0.5 > Pb > Cu > As > Ni > Zn > Cr. Subsequently, we investigated the potential origins of heavy metals through correlation analysis, principal component analysis, and geostatistical analysis and elucidated the primary origins of heavy metals based on the existing land-use scenario: PC1 (As, Cd, Cu, Pb, and Zn) predominantly originated from agricultural pursuits, transportation, and industrial production; PC2 (Cr and Ni) was correlated with soil parent materials; and PC3 (Hg) was attributed to industrial production and open-pit mining of minerals. According to the analysis of the Nemero comprehensive index and potential ecological risk index, the soil environmental risk in the study area was within a controllable range. However, the continuous enrichment of heavy metals in the soil should receive sufficient attention, and continuous monitoring of the site is recommended. This study attempts to use a combination of existing land-use scenarios and statistical analysis methods to analyze the heavy metal pollution conditions in peri-urban industrial cities. Although this study has shortcomings, it provides valuable information for the study of heavy metal sources and environmental risks in typical industrial city suburbs.