Polychlorinated Dibenzo-p-dioxins And Dibenzofurans Research Articles

Phase distribution, migration and relationship of polychlorinated dibenzo-p-dioxins and dibenzofurans and heavy metals in a large-scale hazardous waste incinerator

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) and heavy metals emitted from hazardous waste incinerators have aroused public concern due to the risks to the environment and human health. In the study, phase distribution, migration, and relationship of PCDD/F and heavy metals (arsenic, cadmium, chromium, copper, mercury, nickel, plumbum, zinc) are investigated in a typical hazardous waste incinerator. The PCDD/F mass concentrations and toxic equivalent quantity are reduced to 3.26 ng/Nm3 and 0.0484 ng/Nm3 by air control pollution devices, with 93.1% remove efficiency. High sulfur content in hazardous waste results in low PCDD/F and heavy metals emissions. Moreover, migration analysis of PCDD/F mass concentrations indicates that vast PCDD/F migrates to the mixtures with sodium bicarbonate and activated carbon (52.4%), followed by fly ash (21.8%), sodium hydroxide solution (19.3%), and atmosphere (6.49%). Furthermore, TCDF isomers (37%) dominate among the PCDD/F congeners, while 1,2,3,4,6,7,8-HpCDF (20%) dominates among 2,3,7,8-substituted congeners. Deduced by the ratio of PCDF/PCDD, the dominant mechanism of PCDD/F is de novo synthesis and chlorobenzene route synthesis. Based on the relative enrichment index, heavy metals are classified into three types: volatile heavy metals (plumbum, zinc, cadmium, mercury), medium volatile heavy metals (copper, chromium, arsenic), involatile heavy metals (nickel). Additionally, copper is inclined to deposit into the bottom slag as CuSO4 rather than the volatile substance due to high levels of sulfur dioxide (3000 parts per million). The migration behavior of heavy metals is dependent on the volatility properties of these metals. Statistically, PCDD/F emissions have the highest correlation coefficient with plumbum (r = 0.815), followed by nickel (r = −0.798). Besides, the PCDD/F formation is promoted by the volatile heavy metal, prevented by medium volatile heavy metals. The study not only provides a comprehensive understanding of PCDD/F and heavy metals characteristics but also effective and feasible strategies to reduce the toxic pollutants emissions in large-scale hazardous waste incinerators.

Dechlorination performance in chemical looping conversion of polyvinyl chloride plastic waste using K/Na/Ca-modified iron ore oxygen carriers

The reducing atmosphere of chemical looping conversion (CL) can greatly limit the emission of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) during the heat treatment of polyvinyl chloride plastics waste (PPW). Loading alkali metals and alkaline earth metals (AAEM) on iron ore OC can remove chlorine in situ, reduce HCl corrosion, and further reduce the emission of other harmful chlorine pollutants. In this work, iron ore OC was modified by K, Na, and Ca. The three modified OCs showed good dechlorination and catalytic gasification performances, while the pristine iron ore OC only exhibited weak dechlorination effects. The dechlorination activity of the three OCs was found to decrease in the order K- > Na- > Ca-modified OC. Decreasing the reaction temperature in the range of 750–900 °C and increasing the dechlorination agent loading improved the dechlorination efficiency. The AAEM conversion of K- and Na-modified OCs could reach or approach 100%, while that of Ca-modified OC reached only about 30%. Scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS) and X-ray diffraction (XRD) results showed that the corresponding alkali and alkaline earth metal chlorides were formed on the surface of the OCs during the CL processes.

