Levels, time trends, and distribution of dioxins and polychlorinated biphenyls in fishes from the Baltic Sea

No evidence of an association between size and levels of four per- and polyfluorinated substances (PFAS) in perch (Perca fluviatilis)

It was assessed how the size of perch (Perca fluviatilis) is related to levels of four per- and polyfluorinated substances (PFAS) in its muscle tissue. These were PFOS, PFNA, PFOA, and PFHxS, for which the sum, denoted as ΣPFAS4, has a tolerable intake derived by the European Food Safety Authority. The results indicate that, in contrast to, e.g., mercury levels, ΣPFAS4 levels in perch muscle do not increase with increasing weight of the fish, which implies that consuming larger perch does not increase the risk of exceeding the TWI of ΣPFAS4, in relation to consuming smaller perch. Therefore, for risk assessment, analyzing samples of smaller perch is sufficient, demanding less effort to catch. The credibility of the results was strengthened by applying the same statistical model to mercury levels in the same samples. As expected, larger fish had generally higher levels than small fish for mercury.

Health benefits and health risks of contaminated fish consumption: Current research outputs, research approaches, and perspectives

Background

Fish contains high-quality omega-3 fatty acids, protein, vitamins, and minerals and due to this it is termed as an essential component of a balanced diet. But there have been concerns raised about the risks of consuming fish that is contaminated with toxins such as methylmercury, polychlorinated biphenyls (PCBs), dioxins, pesticides, and plastic waste. Consumption of contaminated fish containing these pollutants is raising global mortality and morbidity rates.

Scope and approaches

The review examines the current research outputs on the health benefits and potential health risks of fish consumption. The review also discusses various approaches to mitigating the health problems caused by fish consumption, highlights the roles of balancing the risks and benefits when consuming fish.

Key findings and conclusion

Different findings indicated that contaminants cause cancer, kidney failure, adverse neurological effect, cardiovascular diseases, and so on to vulnerable groups such as pregnant, child breast-feeding and children. In conclusion, there is a need to get more tangible evidence about the advantages and disadvantages of fish consumption to safeguard the wellbeing of the society.

Comprehensive characterization and prioritization of halogenated organic compounds in fish and their implications for exposure

Fish are an important pollution indicator for biomonitoring of halogenated organic compounds (HOCs) in aquatic environments, and HOCs in fish may pose health threats to consumers. This study performed nontarget and comprehensive analyses of HOCs in fish from an e-waste recycling zone by gas chromatography-high-resolution mass spectrometry, and further prioritized their human exposure risks. A total of 1652 formulas of HOCs were found in the fish, of which 1222, 117, and 313 were organochlorines, organobromines, and organochlorine-bromines, respectively. The total concentrations of HOCs were 15.4-18.7 μg/g (wet weight), and organobromines were the predominant (14.1-16.8 μg/g). Of the HOCs, 41 % were elucidated with tentative structures and divided into 13 groups. The estimated total daily exposures of HOCs via dietary consumption of the fish for local adult residents were 3082-3744 ng/kg bw/day. The total exposures were dominated by several groups of HOCs with the following contribution order: polyhalogenated biphenyls and their derivatives > polyhalogenated diphenyl ethers > halo- (H-)alkanes/olefines > H-benzenes > H-dioxins > H-polycyclic aromatic hydrocarbons > H-phenols. The comprehensive characterization and prioritization results provide an overview of the species and distributions of HOCs in edible fish, and propose an inventory of crucial HOCs associated with high exposure risks.

Occurrence and Formation Mechanism of PCDD/Fs and SCCPs in Chlorinated Paraffin Products

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and short-chain chlorinated paraffins (SCCPs) can be formed during the production of chlorinated paraffins (CPs). Detection and accurate quantification of PCDD/Fs in CPs are challenging because of their matrix complexity. Therefore, the occurrence and formation mechanisms of PCDD/Fs from CPs have not been studied extensively in the past. In this study, 15 commercial samples including solid and liquid CPs were collected in 2022 from China. The average ΣSCCP concentrations detected in the solid and liquid CPs were 158 and 137 mg/g, respectively. The average International Toxic Equivalent (I-TEQ) values of 2,3,7,8-PCDD/F in solid and liquid CPs were 15.8 pg I-TEQ/g and 15.0 pg I-TEQ/g, respectively. The solid and liquid CPs had different predominant congener groups for SCCPs and PCDD/Fs. Possible formation routes for the generation of PCDD/Fs were analyzed by screening precursors in paraffin and laboratory-scale thermochemical experiments of CPs. The transformation between 2,3,7,8-PCDD/Fs and non-2,3,7,8-PCDD/Fs was recognized by calculating the successive chlorination preference. The first reported occurrence of PCDD/Fs in CP commercial products indicated that exposure to CPs and downstream products might be an assignable source of PCDD/F emission, which is of great significance to further explore the control factors of PCDD/Fs in the whole life cycle of CPs.

