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Dioxins: WHO's tolerable daily intake (TDI) revisited
Abstract
In December 1990, the World Health Organization (WHO) established a tolerable daily intake (TDI) of 10 pg/kg b.w. (body weight) for TCDD, based on liver toxicity, reproductive effects and immunotoxicity in experimental animals, and making use of kinetic data in humans and experimental animals. Since then new epidemiological and toxicological data have emerged, in particular with respect to neurodevelopmental and endocrine effects of dioxin. Therefore, the European Centre for Environment and Health of the World Health Organization (WHO-ECEH) and the International Programme on Chemical Safety (IPCS) jointly organized a consultation on the "Assessment of the health risk of dioxins: re-evaluation of the TDI", May 1998, Geneva, Switzerland. The participants discussed the health risks for infants, cancer and non-cancer endpoints in humans and animals, mechanistic aspects, kinetic behaviour, modelling, exposure, and the applicability of the toxic equivalency (TEQ) concept. For the health risk assessment of dioxin-like compounds, the WHO Consultation focused on the most sensitive effects that are considered adverse (hormonal, reproductive and developmental effects) seen at low doses in animal studies (rats and monkeys). Human daily intakes corresponding with body burdens similar to those associated with adverse effects in animals could be estimated to be in the range of 14-37 pg/kg b.w./day. To arrive at a TDI expressed as TEQ, a composite uncertainty factor of 10 was recommended. By applying this uncertainty factor a TDI range of 1-4 pg TEQs/kg body weight was established. An extensive executive summary of the results of this WHO Consultation with all the underlying background documents will be published in Food Additives and Contaminants (in press).
... where BW (kg) is the body weight (70 kg), RfD (pg/(kg d)) is the PCDD/ F and dl-PCB reference dose (the tolerable daily intake set by the World Health Organization, 1 pg toxic equivalent (TEQ)/(kg d) (Van Leeuwen et al., 2000)), and C dioxin (pg TEQ/g) is the total PCDD/F and dl-PCB TEQ in a sample of interest. BRQ b 1 indicates that consuming the fish of interest at the specified rate would provide the recommended daily EPA and DHA intakes and cause no risk. ...
... Various organizations have set recommended EPA + DHA intakes and tolerable PCDD/F and dl-PCB intakes, but each is based on either benefit acquisition or risk prevention (Chinese Nutrition Society, 2013;Kris-Etherton et al., 2009;Strandberg et al., 2016;Van Leeuwen et al., 2000). Fish has been considered as packages of fatty acids and pollutants, so an integrated benefit-risk assessment is necessary. ...
Fish consumption benefits early cognitive development and cardiovascular health because of the n-3 long-chain polyunsaturated fatty acids in the fish, but toxic pollutants in fish, like dioxin-like polychlorinated biphenyls (dl-PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), may decrease or counteract these benefits. In this study, the fatty acids, dl-PCBs, and PCDD/Fs were analyzed in paired muscle and skin from 13 fish and one squid species from the Bohai coast, which have been influenced by serious dioxin pollution from the Bohai Rim Region. The total fatty acid concentrations in the muscle and skin were 2.6–87 and 3.6–156 mg/g wet weight (ww), respectively. The total polyunsaturated fatty acid concentrations were higher in skin than muscle for almost half of the species. The total PCDD/F and dl-PCB toxic equivalents in the muscle and skin were 0.055–0.68 and 0.0099–0.43 pg/g ww, respectively, and were up to five times higher in the muscle than in the skin for eight species. Few benefit–risk studies for fish consumption with and without skin have been performed, so benefit–risk quotients (BRQs) for eating only muscle, only skin, and eating both were calculated. To achieve the recommended 250 mg of EPA + DHA intake, eating only muscle, only skin, and eating both from seven species with BRQs < 1 would cause no significant risk. Removing skin before eating is not necessary for these species. Three fish species had BRQs < 1 for muscle only but BRQs > 1 for skin only. Removing skin before eating would be better for these species. The other four fish species had BRQs > 1 for eating only muscle, only skin, and eating both, indicating the potential risk caused by PCDD/F and dl-PCB. Amounts of the four fish species consumed should be decreased, and other sources of EPA and DHA should be selected.
... TDI для ПХДД/Ф и ДП ПХД были установлены экспертами ВОЗ в диапазоне 1 -4 пг ТЭ ВОЗ кг -1 массы тела в день (van Leeuwen, Feeley et al. 2000). Суточное потребление верблюжьего молока/шубата из Таучика может привести к превышению этого TDI и, соотвественно медианная концентрация, рассчитанная для всех проб, может привести к превышению уровня 1 пг ТЭ ВОЗ кг -1 массы тела в день для детей (см. ...
... Ежедневное потребление верблюжьего молока/шубата из Таучика может привести к превышению допустимого суточного потребления (TDI), установленного ВОЗ для ПХДД/Ф и ДП ПХД диапазона 1-4 пг ТЭ ВОЗ кг -1 веса тела в день (van Leeuwen, Feeley et al. 2000), (см. Таблицу 7 и раздел 4.2.5). ...
English version is here: https://www.researchgate.net/publication/308948216_Toxic_pollutants_in_camel_milk_from_the_Mangystau_Region_of_Kazakhstan_Results_of_sampling_conducted_in_2015-2016
Mангистауская область относится к тем частям Казахстана, где действует крупная нефтяная и горнодобывающая промышленность и есть места, где встречается токсичное наследие советской эпохи в виде значительно загрязненных мест. На пути к стабильному будущему, серьезной проблемой для данного региона может стать загрязнение продуктов питания токсичными веществами. Нурсеитова, Kонуспаева и др. (2016) недавно пытались оценить риски загрязнения продукции животноводства токсичными веществами в Казахстане, являющейся основным источником продуктов питания и пришли к выводу, что «пока еще нет оценок риска загрязнения в Казахстане».
В данном исследовании мы сосредоточили свое внимание на загрязнении верблюжьего молока, так как оно является значительной частью рациона питания в Мангистауской области, которая является основной областью реализации проекта – «Реализация прав граждан и общественное участие в принятии решений по экологическим вопросам – практическая реализация Орхусской конвенции в Мангистауской области». Это совместный проект чешских и казахстанских НПО, финансируемый Европейским Союзом и другими донорами.
