In this study, five potentially toxic elements (PTEs) (Hg, Pb, As, Zn, and Cu) and five physicochemical factors (pH, dissolved oxygen, salinity, chlorophyll a, and chemical oxygen demand) relating to surface seawater were measured along the coast of Guangdong Province (GD), China, during three seasons in 2019. Comprehensive analyses were conducted to explore the distribution characteristics, pollution degrees, and influencing factors of PTE. The results showed that the concentrations of PTE varied spatially and seasonally due to these elements’ complex sources and behaviors. Pb was the most abundant toxic element, reaching considerable contamination levels. Overall, the average pollution degrees of Cu, As, and Zn were higher around the east coast of GD, while Hg and Pb levels were higher in the west coast region of GD. The correlation analysis showed that the variation of different physicochemical parameters had different degrees of influence on PTE transport and transformation. This study can help environmental managers gain deeper insight into the influence of complex factors on PTE and improve the efficiency of pollution control in this significant subtropical coastal area.

The construction of artificial islands not only alleviates the shortage of coastal land resources but also brings new environmental problems. This study focuses on the fundamental changes in the hydrodynamic environment and sediment transport caused by the construction of artificial islands, leading to imbalances in sediment distribution and beach erosion. This article takes the coast of Riyue Bay in Hainan Province, China, as an example and uses various methods such as field surveys and model experiments to explore the evolutionary mechanism of beach landforms under the influence of artificial islands. Based on this, an adaptive “cyclic maintenance” beach restoration plan is proposed. Reasonable distribution of beach sediment is achieved through experimental verification, effectively mitigating the coastal erosion caused by the construction of artificial islands. The expected goals were achieved after 2 years of implementation of the on-site restoration project. The results of this research not only solve practical engineering problems but also provide a good reference for the restoration of similar types of coastal beaches.