Characteristics, correlations and health risks of PCDD/Fs and heavy metals in surface soil near municipal solid waste incineration plants in Southwest China

As primary anthropogenic emission source of toxic pollutants such as heavy metals and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), municipal solid waste (MSW) incineration has caused worldwide concern. However, a comprehensive analysis of the pollution characteristics and health risks of PCDD/Fs and heavy metals in soils around MSW incineration plants is lacking. In this study, 17 PCDD/Fs and 11 heavy metals in soil samples collected near MSW incineration plants in Sichuan province were investigated to evaluate their pollution characteristics and potential health risk. Sichuan was selected as the study area because the MSW incineration amount in this province ranks first among all inland provinces in China. The PCDD/Fs concentrations ranged from 0.30 to 7.50 ng I-TEQ/kg, which were significantly below risk screening and intervention thresholds. Regarding heavy metals, principal component analysis suggested that Hg, Pb and Zn were the primary metals emitted from the MSW incineration plants. Cluster analysis of PCDD/Fs and heavy metals showed that of PCDD/Fs homologs and heavy metals (e.g., Hg, Pb, Zn and Cd) were clustered into one group, indicating the coexistence and coaccumulation of heavy metals (especially Hg, Pb, Zn, and Cd) and PCDD/Fs in soil. These heavy metals are thus candidate tracers for PCDD/Fs in soil near MSW incineration plants. A health risk analysis found that the carcinogenic and non-carcinogenic risks of PCDD/Fs and heavy metals (except for Ni) in the soil samples were all within acceptable levels. This study provides new insights into correlations and health risks of PCDD/Fs and heavy metals in surface soil near MSW incineration plants. The findings have implications for future studies of environmental and human health risk analysis related to waste incineration.

Accumulation characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls in human breast milk from a seaside city of North China

Breast milk samples were collected from 51 mothers in a seaside city Dalian, where the residents usually have higher dietary exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) due to the larger consumption of seafood. The lipid-basis concentrations of ∑Cl2–8DD/Fs, ∑Cl2–10Bs, and total toxicity equivalent (WHO-TEQ) were measured to be in the ranges of 35.7–2727.8 pg/g, 4.91–52.64 ng/g, and 2.27–36.30 pg/g, respectively. The average proportion of ∑Cl2–3DD/Fs was higher than that of ∑Cl4–7DD/Fs in the collected human breast milk samples, suggesting that the health risk of Cl2–3DD/Fs should be especially concerned. The concentration data of PCDD/Fs and PCBs in human breast milk essentially followed a positive skew probability distribution. Women in high-level exposure scenarios exhibited a higher potential to accumulate homologues Cl4DFs, Cl7DFs, Cl8DF, and Cl6Bs in breast milk. Three PCDD/F congeners (1,2,3,6,7,8-Cl6DF, 1,2,3,4,7,8-Cl6DF, and 1,2,3,4,6,7,8-Cl7DD) and three PCB congeners (PCB 126, PCB 138, and PCB 169) were identified as good indicators for the accumulation of PCDD/Fs and PCBs in human breast milk, respectively. The food-to-milk accumulation factors (FMAF) were calculated to evaluate the accumulation potentials of different PCDD/F and PCB congeners in human breast milk via dietary exposure. The calculated FMAF value presented a non-monotonic variation with the logarithm of n-octanol–water partition coefficient (log KOW) with a peak at a log KOW value of about 7.3 and a valley at a log KOW value of about 8. The mean value of the estimated daily intake (EDI) of total WHO-TEQ for breast-fed infants in Dalian, predicted by Monte Carlo simulation, was 10 folds higher than the upper range of the tolerable daily intake (TDI) value (4 pg WHO-TEQ/kg bw/d), suggesting continued and enhanced efforts should be made to reduce the exposure risk of infants to PCDD/Fs and PCBs.

Influence of Different Catalytic Metals on the Formation of PCDD/Fs during Co-combustion of Sewage Sludge and Coal

