Polybrominated dibenzo-p-dioxins and furans (PBDD/Fs) in Italian food: Occurrence and dietary exposure

Association between dietary intake estimated levels of PCDD/Fs and human sperm quality

This study aimed to investigate the association between estimated dietary intake of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) and human sperm quality. This study cross-sectionally assessed the associations between estimated dietary intake of PCDD/Fs and sperm quality parameters in 200 participants aged 18-40 years from the Led-Fertyl study. Linear regression models, accounting for potential confounding variables, were employed to evaluate the relationships. To estimate the PCDD/Fs exposure, food frequency questionnaires and the latest data on PCDD/Fs concentrations in food, primarily from Spanish sources, were used. Our findings indicate that, in comparison to participants in the lowest tertile, those in the highest tertile (T3) of PCDD/Fs dietary intake exhibited significantly elevated body mass index, increased consumption of meat, fish and eggs, and decreased consumption of nuts. Furthermore, individuals in T3 demonstrated a higher percentage of sperm head abnormalities (4.65 % [0.10; 9.24]; p-trend= 0.037) and a corresponding increase per 1-SD increment in energy-adjusted total PCDD/Fs dietary intake (1.84 % [0.38; 3.68]). No significant associations for other sperm parameters were found. Minimal research exists on PCDD/F dietary exposure and human sperm quality. This study shows significant direct association between higher PCDD/Fs intake and the percentage of sperm head abnormalities which potentially may compromise human reproductive health.

Health risks and sources of PCDD/Fs and PCBs residue in cultured crabs

The Chinese mitten crab (Eriocheir sinensis) holds significant importance as a popular aquaculture food source; however, there are concerns about its potential contamination with polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) from both food and aquatic environment. To assess the associated health risks and identify potential sources of contamination in crabs, a comprehensive investigation was conducted, including a total of 70 samples from the crab food web. The results demonstrated that crabs predominantly exhibited elevated concentrations of PCBs and dl-PCBs, with mean concentrations of 12 207 ± 11 962 pg g-1 and 554 ± 203 pg g-1, respectively, while PCDD/Fs concentrations were comparatively lower at 20 ± 17 pg g-1. The accumulation of PCBs in crabs significantly surpassed that of PCDD/Fs. The material balance of PCDD/Fs and PCBs in the crab food web was estimated, indicating that sediments and feeds likely constitute the two primary sources of PCDD/Fs and PCBs in crabs. The monthly intake of PCDD/Fs and PCBs through crab consumption accounted for 30% of the dietary intake, which was well below the provisional tolerable monthly intake (PTMI) limit. The weekly intake of PCDD/Fs and PCBs for adults consuming one crab (100 g) does not pose health risks and the recommended weekly intake of white crabmeat and brown crabmeat is 443 g and 21 g, respectively.

Origin, dietary exposure, and toxicity of endocrine-disrupting food chemical contaminants: A comprehensive review

Endocrine-disrupting chemicals (EDCs) are a growing public health concern worldwide. Consumption of foodstuffs is currently thought to be one of the principal exposure routes to EDCs. However, alternative ways of human exposure are through inhalation of chemicals and dermal contact. These compounds in food products such as canned food, bottled water, dairy products, fish, meat, egg, and vegetables are a ubiquitous concern to the general population. Therefore, understanding EDCs' properties, such as origin, exposure, toxicological impact, and legal aspects are vital to control their release to the environment and food. The present paper provides an overview of the EDCs and their possible disrupting impact on the endocrine system and other organs.

Unintentional formation of mixed chloro-bromo diphenyl ethers (PBCDEs), dibenzo-p-dioxins and dibenzofurans (PBCDD/Fs) from pyrolysis of polybrominated diphenyl ethers (PBDEs)

