Isomer-selective biodegradation of high-molecular-weight azaarenes in PAH-contaminated environmental samples

Critical assessment of the Kendrick mass defect analysis as an innovative approach to process high resolution mass spectrometry data for environmental applications

The growing application of high resolution mass spectrometry (HRMS) over the last decades has dramatically improved our knowledge about the occurrence of environmental contaminants. However, most of the compounds detected remain unknown and the large volume of data generated requires specific processing approaches. Therefore, this study presents the concepts of mass defect (MD), Kendrick mass (KM) and Kendrick mass defect (KMD) to the expert and non-expert reader along with relevant examples of applications in environmental HRMS data processing. A preliminary bibliometric overview indicates that the potential benefits of KMD analysis are rather overlooked in environmental science. In practice, a simple calculation allows transforming a mass from the IUPAC system (normalized so that the mass of ¹²C is exactly 12) to its corresponding KM normalized on a specific moiety such as CH₂ (the mass of CH₂ is exactly 14). Then, plotting the KMD according to the nominal KM allows revealing groups of compounds that differ only by their number of CH₂ moieties. For instance, data processing using KM and KMD was proven particularly useful to characterize natural organic matter in a sample, to reveal the occurrence of polymers as well as poly/perfluorinated alkylated substances (PFASs), and to search for transformation products (TPs) of a given chemical.

Recent Advances in the Study of the Remediation of Polycyclic Aromatic Compound (PAC)-Contaminated Soils: Transformation Products, Toxicity, and Bioavailability Analyses

Polycyclic aromatic compounds (PACs) encompass a diverse group of compounds, often found in historically contaminated sites. Different experimental techniques have been used to remediate PACs-contaminated soils. This brief review surveyed over 270 studies concerning remediation of PACs-contaminated soils and found that, while these studies often measured the concentration of 16 parent polycyclic aromatic hydrocarbons (PAHs) pre- and post-remediation, only a fraction of the studies included the measurement of PAC-transformation products (PAC-TPs) and other PACs (n = 33). Only a few studies also incorporated genotoxicity/toxicity/mutagenicity analysis pre- and post-remediation (n = 5). Another aspect that these studies often neglected to include was bioavailability, as none of the studies that included measurement of PAH-TPs and PACs included bioavailability investigation. Based on the literature analysis, future remediation studies need to consider chemical analysis of PAH-TPs and PACs, genotoxicity/toxicity/mutagenicity, and bioavailability analyses pre- and post-remediation. These assessments will help address numerous concerns including, among others, the presence, properties, and toxicity of PACs and PAH-TPs, risk assessment of soil post-remediation, and the bioavailability of PAH-TPs. Other supplementary techniques that help assist these analyses and recommendations for future analyses are also discussed.