This Spanish study analyses bromides in desalinated drinking water, since the presence of bromophenols causes a medicinal taste and odour.
The shortage of water in the Mediterranean hydrographic basins of the Iberian Peninsula has led to the development of desalination plants which use reverse osmosis to supply drinking water.
This has caused a variation of the organoleptic characteristics in the water supply, which has led to the appearance of a medicinal taste and, to a lesser extent, odour.
This study determines the substances that have led to this state of affairs in south-eastern Spain.
Bromide is a natural constituent in desalinated water, and high bromide content leads to the development of bromine-substituted phenols after chlorination.
Analytical determination using solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC/MS) found that bromophenols (2-bromophenol, 2,4- and 2,6-dibromophenol) are responsible. Their sensory threshold is in some cases lower than 10 ng L−1.
Chlorination (5 mg Cl L−1) of the desalinated water with bromide levels of 0.3–0.8 mg L−1 leads to the development of bromophenols that maintain high levels of concentration even after a month.
This does not occur in the case of continental waters with low bromide content (0.1 mg L−1) when they are treated in the same way.
