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Orthophosphate and Calcium Carbonate Solubilities in the Upper Jordan Watershed Basin
Author(s) -
Salingar Yigal,
Geifman Yoel,
Aronowich Michael
Publication year - 1993
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1993.00472425002200040006x
Subject(s) - calcite , solubility equilibrium , tributary , solubility , calcareous , alkalinity , carbonate , calcium carbonate , chemistry , tufa , geology , environmental chemistry , watershed , phosphate , eutrophication , mineralogy , hydrology (agriculture) , nutrient , paleontology , cartography , geotechnical engineering , organic chemistry , machine learning , computer science , geography
An understanding of the mechanisms controlling the P concentrations in the Upper Jordan River is necessary to develop strategies to avoid eutrophication of Lake Kinneret. This study examines the solubility of orthophosphate and CaCO 3 in the calcareous Upper Jordan Basin via a thermodynamic model. The variation in alkalinity, pH, Ca, and phosphate concentrations in the surface waters of the Jordan River are consistent with an equilibrium between the solution and a metastable Ca phosphocarbonate phase with an apparent composition of Ca 2 (HCO 3 ) 2 HPO 4 . This phase, CBP 2 , has not been observed in sediments or suspended particles. However, it rapidly forms on calcite surfaces in laboratory experiments. The CBP 2 is replaced after a few days by a more stable compound, CBP 3 , with an apparent composition of Ca 3 (HCO 3 ) 3 PO 4 . The apparent solubility product of CBP 2 is 10 −19.96±0.87 . The consistency of the observed water chemistry collected from a variety of stations in the Upper Jordan Watershed over a period of 20 yr with this simple metastable “equilibrium” model suggests that CBP 2 is rapidly formed in the Jordan River waters and its tributaries and needs to be considered in models of fluvial P transport.