Co-combustion of sewage sludge (SS) and coal was developed rapidly in China, however, less attention was paid to the formation characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and the influence factors, such as the catalytic metals (CuCl2, FeCl3, ZnCl2, CuO, Fe2O3, and ZnO), sources of carbon and chlorine. During the co-combustion of SS (2.5 wt.%) and coal (97.5 wt.%), the formation content of PCDD/Fs was 0.51 ng g-1 and 0.01 ng I-TEQ g-1. By adding metal chlorides (2.0 wt.% CuCl2, FeCl3, and ZnCl2), the formation contents of PCDD/Fs were increased significantly to 148.99, 67.38, and 53.63 ng g-1 (i.e., 2.10, 1.09, and 1.34 ng I-TEQ g-1), respectively, while the metal oxides (2.0 wt.% CuO, Fe2O3, and ZnO) only increased the PCDD/F contents to 1.27, 0.76, and 0.57 ng g-1 (0.03, 0.01, and 0.02 ng I-TEQ g-1), respectively. That is, the promotion effect of different metal additives on PCDD/F formation followed a sequence of CuCl2 (292×)＞FeCl3 (132×)＞ZnCl2 (105×) CuO (2.5×)＞Fe2O3 (1.5×)＞ZnO (1.1×), wherein the metal chlorides showed 2 orders of magnitude higher promotion than that of metal oxides. The proportion of highly chlorinated PCDD/Fs was further increased after adding metal chlorides, while the additional metal oxides decreased it. The de novo synthesis was revealed as the major formation pathway of PCDD/Fs except for adding ZnO. The CuCl2 and FeCl3 can also enhance the chlorination routes to generate PCDD/Fs. Only ZnO showed the promotion effect on the CP-route. The chlorine source was an essential limiting factor for generating PCDD/Fs, and the chlorine from metal chlorides was the preference source compared with that contained in SS and coal. The results have important reference value for controlling PCDD/Fs formation in the co-combustion process of SS and coal.

Kaolinitic clays as a potential source of dioxins in the Noosa River catchment, Queensland, Australia

Environmental context Dioxins have been found along the east coast of Australia in agricultural areas where there is no obvious source of dioxins. These dioxins have an unusual signature that does not match common industrial sources, but it has been suggested that they may be associated with pesticide use. This study found a strong correlation between dioxins with this unique signature and the amount of a kaolinitic clay in the sediments sampled. Abstract The presence, concentrations and profiles of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in sediment were investigated in this study with the aim of determining whether dioxin-like compounds were present and, if found, a likely source could be deduced. The sampled catchment lies within an area of high conservation value. Sediments from seven lake sites were sampled as possible sinks for any contamination from historical pesticide use. PCDD/Fs were measured in all the lake sediments. The 2,3,7,8-substituted congener profile was dominated by octachlorodibenzo-p-dioxin (OCDD) with furans at or below the limit of detection, a profile that has been associated with kaolinitic clays from around the world. A strong and significant correlation was found between the total dioxin concentration and the percentage of kaolinitic clay in the sediments. The lack of furans in the 2,3,7,8-substituted PCDD/F profile indicates pesticides or pentachlorophenol (PCP) are unlikely to be the source in the catchment. Further, the concentration of total dioxins and OCDD tended to be higher than those measured outside the study area, even though, overall, the study area is likely to have had less pesticide use than the other intensive agricultural areas previously studied. The results presented in this paper indicate that caution should taken when attributing the presence of dioxins in soil and sediment to anthropogenic sources.

Heat Production in Considering Boilers and their Influence on CO and NOx Emission Values

At present, there is a tendency to make greater use of hot water heat sources for the combustion of solid fuels, such as lump wood, coal, coke, instead of heat sources for the combustion of natural gas. This tendency is due to the high price of natural gas as well as the availability of cheaper solid fuel. In many cases, as part of saving on heating costs, respectively. as part of waste disposal, municipal waste of various compositions is also co-incinerated with solid fuel. This co-incineration entails increased emissions, such as CO (carbon monoxide), NOx (nitrogen oxides), TZL (particulate matter), PM10, HCl (hydrogen chloride), PCDD/Fs (polychlorinated dibenzodioxins and dibenzofurans), PCBs (polychlorinated biphenyls) and others which, with a relatively large number of heat sources for the combustion of solid fuel in municipalities, have a significant impact on the quality of the environment in the locality. Between the population and representatives of the state administration as in Žilina, Thus, the Moravian-Silesian Region also lacks awareness of how the environment is degraded due to the co-incineration of solid fuel and municipal waste. At present, there is no qualitative comparison of the effect of combustion of solid fuel and municipal fuel waste to the emission burden on the environment. There are no real measured emission factors for determining the production of the above emissions from the co-incineration of solid fuels and a certain amount of municipal waste. The combustion of fossil fuels and the consequent occurrence of harmful emissions on the environment are therefore becoming a central theme of current heating technology.

