Characteristics and source analysis of heavy metal accumulation in roadside plants in Harbin, China

The contamination of heavy metals resulting from vehicular traffic constitutes a serious and pervasive concern, posing significant health hazards to humans. The aim of this study was to determine the heavy metal content in 29 commonly used roadside greenery plants in Harbin, assess their bioaccumulation factor (BCF) under urban heavy metal pollution, and evaluate their phytoremediation potential. The results revealed the highest average concentrations for Mn, Zn, and Ni (101, 36.7, and 30.3 mg/kg, respectively). For all heavy metals except Cd and Co, concentrations followed the pattern: grasses (237 mg/kg) > shrubs (178 mg/kg) > trees (113 mg/kg). Additionally, Chrysanthemum morifolium exhibited the strongest heavy metal accumulation capacity. The BCF analysis showed that plants have a greater enrichment capacity for Ni. Correlation analysis and principal component analysis identified traffic-related pollution, including vehicle emissions, tire wear, and gasoline combustion, constitutes the predominant source of trace elements in roadside plants.