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The following paper presents mechanical strength test results of a 160 x 9 mm
PVC-U pipe, in the service of Municipal Water and Sewage Company since
1976, and the impact of the pipe material on the quality of water in contact. The
water quality was evaluated in terms of the leaching of certain chemical elements
from the pipe material to the water. Additional tests were carried out on the
water obtained from different sections of the PVC-U plastics piping systems for
the water supply. Chemical elements detection was performed with inductively
coupled plasma optical emission spectrometry ICP-OES JY 238 Ultrace.
Furthermore, the testing included the analysis of sediment found on the inside
pipe wall, with the application of a Quanta 200 FEG Scanning Electron
Microscope (SEM).
Migration tests showed a clear influence of the pipe material on water quality
which was in contact with the PVC pipe. The highest recorded value of lead in
water samples was 162.2 ppb and significantly exceeded the allowable
concentration of lead contained in Directive 98/83/EC of the European Union
equal to 10 ppb. Leaching of this element from the pipe material into the water
proves the use of lead compounds as stabilizers for the production of pipes. The
study of the chemical structure by Infrared Spectrometry showed changes in the
test samples, demonstrating the degradation of the material, however, without
affecting its strength. But the degradation of the material may affect the
migration of lead into the water. The analysis of sediment on the inside of the
pipe wall allowed us to identify mainly calcium carbonates, oxides and
hydroxides of iron and manganese and also sodium chloride.The elements included in the sediment are also typical for the water supply distribution system
discussed.
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