Body Burden and Influence Factors of Polychlorinated Dibenzodioxins and Dibenzofurans (PCDD/Fs) in Male Workers from a Municipal Waste Incineration Plant in China

Body Burden and Influence Factors of Polychlorinated Dibenzodioxins and Dibenzofurans (PCDD/Fs) in Male Workers from a Municipal Waste Incineration Plant in China

Dietary exposure and potential human health risk of dioxins in South Korea: Application of deterministic and probabilistic methods

Following the reduction of incinerator emission, enacted by the Korean Government in 2001, the levels of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in the air (−96%) have significantly decreased. However, their levels in the human serum of the general Korean population have not reduced at the same rate (−36%), indicating that humans may also be unintentionally exposed to these compounds, primarily through food ingestion. In this study, the risk of dietary exposure was assessed on a large scale, to provide toxicological information and guide the development of food safety policies. The food consumption data of the extreme (95th percentile) group and various subgroups (by age, pregnancy, and lactation), as well as the average group, were utilized. Compared to the tolerable daily intake (TDI) established by the World Health Organization (WHO), the average daily dietary exposure of the general Korean population, calculated using a deterministic method, was 11.9% of the WHO TDI (4 pg-TEQWHO05 kg body weight−1 d−1). For additional comparison, a probabilistic method using a Monte Carlo simulation was applied to the same data. Finally, the associated potential health risk was quantitatively characterized, and the results suggest the importance of non-dioxin-like congeners in future risk assessments.

Polychlorinated dibenzo-p-dioxins and dibenzofurans in lotus from a lake historically polluted by the chlor-alkali industry: Occurrence, organ distribution and health risk from dietary intake

In this study, the organ distribution and exposure risk from dietary intake of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were investigated for lotus collected from Ya-er Lake, a lake in Hubei Province, Central China that was historically polluted by the chlor-alkali industry. The highest concentrations of PCDD/Fs were found in the main and fibrous lotus roots, with mean values of 48.9 ± 90.1 pg/g and 94.6 ± 143 pg/g, respectively. In all the investigated samples, Octa-CDD (OCDD) and Octa-CDF (OCDF) were the predominant congeners, at 26% and 17% of Σ17 PCDD/Fs, respectively, followed by 1,2,3,4,6,7,8-HpCDF (9%). The distribution ratios of PCDD/Fs in adjacent lotus organs indicated that PCDD/Fs accumulated easily in edible organs, such as lotus seeds, membrane and leaves. The WHO-TEQ in the edible lotus organs and the probable daily intake (PDI) of lotus products by residents were calculated: the toxic equivalents in the lotus fruit parts reached a mean of 2 pg WHO-TEQ2005/g dw, and the mean weekly intake of lotus products for adolescents living around Ya-er Lake was 2.3 pg WHO-TEQ/kg bw/week. These results suggested that long-term consumption of lotus products from Ya-er Lake presents a health hazard to residents.

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.

Emission characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans from industrial combustion of biomass fuels

Although biomass fuel has always been regarded as a source of sustainable energy, it potentially emits polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). This study investigated PCDD/F emissions from industrial boilers fired with three types of biomass fuel (i.e., bagasse, coffee residue, and biomass pellets) via stack sampling and laboratory analysis. The measured mass concentrations of PCDD/Fs varied among the boilers from 0.0491 to 12.7 ng Nm−3 (11% O2), with the calculated average international toxic equivalent quantity (I-TEQ) from 0.00195 to 1.71 ng I-TEQ Nm−3 (11% O2). Some of them were beyond the limit value for municipal waste incineration. 2,3,4,7,8-PeCDF could be used as a good indicator of dioxin-induced toxicity of stack flue gases from biomass-fired boilers. The PCDFs/PCDDs ratios were more than 1, likely indicating the formation of dioxins in the boilers favored by de novo synthesis. The emission factor (EF) of total PCDD/Fs averaged 5.35 ng I-TEQ kg−1 air-dry biomass (equivalent to 39.0 ng kg−1 air-dry biomass). Specifically, the mean EF was 6.94 ng I-TEQ kg−1 (52.6 ng kg−1) for biomass-pellet-fired boiler, 11.8 ng I-TEQ kg−1 (74.6 ng kg−1) for coffee-residue -fired boiler, and 0.0277 ng I-TEQ kg−1 (0.489 ng kg−1) for bagasse-fired boilers. The annual PCDD/F emission was estimated to be 208 g I-TEQ in 2020 in China, accounting for approximately 2% of the total national annual emission of PCDD/Fs. The results can be used to develop PCDD/Fs emission inventories and offer valuable insights to authorities regarding utilizing biomass in industry in the future.

