[U-02] 人新世・第四紀の気候および水循環

[U02-P08] Heavy metal pollution recorded in Porites corals from Lanyu Islet, southeast Taiwan

*Yu-Tsung Tai¹、Yi-Wei Liu²、Hong-Wei Chiang³、Huei-Ting Lin⁴、Haojia Abby Ren¹、Kuo-Fang Huang² (1.Department of Geosciences, National Taiwan University, Taiwan、2.Institute of Earth Sciences, Academia Sinica, Taiwan、3.Research Center for Environmental Changes, Academia Sinica, Taiwan、4.Institute of Oceanography, National Taiwan University, Taiwan)

キーワード：Anthropogenic pollution, Heavy metals, Coral, Taiwan, Marine environment, Trace element

Rapid economic and industrial development has significantly intensified human impacts on the environment, raising concerns about environmental pollutants, particularly heavy metals. As the ultimate sink for contaminants, the ocean is highly susceptible to pollution, necessitating comprehensive assessments of contamination levels. Reef-building corals in tropical shallow waters incorporate trace elements into their calcium carbonate skeletons, preserving high-resolution environmental records. Their rapid growth and widespread distribution make them as a reliable proxy for reconstructing historical heavy metal pollution. Taiwan's unique geographic location and climate contribute to a diverse marine ecosystem; however, rapid urbanization and industrialization have substantially increased marine pollution. This study aims to reconstruct a high-resolution historical record of heavy metal pollution in Taiwan’s marine environment by analyzing the concentrations of Lead (Pb), Copper (Cu), and Vanadium (V) in coral skeletons from Lanyu Islet, southeast Taiwan. The findings will offer valuable insights into the extent and temporal trends of heavy metal contamination in Taiwan’s marine environment.

The coral samples were subjected to pre-treatment processes to remove non-carbonate components. Trace element ratios (Pb/Ca, Cu/Ca, and V/Ca) determined using HR-ICP-MS were statistically compared with historical pollution records. The results indicate that Pb/Ca exhibits seasonal variations, with elevated values in spring-winter and lower values in summer-autumn. Furthermore, Pb/Ca has shown a declining trend since 2000, likely associated with the phase-out of leaded gasoline in Taiwan. In contrast, V/Ca remained relatively stable, except for a pronounced peak in 2005, coinciding with the May 2005 oil spill event in Lanyu. Meanwhile, Cu/Ca displayed a steady increase, suggesting potential Cu contamination in the region. Future research will extend coral records from Lanyu, with a particular focus on Pb isotope analysis. Additionally, integrating atmospheric transport models (HYSPLIT) will aid in identifying potential pollution sources and transport pathways, thereby offering a more comprehensive assessment of marine pollution in the Taiwan region.