Dioxin Levels Research Articles

8054 Temporal Trends In Thyroidal Endocrine Disruptor Exposure Among United States Reproductive-Age And Pregnant Women Over 20 Years And Differences By Socioeconomic Status

Abstract Disclosure: C. Han: None. S. Lee: None. E.N. Pearce: None. Background: Widespread exposure to endocrine disrupting chemicals (EDCs) poses a risk to public health and environmental safety. Women of reproductive age and pregnant women may be uniquely vulnerable to adverse thyroidal effects of EDCs. A better understanding of thyroidal EDCs exposure is needed to inform public health strategies. Objective: To examine temporal trends in EDC exposure and their effects on thyroid function among reproductive-age and pregnant women in the U.S. over the last two decades, with a focus on the impact of socioeconomic status. Methods: We analyzed data from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2020 in 25,320 reproductive-age women and 2,525 pregnant women to assess the levels of exposure to thyroid-disrupting chemicals, including dioxins, organochlorides, polyfluoroalkyl substances (PFAS) from serum samples, and polyaromatic hydrocarbons, perchlorates, and metabolites from personal care products, phthalates, and plasticizers from urine samples. We used Kruskal-Wallis tests to analyze changes in EDC exposures over the past 20 years and multivariate linear regression models to identify factors influencing these levels. Results: We found a significant decline in exposures to 20 types of dioxins, 7 organochlorides, 6 PFAS, 5 personal care product chemicals, 6 phthalate metabolites, perchlorate, and thiocyanate, but substantial increases in exposure to 2 polyaromatic hydrocarbons among reproductive-age women. Among pregnant women, trends were similar, with declines in exposures to dioxins, organochlorides, PFAS, and phthalate metabolites; whereas exposure to 3 Polyaromatic hydrocarbons, 1 personal care product chemical, nitrates, and thiocyanates increased. Linear regression indicated a significant positive association between socioeconomic status and the levels of dioxin and PFAS in both reproductive-age and pregnant women, and a negative association between socioeconomic status and perchlorate and polyaromatic hydrocarbons in the participants. Conclusion: The past two decades have witnessed a general decline in the levels of most thyroidal EDCs in U.S. reproductive-age and pregnant women; however, some, particularly polyaromatic hydrocarbons, exposures have increased, especially among women with lower socioeconomic status. This has the potential to worsen disparities in health outcomes. These findings highlight the necessity for targeted public health interventions to reduce the impact of EDCs on thyroid health and address socioeconomic health disparities. Presentation: 6/3/2024

EVALUATION OF THE SPATIAL DISTRIBUTION AND ACCUMULATION OF ARSENIC IN SOIL AT THE CORNER OF THE RUNWAY AT BIEN HOA AIRBASE, VIET NAM

The primary source of arsenic in soil is a combination of anthropogenic and natural weathering processes. The increased concentration of arsenic is a major issue due to its possible negative impacts on both ecosystems and human health. Considering these issues, this work conducts a rigorous and extensive investigation into the intricate dynamics of arsenic accumulation and contamination levels within soil matrices. The focus of this investigation is especially urgent, particularly in the context of the dioxin-contaminated environment. Specifically, the soil environment at Bien Hoa Airbase exhibits high levels of dioxin contamination.A look at the values of the contamination factor, which ranges from 2.8 to 17.3, suggests indicators of a non-natural origin for the arsenic found in the soils. In addition, the arsenic quantities measured vary significantly, ranging from 9.9 mg/kg to 66.2 mg/kg, and the high accumulation distributed almost the Northeast of the study site. This observed range exceeds the World Health Organization's (WHO) and Viet Nam's regulatory guidelines. The contamination level is much higher than the background arsenic concentration. These results emphasize how critical it is to address and lessen the effects of anthropogenic arsenic pollution on the ecosystem and public health.

Effects of dioxin exposure on reproductive and thyroid hormone levels and male sexual function in airbase military workers in Vietnam.

