FACTORS AFFECTING THE COPRECIPITATION OF INORGANIC-PHOSPHATE WITH CALCITE IN HARDWATERS .2. RECIRCULATING EXPERIMENTAL STREAM SYSTEM

Calcite precipitation and phosphate coprecipitation on calcite observed in experimental stream systems has been studied in detail and the results analysed using chemical kinetic models. Two series of experiments were done in the experimental stream systems, both under dark conditions, one without sediment and the other with a flint gravel substrate. The major effect of the gravel was to release inorganic phosphate into the water and so replace a fraction of the phosphate which had been coprecipitated. Under laboratory conditions this release was enough to lead to an increase in phosphate concentration and eventually completely inhibit calcite growth.