Prenatal exposure to endocrine disrupting chemicals is associated with altered DNA methylation in cord blood

ABSTRACT Prenatal exposure to endocrine disrupting chemicals can interfere with development, and has been associated with social-cognitive functioning and adverse health outcomes later in life. Exposure-associated changes of DNA methylation (DNAm) patterns have been suggested as a possible mediator of this relationship. This study investigated whether prenatal low-dose exposure to polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) is associated with altered DNAm patterns across the genome in a Western urban-industrial population. In 142 mother-infant pairs from the Duisburg Birth Cohort Study, PCBs and PCDD/Fs levels were quantified from maternal blood during late pregnancy and associated with DNAm levels in cord blood using the Illumina EPIC beadchip. The epigenome-wide association studies (EWAS) identified 32 significantly differentially methylated positions (DMPs) and eight differentially methylated regions (DMRs) associated with six congeners of PCB and PCDD in females or males (FDRs < 0.05). DMPs and DMRs mapped to genes involved in neurodevelopment, gene regulation, and immune functioning. Weighted gene correlation network analysis (WGCNA) showed 31 co-methylated modules (FDRs < 0.05) associated with one congener of PCDF levels in females. Results of both analytical strategies indicate that prenatal exposure to PCBs and PCDD/Fs is associated with altered DNAm of genes involved in neurodevelopment, gene expression and immune functioning. DNAm and gene expression levels of several of these genes were previously associated with EDC exposure in rodent models. Follow-up studies will clarify whether these epigenetic changes might contribute to the origin for adverse mental and health outcomes.

Ultra-low PCDD/F emissions and their particle size and mass distribution in a hazardous waste treatment system

An integrated gasification-flameless combustion-melting process was approached by a twin-cyclonic flow in a hazardous waste thermal treatment plant. A series of advanced scrubber, cyclonic demister, activated carbon adsorption, and baghouse processes were equipped for the end-of-pipe treatment. The untreated filterable particulate matter, CO, and NOx levels were only 283, 47.1, and 15.9 mg/Nm3, indicating the flameless combustion inhibited their formation by narrowing the post-combustion zone. The filterable particle mass-size distribution was equally contributed by nucleation, accumulation, and coarse formations, while their number concentration was predominated by nucleation (99.6%). That could enhance the adsorption of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) on ultrafine particles. Both total mass and toxic equivalent concentrations of PCDD/Fs were reduced 99.9% by the new air pollution control system when a slight reformation occurred during scrubbing. However, the escaped PCDD/Fs were mainly distributed on the ultrafine particles, which should be further inhibited by either increasing their sizes or equipping backup filtrations. Finally, the new process concentrates the PCDD/Fs into the scrubbing sludge, which could be recirculated back into the thermal process. This study not only reveals the emission risk of the ultrafine particle-bound PCDD/Fs, but also provides an effective process to remove them for industrial application.

Residential proximity to emissions of dioxins and furans and risk of breast cancer in the Sister Study cohort