Dioxins are endocrine disruptors that may disturb male sexual and reproductive function. Studies on human populations are limited, and their results are controversial. This study evaluated the impact of dioxin exposure on reproductive and thyroid hormone levels and sexual function in men. A total of 140 men working in four military airbases (three bases were formerly contaminated with dioxin by the herbicide spraying campaign in the Vietnam War) were recruited to measure the serum dioxin levels. Four reproductive hormones (testosterone, follicle-stimulating hormone, luteinizing hormone (LH), and prolactin) and three thyroid hormones (free triiodothyronine (FT3), free thyroxin (FT4), and thyroid stimulating hormone) were measured. Male sexual function endpoints including sexual drive, erection, ejaculation, problems, and overall satisfaction were assessed by the Brief Male Sexual Function Inventory. The percentage of subjects with low testosterone and LH levels was 19.6% and 16.7%, respectively. Dioxins, especially 2,3,7,8-tetrachlorodibenzo-P-dioxin and toxic equivalent concentrations of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans, were inversely associated with testosterone and prolactin levels, but positively associated with FT3 and FT4, and showed adverse relationships with sexual function, such as sexual drive, problems, and overall satisfaction. Our results suggested that exposure to dioxin disrupts the homeostasis of reproductive and thyroid hormones leading to adverse effects on male sexual function.

Use of Honey Bees and Hive Products as Bioindicators to Assess Environmental Contamination in Targeted Areas of the Campania Region (Italy).

In recent years, biomonitoring has gained more attention, particularly when assessing the environmental health of significant areas, such as those near waste-to-energy facilities. These requirements coincide with the chance to detect environmental pollutants using sensitive organisms. Bees were shown to be quite effective in evaluating the presence of certain compounds by analyzing their associated matrices, such as pollen, honey, or wax. In our study, we employed the honey bee (Apis mellifera) as an indicator to initially monitor the vicinity of the waste-to-energy plant in Acerra, which is situated in the Campania region of Italy. The primary aim was to determine whether the facility was accountable for any environmental releases of dioxins or dioxin-like compounds. Then, we assessed the presence of additional pollutants in the same area, including trace elements, polycyclic aromatic hydrocarbons, and pesticides, released by human activities. To obtain further information about environmental quality, a second biomonitoring station was installed near the Caivano S.T.I.R. (Waste Shredding, Sifting, and Packaging Plant). The results showed the dioxin levels did not exceed predetermined limitations at the Acerra site, thus demonstrating the efficacy of the waste-to-energy facility and the bees' ability to detect the presence of other pollutants. Additionally, this biomonitoring system exhibited sensitivity to environmental variations, thereby enabling the evaluation of xenobiotic flux between two proximate zones and across temporal scales. This pioneering study suggests the advantages of utilizing bees to detect a wide range of contaminants, thereby providing valuable insights into environmental quality and potential health risks for both ecosystems and human populations.

Assessing the bioaccumulation and translocation potential of vetiver grass for dioxins phytoremediation in Bien Hoa airbase, Viet Nam

Dioxins (PCDD/Fs) are well-known toxic organic pollutants that accumulate in the environment and the food chain, imposing a risk to human health and the ecosystem. Due to the use of dioxin-contaminated herbicides during the US-Vietnam War, there are several hotspots in Vietnam with very high levels of dioxins. Phytoremediation has been increasingly developed in recent decades because of its low cost and environmental-friendly aspect. Vetiver grass is a plant that can remediate both organic and inorganic agents. In this study, the uptake and translocation of dioxins in Vetiver grass (Chrysopogon zizanioides) from the dioxin-contaminated soil was investigated in a field experiment on the Bien Hoa airbase, Vietnam. An experimental area was divided into six plots, of which three were planted with Vetiver grass and three served as control plots, with the initial dioxin concentrations as following: FC2>FC3>FC1>FT2>FT3>FT1. Vetiver grass had grown well on the dioxin-contaminated soils, yielding high biomass and the level of dioxins in the roots of vetiver grass was positively correlated (r2 = 0.67; p<0.01) with its growth rate. During the first year of cultivation, Vetiver grass had the greatest capacity to efficiently accumulate dioxin. Accumulation occurs in the roots, with BAF>1 throughout the entire experiment period for FT3, and in the first year for FT1 and FT2. The dioxin translocation from the roots to the shoots was significantly lower than the BAF and less than one (TF<1), with the first and second sampling times having the highest values compared to the others. Dioxin concentrations do not provide a reliable indicator of its bioavailability but numerous other factors, such as physicochemical properties of the soil and microbes. Our study aims to contribute significant insights to capability of Vetiver grass to accumulate and translocate dioxins, hence the arsenal of dioxin remediation. Furthermore, we envisage translating our findings into practical applications in other areas, considering optimized planting techniques, growth conditions, and long-term sustainability.

