Pb and 206Pb/207Pb isotopic analysis of a tree bark pocket near Sheffield, UK recording historical change in airborne pollution during the 20th century.
Pb and 206Pb/207Pb isotopic analysis of a tree bark pocket near Sheffield, UK recording historical change in airborne pollution during the 20th century.
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英国谢菲尔德附近树皮袋的 Pb 和 206Pb/207Pb 同位素分析记录了 20 世纪空气污染的历史变化。
DOI：
10.1016/s0048-9697(01)01037-3
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
K. Satake
中科院分区：
文献类型：
--
作者：
D. Bellis;C. Mcleod;K. Satake
从英国谢菲尔德附近的一个半农村地区采集了一段树干(山毛榉，Fagushalvatica)，其中包含一个逐渐封闭在两个树枝交界处的树皮口袋。根据年轮，树皮袋形成于约1919年至1998年(砍伐日期)之间。树皮袋被分成不同径向深度(也就是年龄)的连续样本，用电感耦合等离子体质谱仪进行分析。铅浓度变化范围为7~78 mg kg−1,206Pb/207Pb同位素比值为1.11~1.15。相比之下，目前的表面树皮含有46 mg kg的−1PB，记录的206Pb/207Pb值为1.11。树皮袋不断变化的元素和同位素组成记录了空气中铅污染水平和来源的历史变化。从1935年到1943年，铅浓度随时间的总体增加伴随着206Pb/207Pb值的逐渐降低。质量平衡计算表明，汽油中的铅添加剂对铅浓度的上升贡献很大，在大约1986-1998年间，最高占总铅的50%，但其他来源总体上占主导地位。约1951年至1973年，铅浓度最高，表明工业污染水平很高。在当前树皮中观察到了铅浓度的降低和206Pb/207Pb值变化趋势的逆转。
A section of tree trunk (beech, Fagussylvatica) containing a bark pocket progressively enclosed at the junction of two branches was collected from a semi-rural location near Sheffield, UK. According to the annual growth rings, the bark pocket formed between ca. 1919 and 1998 (the date of felling). The bark pocket was divided into consecutive samples of differing radial depth (and thus age), that were analysed by ICP mass spectrometry. The Pb concentration varied from 7 to 78 mg kg−1and the206Pb/207Pb isotope ratio from 1.11 to 1.15. In contrast, the current surface bark contained 46 mg kg−1Pb and recorded a206Pb/207Pb ratio of 1.11. The changing elemental and isotopic composition of the bark pocket recorded historical change in the level and sources of airborne Pb pollution. An overall increase in Pb concentration with time was accompanied by a progressive reduction in206Pb/207Pb from ca. 1935 to 1943. Mass balance calculations indicated that Pb additives in petrol contributed significantly to the rise in concentration, accounting for a maximum of 50% of the total Pb for ca. 1986–1998, but that other sources were generally dominant. The highest Pb concentrations were recorded from ca. 1951 to 1973, suggesting a high level of industrial pollution. A reduction in Pb concentration and reversal of the trend in206Pb/207Pb was observed in the current bark.