... TCDD toxicity is a consequence of its chlorine substituents being located in lateral positions (on carbons 2, 3, 7 and 8), resulting in impaired metabolism and clearance. Although the exact duration of TCDD persistence will vary as a consequence of dose, exposure duration and body composition [32], the half-life of TCDD in humans ranges from approximately 7-12 years [33,34]. There have been a number of incidences whereby humans have been exposed to TCDD, including those related to occupations involving chemical and pesticide production. ...
Much of what is known about the Aryl Hydrocarbon Receptor (AhR) centers on its ability to mediate the deleterious effects of the environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; dioxin). However, the AhR is both ubiquitously-expressed and evolutionarily-conserved, suggesting that it evolved for purposes beyond strictly mediating responses to man-made environmental toxicants. There is growing evidence that the AhR is required for the maintenance of health, as it is implicated in physiological processes such as xenobiotic metabolism, organ development and immunity. Dysregulation of AhR expression and activity is also associated with a variety of disease states, particularly those at barrier organs such as the skin, gut and lungs. The lungs are particularly vulnerable to inhaled toxicants such as cigarette smoke. However, the role of the AhR in diseases such as chronic obstructive pulmonary disease (COPD)—a respiratory illness caused predominately by cigarette smoking—and lung cancer remains largely unexplored. This review will discuss the growing body of literature that provides evidence that the AhR protects the lungs against the damaging effects of cigarette smoke.
... The body weights of 60 kg and 15 kg were assigned for Vietnamese adults and children, respectively. The DI values estimated in this study were compared with tolerable daily intake (TDI) of 1-4 pg TEQ/kg/day recommended by the WHO (Van Leeuwen et al. 2010). ...
Polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and dioxin-like PCBs (DL-PCBs) were examined in chicken egg and soil samples collected from Dong Nai Province, southern Vietnam. PCDD/F and DL-PCB levels in egg samples ranged from 5.74 to 1320 (median 350) and from 120 to 51,200 (median 1470) pg/g lipid weight (lw), respectively. Toxic equivalents to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TEQ) in egg samples ranged from 0.817 to 245 (median 10.8) pg TEQ/g lw. Higher dioxin levels were found in free-range eggs than non-free-range ones. We found significant correlation between TEQ levels in paired egg and soil samples collected from the Bien Hoa Airbase and some communities adjacent to industrial areas (Spearman’s ρ = 0.671; p < 0.05), suggesting the co-occurrence of legacy and current dioxin emission sources in these areas.
... where the EDI is the estimated daily intake (EDI), and PTDI is the provisional tolerable daily intake, which is the maximum daily amount of a chemical that is considered safe during the entire human lifetime; here, PTDI value used for PCBs was 10 pg kg −1 body weight (bw) day −1 (Van Leeuwen et al. 2000). The calculated HQ value less than 1 indicates no adverse health effect is expected, whereas an HQ greater than 1 indicates the possibility of adverse health effects. ...
This study assessed the polychlorinated biphenyl (PCB) levels in human milk and its associated health risk to infants from rural and urban settings of five districts of Punjab Province, Pakistan. The ∑34PCB concentrations ranged from 30.9 to 68.3 ng g⁻¹ on lipid weight (l.w.) basis. The ∑8DL-PCB concentrations were ranged from 0.29 to 1.35 ng g⁻¹ l.w., (mean 6.2 ± 8.7 ng g⁻¹ l.w.), with toxicity equivalent to polychlorinated dibenzodioxins (PCDDs) ranging from 8.58 × 10⁻⁶ to 0.05 ng TEQ g⁻¹ l.w. The spatial trend of PCB levels in human milk revealed higher bioaccumulative levels for urban mothers as compared with rural counterparts. The estimated daily intake (EDI) values of DL-PCBs to infants through trans-mammary transfer were considerably higher than tolerable daily intake limits established by WHO (i.e., 1–4 pg TEQ kg⁻¹ bw) and other globally recognized organizations. Similarly, the hazard quotient values for TEQ ∑8DL-PCBs (range 1.21 to 79.87) were far above the benchmark value of 1 at all the sampling sites, indicating the high levels of adverse health risks to infants in the region through breast milk consumption. The ∑34PCB levels were found to be negatively correlated with mother’ age (r = −0.31; p = 0.02), parity (r = − 0.85; p = 0.001), and infant’ birth weight (r = − 0.73; p = 0.01). The present study suggests undertaking comprehensive public health risk assessment studies and firm regulatory measures to safeguard human health risks.
... In addition to these regulations, to ensure food safety, international bodies developed surveillance programs to monitor POP levels in food to protect the public from contaminated food. Since dioxin-like compounds are among the most toxic chemicals, many government and non-governmental organizations established the safety limit for tolerable intake of PCDD/Fs and PCBs [205][206][207]. For example, the European Union set the maximum limits for PCDD/Fs and dioxin-like PCBs in food products in its regulation since 2001 (the most recent one is EC regulation 1259/2011 [208]). ...
Persistent organic pollutants (POPs) present in foods have been a major concern for food safety due to their persistence and toxic effects. To ensure food safety and protect human health from POPs, it is critical to achieve a better understanding of POP pathways into food and develop strategies to reduce human exposure. POPs could present in food in the raw stages, transferred from the environment or artificially introduced during food preparation steps. Exposure to these pollutants may cause various health problems such as endocrine disruption, cardiovascular diseases, cancers, diabetes, birth defects, and dysfunctional immune and reproductive systems. This review describes potential sources of POP food contamination, analytical approaches to measure POP levels in food and efforts to control food contamination with POPs.
... Dioxin concentrations were elevated in the blood not only of individuals working on the airbase, but also that of residents living around the airbase, including pregnant women. Via breast feeding, the total toxic equivalent (TEQ) of polychlorodibenzodioxins (PCDDs) and polychlorodibenzofurans (PCDFs) ingested by infants ranged from 23.4 to 2320 pg TEQ/kg bodyweight/day, which exceeds the tolerable daily intake of 4 pg TEQ/ kg bodyweight/day (Van Leeuwen et al., 2000). It has raised concerns regarding adverse health effects due to high dioxin exposure in these populations, especially in young children. ...