Impacts of dioxin exposure on brain connectivity estimated by DTI analysis of MRI images in men residing in contaminated areas of Vietnam.

Effects of dioxin exposure on gray matter volume have been reported in previous studies, but a few studies reported effects of dioxin exposure on white matter structure. Therefore, this study was undertaken to investigate the impact of dioxin exposure on white matter microstructure in men living in the most severely dioxin-contaminated areas in Vietnam. In 2019 brain MRI scans from 28 men living near Bien Hoa airbase were obtained at Dong Nai General Hospital, Vietnam, on a 3 T scanner using a conventional diffusion tensor imaging sequence. Two exposure markers were indicated by perinatal exposure estimated by assessment of maternal residency in a dioxin-contaminated area during pregnancy and by measurement of blood dioxin levels. A general linear model was used to compare fractional anisotropy (FA) values in 11 white matter tracts in both hemispheres between groups with and without perinatal dioxin exposure and groups with high and low blood dioxin levels after adjusting for covariates. The adjusted mean FA value in the left cingulum hippocampal part (CGH) was significantly lower in the perinatal dioxin exposure group compared with the group without perinatal dioxin exposure. The high blood TCDD group showed significantly reduced FA values in the left and right CGH and right uncinate fasciculus (UNC). Moreover, the high blood TEQ-PCDDs group showed significantly lower FA values in the left and right CGH and the left UNC. There were no significant differences in FA values between the groups with high and low TEQ-PCDFs levels or between the groups with high and low TEQ-PCDD/Fs levels. It was concluded that dioxin exposure during the perinatal period and adulthood may alter the microstructure of white matter tracts in individuals with neurodevelopmental disorders.

Dietary exposure levels to polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and non-ortho-polychlorinated biphenyls in US meat, poultry and siluriform fish from 2018 to 2019

Daily dietary exposure estimates from beef, pork, chicken, turkey and siluriform fish were calculated using toxic equivalency (TEQ) data from the U.S. Department of Agriculture’s survey of dioxins and dioxin-like compounds (DLCs) in the domestic meat supply and consumption data. Exposure estimates for the whole population and age groups were based on mean consumption of a commodity and mean or 90th percentile TEQ dioxin levels from the survey. Ratios of the exposure estimates to the U.S. EPA oral reference dose (RfD) of 0.7 pg TEQ/kg bw/day were calculated to determine if domestic meat might contribute materially to consumer exposure. In general, normal consumption of lean beef, pork, chicken and turkey will not cause exposures exceeding the RfD. Non-lean meats will have higher dioxin levels as dioxins accumulate in fat, therefore consumption of non-lean meat might cause higher exposure than compared to lean meat. However, on a mean basis, none of the exposure estimates for non-lean beef, pork, chicken or turkey exceeded the RfD for any of the age groups. For some age groups, especially toddlers, there are commodities such as non-lean beef in the 90th percentile of dioxin TEQs and siluriform fish that might exceed the RfD on occasion.

Characterization and stabilization of incineration fly ash from a new multi-source hazardous waste co-disposal system: field-scale study on solidification and stabilization.

