Prioritisation, Identification, and Quantification of Emerging Contaminants in Recycled Textiles Using Non-Targeted and Suspect Screening Workflows by LC-ESI-HRMS

Introduction:

The production and use of recycled textiles is an important part of circular economy principles and will directly address the United Nations Sustainable Development Goals by reducing raw materials, waste, water use, land use, and carbon emissions to the atmosphere. The European Union is implementing policies to decrease textiles sent to landfills and promote the development of recycled textile processes. However, the risk of chemical contamination has not been addressed and it is not known if hazardous chemicals are used, produced, degraded or concentrated by current recycling processes. This study aims to develop, validate, and apply a high-resolution mass spectrometry (HRMS) workflow for detecting, identifying as well as assessing the quantity and risk of chemicals extracted from recycled textiles.

Methods:

The method utilizes liquid chromatography coupled with high-resolution mass spectrometry and data analysis with patRoon R-package accessed through RStudio. XCMS was used for feature extraction and alignment followed by filtration based on intensity and relative standard deviation. Peak quality was assessed with NeatMS, and componentization with CAMERA preserved [M+H]⁺ and [M-H]^- adducts. MS² peak lists were extracted using the mzR package. Molecular formulas were generated with SIRIUS CSI:FingerID and structural matching was performed with SIRIUS, MetFrag, and MassBank. Textile-related and persistent, mobile, and toxic (PMT) substances were found by performed suspect screening. The concentration, ecotoxicity and risk were assessed based on SIRIUS fingerprints with MS2Quant and MS2Tox employed.

Preliminary Data or Plenary Speakers Abstract:

This workflow was successfully validated for 38 known substances with a wide range of molecular weight (112.09 to 916.10 g mol^-1) and hydrophobicity (logP = -2.7 to 6.9). Through the detection, identification and prioritization of 20,119 LC-HRMS features, we have demonstrated that there may be restricted or potentially harmful substances present in recycled textiles. Suspect screening revealed six features that were confidently identified as PMT chemicals present on the EU REACH regulatory list. An additional 43 features were matched with other textile-related substances reportedly produced or imported to Sweden by the Swedish Chemicals Agency (Kemi). SIRIUS fingerprints were calculated for a total of 768 features such that the toxicity and concentration could be predicted to establish a priority score. The top 10 ranked features for positive and negative mode contained substances that have commonly reported uses in textile manufacture, including dyes, auxiliary and finishing chemicals. None of the top-ranked features were present in all samples, suggesting that there are differences in the manufacturing process for each textile sample. For example, the confident detection and identification of dinoterb (Level 2b), a toxic pesticide, detected in 69% of recycled textile samples was prioritized with the application of relative aquatic toxicity predictions using machine learning techniques. Further investigation is required to determine the sources of chemicals. Due to the high predicted aquatic toxicity and high concentrations, some substances may be approaching concentrations that may cause adverse impacts to humans or the environment. The continued development and manufacture of recycled textiles is an integral part of the principles of the circular economy and will significantly contribute to the reduction of raw materials, waste production and carbon dioxide emissions to the atmosphere. These goals must be met with equal importance to the chemical health of the environment and should not be the cost of progress.