Background:
We have followed a birth cohort from 2008 to 2009 near a dioxin-contaminated area of Da Nang, Vietnam, and investigated the effects of perinatal dioxin exposure on neurodevelopment from infancy to pre-school age. The present study aimed to investigate the effects of perinatal dioxin exposure on the learning abilities of the elementary-school children from the Da Nang birth cohort.
Methods:
From 241 mother-infant pairs recruited at baseline (134 boys and 107 girls), 185 (76.8%) participated in a follow-up when the children were 8 years of age (108 boys and 77 girls). The children's perinatal dioxin exposure was estimated using the dioxin levels in their mothers' breast milk. The Colorado Learning Difficulties Questionnaire (CLDQ) was used to evaluate the children's learning difficulties. Math- and language-achievement scores were obtained using paper-based tests. Reading fluency was examined by having the children read passages in Vietnamese.
Results:
In boys exposed to high levels of 2,3,7,8-tetrachlorodibenzodioxin (2,3,7,8-TetraCDD), CLDQ reading scores were significantly higher (worse), and language achievement scores were significantly lower. Boys exposed to high levels of 2,3,7,8-TetraCDD as well as high levels of the toxic equivalent (TEQ) of polychlorodibenzodioxins and polychlorodibenzofurans (PCDDs/Fs) had higher numbers of reading errors. Reading errors were higher and math achievement scores were lower with increasing concentrations of 1,2,3,4,7,8-HexaCDD and 1,2,3,4,6,7,8-HeptaCDD. In girls, no significant differences of any learning ability markers were found between high and low exposure groups to TEQ-PCDDs/Fs and these 3 congeners.
Conclusions:
Perinatal dioxin exposure may have adverse effects on the learning abilities of school children, especially boys.
... Dioxins are typical persistent organic pollutants that produce diverse toxicological effects, including chloracne, immunotoxicity, neurotoxicity, hepatoxicity, reproductive toxicity, and tumorigenicity [1][2][3]. One of the most toxic congeners among dioxins is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), whose toxicity and action mechanism have been extensively studied [4]. ...
Emerging data indicate that prenatal exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) could interfere with myogenic differentiation in vivo. Acetylcholinesterase (EC3.1.1.7; AChE), an enzyme critical for cholinergic neurotransmission, is abundantly expressed in neurons and mature myotubes, and we recently found that muscle AChE expression was suppressed in parallel with the inhibition of myogenic differentiation upon TCDD treatment in mouse C2C12 cells. This TCDD-induced suppression of muscle AChE was proposed to involve an aryl hydrocarbon receptor (AhR)-independent mechanism, but the precise underlying mechanism remains unclear. Considering the widely recognized role of muscular activity in AChE expression and its potential crosstalk with the AhR signaling pathway, we sought to investigate the effect of TCDD on muscle AChE expression in the presence of muscular activity. Therefore, we employed a highly contractile rat primary skeletal muscle culture system in which AChE activity and the expression of genes related to it (AChE T subunit and collagen Q (ColQ)) were increased during the myogenic differentiation process. Although TCDD treatment successfully induced the expression of genes regulated by AhR activation, the treatment exerted no notable effects on myogenic differentiation. Moreover, muscle AChE enzymatic activity and mRNA level remained unchanged following TCDD treatment, and only ColQ mRNA expression was slightly increased after 4-day treatment with TCDD (10⁻¹⁰ M). The compensatory role of muscle-contraction-related signaling pathways in this newly identified unresponsiveness of muscle AChE to TCDD warrants further investigation.
... The overall CDI values ranged from 1.3 × 10 −16 to 4.2 × 10 −10 mg TEQ kg −1 d −1 . These daily intake doses were lower than the oral reference dose (RfD) of 7 × 10 −10 mg kg −1 d −1 derived by the US EPA for reproductive effects of TCDD (US EPA 2012) and the tolerable daily intake (TDI) of 1 to 4 pg TEQ kg −1 d −1 established by the WHO (Van Leeuwen et al. 2010). As a result, all the HI values were lower than the critical value of 1 (1.8 × 10 −7 to 6.0 × 10 −1 ), implying unserious non-cancer risk. ...
The residue concentrations and congener profiles of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) were examined in fly ash and bottom ash released from different thermal industrial processes in Vietnam. PCDD/F concentrations and toxic equivalents (TEQs) in the ash samples varied greatly and decreased in the following order: steel making > aluminum recycling > medical waste incinerator > boilers > municipal waste incinerator > tin production > brick production > coal-fired power plant. Both the precursor and de novo synthesis were estimated as possible formation mechanisms of dioxins in the ash, but the latter pathway was more prevalent. The highest emission factors were estimated for the ash released from some steel-making plants, aluminum-recycling facilities, and a medical waste incinerator. The emission factors of PCDD/Fs in ash released from some steel plants of this study were two to six times higher than the UNEP Toolkit default value. The annual emission amount of ash-bound dioxins produced by 15 facilities in our study was estimated to be 26.2 to 28.4 g TEQ year−1, which mainly contributed by 3 steel plants. Health risk related to the dioxin-containing ash was evaluated for workers at the studied facilities, indicating acceptable risk levels for almost all individuals. More comprehensive studies on the occurrence and impacts of dioxins in waste streams from incineration and industrial processes and receiving environments should be conducted, in order to promote effective waste management and health protection scheme for dioxins and related compounds in this rapidly industrializing country.
... France) were each used at doses in the range of their tolerable daily intake (TDI) reference 155 dose and at least 10 times lower than their NoAEL dose (van Leeuwen et al., 2000;WHO, 156 2003; European Food Safety Authority Panel on Food Additives, 2005) (Supplementary Table 157 1). They were diluted in DMSO, solubilized in corn oil and mixed into the diet. ...
