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Environmental fate & pathways

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Boron orthophosphate (CAS 13308-51-5) is an inorganic phosphate substance. Biotic degradation is therefore not relevant for the substance. Furthermore abiotic degradation of the substance as such is an irrelevant process for inorganic substances that are assessed on an elemental basis. In all environmental compartments boron and phosphorus are present in the most stable oxidation states (as B+3 and P+5). Both ions do not undergo oxidation-reduction transformation under normal environmental conditions. Removal of boron and phosphorous from environment compartments is a function of abiotic transformation and chemical cycling, e. g. hydrolysis, precipitation, suspension, leaching, uptaking and releasing of animals and plants, etc.

As elements boron and phosphorus are persistent in environment. Boron compounds normally will be degraded or transformed to boric species and borates, the main compounds of ecological significance (Sprague 1972), which both show remarkable stability in natural aquatic systems. The chemical form of boron found in water is dictated by pH and other constituents (Sprague 1972).

Orthophosphate is available for biological metabolism without further breakdown. Besides of chemical precipitation phosphate can be biologically removed from waste water. Biological phosphate removal process is relies upon microorganisms to uptake phosphate into their cells either via anaerobic or anaerobic pathways, which is subsequently removed from the STP process as a result of sludge wasting.

References

Hem, J. D. (1970). Study and interpretation of the chemical characteristics of natural water, 2d ed. U. S. Geological Survey Water-Supply Paper 1473.

Maier, K. J., and A. W. Knight (1991). The toxicity of waterborne boron to Daphnia magna and Chironomus decorus and the effects of water hardness and sulfate on boron toxicity. Arch. Environ. Contam. Toxicol. 20: 282-287.

Sprague, R. W. (1972) The ecological significance of boron. U. S. Borax Research Corporation, Anaheim, California. 58p.