LTO学术报告2024-8

报告题目：A multidisciplinary approach to characterizing the various contaminant factors of coastal aquifers in South Africa 

报告人：Vetrimurugan Elumalai, South African National Chair of Hydrology (SARChI-Tier 1)

报告人简介：Professor Vetrimurugan Elumalai is the South African National Research Chair in Hydrology (SARChi-Tier 1) and the Head of the Department of Hydrology at the University of Zululand in South Africa. He is a rated (C2) researcher by National Research Foundation (NRF). His area of research focus includes groundwater quality and quantity, geochemistry, groundwater modelling, subsurface and groundwater interaction, impact of climate change on water resources, and sustainable water resource management.  He has published about 65 research papers in reputed journals. He is serving as an editorial board member and guest editors in reputed international scientific journals, including Chemosphere, Water, Discover Water, Environmental Earth Sciences and Frontiers in Marine Science etc., He is registered scientist with SACNASP. He is a life member of International Association of Hydrological Science, International Association of Hydrogeologists, and Geological Survey of South Africa. He is a member of many academic and management committees in South Africa. There are currently several research projects he is involved with nationally and internationally, and he has received the "Emerging Researchers Award" for 2017 and the "Established Researchers Award" for 2018 and 2023 from Vice-Chancellor's Excellence.

报告摘要：Coastal aquifers are generally affected by complex geochemical processes and multiple contamination sources due to rapid urbanization and industrialization. This study in KwaZulu-Natal's coastal aquifers evaluates contamination sources and geochemical processes affecting water chemistry and its suitability for drinking and irrigation using geochemical and statistical approaches. In Umhlathuze, groundwater is suitable for drinking and irrigation despite elevated Total Dissolved Solids (TDS) and Nitrate (NO₃) concentrations in the east. Chemical processes, including ion exchange, mineral dissolution, and evaporation, predominantly control groundwater chemistry, with significant contributions from silicate and carbonate weathering. Industrial activities introduce metals such as Co, Mn, Ni, Zn, and B, while Cd and Cu mainly originate from fertilizers, and Li, Fe, and Ag from mining. Human risk assessment reveals potential health risks associated with Ag, Cu, Mn, and Pb, especially for infants, children, and adults, while Cd and Li pose risks to children and adults. In Maputaland, Na–Cl water type dominates the coastal groundwater, followed by Ca–HCO₃. Ion exchange, reverse ion exchange, silicate weathering, seawater mixing, and agricultural activities govern groundwater chemistry. Most trace metals have HQs and HI below 1, except for Co and Pb in children, indicating higher sensitivity and medium HI values suggest high risk for both groups. In the Tugela, groundwater chemistry is influenced by ion exchange, mineral dissolution, saline sources, and anthropogenic inputs from domestic sewage, septic tank leakage, and irrigation return flow. Principal component analysis (PCA) confirms the role of saline and anthropogenic sources and carbonate dissolution. Groundwater suitability assessments indicate that while most wells exceed WHO and SANS standards, they are suitable for irrigation, especially for coarse-textured soils and salt-tolerant crops. These findings suggest enhanced monitoring and pollution control measures, alongside promoting community awareness and sustainable practices to protect water resources in KwaZulu-Natal.

Keywords: Coastal aquifers, contamination sources, ion exchange,  human health risks, irrigation suitability, South Africa

报告时间：2024年6月11日 10:00

报告地点：2号楼801

主持人：吴梅林 研究员