Excessive consumption of industrialized food and beverages is a major etiologic factor in the epidemics of obesity and associated metabolic diseases because these products are rich in fat and sugar. In addition, they contain food contact materials and environmental pollutants identified as metabolism disrupting chemicals. To evaluate the metabolic impact of these dietary threats (individually or combined), we used a male mouse model of chronic exposure to a mixture of low-dose archetypal food-contaminating chemicals that was added in standard or high-fat, high-sucrose (HFHS) diet. Specifically, the mixture contained bisphenol A, diethylhexylphthalate, 2,3,7,8-tetrachlorodibenzo-p-dioxine and polychlorinated biphenyl 153. Exposure lasted from 5 to 20 weeks of age. Metabolic exploration was conducted setting the basis of candidate gene expression mRNA analyses in liver, jejunum and adipose tissue depots from 20 week-old mice. Strong metabolic deleterious effects of the HFHS diet were demonstrated in line with obesity-associated metabolic features and insulin resistance. Pollutant exposure resulted in significant changes on plasma triglyceride levels and on the expression levels of genes mainly encoding xenobiotic processing in jejunum; estrogen receptors, regulators of lipoprotein lipase and inflammatory markers in jejunum and adipose tissues as well as adipogenesis markers. Importantly, the impact of pollutants was principally evidenced under standard diet. In addition, depending on nutritional conditions and on the metabolic tissue considered, the impact of pollutants could mimic or oppose the HFHS effects. Collectively, the present study extends the cocktail effect concept of a low-dosed pollutant mixture and originally points to tissue-specificity responsiveness especially in jejunum and adipose tissues.
... This complex activates transcription of target genes such as Cyp1A1 and glutathione S-transferase by binding to the aromatic hydrocarbon-responsive elements in the 5′ flanking region of these genes (11). Environmental AhR ligands are exposed to the barrier organs such as the skin, lung and gut, with the gut accounting for most of human dioxin exposure and for other AhR ligands, including many dietary components such as quercetin in apples, resveratrol in red wine and indole-3-carbinol (I3C) in many cruciferous plants (12,13). ...
Aryl hydrocarbon receptor (AhR) regulates both innate and adaptive immune responses by sensing a variety of small synthetic and natural chemicals, which act as its ligands. AhR, which is expressed in dendritic cells (DCs), regulates the differentiation of DCs. However, effects of AhR on the differentiation of DCs are variable due to the heterogeneity of DCs in cell surface marker expression, anatomical location, and functional responses. The plasmacytoid DCs (pDCs), one of DC subsets, not only induce innate as well as adaptive immune responses by secreting type I interferons and pro-inflammatory cytokines, but also induce IL-10 producing regulatory T cell or anergy or deletion of antigen-specific T cells. We showed here that AhR ligands indoxyl 3-sulfate (I3S) and indole-3-carbinol (I3C) inhibited the development of pDCs derived from bone marrow (BM) precursors induced by FMS-like tyrosine kinase 3 ligand (Flt3L). I3S and I3C downregulated the expression of signal transducer and activator of transcription 3 (STAT3) and E2-2 (Tcf4). In mice orally treated with I3S and I3C, oral tolerance to dinitrofluorobenzene was impaired and the proportion of CD11c⁺B220⁺ cells in mesenteric lymph nodes was reduced. These data demonstrate that AhR negatively regulates the development of pDCs from BM precursors induced by Flt3L, probably via repressing the expression of STAT3.
... Most of the developed countries already monitor and control the human exposition to dioxins since the 1980s, with legislation establishing the tolerable daily intake (TDI) and maximum residue levels (MRLs) for these contaminants in foodstuffs (Leeuwen et al., 2000;Committee on Toxicity, 2001;European Commission, 2006;European Commission, 2011b). In Brazil, after the incident with German milk, it was established the MRL of 0.5 ng/kg (WHO-TEQ) for CPP . ...
Dioxins and furans are ubiquitous, anthropogenic environmental contaminants which can be found even in
isolated places. Exposition to these chemicals poses several risks to humans such as thyroid dysfunction, cardiovascular
diseases, and even cancer. In this review, the dioxin issue is analyzed in the light of the events that
brought the World's attention to these pollutants, and the evolution of Brazilian scientific data on this matter
since the citrus pulp crisis in 1998. Soil and air have been the main environmental matrices studied in Brazil.
However, most of the research focuses on contaminated areas, with few or no data available on background
levels. With the ratification of the Stockholm Convention in 2010, Brazil started to implement some measures to
monitor the release of dioxins to the environment, such as the national inventory of sources. Still, the country
lacks specific legislation stating acceptable limits for some industrial processes known to be source of dioxins
emissions. Likewise, food monitoring has grown in recent years with the expansion of food groups monitored in
the National Control Plan for Residues and Contaminants, but the available data do not allow affirming whether
Brazilian residents are safe, as regard to exposure via food consumption. The implementation of a systemic
survey such as a Total Diet Study would be a good strategy for a long-term monitoring not only for dioxins but
also for other contaminants. Unfortunately, progressive cuts in science funds are holding back the scientific
production in Brazil, whereas worldwide new emerging contaminants are being monitored and included in
National Monitoring Plans both on food and environment matrices.
... All the HQ values lower than one and CR values lower than 10 −4 indicate no serious risk from ingestion of dusts contaminated with PCBs in northern Vietnam. Daily intake doses of PCB-TEQs in the settled dusts of this study were also smaller than the tolerable daily intake of 1-4 pg TEQ kg −1 day −1 proposed by Van Leeuwen et al. (2010). ...
Concentrations and congener-specific profiles of total 209 polychlorinated biphenyls (PCBs) were investigated in settled dust samples collected from end-of-life vehicle (ELV) processing, urban, and rural areas in northern Vietnam. Concentrations of total 209 PCBs, seven indicator congeners, and twelve dioxin-like PCBs decreased in the order: ELV working > ELV living ≈ urban > rural dusts. Penta- and hexa-CBs dominated the homolog patterns in all the samples with higher proportions in the ELV dusts compared to the urban and rural house dusts. The abundance and pattern of PCBs in the ELV dusts suggest on-going emissions of these compounds related to processing of vehicular oils and lubricants containing PCBs, whereas the presence of PCBs in the urban and rural house dusts indicate long-time releases. However, levels of some PCBs identified as by-products of pigment manufacturing (e.g., PCB-11 and PCB-209) were higher in the urban house dusts than those from other locations, resulting from human activities utilizing paints and pigments. Daily intake doses (ID), non-carcinogenic hazard quotient (HQ), and lifetime cancer risk (CR) of PCBs through dust ingestion were estimated for ELV workers and residents in the studied areas. The workers and children in the ELV sites were estimated to be at higher risk of PCB exposure, however almost all of the HQ < 1 and CR < 10⁻⁴ indicate no serious risk related to dust-bound PCBs.
