Influence of Natural Waters on the Leaching of Sewer Rehabilitation Resins

Water, vol. 18, pp. 2021

Abstract

The leaching behavior of bisphenol A (BPA) remains a significant environmental concern. Despite EU regulatory restrictions and the World Health Organization (WHO) establishing precautionary values for human exposure to this monomer, BPA is still widely used in polymer-based products, including materials for sewer rehabilitation. Standard leaching assessments typically employ deionized water, although natural waters represent actual field conditions. This study investigates the release of BPA and its substitute, bisphenol F (BPF), from an epoxy resin system and a vinyl ester resin system. Sample discs (0.5 cm in height and 11 cm in diameter) were subjected to dynamic surface leaching tests using groundwater and tap water as leaching media. Eluate replacement intervals followed the standardized Dynamic Surface Leaching Test (DSLT; EN 16637-2), marking the first application of natural waters within this standardized test procedure. The detection limit for the gas chromatography analyses was 0.001 µg/L. Compared with the deionized water prescribed by the standard, natural waters resulted in significantly higher cumulative releases of BPA and BPF, with cumulative BPA release increasing by factors of 5.2–9.2 to a maximum of 0.412 mg/m2. These findings indicate that the standardized 64-day DSLT may underestimate environmentally relevant emissions and that permissible cumulative release values, derived from modeling and regulatory thresholds, may not be maintained under environmentally relevant conditions. GC–MS screening and the Umu test showed no evidence of genotoxic effects in the leachates. Exploratory analysis suggested a positive relationship between BPA release and pH (R2 = 0.79). Overall, the results demonstrate that the choice of leaching medium strongly influences measured emissions and should therefore be reconsidered in assessment frameworks for polymer-based construction materials to better reflect environmentally relevant conditions.

Authors 3

1. Konstantin Ahrens corresponding Aachen Institute of Building Materials Research

   RWTH Aachen University

   Affiliation as printed

   Institute of Building Materials Research (ibac), RWTH Aachen University, Schinkelstr. 3, 52062 Aachen, Germany

2. Reiner Gschwendtner Aachen Institute of Environmental Engineering

   RWTH Aachen University

   Affiliation as printed

   Institute of Environmental Engineering (ISA), RWTH Aachen University, Mies-Van-Der-Rohe-Str. 1, 52074 Aachen, Germany

3. Anya Vollpracht Aachen Institute of Building Materials Research

   RWTH Aachen University

   Affiliation as printed

   Institute of Building Materials Research (ibac), RWTH Aachen University, Schinkelstr. 3, 52062 Aachen, Germany