This study presents the comprehensive investigation for formation pathways of chloro-bromo-mixed products from the pyrolysis of polybrominated diphenyl ethers (PBDEs). In the study, a total of 23 PBDEs with bromination levels from mono-to deca-were selected. Each PBDE standard was sealed in the glass vial and then heated under 450 °C in the muffle furnace to simulate the pyrolysis process. The results demonstrated that PBDEs in the glass vials can unintentionally transform into chloro-bromo diphenyl ethers (PBCDEs) and dibenzo-p-dioxin and dibenzofurans (PBCDD/Fs) during the pyrolysis process. Atmosphere pressure gas chromatography (APGC) coupled with high-resolution mass spectrometry (HRMS) was used to identify these pyrolysis products, which demonstrated that all investigated nPBDEs (n represents the number of bromine substituents) can unintentionally transform into Cl₁-(n-1)BDEs, Cl₂-(n-2)BDEs, Cl₁-(n-1)BDFs, and Cl₁-(n-3)BDDs, while some nPBDEs can transform into Cl₁-(n-2)PBDD/Fs during pyrolysis. Experimental phenomena assisted with density functional theory (DFT) calculations reveal that Cl atom can substitute at C-Br rather than C-H, and Cl₁-(n-1)BDEs can be easily generated by Cl atom attacking at C-Br sites with low energy barriers (3.66-11.9 kcal/mol). In addition, nPBDEs with lower bromination levels are more favorable to generate Cl₁-(n-1)BDEs than those with higher bromination levels. Further DFT calculations suggest that PBDEs are preferentially first transformed into Cl₁-(n-1)BDEs, then subsequentially transform into PBCDD/Fs. We believe the results of this study can greatly improve our understanding of the transformation mechanism from PBDEs to cholo-bromo-mixed products in thermal treatment processes and provide new insight into controlling the emission of toxic cholo-bromo-mixed products.

Chlorinated Persistent Organic Pollutants (PCDD/Fs and PCBs) in Loggerhead Sea Turtles Stranded along the Central Adriatic Coast

Persistent organic pollutants are widespread in the marine environment. They can bioaccumulate and biomagnify in marine organisms through the food web with a potentially toxic effect on living organisms. The sea turtle Caretta caretta is a carnivorous animal with opportunistic feeding behavior. These turtles tend to bioaccumulate pollutants through food, and hence they can be considered an indicator of chemical pollutants in the marine ecosystem. In this study, 44 loggerhead sea turtles were considered, and liver and fat tissue were sampled from each of them to investigate the levels of dioxins (PCDD/Fs) and polychlorinated biphenyls (PCBs) in sea turtles and their potential correlation with sex and size in terms of curved carapace length (CCL). Results suggested that these contaminants were easily bioaccumulated, and PCBs were predominant compared to dioxins in both liver and fat tissue. The congener patterns were similar to those found in sea fish. Moreover, there were no differences in the contamination levels between females and males, nor was there a correlation with the size. There is a need to harmonize the methodological approaches to better evaluate the results and trends over time and to monitor the species and indirectly the health status of the marine environment.

Application of a ready-to-use cell sensor for dioxins and dioxin-like compounds screening in foodstuffs

Dioxins and dioxin-like compounds (DLCs) in foodstuffs are closely related to human health. As China is the largest food-consuming country, there is a potentially large demand for screening bioassays that are rapid, cost-effective and capable of determining dioxins and DLCs in foodstuffs. CBG2.8D is a reporter gene-based recombinant cell sensor that was recently developed for determining dioxin and DLCs in ambient and seafood samples. In this study, we established a bioanalytical method with this ready-to-use cell sensor for the bioanalysis of dioxins and DLCs in different types of meat samples. Twenty-nine samples from three typical types of meat (beef, pork and fish) were collected and subjected to both instrumental analysis and a CBG2.8D bioassay. The intra- and inter-lab reproducibility of the bioassay was investigated and the coefficients of variation (CVs) were lower than 25%, suggesting that the cell sensor had a good reproducibility for the meat samples. Based on the correlation equation and coefficient obtained by comparing the data from the instrumental analysis and CBG2.8D bioassay, we found that this method had better performance with pork and fish than with beef. The compliance rate was also determined by comparing the results from the instrumental analysis and there were no false results for the pork and fish samples. Lastly, a complete operation procedure was summarized as a guideline for practical application. In conclusion, the CBG2.8D cell sensor exhibits excellent stability and is capable of screening dioxins and DLCs in meat samples.

