Of these, triclosan is the most widely used and is commonly found as an antibacterial in soaps and other cosmetic products including toothpaste, although use has been declining recently. It is listed as a “specific pollutant” under the Water Framework Directive. It was estimated in 2014, by the Environment Agency, that as many as 450 water bodies in the United Kingdom could have triclosan levels in excess of the proposed limit of 0.28 µg/L.
Triclosan can be measured in waters at or below the above level using High Performance Liquid Chromatography linked to tandem mass spectrometry (HPLC-MS/MS). This technique can also be used to measure the levels of triclosan in cosmetic products, following extraction of the triclosan.