Geochemical Baseline, Pollution Evaluation, and Source Apportionment of Topsoil Heavy Metals in Eastern Yongqiao District of Suzhou City, China

Heavy metals constitute a group of toxic environmental contaminants with complex and varied origins. This study provides a comprehensive framework for deciphering soil heavy metal pollution in rapidly developing regions. The geochemical baselines, pollution levels, and sources of ten heavy metals (V, Cr, Mn, Co, Ni, As, Cd, Pb, Cu, and Zn) were analyzed in topsoil from the industrial–agricultural–transportation hub of Eastern Yongqiao District, Suzhou City, Anhui Province, China. Overall, 48 topsoil samples were analyzed using geochemical baseline determination, the geo-accumulation index (I geo ), the Nemerow comprehensive index, and a multiple linear regression model based on absolute principal component scores (APCS-MLR). The geochemical baseline determination indicates that the elevated mean concentrations of Cr (218.51 mg/kg) and Ni (103.19 mg/kg) are significantly associated with anthropogenic activities. Three samples were identified with moderate-to-strong Cr and Ni pollution by the I geo method, while all other samples had slight-to-moderate pollution levels. The Nemerow comprehensive index showed heavy metal pollution above the moderate level in five samples. The APCS-MLR model identified four pollution sources for heavy metals: industrial sources (40.5%, dominated by Cr, Co, and Ni), traffic-related sources (23.7%, dominated by V, As, Pb, Cu, and Zn), natural sources (12.6%, dominated by Mn), and agricultural sources (9.4%, dominated by Cd). This research provides a scientific basis for the management of heavy metal pollution derived from industrial production, agricultural activities, and transportation.