Multi-level assessment of the origin, feeding area and organohalogen contamination on salmon from the Baltic Sea

The Atlantic salmon (Salmo salar) population in the Baltic Sea consists of wild and hatchery-reared fish that have been released into the sea to support salmon stocks. During feeding migration, salmon migrate to different parts of the Baltic Sea and are exposed to various biotic and abiotic stressors, such as organohalogen compounds (OHCs). The effects of salmon origin (wild or hatchery-reared), feeding area (Baltic Main Basin, Bothnian Sea, and Gulf of Finland), and OHC concentration on the differences in hepatic proteome of salmon were investigated. Multi-level analysis of the OHC concentration, transcriptome, proteome, and oxidative stress biomarkers measured from the same salmon individuals were performed to find the key variables (origin, feeding area, OHC concentrations, and oxidative stress) that best account for the differences in the transcriptome and proteome between the salmon groups. When comparing wild and hatchery-reared salmon, differences were found in xenobiotic and amino acid metabolism-related pathways. When comparing salmon from different feeding areas, the amino acid and carbohydrate metabolic pathways were notably different. Several proteins found in these pathways are correlated with the concentrations of polychlorinated biphenyls (PCBs). The multi-level analysis also revealed amino acid metabolic pathways in connection with PCBs and oxidative stress variables related to glutathione metabolism. Other pathways found in the multi-level analysis included genetic information processes related to ribosomes, signaling and cellular processes related to the cytoskeleton, and the immune system, which were connected mainly to the concentrations of Polychlorinated biphenyls and Dichlorodiphenyltrichloroethane and their metabolites. These results suggest that the hepatic proteome of salmon in the Baltic Sea, together with the transcriptome, is more affected by the OHC concentrations and oxidative stress of the feeding area than the origin of the salmon.

Concentration levels, spatial variations and exchanges of polychlorinated biphenyls (PCBs) in ambient air, surface water and sediment in Bursa, Türkiye

In this study, ambient air, surface water and sediment samples were simultaneously collected and analyzed for PCBs to investigate their levels, spatial variations and exchanges between these three compartments at different sampling sites for 12 months in Bursa, Türkiye. During the sampling period, a total of 41 PCB concentrations were determined in the ambient air, surface water (dissolved and particle phase) and sediment. Thus, 945.9 ± 491.6 pg/m³ (average ± STD), 53.8 ± 54.7 ng/L, 92.8 ± 59.3 ng/L and 71.4 ± 38.7 ng/g, respectively. The highest concentrations of PCBs in the ambient air and in water particulate phase were measured at the industrial/agricultural sampling site (1308.6 ± 252.1 pg/m³ and 168.7 ± 21.2 ng/L, respectively), ∼ 4-10 times higher than background sites; while the highest concentrations in the sediment and dissolved phase were measured at the urban/agricultural sampling sites (163.8 ± 27.0 ng/L and 145.7 ± 15.3 ng/g, respectively), ∼ 5-20 times higher than background sites. PCB transitions between ambient air-surface water (f_A/f_W) and surface water-sediment (f_W/f_S) were investigated by fugacity ratio calculations. According to the fugacity ratios obtained, volatilization from the surface water to the ambient air was observed at all sampling sites (98.7 % of f_A/f_W ratios are <1.0). Additionally, it has been determined that there is a transport from the surface water to the sediment (100.0 % of f_W/f_S ratios are higher than 1.0). The flux values in ambient air-surface water and surface water-sediment environments ranged from -1.2 to 1770.6 pg/m²-day and from -225.9 to 0.001 pg/m²-day, respectively. The highest flux values were measured for PCBs with low chlorine content (Mono-, Di-Cl PCBs), while the lowest flux values were measured for the high chlorine content PCBs (Octa-, Nona- and Deca-Cl PCBs). As it was determined in this study that surface waters contaminated by PCBs have the potential to pollute both air and sediments, it will be important to take measures to protect surface waters.

Organochlorine residues in muscle of European eels (Anguilla anguilla) from four Spanish Mediterranean wetlands and coastal lagoons

European eels (Anguilla anguilla) are an endangered species throughout their range, and chlorine organic compounds are some of the most important pollutants for marine species. Data on contaminants in eel stocks remain incomplete, so organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in muscle of European eels from four Spanish Mediterranean ecosystems were analyzed. COPs are presents in eels from all areas, but some compounds are not detected: HCH α, β and γ (lindane), endosulfan sulfate, heptachlor, and PCBs 28, 52 and 180. The high percentage of DDT 2,4' in eels from S'Albufera des Grau Natural Park, an ecosystem with good ecological status according to the Water Framework Directive, and the presence of PCBs in S'Albufereta Natural Reserve indicate the need to carry out further studies in the future. The results obtained can improve the management of this species in the studied areas.