Occurrence of volatile organic contaminants in tap water due to the use of plastic plumbing pipes

Abstract

In the present era, polymeric pipes have emerged as the replacement for metallic alternatives in constructing water distribution networks within cities or homes, due to their notable flexibility and durability. Nevertheless, there have been increased concerns over the safety of consuming water that has come into contact with polymeric materials. This issue arises from the possible leaching of organic contaminants, either due to plastic deterioration or from biofilms that typically develop within polymeric pipes. These biofilms may act as a source of disinfection byproducts during water and/or system disinfection. The objective of the study was to investigate the presence of volatile organic compounds (VOCs) that could migrate from plastic plumbing pipes into tap water. For this purpose, 50 tap water samples from different houses within the Al-Madinah Al-Munawwarah residential area (Saudi Arabia) were collected and analysed for the occurrence of VOCs; trichloromethane (1,1,1-TCA), dichloropropane (1,2-DCP), 1,2,3-trichloropropane (1,2,3-TCP) benzyl chloride (BC) 2-nitropropane (2-NP) 2,4-dichlorophenol (2,4-DCP), 4-ethylphenol (4-EP), benzene and 2-butanone using CG-MS. The most prevalent compounds were benzene, 2-butanone, 1,1,1-TCA, 1,2-DCP, BC, and 1,2,3-TCP. These were identified in 78%, 76%, 68%, 58%, 50%, and 42% of the samples assessed, respectively. The levels of 1,2,3-TCP, benzene, 2,4-DCP and BC exceeded the allowable limit in 43%, 10%, 8% and 6% of the samples, respectively. The remaining VOCs were within the WHO standards. The analysis of water source samples revealed the presence of BC, 1,2-DCP, and 4-EP in 40%, 40%, and 30% of samples, respectively, with no other VOCs detected. This suggests that these contaminants primarily originate from polymeric pipes used in household plumbing systems.