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Utilization of Intrinsic Boron Isotopes as Co‐Migrating Tracers for Identifying Potential Nitrate Contamination Sources
Author(s) -
Leenhouts James M.,
Basset R.L.,
III T. Maddock
Publication year - 1998
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/j.1745-6584.1998.tb01089.x
Subject(s) - irrigation , nitrate , groundwater , environmental science , return flow , environmental chemistry , boron , isotope , trace element , stable isotope ratio , isotopic signature , isotopes of boron , hydrology (agriculture) , isotopes of nitrogen , nitrogen , chemistry , flow (mathematics) , geology , agronomy , geometry , geotechnical engineering , mathematics , organic chemistry , physics , quantum mechanics , biology
The stable isotopes of the conservative element boron, 11 B and 10 B, have been employed as co‐migrating isotopic tracers to trace potential sources of nitrate observed in ground water pumped from a large capacity 0.167 m 3 /s irrigation well in the Avra Valley of southeastern Arizona. The isotopic ratios provided an identifying signature for two nitrogen carrying source waters: municipal waste water and agricultural return flow. Additional chemical parameters were also examined to corroborate the isotopic indications. Boron isotopes provided a superior delineation of mixing processes in the system compared to the general inorganic chemical parameters. Findings of this investigation indicate that the water pumped by the study well at the beginning of the 1993 irrigation season was composed of a mixture of approximately 25 % municipal waste water and 75 % background ground water. As the irrigation season progressed, an increasing proportion of water was contributed by irrigation return flow from neighboring agricultural fields.