... Nevertheless, all the HQ and CR values were several orders of magnitude lower than critical values (HQ b 1 and CR b 10 −6 ), indicating negligible non-cancer and cancer risks of PCBs associated with street dusts in these study areas. Furthermore, the daily intakes of dl-PCB-TEQs in our study were also smaller than tolerable daily intake range of 1-4 pg TEQ kg −1 d −1 (Van Leeuwen et al., 2010). As compared with the overall daily intake of PCBs (comprising diet, indoor dust ingestion, and inhalation pathways) of 50 ng d −1 previously reported by Tue et al. (2013) for Hanoi residents, the contribution of street dust ingestion was insignificant for normal adults but it can contribute about 2% in total PCB intake by occupationally exposed individuals. ...
A full congener-specific determination of polychlorinated biphenyls (PCBs) was conducted for street dusts in some areas in northern Vietnam. Total 209 PCB concentrations (median and range) of 14 (2.2–120), 11 (6.6–32), and 0.25 (0.10–0.97) ng g⁻¹ were measured in the street dusts from an industrial park, an urban area, and a rural commune, respectively, suggesting environmental loads of PCBs related to industrialization and urbanization in northern Vietnam. PCB patterns of street dusts from the industrial park were dominated by lightly chlorinated homologs (tri- and tetra-CBs), while more highly chlorinated homologs (penta- and hexa-CBs) were the major contributors to total PCBs in the urban samples, indicating different emission sources. Linear correlations of log-transformed sum of 7 indicator congeners with total PCBs and sum of dioxin-like PCBs were observed. PCB-11, an inadvertently produced congener of pigment manufacturing processes, was detected in all the samples with more elevated proportions in the urban and rural areas than industrial park. Our results have revealed complex emission sources of PCBs in the study areas, including both historical (e.g., the past usage of imported PCB-containing oils and old electric equipment) and current sources such as releases from industrial activities and increasing use of new consumer products. Occupationally exposed persons (e.g., street sweepers, street vendors, and traffic policemen) and children in the urban and industrial areas were estimated to receive much higher doses of dust-bound PCBs than general population, suggesting the need for appropriate protection conditions.
... Toxicities of dioxins include carcinogenicity and endocrine, immune, reproductive, and neurobehavioral effects (1). As a dietary intake safety standard, the tolerable daily intake (TDI) range of dioxins has been set to 1 -4 pg Toxic Equivalents (TEQ)/kg/day by the World Health Organization (WHO) (3). TDI was determined on the basis of the body burden at which the most sensitive adverse health effects, such as reproductive, immune, and developmental effects, were observed in offspring, and by applying an uncertainty factor of 10 (3). ...
The author reviewed recent reports about the blood levels and dietary intake of polychlorinated dibenzo‐p‐dioxins (PCDDs)/furans (PCDFs)/dioxin‐like polychlorinated biphenyls (DL‐PCBs) to investigate the trends of dioxin exposure, and epidemiologic studies on the associations of blood levels of dioxins with metabolic diseases. In recent years, dietary intake of dioxins has been decreasing, and the means are equal to or less than 1.0 pg Toxic Equivalents (TEQ)/kg/day in the general populations of several countries. The blood levels of dioxins are also decreasing, probably because of reduced dietary intake. Many cross‐sectional studies reported positive associations between blood levels of some isomers or TEQ‐based concentrations of PCDDs/PCDFs/DL‐PCBs and diabetes in general populations. Three cohort studies on populations with heavy exposure and two nested case‐control studies on general populations have also been published, but the results are inconsistent. Three large‐scale cross‐sectional studies and two cohort studies reported an association between blood levels of some isomers or TEQ‐based concentrations of PCDDs/PCDFs/DL‐PCBs and metabolic syndrome. In addition, three cross‐sectional studies reported significant positive associations with gout/hyperuricemia. Further prospective studies and experimental studies are needed to establish cause‐effect relationships, and to clarify the biological mechanisms for the association between background exposure to dioxins and potential health effects. J. Med. Invest. 65:151‐161, August, 2018
... pg I-TEQ kg -1 day -1 ), respectively, slightly higher than a previous study (adults: 2.54 pg WHO-TEQ kg -1 bw day -1 ; children: 4.5 pg WHO-TEQ kg -1 bw day -1 ) (Li et al. 2007a). Whether adult or child of Guiyu, their DEDair values were far higher than that of general population from non-e-waste site in China (6.93 9 10 -2 pg WHO-TEQ kg -1 bw day -1 ) (Li et al. 2007b;Zhang et al. 2007b), even slightly higher than the tolerable daily human intake (1-4 pg WHO-TEQ kg -1 day -1 ) and the average DEDair of special population from e-waste site in China (2.54 pg WHO-TEQ kg -1 bw day -1 ) (van Leeuwen et al. 2000). The results of both studies indicate that the influence on children was almost twofold that of adults (Li et al. 2007a;Xiao et al. 2012). ...
This paper reviews the concentrations of persistent organic pollutants (POPs) in atmosphere of an electronic waste (e-waste) recycling town, Guiyu, in Southeast China, focusing on polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). We assess the evidence for the association between air pollution and human body burden, to provide an indication of the severity of respiratory exposure. Compared with standards and available existing data for other areas, it clearly shows that four typical POPs, derived from recycling processes, lead to serious atmospheric pollution and heavy body burden. From published data, the estimated respiratory exposure doses of Guiyu adults and children, varied between 2.48–10.37 and 3.25–13.6 ng kg⁻¹ body weight (bw) day⁻¹ for PBDEs, 2.31–7.6 and 4.09–13.58 pg World Health Organization-Toxic Equivalent Quantity (WHO-TEQ) kg⁻¹ bw day⁻¹ for PCDD/Fs, 5.57 and 20.52 ng kg⁻¹ bw day⁻¹ for PCBs, and 8.59–50.01 and 31.64–184.14 ng kg⁻¹ bw day⁻¹ for PAHs, respectively. These results show that air pollution is more harmful to children. Furthermore, except for PBDEs, the hazard quotient (HQ) of the other three pollutants was rated more than 1 by respiratory exposure only, and all of them are at risk of carcinogenesis. So we speculate these pollutants enter the body mainly through air inhalation, making respiratory exposure may be more important than dietary exposure in the Guiyu e-waste recycling area. Effective management policies and remediation techniques are urgently needed to prevent the deterioration of ambient air quality in the e-waste recycling area.
