Particulate and Dissolved Metals in the Pearl River Estuary, China—Part 2: Partitioning Characteristics and Influencing Factors

Metals in the Pearl River Estuary are potentially significant pollutants influenced by the region’s high population density and rapid industrial growth, but their distribution and impacts have not yet been thoroughly investigated. This study investigates the spatial distribution and environmental impacts of particulate and dissolved metals (including Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Cd, Tl, and Pb) in the Pearl River Estuary using a combination of statistical methods and spatial analysis techniques. This is Part 2 of a series of papers. In Part 1, we mainly focused on the spatial characteristics of particulate and dissolved metals and the water environment factors influencing them. In Part 2, we mainly focus on the partitioning of metals between their particulate and dissolved forms and its influencing factors. The results show that the distribution of metals in the estuary is predominantly in the dissolved phase, except for Mn, which is more associated with particulates. Environmental factors such as temperature, oxygen content, and water depth exert a substantial impact on the metals’ partitioning behavior. In contrast, the pH value, salinity, and concentration of suspended matter have a minor influence. The results of this study highlight the importance of understanding metal partitioning in the estuary for effective water quality management and pollution control, which also provides valuable insights for pollution source tracking in this area.