INFLUENCE OF SEAWATER INTRUSION AND TRACE METAL CONTAMINATION ON THE GROUNDWATER IN COASTAL AREAS OF SOUTH CHINA

Seawater intrusion and trace metal contamination poses serious threats to groundwater, which is the local predominant water source in coastal areas of South China. However, the monitoring data on the groundwater quality in this area is extremely scarce. To bridge this gap, groundwater contamination, concerning hydrochemical parameters (inorganic ions, total dissolved solids, hardness, and pH) and trace metal concentrations, were evaluated during neap and spring tides. The groundwater is of the sodium chloride type thus it might have potential unfavourable influence on the water requirement in the study area. This indicates the strong influence of seawater intrusion and the over-exploitation of groundwater in the coastal areas of South China. The fuzzy model was used for the assessment of seawater intrusion risk of this area. The analysis of trace metals highlights that groundwater is contaminated by Al, as and Cd. In addition, water hyacinths, as an invasive alien species inducing surface water disaster, was used for the preparation of biochar to remove Cd contamination in water environment. This study provides insights into the influence of seawater intrusion and trace metal contamination on the groundwater in coastal areas of South China.