... The non-carcinogenic risk, expressed as hazard quotient (HQ), was calculated by comparing environmental exposure and total dietary intake established by the European strategy for reducing human exposure to PCDD/Fs, stated at 2 pg I-TEQ/kg/day (European Commission 2001). The World Health Organization established the range of l-4 pg I-TEQ/ kg/day for the tolerable daily intake (van Leeuwen et al. 2000). HQ for all surveys did not exceed the most restrictive legal limit, ranging between 0.003 and 0.04. ...
In 1996-1998, a wide surveillance program was initiated in the vicinity of a new hazardous waste incinerator (HWI) placed in Constantí (Catalonia, Spain), which started its regular operations in 1999. The program was aimed at assessing the environmental impact of the facility on the surrounding environment, as well as to evaluate the potential risks for the population living in the neighborhood. Since then, among other measurements, the concentrations of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) have been periodically determined in soil and herbage samples. This study shows the results, corresponding to the period 2013-2016. Data were compared with those obtained in the baseline survey (1996-1998), as well as with those of the previous survey (2011-2012). The median PCDD/F concentrations in soils were 0.44 and 0.33 ng toxic equivalent (I-TEQ)/kg in 2015 and 2016, respectively, with a significant decrease in relation to the baseline survey, and a non-significant decrease between 2015 and 2016. In turn, PCDD/F levels in vegetation showed some fluctuations over time, being the concentrations of PCDD/Fs in 2013 very similar to those found in 2012 (1.11 and 1.23 ng I-TEQ/kg, respectively). These concentrations notably decreased along the three last campaigns (0.16, 0.23, and 0.17 ng I-TEQ/kg in 2014, 2015, and 2016, respectively). These changes would be more related to a number of environmental factors rather than to a variation of PCDD/F emissions by the HWI. With respect to human health risks, exposure to PCDD/Fs in the area under potential influence of the HWI is not of concern, as the current environmental concentrations of PCDD/Fs do not mean additional carcinogenic or non-carcinogenic risks for the local population.
... Due to methodological difficulties in assessing deficiency of iron, a particularly central micronutrient present in red meat, from dietary sources, and due to lack of good dose-response relationships to characterize the risks associated with iron deficiency (The Scientific Advisory Committee on Nutrition, 2010) it was not possible to quantify the health impact of potential changes in iron intake due to the year and removes all symptoms. (Larsen and Nørhede, 2013;US EPA, 2012;Van Leeuwen et al., 2000) Red meat ...
Danish dietary guidelines recommend the Danish population to increase the consumption of fish while decreasing the consumption of red and processed meat to prevent nutrition-related diseases. However, the presence of contaminants in these foods may affect the overall risk-benefit balance of such substitution. We performed a quantitative risk-benefit assessment on substituting red and processed meat with fish in a Danish diet. We modeled the substitution among Danish adults based on data from a Danish dietary survey and compared four alternative scenarios based on varying chemical and nutrient exposures to the current consumption. We quantified the overall health impact of the substitutions in terms of Disability-Adjusted Life Years (DALYs). Approximately 150 DALYs/100,000 individuals could be averted each year if Danish adults consumed 350 g of fish/week (fatty or mix of fatty and lean) while decreasing the consumption of red and processed meat. A lower beneficial impact was observed when consumption of fish was restricted to lean fish (80 DALYs/100,000 averted), and a marked health loss (180 DALYs/100,000) was estimated when consumption was restricted to tuna. Our results show an overall beneficial effect of the substitution if the consumption of large predatory fish is low and at least half is fatty fish.
... On the other hand, 2,3,7,8tetrachlorodibenzo-p-dioxin (TCDD) is a persistent organic pollutant generated from waste incinerators as an undesired by-product. TCDD contaminates the body because of a long half-life and bioaccumulates in the food chain [27]. Exposure of pregnant rats to TCDD results in altered bone geometry, mineral density, and mechanical strength in the offspring [28]. ...
People are frequently and unintentionally exposed to many chemical compounds, such as environmental pollutants and endocrine-disrupting chemicals (EDCs), in food and from the atmosphere. In particular, endocrine-disrupting TBBPA and dioxins are found in human breast milk and in the body. Conventional studies evaluate toxicity by administering a single substance to cells or animals, but evaluation of the toxicity of mixtures of these ingested compounds is essential for "true" toxicological assessment. We evaluated toxic effects in vitro using human mesenchymal stem cells (hMSCs). TBBPA increased the number of lipid droplets, and upregulated the expression of adipocyte-related mRNA, aP2 and LPL, through a PPARγ-dependent mechanism. TCDD suppressed lipid droplets and adipocyte-related mRNA levels. Adipocyte differentiation was stimulated by TBBPA and inhibited by TCDD in a dose-dependent manner. TBBPA did not influence osteoblast differentiation, but TCDD suppressed ALP staining and activity, calcium deposition, and osteoblast-related mRNA levels. In a mixture of TBBPA and TCDD, TBBPA inhibited TCDD suppression of adipocyte and osteoblast differentiation in a dose-dependent manner. Interestingly, we observed lipid droplets in TBBPA-treated cells differentiated into osteoblasts. These results suggest that TBBPA and TCDD disrupted differentiation into adipocytes and osteoblasts and contributes to a more complete toxicological understanding of exposure to these chemical substances.
... One of the aims of this review was to compare polar bears with the OHC exposed farmed Norwegian Arctic foxes and housed West Greenland sledge dogs serving as proxy species for polar bear health Leeuwen et al. (2000). ...