Occurrence and formation pathways analysis of PBDD/Fs from 2,4,6-tribromophenol under thermal reaction conditions

Polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) are highly toxic and persistent compounds that provoke a wave of publicity. Bromophenols are important precursors for forming PBDD/Fs, and their reaction path has always been a research hotspot. In this study, the formation characteristic of PBDD/Fs from 2,4,6-TBP were studied. The yields of 2,3,7,8-substituted PBDD/Fs and 2,4,6,8-TBDF for the different thermal products ranged from 0.067 to 10.3 ng/g and 0.207-9.68 ng/g, respectively. The effects of adding Cu, Fe, and Sb₂O₃ were investigated and found to be more inclined to accelerate the formation of ortho-substituted PBDD/Fs than 2,3,7,8-PBDD/Fs. The formation pathways of 2,3,7,8-substituted PBDD/Fs and 2,4,6,8-TBDF were also proposed. 2,4,6,8-TBDF is generated in the C-C coupling reactions of some radical intermediates from the debromination of 2,4,6-TBP. The 2,3,7,8-PBDD/Fs are produced through more complex debromination, bromine substitution, and bromine rearrangement reactions. In addition, various catalytic effects on PBDD/F formation pathways were found, and the catalytic effect of Cu by the Ullmann reaction was the highest, while bromophenol oxidation by Fe was the highest. These results proved that both 2,3,7,8-substituted and non-2,3,7,8-substituted PBDD/Fs would be generated from 2,4,6-TBP, and the effects of the catalyst on the Br substituted position of 2,3,7,8-substituted PBDD/Fs were much lower than the Br-substituted position on bromophenol.

Brominated and chlorinated contaminants in food (PCDD/Fs, PCBs, PBDD/Fs PBDEs): Simultaneous determination and occurrence in Italian produce

Validated methodology for the simultaneous determination of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) and polybrominated diphenyl ethers (PBDEs) in foods of animal origin is presented. Method performance indicators were equivalent or better than those required for the control of EU regulated (EU, 2017/644) PCDD/F and PCB congeners in these foods, and for risk assessment through dietary intake. The method uses a high (>90%) proportion of ¹³Carbon-labelled surrogates for internal standardisation combined with high resolution mass spectrometry that allow accurate quantitation, and this was confirmed by multiple successful participations in proficiency testing for PCDD/Fs, PCBs and PBDEs in food. The same validation and method performance requirements as used for PCDD/Fs were followed for PBDD/Fs. The analysis of a range of food samples (eggs, milk, fish, shellfish, pork, beef and poultry), showed the occurrence of all four classes of contaminants at varying concentration ranges. In general, PCBs were the most prominent contaminant, both, in terms of dioxin-like toxicity, as well as in the occurrence of non-dioxin-like congeners, an observation that concurs with those made in other studies on Italian foods. The levels of PCDD/F and PCB occurrence are consistent with a gradual decline in contamination as reported by some other similar studies. Although all the determined contaminants were detected in the sampled foods, there was poor correlation between the occurrences of the brominated and chlorinated contaminants, and between PBDEs and PBDD/Fs, but better associations were observed between the occurrences of the chlorinated contaminants.

Polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) in soil around municipal solid waste incinerator: A comparison with polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs)

Polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) share similar toxicities and thermal origins, e.g., municipal solid waste incinerator (MSWI). Recently, PBDD/Fs from MSWI attracted rising concern because their important precursors, i.e., brominated flame retardants (BFRs), were frequently found in various wastes for landfill or MSWI feedstock. So far, however, little is known about PBDD/Fs and their associated risks in the vicinal environments of MSWI. Here we analyzed PBDD/Fs and PCDD/Fs in 29 soil samples collected around a multiyear large-scale MSWI, and compared their spatial distributions, sources and risks. PBDD/Fs demonstrated comparable concentrations and toxic equivalent quantities (TEQs) to PCDD/Fs in these samples. Spatially, both the concentrations of PBDD/Fs and PCDD/Fs decreased outwards from the MSWI, and exhibited significant linear correlations with the distances from the MSWI in the southeast downwind soil, suggesting the influence of the MSWI on its vicinal soil environment. However, the existence of other dioxin sources concealed its influence beyond 6 km. PBDD/Fs in the soils were characterized by highly-brominated PBDFs, especially Octa-BDF, and their sources were diagnosed as the MSWI and diesel exhaust; PCDD/Fs, however, were dominated by highly-chlorinated PCDDs, particularly Octa-CDD, and were contributed individually or jointly by the MSWI, automobile exhaust and pentachlorophenol (PCP)/Na-PCP. The non-carcinogenic risks of dioxins in all the soil samples were acceptable, but their carcinogenic risks in 17% of the samples were unacceptable. These samples were all located close to the MSWI and highways, therefore, the land use of these two high-risk zones should be cautiously planed.

