Research on the Characteristics of Heavy Metal Concentrations of Atmospheric Wet Deposition and Source Analysis for the Typical Mountains in the Poyang Lake Plain Area

Atmospheric heavy metal pollution seriously threatens human health and ecological security and has become a major ecological and environmental issue restricting socioeconomic development. To reveal the concentration variations and sources of heavy metals in precipitation in typical mountainous areas of the Poyang Lake Plain, precipitation samples were collected in the Lushan area from January 2018 to December 2020. The concentrations of seven heavy metal elements, namely manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), and lead (Pb), were determined. The concentration levels and sources were analyzed using precipitation-volume-weighting, one-way analysis of variance (ANOVA), the Positive Matrix Factorization (PMF) model, and the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. The research results show that, among the seven heavy metals in precipitation, zinc (Zn) has the highest volume-weighted concentration (41.87 μg·L^-1), whereas cadmium (Cd) had the lowest concentration (0.14 μg·L^-1). Moreover, the concentrations of all seven heavy metals were lower than the Class Ⅱ groundwater quality standards. Heavy metal concentrations in precipitation were jointly influenced by precipitation, temperature, precipitation pH and human activities and exhibited obvious seasonal variations. The concentrations of heavy metals in precipitation were also affected by the combined effects of industrial activities and the prevention and control measures implemented during the pandemic, resulting in significant interannual variation. The source of heavy metals in precipitation were mainly transported to Lushan from the southwest and east. The identified sources included energy consumption sources and domestic pollution sources (22.6%), non-ferrous metal mining sources (22.5%), mixed transportation and agricultural production sources (27.2%), and industrial sources (27.7%). This study has important practical implications for monitoring and controlling atmospheric heavy metal deposition in typical mountainous areas of the Poyang Lake Plain and for maintaining ecological environment security.