In vitro toxicity assessment of emitted materials collected during the manufacture of water pipe plastic linings

Abstract

Objectives: US water infrastructure is in need of widespread repair due to age-related deterioration. Currently, the cured-in-place (CIPP) procedure is the most common method for water pipe repair. This method involves the on-site manufacture of a new polymer composite plastic liner within the damaged pipe. The CIPP process can release materials resulting in occupational and public health concerns. To understand hazards associated with CIPP-related emission exposures, an in vitro toxicity assessment was performed.

Materials and Methods: Mouse alveolar epithelial and alveolar macrophage cell lines and condensates collected at 3 worksites utilizing styrene-based resins were utilized for evaluations. All condensate samples were normalized based on the major emission component, styrene. Further, a styrene-only exposure group was used as a control to determine mixture related toxicity.

Results: Cytotoxicity differences were observed between worksite samples, with the CIPP worksite 4 sample inducing the most cell death. A proteomic evaluation was performed, which demonstrated styrene-, worksite-, and cell-specific alterations. This examination of protein expression changes determined potential biomarkers of exposure including transglutaminase 2, advillin, collagen type 1, perilipin-2, and others. Pathway analysis of exposure-induced proteomic alterations identified MYC and p53 to be regulators of cellular responses. Protein changes were also related to pathways involved in cell damage, immune response, and cancer.

Conclusions: Together these findings demonstrate potential risks associated with the CIPP procedure as well as variations between worksites regarding emissions and toxicity. Our evaluation identified biological pathways that require a future evaluation and also demonstrates that exposure assessment of CIPP worksites should examine multiple chemical components beyond styrene, as many cellular responses were styrene-independent.

Keywords:

• Cured-in-place pipe
• proteomics
• macrophages
• epithelial cells
• styrene
• cancer

Acknowledgements

The authors would like to thank Dr. Uma K. Aryal, Victoria Hedrick, and Dr. Tiago Sobreira of Purdue Proteomics Facility for their support in performing proteomic experiments, data analysis and interpretation. All mass spectrometry experiments were performed at the Purdue Proteomics Facility located at the Bindley Bioscience Center of Purdue University. The Q Exactive Orbitrap HF and UltiMate 3000 HPLC system used for LC-MS/MS analysis was purchased from funding provided by the Purdue Office of the Executive Vice President for Research and Partnership. Further we would like to thank Dr. Jennifer Freeman for assistance in performing the pathway analysis of CIPP emission condensate-induced protein alterations.

Disclosure statement

AJW, BEB, JAH, and SMTS are named in a patent application (PCT/US18/28173) filed April 18, 2018 by the Purdue Research Foundation. The patent application pertains to the technologies for capturing, identifying, analyzing, and addressing emissions that are potentially hazardous to the environment and humans.

Additional information

Funding

This publication was supported by the National Institute for Occupational Safety and Health Grant #T42/OH008672 and the National Institute of Environmental Health Sciences Grant R00/ES024392. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of NIOSH and NIEHS.