The multi-source hazardous waste co-disposal system, a recent innovation in the industry, offers an efficient approach for hazardous waste disposal. The incineration fly ash (HFA) produced by this system exhibits characteristics distinct from those of typical incineration fly ash, necessitating the use of adjusted disposal methods. This study examined the physicochemical properties, heavy metal content, heavy metal leaching concentration, and dioxin content of HFA generated by the new co-disposal system and compared them with those of conventional municipal waste incineration fly ash. This study investigated the solidification and stabilization of HFA disposal using the organic agent sodium diethyl dithiocarbamate combined with cement on a field scale. The findings revealed significant differences in the structure, composition, and dioxin content of HFA and FA; HFA contained substantially lower levels of dioxins than FA did. Concerning the heavy metal content and leaching; HFA exhibited an unusually high concentration of zinc, surpassing the permitted emission limits, making zinc content a critical consideration in HFA disposal. After stabilization and disposal, the heavy metal leaching and dioxin content of HFA can meet landfill disposal emission standards when a 1% concentration of 10% sodium diethyldithiocarbamate (DDTC) and 150% silicate cement were employed. These results offer valuable insights into the disposal of fly ash resulting from incineration of mixed hazardous waste.

Performance of sustainable ternary blended cement containing municipal solid waste incineration fly ash coupled with slag, coal fly ash or metakaolin

Developing low-clinker cements can effectively reduce carbon footprint of the cement industry. Additionally, more sustainable methods over landfilling are needed to tackle the increasing annual generation of municipal solid waste incineration fly ash (IFA). In this study, carbonated-washed IFA coupled with slag (SG), coal fly ash (CFA) or metakaolin (MK) were used to substitute 60 % of Portland cement to form ternary blended cement. Performance of the blended cements was investigated and compared with pure Portland cement in terms of hydration kinetics, binding capacity, hydration mechanisms, pore characteristics, microstructure, and leaching toxicity. Results indicated that in the blended cement systems, ettringite was stabilized by the formation of hemicarboaluminate as a result of the reaction between calcium carbonate in the IFA and aluminate in SG, CFA and MK. The SG displayed the best synergy with IFA, refining pore structure through pozzolanic reaction and increased formation of ettringite and hemicarboaluminate. For an optimal 40 % SG+20 % IFA blended cement, the mortar compressive strength reached 90 % of that for pure Portland cement at 90 days. Although CFA had abundant aluminate, its low reactivity restrained the performance of the blended cement, resulting in poorer pore structure and lower compressive strength. The MK had abundant reactive silicate and aluminate, but the rapid consumption of calcium hydroxide by the pozzolanic reaction and hemicarboaluminate formation restrained further reaction, limiting the performance of the blended cement at the later stage. Besides, the heavy metal leachability and dioxin level in the produced mortar satisfy the prerequisites to be categorized as nonhazardous according to HJ 1134. This study demonstrated the promising potential of the blended cements to simultaneously divert IFA from landfills and reduce the clinker content of cement.

Characteristics and Outcomes of Lymphoid Malignancies in Veterans Exposed to Burn Pits

