RapMixTox: Rapid and automated prediction of complex mixture toxicity by nontarget instrumental analysis

Anneli Kruve, Magnus Breitholtz, Jonathan Martin, Matthew MacLeod

FORMAS 2021 – 2023

The Swedish Government recently launched a comprehensive report on the future of chemical risk management accounting for combination effects and assessing chemicals in groups. The major conclusions from the report were that there is a need to improve the assessment and management of mixture risks and increase and develop group-wise assessment and management of chemicals. In more detail, modelling both co-exposures and combined toxicity was identified as key for regulatory progress.

Unfortunately, assessing the effect of the mixtures traditionally requires expensive and slow testing in vivo, and the constituents of the mixture need to be known. Real-world environmental water samples may contain hundreds if not thousands of chemical compounds, which vary strongly depending on the location and proximity to industrial and agricultural activities. Water samples are routinely analysed using liquid chromatography mass spectrometry, which allows separating the components and measuring several characteristics of these compounds. Still, identification of all of the constituents of an environmental water sample is a very challenging task, and all constituents of a sample do not contribute equally to the mixture effect.

In the current project, we will develop a method to predict the mixture toxicity of water samples without the need for identification of each constituent, and without biological testing. Specifically, we will use the information collected while analysing surface water sample with liquid chromatography mass spectrometry directly for predicting the toxic effect of the compounds. This will allow us to evaluate the mixture toxicity rapidly, without identifying the structure of all chemical compounds in the sample. Moreover, it will become possible to pinpoint the compound(s) with the greatest contribution to the mixture effect prior to the identification of the compounds and without the need for time-consuming and expensive animal testing.

Tandem development of waste textile recycling process and chemical screening for a non-toxic Re:Start

Aji Pallikunnel Mathew & Anneli Kruve

FORMAS dual project 2021 – 2023

Re:start aims to establish a tandem method combining sustainable processes and online chemical analysis to enhance the sustainability and safety related to recycling of waste textiles. The focus will be on reclaiming PET, acrylics, nanocellulose and its hybrids from textile waste for subsequent conversion to monomers, chemicals or new materials for recirculation. This will yield positive benefits as i) reduced need for virgin resources in industrial process ii) decreased materials that will be phased out and end up in incineration or landfill and iii) safe and toxic free products. However, the circulation should not come at the cost of quality, human health, or ecosystem. The project will therefore develop fast and non-invasive analysis methods to detect possibly harmful chemicals before and during recycling processes. Furthermore, our approach to partially fractionate the textiles to suitable hybrids without separating them completely into the component chemical fractions is expected to be more toxic free and resource efficient than chemical routes used today. New thermomechanical recycling processes will contribute significantly to green recycling and also put Sweden as forerunners of sustainable textile recycling and recovery of valuable resources.The developed tandem method is expectd to enable the emergence of a resource-efficient industries, chemical-smart society and new start ups focusing on toxic free and sustainable products from recycling.

Quantification of emerging contaminants with liquid chromatography high resolution mass spectrometry and graph-based machine learning

Anneli Kruve & Meelis Kull

VR 2022 – 2025

Understanding the toxicity of real-world complex mixtures, and identification of the most toxic chemicals is an essential starting point for the intelligent design of water treatment solutions and chemical regulation. To evaluate the risk possessed by water contaminants to humans and wildlife we need to know the structure, concentration (exposure), and toxic endpoint of the contaminants. Liquid chromatography-electrospray mass spectrometry (LC/ESI/HRMS) in combination with machine learning has offered significant improvements in detecting, identifying, and estimating the toxic endpoint for hundreds and thousands of water contaminants simultaneously; however, the quantification is lagging. The main reason is that analytical standards are required for the quantification of the detected contaminants.

In this project, we will develop machine learning methods to quantify the contaminants detected with LC/ESI/HRMS even if analytical standards are not available. Specifically, we will develop machine learning models to predict the response of the detected compounds in LC/ESI/HRMS from the structure of the compounds and use this for the quantification of these compounds. This will allow us to evaluate the risk possessed by the detected compounds, without time-consuming synthesis of the analytical standards. Moreover, it will become possible to pinpoint the compound(s) with the greatest contribution to the mixture toxicity.

Interlaboratory comparison of (semi-)quantitative LC/HRMS non-targeted screening

Anneli Kruve & Nikolaos S. Thomaidis

NORMAN 2020 – 2022

The identification and quantification of emerging contaminants from complicated organic mixtures have traditionally been based on the “calibration” standard substances. Non-targeted analysis has redefined the (tentative) identification of the compounds. Now several new methods for (semi-)quantification of the tentatively identified compounds are emerging both inside and outside NORMAN non-targeted community. However, the validity of the methods remains ambiguous as (1) they have been tested on limited type of samples and (2) commonly accepted datasets suitable for benchmarking of the
(semi-)quantification approaches are unavailable. A possibility to overcome and speed up the development of (semi-)quantification approaches is to provide a common ground for testing the developed approaches via a collaborative trial.