Particulate and Dissolved Metals in the Pearl River Estuary, China—Part 1: Spatial Distributions and Influencing Factors

Metals in the Pearl River Estuary are of great importance due to the dense population and rapid industrialization, but they have not been systematically studied. This study investigates the spatial distribution and environmental impacts on dissolved and particulate metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Cd, Tl, Pb) in the Pearl River Estuary by integrating statistical methods and spatial analysis techniques. The areas with high concentrations of particulate metals are mainly located north of the Humen Bridge. Some metals also show higher concentrations near the Hong Kong–Zhuhai–Macao Bridge or around Macau. Overall, the spatial distribution patterns of metals such as Mn, Co, Ni, Cu, Mo, Cd, Tl, and Zn show clustering features. Oxygen content, salinity, and temperature significantly influence most particulate metals. The areas with high concentrations of dissolved metals are mainly located north of the Humen Bridge or in waters closer to the sea. Cr, Cd, Cu, Fe, Ni, Mo, and Tl show a clustered distribution. Dissolved Fe, Ni, and Mo are significantly influenced by environmental factors, except for water depth. This study fills the research gap on dissolved and particulate metals in the Pearl River Estuary, providing essential data to support metal pollution management in the region.