Introduction Military personnel were deployed to the Middle East for the Persian Gulf War (8/1990-7/1991), Operation Enduring Freedom (10/2001-12/2014), and Operation Iraqi Freedom (3/2003-11/2011), where they were exposed to environmental hazards including geological dust chemical smoke from burn pits, and heavy metal condensates 1. Burn pits are open-air fires that are used to dispose of food, human waste, plastic bottles, and electronic equipment during the conflicts in the Middle East and release high levels of dioxins, furans, particulate matter, polycyclic aromatic hydrocarbons, and volatile organic compounds, all well established as known human carcinogens 1. Outcomes in veterans diagnosed with lymphoid malignancies with and without burn pit exposure are unknown and warrant further study. Methods This is a retrospective case-case analysis of veterans diagnosed with mature lymphoid malignancies identified from the VA Cancer Registry 2. Descriptive statistics were used to compare cases with and without burn pit risk. Burn pit risk was defined as exposure to Iraq or Afghanistan from the VA Cancer Registry, combat in the Middle East from the VA disability database, or exposure to known chemical locations at Al Jubayl in Saudi Arabia or Khamisiyah in Iraq from USVETS. The Persian Gulf War began 8/2/90 and was considered the presumptive start date of burn pit risk, which was calculated from time at risk until exit from the military. Latency was defined as the time from exposure to the development of a lymphoid malignancy. Cases were excluded if veterans exited the military before 8/2/90 or entered after 12/31/14, latency of exposure to the diagnosis of lymphoid malignancy <6 months, or the burn pit risk was <1 month from 8/2/90 to exit from military. Overall survival (OS) was calculated by time from diagnosis to date of death or last contact, and disease specific survival (DSS) was calculated from time from diagnosis to date of death from a hematologic malignancy or last contact. OS and DSS by histologic subtype were compared by the Kaplan Meier method. Dates and causes of death were determined by the National Death Index, which provided data up to 12/31/20 (data cut off date) 3. Results Patient characteristics are summarized in Table 1. Veterans exposed to burn pits were diagnosed with a lymphoid malignancy at a younger age compared to the unexposed group (47 vs 52 years, p<0.0001). There were differences in racial distribution between the two groups (p=0.0463). More veterans who were exposed to burn pits enlisted in the army (56.8% vs 37.3%) and fewer in the navy (10.2% vs 21.0%) compared to the unexposed group (p<0.0001). Exposed patients had a higher frequency of Hodgkin lymphoma (17.5% vs 12.7%) and lower frequency of plasma cell neoplasms (17.8% vs 20.6%) and chronic lymphocytic leukemia (14.4% vs 16.2%) compared to those who were unexposed (p=0.0002). The difference in age between the exposed and unexposed group may contribute to the different frequencies of these subtypes. By histologic subtypes, the median OS and DSS were not significantly different between the two groups. More patients in the unexposed group died when compared to the exposed group (25.2% vs 18.9%, p<0.0001), but the causes of death did not differ. Conclusion Veterans exposed to burn pits may be diagnosed with a lymphoid malignancy at a younger age compared to unexposed veterans, but there is no difference in median OS or DSS by histologic subtype. More veterans who were unexposed to burn pits died but there were no differences in the causes of death between the two groups. This may be explained by the exposed group being younger and the “healthy soldier effect”. We are continuing to examine the effect of burn pits on the development and outcomes of lymphoid malignancies in more detail. Citations 1 Institute of Medicine. Long-Term Health Consequences of Exposure to Burn Pits in Iraq and Afghanistan. Washington, DC: The National Academies Press; 2011. 2 US Department of Veteran Affairs. VA Informatics and Computing Infrastructure (VINCI), VA ORD 22-D4V, U.S. Department of Veterans Affairs. 2008. Retrieved August 1, 2022, from https://vincicentral.vinci.med.va.gov. 3 Veterans Health Administration Center of Excellence for Suicide Prevention. Joint Department of Veterans Affairs and Department of Defense Mortality Data Repository. 2022. Data compiled from the National Death Index. Extract December 6, 2022.

Occurrence and dietary intake of dioxins, furans (PCDD/Fs), PCBs, and flame retardants (PBDEs and HBCDDs) in baby food and infant formula

