Transfer of phthalates from c-polyvinyl chloride and cross-linked polyethylene pipe (PEX-b) into drinking water

Several different materials have been used for production of domestic water pipes throughout history. In recent years, the use of cross-linked polyethylene (PEX) pipe has increased dramatically, yet the potential for leaching of phthalates, which are endocrine disrupting compounds associated with adverse reproductive effects in humans, has not been examined. In this study, the potential of chlorinated polyvinyl chloride (cPVC) and red, blue, and heat PEX piping to leach phthalates into static hot and cold water after 2,8, and 48 hours was evaluated. Concentrations of six phthalates, dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), benzyl-butyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), and di(n-octyl) phthalate (DNOP), were determined by gas chromatography-mass spectrometry. Pipe type (F_3,71 = 15.6, P = 0.001) contributed significantly to phthalate concentrations in water, while temperature (F_4,71 = 1.74, P = 0.106) and time (F_4,71 = 1.02, P = 0.427) were not significant factors. Significantly higher concentrations of DEP, DBP, and BBP were observed in cPVC pipe (method detection limits (MDL) to 466 ng L^-1,252-4,219 ng L^-1, 473-18,400 ng L^-1, respectively) compared to blue PEX (T² = 12.2, P < 0.001; <MDL, <MDL - 140 ng L^-1, <MDL - 459 ngL^-1, respectively), red PEX (T² = 19.3, P< 0.001; <MDL, <MDL-188ngL^-1, <MDL-881 ngL^-1, respectively), and heat PEX (T² = 19.9, P< 0.001; <MDL, <MDL-162ngL^-1, <MDL-169 ng L^-1, respectively). Phthalate exposure from drinking water via cPVC or PEX is low when compared to other dietary sources. Nonetheless, a shift from cPVC to PEX pipes in households would decrease potential exposure to phthalates.