Occurrence of the mutagenic compound ‘MX’ in drinking water and its removal by activated carbon

Recent studies have shown that the compound MX [3‐chloro‐4‐(dichloromethyl)‐5‐hydroxy‐2(5H)‐furanone] can account for up to 57% of the observed acid fraction mutagenicity of chlorinated drinking water. In the present study laboratory investigations showed MX to be very well removed by activated carbon over a wide concentration range. Samples obtained from two water treatment plants following pre‐chlorination showed MX to be present in the range of 38 to 60 ng L−1. MX concentrations were not always correlated with TOC levels, suggesting that the type of organic matter present may play a role in MX formation. GAC appeared to be capable of removing MX precursors.