Utilizing HPLC-FLD for Large-Scale Biomonitoring of Atmospheric PAHs

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants that are released into the atmosphere from both natural sources and human activity. A joint study conducted by researchers at the Université de Sherbrooke (Québec, Canada) and Environment and Climate Change Canada (Montréal, Québec, Canada) performed the first large-scale spatial assessment of atmospheric PAHs across Quebec, using passive biomonitoring with Pleurozium schreberi moss. PAH analysis was conducted using high-performance liquid chromatography with fluorescence detection (HPLC-FLD), targeting 10 PAHs for spatial biomonitoring and 15 PAHs to assess the impacts of the 2023 wildfire events. A paper based on this research was published in Science of the Total Environment.¹

Widely recognized as indicators of air pollution and anthropogenic activity, PAHs are continual and abundant contaminants within the environment which are emitted primarily during the incomplete combustion of organic materials.² Their persistence in the environment, combined with their ability to dissolve in lipids, oils, and non-polar solvents, as well as their toxicity increase with their molecular weight, have resulted in numerous studies demonstrating their immediate or long-term negative effects on ecosystems and human health. ^3-7

Among the reasons that the researchers set out on this research was to provide an initial insight into the possible effect of wildfires on atmospheric PAH levels in southern Québec following the extraordinary 2023 fire season which burned nearly 460,000 hectares.⁸ By filling the current data gap in PAH monitoring across southern Québec, it was the hope of the research team to support the development of future biomonitoring frameworks for atmospheric organic pollutants in Canada.¹

Over 200 moss samples were collected by the researchers, primarily from southern Quebec, the most populated region with major urban and industrial centers, as well as from remote northern regions to capture background deposition levels. Despite the influence of intense regional wildfires and transboundary air masses, PAH concentrations across most of Quebec remained low, highlighting the province relatively clean atmospheric conditions. Elevated PAH levels were largely confined to the St. Lawrence Urban Corridor and corresponded with local industrial and urban activity, as well as potentially prevailing winds from the U.S.¹

“The intense wildfire events of 2023,” write the authors of the study,¹ “did not increase total PAH loads in the tested sites but led to marked compositional shifts, with diagnostic ratios indicating amplified contributions from pyrogenic sources. These findings reinforce the effectiveness of moss biomonitoring for detecting both regional pollution gradients and temporal shifts in source signatures, while establishing a valuable baseline for future atmospheric studies in eastern North America.”

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References

1. Ramezany, S.; Michel, L.; Houle, D. et al. Monitoring Polycyclic Aromatic Hydrocarbons Deposition in Eastern Canada Using Moss Biomonitoring: A Large-Scale Study of Spatial Patterns and Environmental Influences. Sci Total Environ. 2026, 1019, 181530. DOI: 10.1016/j.scitotenv.2026.181530
2. Act, Canadian. Environmental Protection Act Priority Substances List Assessment Report. Government of Canada website 1993.https://www.canada.ca/en/health-canada/services/environmental-workplace-health/reports-publications/environmental-contaminants/canadian-environmental-protection-act-priority-substances-list-assessment-report-polycyclic-aromatic-hydrocarbons.html
3. Feng, Y.; Li, Z.; Li, W. Polycyclic Aromatic Hydrocarbons (PAHs): Environmental Persistence and Human Health Risks. Nat. Prod. Commun.2025, 20 (1), 1934578X241311451. DOI: 10.1177/1934578X2413114
4. Barbosa, F. Jr.; Rocha, B. A.; Souza, M. C. O. et al. Polycyclic Aromatic Hydrocarbons (PAHs): Updated Aspects of their Determination, Kinetics in the Human Body, and Toxicity. J Toxicol Environ Health B Crit Rev. 2023, 26 (1), 28-65. DOI: 10.1080/10937404.2022.2164390
5. Arif, I.; Adams, M. D.; Johnson, M. T. J. A Meta-Analysis of the Carcinogenic Effects of Particulate Matter and Polycyclic Aromatic Hydrocarbons. Environ Pollut. 2024, 351, 123941. DOI: 10.1016/j.envpol.2024.123941
6. Sari, M. F.; Esen, F. Concentration Levels and an Assessment of Human Health Risk of Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs) in Honey and Pollen. Environ Sci Pollut Res Int. 2022, 29 (44), 66913-66921. DOI: 10.1007/s11356-022-20545-y
7. Xu, P.; Liu, B.; Chen, H. et al. PAHs as Environmental Pollutants and their Neurotoxic Effects. Comp Biochem Physiol C Toxicol Pharmacol. 2024, 283, 109975. DOI: 10.1016/j.cbpc.2024.109975
8. Canada's Record-Breaking Wildfires 2023: Fiery Wake-Call. Natural Resources Canada Website 2023.https://natural-resources.canada.ca/stories/simply-science/canada-s-record-breaking-wildfires-2023-fiery-wake-call