Abstract
Perchlorate (ClO4−) is an emerging persistent pollutant that is ubiquitous in the environment at trace concentrations. Perchlorate ingestion poses a risk to human health because it interferes with thyroidal hormone production. The identification of perchlorate sources in groundwater is a primary concern. Chlorine and multi-oxygen isotopic tracing of perchlorate (δ37Cl, 36Cl/Cl, δ18O, and Δ17O) can provide a unique tool for identifying the origin and transport of perchlorate in groundwater. Along with the kinetic fractionation of chlorine and oxygen isotopes, the Δ17O value, 36Cl/Cl ratio, and ε18O/ε37Cl (the fractionation coefficient of oxygen and chlorine isotopes) are constant, potentially indicating the biodegradation of perchlorate, without disguising its source information. Therefore, comprehensive characterization of stable chlorine and poly-oxygen isotopes is expected to provide direct evidence for identifying the source of perchlorate in groundwater. However, further studies are needed to increase the amount of isotopic data of different perchlorate sources, to make the end-member model available to broader regions. It is critically important to understand the range of values and differences of isotopes among natural perchlorate sources and the perchlorate formation mechanisms.
Highlights
Groundwater is an important water resource, which is of strategic significance to the sustainable development of a country and its people
Investigating and determining the isotopic composition of different sources of ClO4− provide necessary data support for establishing the end-member model of the isotope characteristic value of different sources of ClO4−. e isotope kinetic fractionation characteristics of ClO4− biodegradation provide a theoretical basis for tracing the source of ClO4− in environmental media. e Chino Basin in California, Long Island in New York, and San Bernardino Basin in California are three typical ClO4−-contaminated aquifers. e isotopic composition of ClO4− (δ37Cl, δ18O, and Δ17O) in groundwater in the three regions was plotted on the endmember model diagram of the isotopic composition of ClO4− from different sources. e comprehensive characteristics of Cl and poly-oxygen δ37Cl (‰ vs. SMOC)
Perchlorates from different sources have different isotopic characteristic values (δ18O, Δ17O, δ37Cl, and 36Cl/Cl) and are related to their formation mechanisms. e 17O abnormal signal can be preserved for thousands or even millions of years in arid environments
Summary
Groundwater is an important water resource, which is of strategic significance to the sustainable development of a country and its people. E US EPA in February 2011 officially listed ClO4− for regulation under the Safe Drinking Water Act; perchlorate has become an important research topic. Perchlorate originates from both natural and human sources. A recent investigation shows that 86% of 300 water samples from 13 provinces and cities in China had ClO4− detected in them [17]. E results show that the environmental pollution problem of perchlorate has been widespread in China, and research on the prevention and control of ClO4− pollution in groundwater is imminent. E results showed that 67% of the samples, with detectable ClO4−, were obtained from water plants that used groundwater as their water source. The results of 131 blood samples from donors in Nanchang showed that the concentration of ClO4− in human blood of different age groups (0.4–90 year) was as high as 10.5 μg/L, with an average value of 2.68 μg/L [16]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