The aim of the present review is to assess the health eff ects from long-range transported industrial contaminants on polar bears (Ursus maritimus). Based on the international scientifi c literature on polar bears and controlled studies on sledge dogs and Arctic foxes; hormone and vitamin concentrations , liver, kidney and thyroid gland morphology as well as reproductive and immune systems of polar bears are likely to be infl uenced by a mixture of long-range transported industrial contaminants. Furthermore, exclusively based on polar bear contaminant studies, bone density reduction and neurochemical disruption and DNA hypomethylation of the brain stem seemed to occur. Furthermore, PFC concentrations , at which population eff ect levels could occur, are likely to be reached around year 2012 for the East Green-land polar bear subpopulation if current increasing temporal trends continue. Such proposed reproductive population eff ects were supported by physiological based pharma-cokinetic (PBPK) modelling of critical body residues (CBR). The estimated daily TEQ for East Greenland polar bears and East Greenland sledge dogs were 32-281 folds above WHO ∑TEQ guidelines for humans. Compared to human tolerable daily intake (TDI), these were exceeded for PCBs, dieldrin, chlordanes and ∑HCH in East Greenland polar bears. In conclusion, polar bears seem to be susceptible to contaminant induced stress that may have an overall sub-clinical impact on their health and population status via impacts on their immune and reproductive systems.
... Q. Dai, et al. Environment International 139 (2020) 105731 three major EWRS of China account for 19%−54% (mean 40%) of the total daily intake, which far exceeds the WHO recommended total daily intake limit [1-4 pg TEQ kg −1 body weight (bw) day −1 ] (WHO, 1998b;van Leeuwen et al., 2000). High exposure quantity and absorption rate lead to higher intake of PCDD/Fs by infants (103.0 pg WHO-TEQ kg −1 bw day −1 ) for their exclusive consumption of breast milk with relatively high PCDD/F concentration in Taizhou Gies et al., 2007). ...
Electrical and electronic waste (e-waste) burning and recycling activities have become one of the main emission sources of dioxin-like compounds (DLCs). Workers involved in e-waste recycling operations and residents living near e-waste recycling sites (EWRS) are exposed to high levels of DLCs. Epidemiological and experimental in vivo studies have reported a range of interconnected responses in multiple systems with DLC exposure. However, due to the compositional complexity of DLCs and difficulties in assessing mixture effects of the complex mixture of e-waste-related contaminants, there are few studies concerning human health outcomes related to DLC exposure at informal EWRS. In this paper, we have reviewed the environmental levels and body burdens of DLCs at EWRS and compared them with the levels reported to be associated with observable adverse effects to assess the health risks of DLC exposure at EWRS. In general, DLC concentrations at EWRS of many countries have been decreasing in recent years due to stricter regulations on e-waste recycling activities, but the contamination status is still severe. Comparison with available data from industrial sites and well-known highly DLC contaminated areas shows that high levels of DLCs derived from crude e-waste recycling processes lead to elevated body burdens. The DLC levels in human blood and breast milk at EWRS are higher than those reported in some epidemiological studies that are related to various health impacts. The estimated total daily intakes of DLCs for people in EWRS far exceed the WHO recommended total daily intake limit. It can be inferred that people living in EWRS with high DLC contamination have higher health risks. Therefore, more well-designed epidemiological studies are urgently needed to focus on the health effects of DLC pollution in EWRS. Continuous monitoring of the temporal trends of DLC levels in EWRS after actions is of highest importance.
... Last, this study was conducted among foundry workers and controls. Although the estimated PCDD/Fs intake of the workers did not exceed the tolerable daily intake of WHO (van Leeuwen et al., 2000), further epidemiologic studies are needed to confirm the findings in general populations. ...
The lung has been reported to be one of the target organs of polychlorinated dibenzo-dioxins and polychlorinated dibenzo-furans (PCDD/Fs) in many toxicological studies. While the associations between PCDD/Fs exposure and lung function levels have not been investigated thoroughly. This study aimed to explore these associations and the potential mediating role of oxidative stress. In this study, 201 foundry workers and 222 non-exposed general residents were recruited from central China, and their lung function parameters were measured. Air and food samples were collected to determine the PCDD/Fs levels for individual PCDD/Fs exposure estimation. Serum PCDD/Fs levels were determined in a subgroup of individuals randomly selected from the study population to reflect the body burden. It was found that each 1-unit increase in ln-transformed concentration of PCDD/Fs exposure (fg TEQ/bw/day) was associated with a 0.47 L decrease in FVC and a 0.25 L decrease in FEV1. Each 1-unit increase in ln-transformed concentration of serum PCDD/Fs (fg TEQ/g lipid) was associated with a 0.36 L decrease in FVC and a 0.24 L decrease in FEV1. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) was not only positively related to PCDD/Fs exposure, but also inversely associated with FVC and FEV1 are FVC (β = -0.15, 95% CI: -0.22 to -0.08) and FEV1 (β = -0.07, 95% CI: -0.13 to -0.02). Mediation analysis revealed that urinary 8-OHdG mediated 12.22% of the associations of external PCDD/Fs exposure with FVC levels, 28.61% and 27.87% of the associations of serum PCDD/Fs with FVC and FEV1 levels respectively. Our findings suggested that PCDD/Fs exposure was associated with decreased lung function levels by a mechanism partly involving oxidatively generated damage to DNA.
... In our study TEQs of the seven dl-PCBs for all investigated fish species did not exceed this limit. The EDI dl PCBs value in this study were low, while the WHO set for TDI for the sum of TEQ and l-PCB-TEQ of 1-4 pg TEQ kg/ body weight [13], which is comparable with a tolerable weekly intake of 14 pg TEQ/kg body weight as fixed by the European Union Scientific Committee on Food [14,15]. ...
... Hence people working in the EW sector might be exposed to high inhalation risk. 89 Furthermore, in EW transect, the median value of the estimated WHO tolerable daily intake via inhalation expressed as TEQs for dioxin like compounds was the highest and, exceeded the maximum recommended limit (1−4 pg TEQ/kg bw-day) 90 for youth and adult. This was due to high dl-PCBs in the EW sites and PCB-126 was the major contributor. ...
... When compared to the tolerable daily intake (TDI), EDIs were higher than the suggested values given by the World Health Organization (WHO) of 1-4 pg TEQ/kg bw per day [33]. These safety standards are intended for chronic lifetime exposure; thus, they are not directly applicable to breastfeeding, which covers a much shorter period of life [27]. ...
