Biologically Available Phosphorus: Estimation and Prediction Using an Anion-Exchange Resin

The suitability of ion-exchange resin extraction for assessing biologically available P (phosphorus) concentrations was evaluated in a wide range of water samples of different origins (natural waters, wastewater treatment plant effluents, and industrial effluents). A recycling system was specifically designed to enhance P adsorption by the resin by maintaining a steep P gradient. Resin extractable P compared favorably with total P, total soluble P, and soluble reactive P, as a predictor of bioassay available P (BAP). Biologically available P was generally greater than soluble reactive P and less than total soluble P. Over the diverse water samples tested, the best model for predicting BAP used resin extractable P and soluble reactive P.