Washing procedure for mixed-bed ion exchange resin decontamination for in situ nutrient adsorption

Mixed-bed cation + anion exchange resin bags are frequently used to assess in situ nutrient availability in forest soils, and have demonstrated their utility for comparing the impacts of different disturbances associated with treatments. They are generally installed in organic or mineral soil horizons for a certain time period, then recovered and extracted, to inform about nutrient availability during that period. For the method to be effective, the ion exchange sites of resins must be clear from any contaminants prior to installation in the soil. A washing procedure to be conducted before in situ burial of mixed-bed resins was developed and is described. The IONAC NM-60 H+/OH- resins are consecutively washed with 2 N NaCl, deionized water, and 0.1 N NaOH. Finally, resins are rinsed with deionized water and stored moist and cold until bag preparation and burial in the soil.