Interlaboratory assessments for dioxin-like POPs (2016/2017 and 2018/2019)

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Toxicology

Background:

• The United Nations Environment Programme (UNEP) coordinates biennial interlaboratory assessments to evaluate laboratories analyzing persistent organic pollutants (POPs).
• These assessments are crucial for ensuring data quality for global monitoring plans, such as the Stockholm Convention.

Purpose of the Study:

• To assess the global analytical capacity for dioxin-like persistent organic pollutants (dl-POPs) across different UN regions.
• To evaluate laboratory performance in analyzing dl-POPs in various matrices and identify areas for improvement.

Main Methods:

• Two rounds of interlaboratory comparisons (2016/2017 and 2018/2019) involving 56 and 46 laboratories, respectively.
• Analysis of test matrices including analytical standards, sediment, air extract, fish, and human milk.
• Performance assessment using z-scores (satisfactory performance defined as ±25%).

Main Results:

• Analytical capacity for dl-POPs exists globally, but is limited in Africa and Central/Eastern Europe, with increasing capacity in Latin America.
• Laboratories in developing countries (e.g., China, Brazil, Vietnam) demonstrate significant dioxin analysis capabilities.
• Established methods using gas chromatographs coupled to high-resolution mass spectrometers (HRMS) yielded the best results.
• Human milk and fish samples presented significant challenges, indicating a need for improved performance, particularly for low-concentration foodstuff analysis.

Conclusions:

• Global analytical capacity for dl-POPs is present but unevenly distributed, necessitating targeted capacity-building efforts.
• High-resolution mass spectrometry is the preferred method for accurate dl-POP analysis.
• Further improvement in analytical performance is required for complex matrices like fish and human milk, especially at trace levels.