Tracing the sources of PCDD/Fs in Baltic Sea air by using metals as source markers

Polychlorinated biphenyls (PCB) and polychlorinated dibenzo-para-dioxins and dibenzofurans (PCDD/F) in ambient air and deposition in the German background

PCDD/Fs (17 congeners and Σ tetra -to octachloro homologues) and 209 PCBs were investigated in monthly samples of ambient air (gas + particle phase) and atmospheric deposition at two background monitoring sites in Germany in 2018/19. In atmospheric deposition samples, PCDD/F congeners as well as certain PCBs were frequently below the method quantification limits whereas values for PCDD/F homologue groups could be quantified more often. Annual deposition averages for individual PCDD/Fs were between <0.1 μg/m²d and 6.7 μg/m²d. Averages for Σ TeCDD/F to OCDD/F homologue totals in deposition were about 11 pg/m²d and 19 pg/m²d. Total PCB deposition rates were about 1900 pg/m²d and 1550 pg/m²d. PCDD/F + PCB-deposition rates were below 1 pg WHO₂₀₀₅-TEQ/m²d on average. In ambient air, both substance groups were frequently observed. Annual concentration averages for individual PCDD/F were between 0.1 fg/m³ and 50 fg/m³. Average values for Σ TeCDD/F to OCDD/F homologue totals in ambient air were 283 fg/m³ and 162 fg/m³. Total PCB concentrations were about 50 pg/m³ at both sites. PCDD/F + PCB-TEQ values were lower than 5 fg WHO₂₀₀₅-TEQ/m³ on average. Besides the frequently studied dioxin-like PCBs and six indicator PCBs, the analysis of the 209 PCBs (166 separated PCB-peaks) enabled the identification and evaluation of additional PCBs that might be of environmental concern. Of 166 PCBs or PCB-coelutions, up to 144 were quantified in air samples and up to 94 in atmospheric deposition samples. In ambient air, some of these PCBs were observed at levels similar to or exceeding those of the six indicator PCBs. Important additional PCBs in ambient air were PCB 5 + 8, PCB 11, PCB 17, PCB 18, PCB 20 + 33, PCB 31, PCB 43 + 49, PCB 44, PCB 47 + 48 + 65 + 75, PCB 93 + 95 + 98 + 102, PCB 139 + 149, and PCB 151. The presence of these PCBs in atmospheric samples implies that by analysing only selected PCBs potentially important contaminants are overlooked.

Spatial aspects of the dioxin risk formation in the Baltic Sea: A systematic review

Dioxins have been an inconvenience to the Baltic Sea ecosystem for decades. Although the concentrations in the environment and biota have continuously decreased, dioxins still pose a risk to human health. The risk and its formation vary in different parts of the Baltic Sea, due to variability in the environmental and societal factors affecting it. This paper presents a systematic literature review and knowledge synthesis about the regional dioxin risk formation in four sub-areas of the Baltic Sea and evaluates, whether systemic approach changes our thinking about the risk and its effective management. We studied the dioxin flux from atmospheric deposition to the Baltic Sea food webs, accumulation to two commercially and culturally important fish species, Baltic herring (Clupea harengus membras) and Baltic salmon (Salmo salar), and further to risk group members of four Baltic countries. Based on 46 studies, we identified 20 quantifiable variables and indexed them for commensurable regional comparison. Spatial differences in dioxin pollution, environmental conditions, food web dynamics, and the following dioxin concentrations in herring and salmon, together with fishing and fish consumption, affect how the final health risk builds up. In the southern Baltic Sea, atmospheric pollution levels are relatively high and environmental processes to decrease bioavailability of dioxins unfavorable, but the growth is fast, which curb the bioaccumulation of dioxins in the biota. In the North, long-range atmospheric pollution is minor compared to South, but the local pollution and slower growth leads to higher bioaccumulation rates. However, based on our results, the most remarkable differences in the dioxin risk formation between the areas arise from the social sphere: the emissions, origin of national catches, and cultural differences in fish consumption. The article suggests that acknowledging spatial characteristics of socio-ecological systems that generate environmental risks may aid to direct local focus in risk management.

Assessment of Air Pollution with Polychlorinated Dibenzodioxins (PCDDs) and Polychlorinated Dibenzofuranes (PCDFs) in Lithuania

Polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDD/F) are highly bioavailable in humans, either through direct inhalation or indirectly by trophic transfer from contaminated food or water. The main sources of pollution with PCDD/F include industrial and non-industrial combustion sources, like domestic contaminated wood burning, house fires, burning of leaves from trees, etc. When looking for alternative energy sources and reduced energy costs, solid waste incineration plants are intended to be built in the vicinity of urbanized areas, and thus, the need emerges for examination and prediction of to what extent the solid waste incineration plants might affect the surrounding ecosystem, air pollution, and human health. Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) (or simply PCDD/F congeners) belong to the group of semi-volatile organic compounds with environmental stability and long-range transfer in the ambient air. Dioxin isomers are highly toxic and may have carcinogenic and mutagenic effects in humans. PCDD/F is detected in air, water, sediment, plants and animals. PCDD/F is generally distributed in the particulate phase in ambient air. For solid waste incineration plant emissions, the distribution of PCDD/F particles into particles with a diameter of <10 μm is more than 81% of the total particulate matter, and more than 54% of the PCDD/F is distributed into particles with a diameter of <2.5 μm. The aim of this study is to investigate the sources of PCDD/F, emissions and potential hazards, i.e., a toxic equivalent in Lithuania. The measurements were performed in two largest cities of Lithuania Vilnius and Kaunas, where the level of PCDD/F discovered was from 0.015 to 0.52 pg/m3 and from 0.02 to 0.05 pg/m3, respectively. The sites for the monitoring were selected based on their proximity to the locations of the planned cogeneration power plants in these cities.