Lead, sulphate, and aluminium concentrations and lead crustal enrichment factors in Mt. Logan ice core during pre-anthropogenic to modern periods

A high-resolution, 8000 year-long ice core record from the Mt. Logan summit plateau (5300 m asl) reveals the initiation of trans-Pacific lead (Pb) pollution by ca. 1730, and a >10-fold increase in Pb concentration (1981-1998 mean = 68.9 ng/l) above natural background (5.6 ng/l) attributed to rising anthropogenic Pb emissions from Asia. The largest rise in North Pacific Pb pollution from 1970-1998 (end of record) is contemporaneous with a decrease in Eurasian and North American Pb pollution as documented in ice core records from Greenland, Devon Island, and the European Alps. The distinct Pb pollution history in the North Pacific is interpreted to result from the later industrialization and less stringent abatement measures in Asia compared to North America and Eurasia. The Mt. Logan record shows evidence for both a rising Pb emissions signal from Asia and a trans-Pacific transport efficiency signal related to the strength of the Aleutian Low.取自洛根山（Mt. Logan）峰顶高原（海拔5300米）的高分辨率、8000年时长冰芯记录显示，跨太平洋铅（Pb）污染的起始时间约为1730年；其铅浓度较自然背景值（5.6 ng/l）升高10倍以上（1981-1998年平均值为68.9 ng/l），该现象归因于亚洲人为铅排放量的持续攀升。1970年至1998年（本记录的截止年份），北太平洋地区铅污染出现最大增幅，这与格陵兰、德文岛及欧洲阿尔卑斯山冰芯记录中所记载的欧亚大陆与北美铅污染排放量下降的时期完全同步。北太平洋地区独特的铅污染历史，被认为源于亚洲较北美与欧亚大陆更晚开启工业化，且减排措施更为宽松。洛根山冰芯记录同时提供了两方面的证据：一是源自亚洲的铅排放量上升信号，二是与阿留申低压强度相关的跨太平洋传输效率信号。