This study determines the levels of 49 persistent organic pollutants which were grouped into polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and hexabromocyclododecanes (HBCDDs), in infant formula and varieties of baby food. The analyzed samples (n = 80) came from stores all over Poland.The presence of PCDD/F, PCDD/F/PCB and non dioxin-like (ndl)-PCB congeners above the maximum levels stipulated in Commission Regulation (EU) No 1259/2011 was not detected in any sample. The determined average content of PCDD/Fs/dl-PCBs in the tested baby foods was in the range of 4–10 % of the maximum level, and content of ndl-PCBs was in the range of 2–6 % of the maximum level. Despite these low levels of dioxins, furans, and PCBs, a risk analysis assuming weekly consumption of the recommended food intake showed exceedances of the tolerable weekly intake (TWI).The content of flame retardants was low in all examined categories of food for children and infant formula. The lower-bound concentration of the sum of HBCDD isomers (LB ∑HBCDDs) ranged from below the limit of quantification (LOQ) to 0.0313 ng/g w.w. and the concentration of ∑PBDEs was in a 0.001–1.014 ng/g w.w. range. Neither infant formula nor baby food contributed considerably to infant exposure to HBCDDs or PBDEs.Our research indicates that the safe exposure thresholds for dioxins and PCBs in foods for infants and young children may be too high and perhaps it may be necessary to amend the legislation setting acceptable limits for baby food. It seems reasonable to introduce a recommendation on the frequency of food consumption for children and the control of raw materials for food production, in particular fish and cow milk, should be a permanent control point in the food safety assurance system.

Occurrence and carcinogenic potential of airborne PBDD/Fs and PCDD/Fs around a large-scale municipal solid waste incinerator: A long-term passive air sampling study

Municipal solid waste incinerator (MSWI) not only is deemed one of the uppermost sources of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), but also produces substantial amount of polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) owing to the existence of brominated flame retardants (BFRs) in the waste. So far, however, PBDD/Fs in the vicinal environments of MSWI and their associated risks remain rarely studied. Based on a one-year passive air sampling (PAS) scheme, we investigated airborne PBDD/Fs and PCDD/Fs around a large-scale MSWI that has been operated for multi-years. Both the concentrations of PBDD/Fs and PCDD/Fs showed spatially decreasing trends with the distance away from the MSWI, confirming the influence of the MSWI on the dioxin levels in its ambient air. But its influence on PBDD/Fs was less because PBDD/Fs exhibit lower volatility and therefore lower gaseous concentrations than PCDD/Fs. Compared to the existing global data of airborne PCDD/Fs and PBDD/Fs, our data of the MSWI vicinity were at medium levels, despite PAS samples only represent the concentrations of gaseous dioxins in theory. The seasonal data suggest that meteorological conditions exerted apparent influences over the concentrations and sources of airborne dioxins around the MSWI. As for PCDD/Fs, the MSWI was diagnosed as their uppermost source, followed by local traffic and volatilization/deposition. Whereas the top three PBDD/F sources were related to PBDEs, bromophenol/bromobenzene, and traffic vehicles, respectively. The bioassay-derived TEQs based on the aryl hydrocarbon receptor activation of airborne dioxins around the MSWI were one or two orders of magnitudes higher than their concentration-based TEQs, and the corresponding carcinogenic risks at some MSWI-vicinal sites exceeded the acceptable threshold proposed by the U. S. EPA (10−6 ∼ 10−4) and deserve continuous attention.

Baseline Soil Dioxin Levels from Sites Where Municipal Solid Waste Incineration Construction Is Planned throughout China: Characteristics, Sources and Risk Assessment

The determination of baseline dioxins levels in soils is fundamental for the quantitative assessment of the net environmental and health impacts of municipal solid waste (MSW) incineration plants, which remains unexplored. Therefore, this study develops a Chinese baseline soil dioxins database (covering 918 soil samples from 292 pre-construction MSW incineration plants nationwide during 2016–2020) to thoroughly explore the baseline contamination characteristics and health risks of dioxins in soils. The empirical results show that (1) for concentration levels, the baseline international toxic equivalency (I-TEQ) concentrations vary from 0.0015 to 32 ng I-TEQ/kg, which are close to or even lower than those in most existing studies and show significant heterogeneity across provinces; (2) for dioxins homolog, highly chlorinated dioxins (i.e., PCDDs) are the dominant contributor to the total dioxins in soils (contributing 54.30% of the total I-TEQ concentrations), implying that dioxins in baseline soils often have an atmospheric fingerprint; and (3) for health risks, the carcinogenic risk and non-carcinogenic risk of dioxins in soils are mostly below acceptable levels, close to or even lower than the results of previous studies. Despite these results being considered as quite preliminary, they have certain implications for local authorities. Future studies can expand the size of the database and the generalizability of the results, and if necessary, establish a long-term dynamic monitoring of dioxins in soils for systematically evaluating the net impact of MSW incineration on environment and human health.

