Finger Printing Standard Colas Using Phosphate Oxygen Isotopes - Abstract
Eutrophication is a globally significant challenge facing freshwater ecosystems and is closely associated with anthropogenic enrichment of phosphorus (P) from a number of sources in the aquatic environment. Phosphate oxygen isotopes (?18O-PO4) provide a possible tool for identifying P sources, although there are methodological challenges depending on associated dissolved organic matter. Cola drinks are commonly manufactured with high concentrations of phosphoric acid to make them a sharper flavour as well as slow the growth of bacteria. Although in themselves they are not likely to be a significant source of aquatic phosphate pollution globally, there is the potential for large spillages at the point of production in addition to the use of waste sludges from the
manufacturing process being used as fertilisers in some countries. Here we present ?18O-PO4 data for 8 different colas using a XAD and ion exchange column method previously published by the authors. Concentrations of SRP ranged from 77.6 to 192 mg P/L. Yields of AgPO4 from 10 fold dilutions of the original cola solutions ranged from 60 to 87%. The range of ?18O-PO4 was from 17.7-20.6 ‰ ± 0.3 with a mean of 19.3 which compares with a range of 19.3-20.0‰ ± 0.3 with a mean of 19.7 for commercially available phosphoric acids. Within brand there were significant differences in ?18O-PO4 for the diet and regular colas. Diet colas also had lower SRPs than their regular counter parts. This work suggests that the method used is suitable for effluents with high very organic loads and that there are traceable differences between different colas.