Behavior of Drinking Water Distribution Pipes Made of HDPE, AC, OLT 37, and OL37.1 in Contact with Water

Our plain-English summary of Behavior of Drinking Water Distribution Pipes Made of HDPE, AC, OLT 37, and OL37.1 in Contact with Water, by D.S. Stefan, G. Teodorescu, A.I. Nicoara, et al (Polymers, 2026).

The study

• Authors: D.S. Stefan, G. Teodorescu, A.I. Nicoara, L. Ghenghea, A.I. Stefan
• Journal: Polymers
• Published: 2026;18(18)
• Read it: PubMed · Publisher · Free full text

Abstract

Drinking water is essential for humans; its quality determines the health and proper functioning of the body. In order to obtain drinking water in accordance with the legislation in force, the performance of the technology applied for water treatment and the infrastructure for transport and distribution to the consumer are equally important. Particular importance to this last aspect was given by the introduction of European Directive 2020/2184. Infrastructure can significantly influence water quality due to the fact that there are periods when water stagnates in the pipe and electro-corrosion processes, and salt deposits or degradation/corrosion of the pipes can occur, or periods when water circulates under pressure, when deposits but also particles from the pipes are mechanically detached and transported to the consumer. In this article, we aim to present the behavior of asbestos-cement pipes, AC, special steel for pipes OLT 37, galvanized steel, OLT 37.1, and high-density polyethylene, HDPE, in contact with drinking water. The study was conducted in Calarasi city, Calarasi county, Romania, where some of the old pipes were replaced. A comparative study of new pipes of the same type with pipes in use for more than 20 years, up to 46 years, was conducted, and at the same time the changes that the pipes (which have not yet been replaced) have on the quality of drinking water for street consumers were also analyzed. Following the analyses performed, it can be stated that the water quality is within the maximum permissible limits, but the micropollutants that appear can accumulate in the body (such as AC microfibers, microplastics, metallic zinc, zinc ions, iron ions, manganese, aluminum) with effects that can be evident after a long period of consumption through bioaccumulation.

In plain English

This study, from Calarasi, Romania, compared new and used drinking-water pipes made of asbestos cement, OLT 37 steel, galvanized OLT 37 steel (OLT 37.1) and high-density polyethylene (HDPE). It used electron microscopy, elemental analysis and wall-thickness measurements. It also tested water leaving the treatment plant and at four street points in 2023, 2024 and 2025. An asbestos-cement pipe used for 46 years had thinned from 12 mm to 11.1 mm. Its inner surface was corroded, the cement had degraded, and asbestos fibers of different sizes were visible. The article does not name the asbestos fiber type, and the water tests did not count asbestos fibers. At the street point served by asbestos-cement pipe, conductivity was higher than at the plant in all three years. Turbidity there was higher in 2023 and 2025 but lower in 2024. The steel and HDPE pipes also showed corrosion, deposits or cracking. The authors reported that water quality was within the maximum permissible limits. They ranked risk as highest for asbestos cement, then OLT 37, then OLT 37.1, and lowest for HDPE.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Comparative laboratory study of new versus used water pipes (scanning electron microscopy, energy-dispersive X-ray analysis, FTIR for HDPE, wall-thickness measurement), combined with water sampling at a treatment plant and street points
• Who was studied: New and used pipes supplied by the regional water operator in Calarasi, Romania, and water samples from the treatment plant and 4 public street points, taken in three campaigns (21 September 2023, 22 August 2024, 22 September 2025)
• Exposure: Drinking water carried through asbestos-cement, OLT 37 steel, galvanized OLT 37.1 steel and HDPE pipes in use for roughly 20 to 46 years. The street point P1 was served by a 200 mm asbestos-cement pipe described as 44 years old. The asbestos fiber type is not stated.
• Main results:
  • The asbestos-cement pipe wall thickness went from 12 mm (new) to 11.1 mm after 46 years of use.
  • Under the microscope, the inner surface of the used asbestos-cement pipe was corroded and uneven, the cement had degraded, and asbestos fibers of different sizes were visible. In the unused pipe the fibers were well incorporated into the cement.
  • On the used asbestos-cement pipe surface, magnesium fell from 24.8% to 5.08% and silicon from 21.3% to 9.84%, compared with the unused pipe.
  • On the used asbestos-cement pipe surface, calcium rose from 0.5% to 27.78%. The authors interpreted this as calcium compounds deposited on the pipe.
  • Conductivity in microsiemens per cm at the plant versus street point P1 (asbestos cement): 440 vs 587 (2023), 347 vs 463 (2024), 320 vs 460 (2025).
  • Turbidity in NTU at the plant versus P1 (asbestos cement): 0.13 vs 0.293 (2023), 0.280 vs 0.210 (2024), 0.210 vs 0.360 (2025).
  • Water in the city network was tested only for pH, turbidity, conductivity, chemical oxygen demand, nitrates, iron, manganese and aluminum. Asbestos fibers in water were not measured.
  • The OLT 37 steel pipe wall went from 4 mm initially to 3 mm in corroded areas and up to 12 mm in areas with deposits, after 42 years of use.
  • The HDPE pipe showed deep microcracks after 20 years of use.
  • The authors stated that water quality was within the maximum permissible limits.
• The authors' conclusion: The authors concluded that the asbestos-cement pipes were corroded, with exposed fibrous asbestos. They ranked the pipe materials by risk category as asbestos cement highest, then OLT 37, then OLT 37.1, then HDPE.
• Limitations the authors state:
  • For HDPE, the authors stated that the FTIR results do not allow them to assert advanced oxidative degradation.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos-Cement Pipe.

Related studies

• Epidemiology study of the use of asbestos-cement pipe for the distribution of drinking water in Escambia County, Florida — J.R. Millette, G.F. Craun, et al. (1983)
• Long-term influences of pipe materials on bacterial communities of matured biofilms (> 40 years' old) in drinking water distribution systems — A. Ren, J. Li, et al. (2026)
• Improving pipe failure predictions: Factors affecting pipe failure in drinking water networks — N.A. Barton, T.S. Farewell, et al. (2019)
• Is there a risk to health in using asbestos--cement pipes for the carriage of drinking water? — S.F. McCullagh (1980)
• Evidence of arsenic release promoted by disinfection by-products within drinking-water distribution systems — S.S. Andra, K.C. Makris, et al. (2014)
• Stimulation of 2-methylisoborneol (MIB) production by actinomycetes after cyclic chlorination in drinking water distribution systems — M. Abbaszadegan, M. Yi, et al. (2015)

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