Safety Evaluation and Probabilistic Health Risk Assessment of Cow Milk Produced in Northern Italy According to Dioxins and PCBs Contamination Levels.

Contamination levels of dioxins and polychlorinated biphenyls (PCBs) were monitored over 2018-2021 in 214 bovine milk samples from farms located in two regions in northern Italy (Lombardy and Emilia-Romagna). The average concentrations of the sum of dioxins and dioxin-like PCBs (0.78 ± 0.55 pg TEQ/g fat) and six non-dioxin-like PCBs (6.55 ± 2.24 ng/g fat) were largely below the maximum, and action limits established at European level, confirming a decreasing trend observed both locally and across Europe in recent years. The impact of contamination levels on chronic dietary exposure of the Italian population to dioxins and PCBs was found to be highly variable based on the type of cow milk (skimmed, semi-skimmed, or whole-fat milk) and the population age group considered. Indeed, a first-tier screening of the potential exposure via determinist methods allowed for the identification of the youngest population as the group with the worst risk profile. The refinement of exposure assessment via Monte Carlo probabilistic methods suggested that, at the less pessimistic middle-bound simulation scenario, infants, toddlers, and children consuming whole cow milk may be exposed to dioxins and PCBs levels above the toxicological reference values with a probability of 76, 56, and 22%, respectively.

Bacterial distribution in long-term dioxin-contaminated soil in Vietnam and novel dioxin degrading bacteria isolated from Phu Cat airbase

ABSTRACT Herbicide-/dioxin-contaminated contamination in Vietnam is an environmental issue nowadays, despite Agent Orange being sprayed a long time ago. High levels of dioxin in military airbases cause hot spots of dioxin contamination sites in which potential biological source of microorganisms has developed. Understanding microorganism structure in contaminated soil is crucial for the bioremediation of the sites. Illumina Miseq platform was applied to sequence V3-V4 amplicons of long-term contaminated communities to evaluate the bacterial distribution. Contaminated soil from different regions Bien Hoa and Phu Cat showed a low level of connectedness; the species richness of Bien Hoa was much higher than that of Phu Cat. However, they shared similarities in the most abundant bacterial phyla: Actinobacteriota, Chloroflexi, Proteobacteria, Acidobacteriota, and Planctomycetota. Several xenobiotic-degrading genera were found, such as Terrabacter, Nocardioides, and Streptomyces of Actinobacteriota; Bacillus, Paenibacillus, and Clostridium of Firmicutes; Burkholderia, Sphingomonas, Pseudomonas and Klebsiella of Proteobacteria. Seven bacterial isolates grew on dioxin-containing medium belonging to Firmicutes, they were classified in order Bacillales, in which two strains belong to Paenibacillaceae, and the rests are in Bacillaceae. Two isolates removed more than 80% of total toxicity (mainly 2,3,7,8-Tetrachlorodibenzo-p-dioxin); strain PC5 is the first dioxin-degrading bacterium recognized in the genus Neobacillus.

Spatiotemporal bioavailability of PCDD/Fs and dl-PCBs in wild mussels from the Portuguese Atlantic coast

