Preliminary trends over ten years of persistent organic pollutants in air - Comparison of two sets of data in the same countries

In two series of ambient air measurement campaigns to support the implementation of the global monitoring plan (GMP) component of the Stockholm Convention on Persistent Organic Pollutants (POPs), passive air samplers (PAS) using polyurethane foams were implemented by the United Nations Environment Programme (UNEP). With the same laboratories responsible for the chemical analyses of the different groups of POPs, a total of 423 PUFs were analyzed for organochlorine pesticides (OCPs) including hexachlorobenzene (HCB) and polychlorinated biphenyls (PCB); 242 for dioxin-like POPs. For trend analysis, to compare amounts of POPs in the PUFs during the first phase in 2010/2011 and the second phase from 2017 to 2019, only results were assessed that were generated in the same country and for the same POP in both campaigns. Finally, there were 194 PUFs available for OCPs (GMP1 = 67 and GMP2 = 127), 297 for PCB (GMP1 = 103, GMP2 = 194), 158 for polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDD, PCDF) (GMP1 = 39, GMP2 = 119), and 153 for dl-PCB (GMP1 = 34, GMP2 = 119). Indicator PCB and dioxin-like POPs were quantified in all countries at all times; decreases of about 30% based on median values were determined. A 50% increase was found for HCB. By scale, DDT remained with the highest values, although more than 60% decrease was found; mainly due to smaller values in the Pacific Islands region. Our assessment showed that on relative scale - per PUF - trend analysis was achieved and that such approach should be undertaken at regular intervals, not necessarily on an annual basis.

Assessment of four rounds of interlaboratory tests within the UNEP-coordinated POPs projects

Since 2005, the United Nations Environment Programme (UNEP) has supported developing countries with capacity building, including on-site training courses and provision on laboratory materials and consumables, and analysis of samples from Africa, Asia-Pacific and Latin America and the Caribbean (GRULAC) in designated expert laboratories. In order to check the performance of laboratories analyzing persistent organic pollutants (POPs) and giving trust into chemical analytical results, four rounds of interlaboratory assessments (ILs) were organized between 2010 and 2019. These were open to all POPs laboratories. In total, 41 575 z-scores, as indicators of performance, were generated in these four ILs; of these, 8 912 were from laboratories in countries supported by UNEP projects and 3 923 were from expert laboratories; these together constitute 31% of the total. 69% of all z-scores came from laboratories not participating in the UNEP projects, especially from China, who recognized the importance of such exercises for quality control at an early stage. The results showed that POPs analytical capacity has increased over the years, but some gaps could not be closed especially not when LC-MS/MS equipment is essential such as for PFAS and congener-specific HBCD. Use of mass spectrometers provides better results than ECD instruments due to the broad spectrum of organochlorine pesticides to be analyzed under the Stockholm Convention. The main conclusion for all laboratories is that interlaboratory assessments provide important and objective snapshots of performance for the laboratories themselves and for external clients. The methods used in any interlaboratory testing should be the same as during routine analysis between such tests.

Levels of Persistent Organic Pollutants (POPs) in sediments from Lenga estuary, central Chile

Superficial sediments from Lenga estuary in the VIII region of central Chile were analysed for Polychlorinated Biphenyls (PCBs) and Hexachlorobenzene (HCB). Organic carbon (OC) analysis was also performed and the statistical correlations (Pearson correlations) between compounds were also tested. Results showed the total PCB concentrations (ng g(-)(1)d.w.) fluctuated from ∼ 20 to 10,000. These levels are higher than those reported in other coastal sediments of the world. The PCB profile was dominated by middle to highly chlorinated congeners (6-Cl=40% and 7-Cl=30%). HCB concentrations (ng g(-)(1)d.w.), were lower than the PCBs and, fluctuated between 1 (at L1) and 870 (at L4). OC values ranged from 1% (L1) to 7% (L4) showing a significant positive correlations between OC% and PCBs (r=0.86; p<0.05) and for HCB (r=0.71). These results are an important contribution to knowledge of levels of POPs levels in coastal Chilean environments.