BACKGROUND AND AIM: Few studies have investigated the relationship between ambient polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) and risk of breast cancer. We evaluated associations between proximity-based residential exposure to industrial emissions of PCDD/F and breast cancer risk in a U.S. cohort. METHODS: Sister Study participants, who have a sister with breast cancer but no history of breast cancer themselves at enrollment, were followed for incident breast cancer. PCDD/F exposures were estimated using a historical U.S. Environmental Protection Agency database of 4,478 facilities (85% of PCDD/F air emissions) and their toxic equivalency quotient (TEQ) emissions. After restricting to participants with at least 10 years of continuous residential history prior to enrollment (2003-2009; n=34,103), we generated 10-year distance- and TEQ-weighted average emissions indices (AEI [g TEQ/km2]) within 3, 5, or 10km of participants’ residences, overall and by facility type. Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between AEI (dichotomized, quartiles) and risk of breast cancer (invasive or ductal carcinoma in situ). Models were adjusted for breast cancer risk factors and residential outdoor air pollutants. We evaluated whether associations differed by smoking status and tumor estrogen receptor (ER) status. RESULTS:There were 2,583 incident breast cancer cases over a median of 11 years of follow-up. We found an increased risk of breast cancer associated with AEI exposure within 3km (HR Q4.vs.0:1.19, 95% CI: 1.00,1.42, Ptrend=0.03). The relationship was stronger for exposure to emissions from municipal solid waste facilities (HR ≥median.vs.0:1.46, 95% CI: 0.96,2.24; Ptrend=0.08) and among former smokers (HR Q4.vs.0: 1.46, 95% CI: 1.14,1.87, Ptrend=0.004), but did not differ by ER status (Pheterogeneity=0.47). No associations were observed for the AEI at 5 or 10km. CONCLUSIONS:Our findings suggest that increased residential exposure to PCDD/F emissions may confer a higher risk of breast cancer. KEYWORDS: air pollution, chemical exposures, long-term exposure, cancer and cancer precursors, female, environmental epidemiology

Dioxins Exposure and the Risk of Breast Cancer: A Systematic Review and Meta-Analysis

Context: Dioxins and dioxin-like chemicals composed of 419 compounds are a large group of compounds, including polychlorinated di-benzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs). Dioxins are extremely persistent in the environment and disperse in a great distance from the emission source, and bioaccumulation in the food chain is one of their critical properties. The incidence of breast cancer among Iranian women is about 30 to 35 per 100,000 cases. The present study is a systematic review of published studies in English language to discover the relationship between exposure to dioxin compounds and breast cancer. Methods: We conducted a comprehensive literature review utilizing PubMed, Embase, Scopus, and ISI web of science databases. The MeSH-based keywords used included Organic Chemical (MeSH) OR Dioxins (MeSH) AND cancer (MeSH) OR Breast cancer (MeSH) AND Breast disease (MeSH). Results: The review of the literature indicated a significant positive association between dioxins exposure and the risk of breast cancer. Only in one study, breast cancer mortality rate was reported in terms of exposure to dioxins, and standardized mortality rates (SMRs) were determined. Conclusions: Although there were limitations in this study, statistical analyses in various epidemiological studies demonstrated that dioxins exposure is linked to an increased risk of breast cancer.

Occurrence and risks of PCDD/Fs and PCBs in three raptors from North China

Concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) were investigated in muscle samples from common kestrels (Falco tinnunculus), eagle owls (Bubo bubo), and little owls (Athene noctua) collected in Beijing, China. The concentrations of PCDD/Fs were in the ranges of 22.7–5280, 67.5–1610, and 68.4–3180 pg/g lipid weight (lw), while levels of dioxin-like PCBs ranged from 4.91 to 1560, 8.08–294, and 28.2–3540 ng/g lw, in common kestrel, eagle owl, and little owl, respectively. The main PCDD/Fs congener was 2,3,4,7,8-PeCDF, and CB-153 dominated the seven indicator PCBs. PCB levels have shown a decreasing trend in the last decade for the common kestrel, but not for little owl in Beijing, which exhibited higher levels of pollutants and toxic equivalency (TEQ) values than the other two species. Concentrations of PCDD/Fs, dioxin-like PCBs, and indicator PCBs differed between fledgling and adult raptors for certain species. Raptors in this study generally had a higher TEQ than the no-observed-effect level in the literature, indicating significant exposure risks to PCDD/Fs and dioxin-like PCBs in raptors, especially in adult little owls.

