Aging of drinking water transmission pipes during long-term operation as a potential source of nano- and microplastics.

Microplastics (MPs) and nanoplastics (NPs) released into drinking water from transmission pipes can pose a potential health risk to consumers. This paper presents the results of a comprehensive study of PE and PVC pipes after long-term operation in drinking water distribution networks, which confirmed that degradable polymers can be a significant source of MPs. Both plastics age relatively quickly, and the degree of damage to the pipe surface depends on the time and operating conditions. During aging, polymer chains deteriorate, leading to a weakening of the structure and increased amorphousness of the plastics. As a result, the surfaces of PE and PVC crack and peel, resulting in the formation of particles with sizes corresponding to NP and MP with high potential for release into water. The magnitude of the phenomenon increases as the diameter of the pipes decreases, indicating that the most vulnerable customers are those at the ends of the network to which drinking water is supplied through small-diameter pipes. Aging PE and PVC pipes should be considered a real and very important source of MPs and NPs in drinking water, and water quality in this aspect should be monitored by manufacturers.