Public water utilities routinely treat drinking water supplies with phosphate to prevent corrosion of legacy pipes that could release lead into the water. Lead phosphate is less soluble than lead carbonate corrosion products, and it forms deposits in water supply pipes. However, phosphate causes its own problems. Wastewater and leakage from water distribution networks release an estimated 1000 tonnes of phosphate into the environment in the UK annually.
Daren Gooddy, British Geological Survey, Wallingford, UK, and colleagues evaluated the use of stable oxygen isotope ratios to identify sources of phosphate in several drinking water supplies from England and Wales. They could distinguish between phosphate of local origin and from water treatment. They also examined the effects of microbes, water chlorination, and abiotic sorption and dissolution.
The UK uses orthophosphoric acid exclusively, and it comes from one of three distributors. Other countries use a wider variety of phosphate species and distributors, which could complicate the application of this technique. Expansion of reference datasets and focusing on local water utilities could simplify the process.
- Isotopic Fingerprint for Phosphorus in Drinking Water Supplies,
Daren C. Gooddy, Dan J. Lapworth, Matthew J. Ascott, Sarah A. Bennett, Timothy H. E. Heaton, Ben W. J. Surridge,
Environ. Sci. Technol. 2015.