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Characterizing the oxygen isotopic composition of phosphate sources to aquatic ecosystems

January 1, 2009

The oxygen isotopic composition of dissolved inorganic phosphate (δ18Op) in many aquatic ecosystems is not in isotopic equilibrium with ambient water and, therefore, may reflect the source δ18Op. Identification of phosphate sources to water bodies is critical for designing best management practices for phosphate load reduction to control eutrophication. In order for δ18O p to be a useful tool for source tracking, the δ18Op of phosphate sources must be distinguishable from one another; however, the δ18Op of potential sources has not been well characterized. We measured the δ18O p of a variety of known phosphate sources, including fertilizers, semiprocessed phosphorite ore, particulate aerosols, detergents, leachates of vegetation, soil, animal feces, and wastewater treatment plant effluent. We found a considerable range of δ18Op values (from +8.4 to +24.9‰) for the various sources, and statistically significant differences were found between several of the source types. δ18Op measured in three different fresh water systems was generally not in equilibrium with ambient water. Although there is overlap in δ18Op values among the groups of samples, our results indicate that some sources are isotopically distinct and δ18Op can be used for identifying phosphate sources to aquatic systems.

Citation Information

Publication Year 2009
Title Characterizing the oxygen isotopic composition of phosphate sources to aquatic ecosystems
DOI 10.1021/es900337q
Authors M.B. Young, K. McLaughlin, C. Kendall, W. Stringfellow, M. Rollog, K. Elsbury, E. Donald, A. Paytan
Publication Type Article
Publication Subtype Journal Article
Series Title Environmental Science & Technology
Index ID 70036545
Record Source USGS Publications Warehouse
USGS Organization Toxic Substances Hydrology Program

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