Abstract
The experiment was conducted in three model drinking water distribution systems (DWDSs) made of unplasticized polyvinyl chloride (PVC), silane cross-linked polyethylene (PEX) and high density polyethylene (HDPE) pipes to which tap water was introduced. After 2 years of system operation, microbial communities in the DWDSs were characterized with scanning electron microscopy, heterotrophic plate count, and denaturing gradient gel electrophoresis. The most extensive biofilms were found in HDPE pipes where bacteria were either attached to mineral deposits or immersed in exopolymers. On PEX surfaces, bacteria did not form large aggregates; however, they were present in the highest number (1.24 × 107 cells cm−2). PVC biofilm did not contain mineral deposits but was made of single cells with a high abundance of Pseudomonas aeruginosa, which can be harmful to human health. The members of Proteobacteria and Bacteroidetes were found in all biofilms and the water phase. Sphingomonadales and Methylophilaceae bacteria were found only in PEX samples, whereas Geothrix fermentans, which can reduce Fe(III), were identified only in PEX biofilm. The DNA sequences closely related to the members of Alphaproteobacteria were the most characteristic and intense amplicons detected in the HDPE biofilm.
Highlights
In recent years, there has been a great increase in the use of plastic pipes in drinking water distribution systems (DWDSs) and household installations because they are easy to cut, install, and they are resistant to corrosion
The observation of the surfaces of high density polyethylene (HDPE) pipes in Scanning electron microscopy (SEM) showed that they were completely covered with biofilm
The results showed that biofilm formation potential of plastic pipes differs depending on the material which is used
Summary
There has been a great increase in the use of plastic pipes in drinking water distribution systems (DWDSs) and household installations because they are easy to cut, install, and they are resistant to corrosion. The quality of water passing through plastic pipes can be worsened by organic compounds such as additives (e.g. stabilizers, antioxidants, softeners, colouring agents), monomers or products of polymer degradation (Brocca et al 2002; Koch 2004; Skjevrak et al 2005; Kowalska et al 2011) migrated from plastics. These substances may be used by bacteria to support their growth in oligotrophic conditions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