Levels of Polychlorinated Dibenzo-p-Dioxins/Furans and Polychlorinated Biphenyls in Free-Range Hen Eggs in Central Italy and Estimated Human Dietary Exposure

The aim of the present study was to evaluate the contamination levels of some classes of persistent organic pollutants in free-range hen eggs and to estimate the related human dietary exposure in a site of national interest, characterized by a serious state of environmental pollution in the Bussi sul Tirino area in central Italy. For these purposes, 17 samples of free-range hen eggs collected in home-producing farms located in the site of national interest territory were analyzed for 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), 12 dioxin-like polychlorinated biphenyls (dl-PCBs), and 6 non-dioxin-like PCBs (ndl-PCBs). Dietary exposure was assessed assuming a standard consumption of eggs per week. The concentration of ∑PCDD/Fs plus dl-PCBs ranged from 0.463 to 8.028 pg toxic equivalent g-1 fat, whereas the mean contamination level of the ∑ndl-PCBs ranged from 0.234 to 7.741 ng toxic equivalent g-1 fat. PCDD/Fs and PCBs contamination levels were lower than maximum values established by the Commission Regulation (European Union) 1259/2011, except for one sample. The estimated weekly intake, calculated to evaluate the contribution in terms of the monitored pollutants of the locally produced eggs to the diet, was lower than the tolerable weekly intake established by the European Food Safety Authority.

Stable and Effective Online Monitoring and Feedback Control of PCDD/F during Municipal Waste Incineration.

For the long-term operation of municipal solid waste incineration (MSWI), online monitoring and feedback control of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) can be used to control the emissions to national or regional standards. In this study, 500 PCDD/F samples were determined by thermal desorption gas chromatography coupled to tunable-laser ionization time-of-flight mass spectrometry (TD-GC-TLI-TOFMS) for 168 h. PCDD/F emissions range from 0.01 ng I-TEQ/Nm3 to 2.37 ng I-TEQ/Nm3, with 44% of values below 0.1 ng I-TEQ/Nm3 (the national standard). In addition, the temperature of the furnace outlet, bed pressure, and oxygen content are considered as key operating parameters among the 13 operating parameters comprising four temperature parameters, four pressure parameters, four flow parameters, and oxygen content. More specifically, maintaining the furnace outlet temperature to be higher than 800 °C, or bed pressure higher than 13 kPa, or the oxygen content stably and above 10% are effective methods for reducing PCDD/F emissions. According to the analysis of the Pearson coefficients and maximal information coefficients, there is no significant correlation between operating parameters and PCDD/F I-TEQ. Only when there is a significant change in one of these factors will the PCDD/F emissions also change accordingly. The feedback control of PCDD/F emissions is realized by adjusting the furnace outlet temperature, bed temperature, and bed pressure to control the PCDD/F to be less than 0.1 ng I-TEQ/Nm3.

Spraying polyacrylamide solution to improve the removal of particle-phase dioxins by bag filter in a full-scale municipal solid waste incineration system

A field experiment was conducted in a modern municipal solid waste (MSW) incineration power plant to explore the feasibility of using chemical agglomeration agent anionic polyacrylamide (PAM) to reduce the atmospheric emission of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Spraying PAM solution into the cooling tower caused an obvious decrease in the volume fraction of ultrafine and fine particles with diameter of 0.3–30 μm in BF fly ash, and a significant reduction in dust content in stack gas. The increased agglomeration of particles promoted the removal of particle-phase PCDD/Fs by BF, and thus resulted in a lower atmospheric emission of PCDD/Fs. The calculated removal efficiency of PCDD/Fs by BF was almost positively proportional to the concentration of PAM solution, while inversely proportional to the average content of dusk in stack gas. Compared with the control treatment, the spraying of 0.1 g/L PAM solution enhanced the removal efficiency of total tetra-to octa-CDD/Fs (∑PCDD/Fs) from 93.8% to 97.8% by BF, and resulted in a decrease of 47.0% in the concentration of international toxicity equivalent (I-TEQ) in stack gas. During the experiment of 2 d, the spraying of PAM solution did not induce a significant change in the differential pressure of BF, and did not essentially affect the partitioning behaviors of PCDD/F homologues between flue gas and BF fly ash. In view of technical safety and low cost, PAM application is recommended for reducing the atmospheric emission of PCDD/Fs from MSW incineration system.