Determination of Polychlorinated Naphthalenes in Solid and Aqueous Matrices

Significance of the Topic

Polychlorinated naphthalenes (PCNs) are persistent organic pollutants regulated under EU Regulation 2019/1021 due to their environmental persistence, bioaccumulation potential, and toxicity. These compounds, historically used in industrial applications such as dielectric fluids, wire insulation, and wood preservatives, continue to pose risks because of legacy contamination and ongoing unintentional releases from processes like waste incineration and metal production.

Objectives and Study Overview

This whitepaper from ALS Laboratories outlines the analytical approach for quantifying PCNs in solid and aqueous matrices. It aims to demonstrate a robust method compliant with regulatory limits, covering eight representative congeners from monochloronaphthalene to octachloronaphthalene, and to discuss the environmental significance of accurate PCN monitoring.

Methodology and Instrumentation

The analytical workflow combines sample extraction, clean-up, and quantification using high-resolution chromatographic techniques. Key steps include:

• Sample preparation: extraction of PCNs from soil, sediment, water, or waste matrices
• Clean-up: removal of matrix interferences to improve selectivity
• Chromatographic separation: resolving congeners by gas chromatography
• Detection: isotope dilution quantification for high accuracy and precision

Instrumentation Used

• Gas chromatography coupled with high-resolution mass spectrometry (GC-HRMS) using electron ionization
• Gas chromatography coupled with triple quadrupole mass spectrometry (GC-MS/MS) with electron ionization

Key Results and Discussion

The developed method achieves quantification limits in line with EU requirements, enabling reliable detection of PCN congeners across environmental samples. Higher chlorinated congeners display strong particle affinity and persistence in sediments, while lower chlorinated compounds are more volatile. The data confirm widespread environmental distribution driven by historical use and unintentional formation, highlighting the need for targeted monitoring of key sources such as metallurgical processes and waste incineration.

Benefits and Practical Applications

• Regulatory compliance: meets or exceeds detection limits established by EU Regulation 2019/1021
• Environmental monitoring: supports mapping of PCN distribution in soils, sediments, and water bodies
• Risk assessment: provides accurate congener profiles for toxicological evaluation
• Remediation planning: informs strategies for contaminated site management

Future Trends and Opportunities

Advances in emission inventory modeling and atmospheric transport analysis will refine global PCN source attribution. Emerging analytical technologies, including miniaturized and field-deployable mass spectrometers, could enable more frequent on-site monitoring. Integration of non-target screening approaches may reveal additional PCN congeners and transformation products, further enhancing our understanding of their environmental fate.

Conclusion

The ALS Laboratories’ GC-HRMS and GC-MS/MS methods provide sensitive, accurate, and regulatory-compliant analysis of PCNs in diverse matrices. These tools are essential for effective environmental monitoring, risk management, and compliance with persistent organic pollutant regulations.

References

• Lee H.-H., Lee S., Lee J.-S., Moon H.-B. Distribution of Polychlorinated Naphthalenes in Sediment from Industrialized Coastal Waters of Korea with Optimized Cleanup and GC-MS/MS Methods. Frontiers in Marine Science 8:754278 (2021).
• ISO/TS 16780: Technical specification for analysis of polychlorinated naphthalenes.
• European Union Regulation 2019/1021 on persistent organic pollutants.
• Fernandes A.R., Kilanowicz A., Stragierowicz J., Klimczak M., Falandysz J. The Toxicological Profile of Polychlorinated Naphthalenes (PCNs). Science of The Total Environment 837:155764 (2022).