This study aimed to assess the spatiotemporal bioavailability of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in wild adult mussels, Mytilus galloprovincialis, collected along the Portuguese Atlantic coast between 2009 and 2020. The work is part of a national environmental monitoring program. The purpose was to evaluate the dioxins’ temporal trends, the human and ecological risks, and the correlation between mussels’ location and the main pollutant sources in Portugal. The levels and congener patterns of the most toxicity-relevant 17 PCDD/Fs and 12 dl-PCBs were determined, with the dl-PCBs dominant. The sum of Σ17PCDD/Fs and Σ12dl-PCBs values ranged from 2.0 to 4.0 ng WHO-TEQ kg−1, (wet weight basis), below the limits established by the European Commission for contamination in fish and fishery products (6.5 ng per kg−1). The study included five years – 2009, 2010, 2016, 2018 and 2020 –, allowing to verify the impact of European Directive 2013/39/UE against the pollution of water in Portugal; it was observed that dioxin levels in mussels diminished over the time. Statistical analysis allowed verification of different spatial trends of dl-PCB profiles along the Portuguese Atlantic coast. The mono-ortho dl-PCB pentachlorinated congener IUPAC #118 prevailed in 2009 and 2018 in all sampling sites, and it was predominant in 2010, 2016 and 2020, followed by the congeners IUPAC #105, #156 and #167. The IUPAC #167, #169 and #123 were the most abundant hexachlorinated congeners, and the IUPAC #77 the most abundant tetrachlorinated congener. This work emphasises the importance of monitoring dioxins and mapping the congeners in Atlantic coastal ecosystems, to contribute to their elimination.

Abstract 2663: Rising level of pulmonary dioxin might trigger CMV and HSV-1 reactivation via bHLH/PAS/AhR:ARNT transcription pathway in lungs of immunocompetent COVID-19 patients with ARDS

Abstract 2663: Rising level of pulmonary dioxin might trigger CMV and HSV-1 reactivation via bHLH/PAS/AhR:ARNT transcription pathway in lungs of immunocompetent COVID-19 patients with ARDS

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.

Associations between Maternal Polychlorinated Dibenzo-p-dioxin and Dibenzofuran Serum Concentrations and Pulse Pressure in Early Pregnancy: A Cross-Sectional Study.

Pulse pressure (PP) is the difference between systolic blood pressure (SBP) and diastolic blood pressure (DBP), and an independent predictor of cardiovascular risk. Previous research suggests, with different conclusions, that exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) could affect blood pressure (BP). We conducted a cross-sectional study to determine the association of dioxin exposure with PP in early pregnancy. A total of 305 pregnant women in early pregnancy in Yingcheng, China, recruited from May 2018 to February 2021, were included in this study. We measured 17 congeners of PCDD/Fs in maternal serum via high-resolution gas chromatography tandem high-resolution mass spectrometry. A generalized linear regression model was used to analyze the influencing factors of dioxin exposure and their relationships with PP. The levels of total PCDD/Fs (∑PCDD/Fs) ranged from 163.52 pg/g lipid to 1,513,949.52 pg/g lipid, with a mean of 10,474.22 pg/g lipid. The mean toxicity equivalent (TEQ) of total PCDD/Fs (∑TEQ-PCDD/Fs) was 42.03 pg/g lipid. The ratio of tetrachlorinated to octa-chlorinated congeners in maternal serum was enriched with an increasing number of chlorines. Pregnant women with college and above education had higher concentrations of ∑PCDD/Fs than those with education levels of junior high school and below (β = 0.34, 95% CI: 0.01, 0.67). The adjusted model for ∑TEQ-PCDD/Fs was significantly and negatively associated with PP (β = -1.79, 95% CI: -2.91, -0.68). High levels of dioxins were found in this area, and exposure to dioxins may affect the PP of women in early pregnancy, with health risks.

The first German total diet study (BfR MEAL Study) confirms highest levels of dioxins and dioxin-like polychlorinated biphenyls in foods of animal origin.

The first German Total Diet Study, called the BfR MEAL Study, generated a comprehensive dataset of polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in foods representative for the consumption habits in households in Germany. PCDD/Fs and dl-PCBs are persistent organic pollutants. Dietary intake is considered to be the most relevant exposure pathway for humans. Levels were examined in 300 foods that were prepared as typically consumed by the population in Germany. Highest PCDD/F and dl-PCB levels were detected in animal-based foods such as fish, butter, dairy products, liver, and meat. The comparison of conventionally and organically produced foods revealed a trend to slightly higher contents in organically produced foods. Sampling discriminated by region and season showed no major differences. Analysed occurrence data will improve future dietary exposure and food safety assessments in Germany.