Research has shown a greater potential for polymer materials to impact taste and odor than
traditional metal pipes. These materials leach odorous compounds that when detected by
consumers negatively influence their perception of water quality at the tap (McGuire, 1995;
Dietrich, 2006). Polymer pipe materials, which consist of the polymer and additives, leach
volatile (VOCs) and semi-volatile organic (SVOCs) compounds to water which impact either
water quality, sensory quality, or both (Anselme et al., 1985; Rigal and Danjou, 1999; Khiari et al.
1999; Skjevrak et al., 2003; Marchesan and Morran, 2004). Plumbing materials can also
consume residual disinfectant in drinking water, which can lead to changes in tastes and odor and
increased growth or microorganisms. Repeated studies demonstrated that leaching of polymer
additives, organic compounds, and oxidation of the surface of the pipe during extrusion leads to
perceptible odors in drinking water. Water utilities strive to avoid sensory problems in the
drinking water because aesthetics play a critical role in consumers' perception of both the quality
and safety of drinking water. Thus, if premise plumbing can impact taste and odor at the tap,
utilities and consumers want to know this so that they can plan accordingly in the materials
chosen for plumbing.
This interdisciplinary research performed comprehensive testing of piping materials under
realistic drinking water quality conditions. A unique aspect was that both chemical and consumer-assessed
sensory characteristics of water in contact with new materials were determined. Copper
and five polymer (cPVC, HDPE, PEX-a, PEX-b, epoxy lining) pipe materials from commercial
sources were investigated for their propensity to leach organic chemicals, consume disinfectants,
and alter water quality. Replicate seven (7) foot lengths of 3/4 inch (internal diameter) pipes were
tested. All pipe materials were certified according to National Sanitation Foundation (NSF-61)
standards. The Utility Quick Test (Schweitzer et al., 2002), a standard leaching protocol for new
materials, was conducted at room temperature using a low alkalinity water of pH 7.8-8 with no
disinfectant, 2 mg/L chlorine, or 4 mg/L monochloramine. Three consecutive cycles of fill and
flush were used, with a 72-96 hour period between flushes. A trained human panel used Flavor
Profile Analysis (Standard Method 2170) to assess odors. SPME-GC-MS was used to detect and
identify organic compounds. Chlorine and monochloramine were determined using the DPD
method; TOC was measured with a Seivers low TOC instrument. Includes 12 references.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 1.4 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 43 |
| Published : | 06/01/2007 |
