講演情報
[U11-P18]Corals as High-Resolution Archives of Marine Lead Pollution in the Western North Pacific
*Kuo-Fang Huang1、Yi-Ning Chen1、Yu-Tsung Tai1、Hong-Yi Chen1、Yi-Wei Liu1、Li Lo2 (1.Institute of Earth Sciences, Academia Sinica、2.Department of Geosciences, National Taiwan University)
キーワード：
Marine Lead pollution、Heavy metals、Isotopic composition、Porites coral、Western North Pacific
Rapid industrialization has substantially increased anthropogenic metal emissions, with the ocean functioning as a major sink for contaminants. Among these, lead (Pb) is of particular concern owing to its persistence and toxicity. Reef-building corals in tropical shallow waters incorporate trace metals into their aragonitic skeletons, thereby preserving high-resolution geochemical records of past environmental change. Here we reconstruct seasonally resolved marine Pb variability in the western North Pacific using Pb concentrations and isotope ratios measured in Porites corals (1975-2010) from Dongsha Atoll (DSA) and Lanyu Islet (LY), near Taiwan.
Pb/Ca ratios display pronounced seasonal variability at both sites 13.3-56.6 nmol/mol at DSA; 20.1-64.1 nmol/mol at LY), with elevated values in winter-spring and reduced values in summer-autumn. Superimposed on this seasonal signal is a long-term decline since the early 20th century, consistent with the progressive phase-out of leaded gasoline in East Asia. Pb isotope compositions (206Pb/207Pb = 1.147-1.168; 208Pb/206Pb = 2.090-2.118) further constrain source contributions. Coupling these geochemical records with atmospheric transport models (HYSPLIT) reveals distinct source regions and transport pathways, providing a spatially and temporally resolved assessment of marine Pb pollution in the western North Pacific.
Pb/Ca ratios display pronounced seasonal variability at both sites 13.3-56.6 nmol/mol at DSA; 20.1-64.1 nmol/mol at LY), with elevated values in winter-spring and reduced values in summer-autumn. Superimposed on this seasonal signal is a long-term decline since the early 20th century, consistent with the progressive phase-out of leaded gasoline in East Asia. Pb isotope compositions (206Pb/207Pb = 1.147-1.168; 208Pb/206Pb = 2.090-2.118) further constrain source contributions. Coupling these geochemical records with atmospheric transport models (HYSPLIT) reveals distinct source regions and transport pathways, providing a spatially and temporally resolved assessment of marine Pb pollution in the western North Pacific.