Dioxin-like POPs in national samples from global monitoring plan projects (2017-2019)

The global monitoring plan (GMP) established under the Stockholm Convention on Persistent Organic Pollutants (POPs) had defined ambient air, human milk or blood, and water as core matrices to be analyzed and assessed for spatial and temporal distribution. Within projects coordinated by the United Nations Environment Programme (UNEP), developing countries were offered to have other matrices analyzed for dioxin-like POPs (dl-POPs) in experienced laboratories. Subsequently, 185 samples from 27 countries located in Africa, Asia, and Latin America were collected during 2018-2019 and analyzed for polychlorinated dibenzodioxins (PCDD), dibenzofurans (PCDF), and biphenyls (PCB). Using the WHO₂₀₀₅ toxic equivalency approach (TEQ), the amounts of dl-POPs found were low (<1 pg TEQ/g); however, singular samples had higher values; e.g., egg from Morocco, fish from Argentina or Tunisia; soil and sediment samples. Results showed that the matrix, abiotic or biota, had more impact on the TEQ pattern than the geographic location. Independent of the location and across all samples, dl-PCB in (shell)fish and beef samples had a contribution of 75% to the total TEQ; milk (63%), chicken (52%), and butter (50.2%) more than 50%. Sediment (57% and 32%) and soil (40% and 36%)) samples were dominated by PCDD and PCDF, respectively; therein, dl-PCB had shares of 11% and 24%. Egg samples (N = 27) did not follow the general biota pattern and had 21% of the TEQ from the PCDD, 45% from PCDF, and 34% from dl-PCB; thus, indicating that abiotic matrices such as soil or other material may have an impact.