Monitoring the active sessile-colonisation of two drinking water distribution systems based on the protein contents in native biofilm samples.
Biofilms are present to a greater or lesser degree in virtually all drinking water distribution systems. In order to investigate the relative intensity and the spatial and temporal distributions of the active sessile-colonization, protein was determined in native biofilm samples from the Oeiras-Amadora (OADS) and the Almada (ADS) distribution systems in Portugal. Samples (25 cm2) were taken from lengths of asbestos cement pipes of different ages and diameters. Protein was detected at levels from 0.3 to 68 microg/cm2 in samples from all analysed pipe diameters and ages. At OADS, protein was found at 0.3 to 1 mg/cm2 in 99% of the samples. At ADS, protein was only found in 30% of the samples, but at significantly higher levels (0.3 to 68 mg/cm2). In addition to displaying a more intense and scattered active colonization, ADS's oldest-pipes (in use for over 30 years) solely exhibited protein at the highest levels found (> 19 mg/cm2), in contrast with the younger pipes where protein levels ranged from 0.3 to 19 mg/cm2. Observed results suggest that the spatial and temporal distribution patterns of the active biofilm colonization may vary significantly among drinking water networks and may have a rather slow evolution, possibly at the decades scale.
Menaia
J
J
Urban Water Division, National Civil Engineering Laboratory, Av. do Brasil, 101-1700 Lisbon, Portugal.
Alves
R
R
Sanches
S
S
Santos
G
G
Mesquita
E
E
D018441:Biofilms; D004784:Environmental Monitoring / Q000379:methods*; D011506:Proteins / Q000032:analysis*; D014867:Water / Q000737:chemistry; D014871:Water Microbiology; D014881:Water Supply
D011506:Proteins; D014867:Water