Natural Perchlorate Has a Unique Oxygen Isotope Signature
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- 作者：Huiming Bao and Baohua Gu
- 刊名：Environmental Science & Technology
- 出版年：2004
- 出版时间：October 1, 2004
- 年：2004
- 卷：38
- 期：19
- 页码：5073 - 5077
- 全文大小：86K
- 年卷期：v.38,no.19(October 1, 2004)
- ISSN：1520-5851
文摘
Perchlorate is known to be a minor component of thehyperarid Atacama Desert salts, and its origin has longbeen a subject of speculation. Here we report the firstmeasurement of the triple-oxygen isotope ratios (18O/16O and17O/16O) for both man-made perchlorate from commercialsources and natural perchlorate extracted from Atacamasoils. We found that the 
18O values (i.e., normalized 18O/16O ratios) of man-made perchlorate were at -18.4 ±1.2”, whereas natural perchlorate has a variable 18O value,ranging from -4.5” to -24.8”. The 18O and 17Ovalues followed the bulk Earth's oxygen isotope fractionationline for man-made perchlorate, but all Atacama perchloratesdeviated from this line, with a distinctly large and positive17O anomaly ranging from +4.2” to +9.6”. These findingsprovide a tool for the identification and forensics ofperchlorate contamination in the environment. Additionally,they confirm an early speculation that the oxidation ofvolatile chlorine by O3 and the formation of HClO4 can bea sink (albeit a minor one) for atmospheric chlorine.
18O values (i.e., normalized 18O/16O ratios) of man-made perchlorate were at -18.4 ±1.2”, whereas natural perchlorate has a variable 18O value,ranging from -4.5” to -24.8”. The 18O and 17Ovalues followed the bulk Earth's oxygen isotope fractionationline for man-made perchlorate, but all Atacama perchloratesdeviated from this line, with a distinctly large and positive17O anomaly ranging from +4.2” to +9.6”. These findingsprovide a tool for the identification and forensics ofperchlorate contamination in the environment. Additionally,they confirm an early speculation that the oxidation ofvolatile chlorine by O3 and the formation of HClO4 can bea sink (albeit a minor one) for atmospheric chlorine.