Daily Archives: July 5, 2015

Aromatic Compounds Migrate from PEX Pipes into Drinking Water

Sune Thyge Ryssel, Erik Arvin, Hans-Christian Holten Lützhøft, Mikael Emil Olsson, Zuzana Procházková, Hans-Jørgen Albrechtsen. Degradation of specific aromatic compounds migrating from PEX pipes into drinking water. Water Research 15 September 2015 81:269-278

Nine specific compounds identified to migrate from polyethylene (PE) and cross-linked polyethylene (PEX) to drinking water were investigated for their degradation in drinking water. Three sample types were studied: field samples (collected at consumer taps), PEX pipe water extractions, and water samples spiked with target compounds. Four compounds were quantified in field samples at concentrations of 0.15–8.0 μg/L. During PEX pipe water extraction 0.42 ± 0.20 mg NVOC/L was released and five compounds quantified (0.5–6.1 μg/L). The degradation of these compounds was evaluated in PEX-pipe water extractions and spiked samples. 4-ethylphenol was degraded within 22 days. Eight compounds were, however, only partially degradable under abiotic and biotic conditions within the timeframe of the experiments (2–4 weeks). Neither inhibition nor co-metabolism was observed in the presence of acetate or PEX pipe derived NVOC. Furthermore, the degradation in drinking water from four different locations with three different water works was similar. In conclusion, eight out of the nine compounds studied would – if being released from the pipes – reach consumers with only minor concentration decrease during water distribution.