Characterising the stable (d 88/86 Sr) and radiogenic ( 87 Sr/ 86 Sr) isotopic composition of strontium in rainwater
Characterising the stable (d 88/86 Sr) and radiogenic ( 87 Sr/ 86 Sr) isotopic composition of strontium in rainwater
复制标题
表征雨水中锶的稳定（d 88/86 Sr）和放射性（ 87 Sr/ 86 Sr）同位素组成
DOI：
10.1016/j.chemgeo.2015.05.010
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发表时间：
2015
期刊：
影响因子：
3.9
通讯作者：
Pearce C
中科院分区：
文献类型：
--
作者：
Pearce C
雨水在决定元素和污染物向土壤和水文流域的转移方面发挥着重要作用，其成分变化反映了海洋（海盐）、陆地（灰尘和植被）和人为气溶胶之间的混合程度。虽然放射性锶同位素系统 (87Sr/86Sr) 通常用于帮助限制大气 Sr 的不同来源，但稳定锶同位素系统 (δ88/86Sr) 的变异程度仍未解决。为了确定大气 Sr 如何影响进入水文循环的水的 δ88/86Sr 成分，本研究分析了巴黎市中心一年中收集的一系列雨水样本。发现雨水δ88/86Sr成分范围为0.13‰至0.32‰，其中87Sr/86Sr比率在0.70796至0.71093之间变化。 δ88/86Sr 没有观察到季节性，而 87Sr/86Sr 比值通常在夏季放射源性较高，在冬季放射源性较低。锶富集因子显着高于海水，这意味着雨水中的 Sr 主要来自陆地（非海盐），该陆地部分的 δ88/86Sr 和 87Sr/86Sr 组成与源自碳酸盐粉尘和农业肥料的 Sr 混合物一致。塞纳河流经巴黎时，δ88/86Sr 成分减少约 0.1‰ 的证据表明，人为污染物可能导致水文循环中 Sr 成分的显着区域变化。这些结果共同表明，雨水的 δ88/86Sr 和 87Sr/86Sr 成分在时间和空间上存在巨大的变化潜力，在研究局部流域的 δ88/86Sr 变化时需要考虑这些变化。
Rainwater plays a major role in determining the transfer of elements and pollutants to soils and hydrological catchments, with compositional variations reflecting the extent of mixing between marine (sea-salt), terrestrial (dust and vegetation) and anthropogenic aerosols. While the radiogenic strontium isotope system (87Sr/86Sr) is often used to help constrain the different sources of atmospheric Sr, the degree of variability in the stable strontium isotope system (δ88/86Sr) remains unresolved. In order to determine how atmospheric Sr affects the δ88/86Sr composition of water entering the hydrological cycle this study analysed a suite of rainwater samples collected over the course of a year in central Paris. Rainwater δ88/86Sr compositions were found to range from 0.13‰ to 0.32‰, with87Sr/86Sr ratios varying between 0.70796 and 0.71093. No seasonality was observed in δ88/86Sr, whereas87Sr/86Sr ratios were observed to be generally more radiogenic in the summer and less radiogenic in the winter. Strontium enrichment factors significantly above seawater implied a predominantly terrestrial (non-sea-salt) origin of Sr in rainwater, with the δ88/86Sr and87Sr/86Sr composition of this terrestrial fraction consistent with a mixture of Sr derived from carbonate dust and agricultural fertiliser. Evidence for a ~ 0.1‰ decrease in the δ88/86Sr composition of the River Seine as it passes through Paris suggests that anthropogenic pollutants may contribute to significant regional variations in the composition of Sr in the hydrological cycle. Together these results demonstrate that there is significant potential for both temporal and spatial variations in the δ88/86Sr and87Sr/86Sr composition of rainwater that need to be taken into consideration when studying δ88/86Sr variations in localised catchments.