Profiles, spatial distributions and inventory of brominated dioxin and furan emissions from secondary nonferrous smelting industries in China

Nonferrous metallurgical processes are important sources of carcinogenic polybrominated dibenzo-p-dioxin and dibenzofuran (PBDD/Fs) that transport globally. Studies on the profiles, spatial distributions and inventory of PBDD/F emissions into the atmosphere from nonferrous metallurgical plants are needed for better source control. In this study, field investigations on PBDD/F emissions from typical nonferrous metallurgical plants were conducted to characterize the PBDD/F profiles and derive their emission factors. Based on the PBDD/F profiles, diagnostic ratios of PBDD/Fs for secondary copper, zinc and lead smelting were proposed for identifying the potential sources of PBDD/Fs in environment. The PBDD/F emission factors for the secondary copper, lead, and zinc smelting plants were 0.71, 1.65, and 1.54 μg toxic equivalents/t, respectively. The estimated annual input of PBDD/Fs into atmosphere by secondary nonferrous metallurgical plants in China was 212.4 g by mass and 3511.3 mg by toxic equivalents, which is of significance for further evolving a global inventory. The spatial distribution of PBDD/F emissions from nonferrous metallurgical plants in China was mapped. Larger amounts of PBDD/Fs were emitted in the southeastern coastal region and northern China than elsewhere in China.

Occurrence, Human Exposure, and Risk Assessment of Polybrominated Dibenzo-p-Dioxins and Dibenzofurans, Polychlorinated Naphthalenes, and Metals in Atmosphere Around Industrial Parks in Jiangsu, China

Air samples were collected around industrial parks in Jiangsu, China, to allow the concentrations, profiles, and risk assessment of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), polychlorinated naphthalenes (PCNs), and metals to be investigated. The concentrations of ΣPBDD/Fs and ΣPCNs were 1324.26-2080.98 fg/m³ (11.35-42.57 fg I-TEQ/m³) and 10,404.9-29,322.9 fg/m³ (1.32-7.19 fg I-TEQ/ m³), respectively. The highest concentration of ΣPBDD/Fs and ΣPCNs were observed at site C. PBDD/Fs were mainly dominated by PBDFs. The main contributor to the ΣPBDD/Fs in all samples was 1,2,3,4,6,7,8-HpBDF, which accounted for 25.75%-39.4%. For PCNs, the predominating homologues were tetra-, tri- and penta-CNs, which contributed 30.7%-43.3%, 24.7%-31.0%, and 10.6%-21.6%, respectively. As for metals, the pollution of As, Mn, Cr, and Ni in most samples exceeded National Ambient Air Quality Standards of China. Assessing the risk of inhalation exposure showed that there were potential carcinogenic risks to local residents.

Polybrominated dibenzo-p-dioxins and furans (PBDD/Fs): Contamination in food, humans and dietary exposure

Polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) have been recognised as environmental pollutants for decades but their occurrence in food has only recently been reported. They elicit the same type of toxic response as analogous polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) with similar potencies and effects, and share similar origins - inadvertent production during combustion and occurrence as by-products in industrial chemicals. Surprisingly, PBDD/Fs have received considerably less attention than PCDD/Fs, perhaps because determination requires a higher degree of analytical competence, a result of the higher adsorptivity and lability associated with carbon-bromine bonding. For most populations, the principal exposure pathway is dietary intake. The PBDD/F toxicity arising from occurrence in foods has often been expressed as toxic equivalents (TEQs) using the same scheme developed for PCDD/Fs. This approach is convenient, but resulting TEQ estimates are more uncertain, given the known differences in response for some analogous congeners and also the different patterns of PBDD/F occurrence confirmed by the newer data. Further studies to consolidate potency factors would help to refine TEQ estimates. Characteristically, most foods and human tissues show more frequent and higher PBDF concentrations relative to PBDDs, reflecting major source patterns. Occurrence in food ranges from <0.01 to several thousand pg/g (or up to 0.3 pg TEQ/g whole weight) which is comparable to PCDD/F occurrence (ΣPBDD/F TEQs are underestimated as not all relevant congeners are included). Plant based foods show higher PBDD/F: PCDD/F TEQ ratios. Reported PBDD/F dietary intakes suggest that some population groups, particularly young children, may exceed the revised tolerable weekly intake for dioxin-like contaminants (2 pg TEQ/kg bw/week), even for mean consumption estimated with lower bound data. It is evident that the omission of PBDD/Fs from the TEQ scheme results in a significant underestimation of the cumulative toxicity and associated risk arising from this mode of action.