Persistent organic pollutants (POPs) are organic compounds that resist biochemical degradation , moving long distances across the atmosphere before deposition occurs. Our goal was to provide up-to-date data on the levels of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in breast milk from Chilean women and to estimate the exposure of infants due to breast milk consumption. In Chile, we conducted a cross-sectional study based on methodologies proposed by the WHO, with a sample of 30 women recruited from three defined areas: 10 from the Arica Region (urban; Arica and Parinacota Region), 10 from Coltauco (rural; O'Higgins Region), and 10 from Molina (40% rural; Maule Region). High-resolution gas chromatography coupled with high-resolution mass spectrometry (HRGC/HRMS) was performed on pooled samples from each area. We calculated equivalent toxic concentrations (WHO-TEQ) based on the current WHO Toxic Equivalency Factors (TEF). The minimum and maximum values of ∑ PCDDs/Fs + DL-PCBs-TEQ were 4.317 pg TEQ/g fat in Coltauco and 6.31 pg TEQ/g fat in Arica. Molina had a total TEQ of 5.50 pg TEQ/g fat. The contribution of PCDD/Fs was approximately five-fold higher than that of DL-PCBs. The Estimated Daily Intake (EDI) of ∑ PCDDs/Fs + DL-PCBs based on the three pooled samples ranged between 6.71 and 26.28 pg TEQ/kg body weight (bw)/day, with a mean intake of 16.11 (±6.71) pg TEQ/kg bw/day in breastfed children from 0 to 24 months old. These levels were lower than those reported in international studies. Despite the fact that the observed levels were low compared to those in most industrialized countries, the detection Citation: Foerster, C.; Zúñiga-Venegas, L.; Enríquez, P.; Rojas, J.; Zamora, C.; Muñoz, X.; Pancetti, F.; Muñoz-Quezada, M.T.; Lucero, B.; Saracini, C.; et al.
... Costopoulou 3.94, 5.57 and 6.14 pg/g fat WHO-TEQ ) [80]. WHO has estimated the range of tolerable daily dose as 1-4 pg TEQ/kg bs per day for babies exposed to dioxin contaminants such as PCDD/Fs and PCBs [81]. Focant et al. calculated the average concentration for total TEQ (PCDD/Fs and PCBs) as 17.81 pg/g and the daily intake of PCDD/Fs and PCBs as 62.3 TEQ/kg bw per day [82]. ...
This review attempted to evaluate the exposure of thermal processing contaminants such as furan, chloropropanols and acrylamide from infant formulas. Furan, chloropropanols and acrylamide exist at varying levels in several types of foods that are consumed in daily diet including infant formulas. The consumption of these foods leads to the exposure to the thermal processing contaminants. In this sense, it is apparent that humans face hidden danger through dietary exposure throughout their lives. Infants are considered as the age group that expose to the highest levels of these substances as a result of the fact that they have low body weight and consume infant formulas in their diets as alternative nutrition. The review emphasizes that the infant formulas are not innocent, on the contrary, they can be considered as safety critical for infants considering that infant formulas include furan, chloropropanols and acrylamide. Therefore, this review suggests that in this sense all shareholders’ (university, non-governmental organizations, public and private sector) acting in concert with each other is crucially important for the health of individuals and overall society.
... Calculated on the basis of default values for population body weight reported by the European Food Safety Authority (EFSA 2012), daily intakes for an adult (70 kg) of PCDD/Fs for the high concentration of airborne ash equate to 1.4 × 10 -6 pg TCDD BEQ/kg bw/day, whereas the intake of PAHs is 0.3 pg BaP BEQ/kg bw/day. Referencing the WHO guideline values of 10-40 pg of TCDD/kg bw/day (van Leeuwen et al. 2000) and 100 µg of BaP/kg bw/day (JECFA 2006), the measured values are far below the TDI. Considering that the exposure to airborne ash is typically of limited duration, whereas the guidance values for health-based exposure limits relate to long-term exposure, it can be said that direct exposure to PCDD/Fs and PAHs via inhalation of ash likely represents a low immediate concern for human health. ...
Exposure to volcanic ash is a long-standing health concern for people living near active volcanoes and in distal urban areas. During transport and deposition, ash is subjected to various physicochemical processes that may change its surface composition and, consequently, bioreactivity. One such process is the interaction with anthropogenic pollutants; however, the potential for adsorbed, deleterious organic compounds to directly impact human health is unknown. We use an in vitro bioanalytical approach to screen for the presence of organic compounds of toxicological concern on ash surfaces and assess their biological potency. These compounds include polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo- p -dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dlPCBs). Analysis of ash collected in or near urbanised areas at five active volcanoes across the world (Etna, Italy; Fuego, Guatemala; Kelud, Indonesia; Sakurajima, Japan; Tungurahua, Ecuador) using the bioassay inferred the presence of such compounds on all samples. A relatively low response to PCDD/Fs and the absence of a dlPCBs response in the bioassay suggest that the measured activity is dominated by PAHs and PAH-like compounds. This study is the first to demonstrate a biological potency of organic pollutants associated with volcanic ash particles. According to our estimations, they are present in quantities below recommended exposure limits and likely pose a low direct concern for human health.
... Contaminated animal feed supplies can also introduce POPs into food as occurred in the Belgian dioxin crisis in 1999 [21] and the Ireland dioxin accident in 2008 [22]. To ensure food safety, many international and national bodies have set food and animal feed limits for commonly found POPs, and related surveillance programs have been developed to ensure that POPs contamination is below harmful level [23][24][25]. ...
Persistent Organic Pollutants (POPs) are a serious food safety concern due to their persistence and toxic effects. To promote food safety and protect human health, it is important to understand the sources of POPs and how to minimize human exposure to these contaminants. The POPs Program within the U.S. Food and Drug Administration (FDA), manually evaluates congener patterns of POPs-contaminated samples and sometimes compares the finding to other previously analyzed samples with similar patterns. This manual comparison is time consuming and solely depends on human expertise. To improve the efficiency of this evaluation, we developed software to assist in identifying potential sources of POPs contamination by detecting similarities between the congener patterns of a contaminated sample and potential environmental source samples. Similarity scores were computed and used to rank potential source samples. The software has been tested on a diverse set of incurred samples by comparing results from the software with those from human experts. We demonstrated that the software provides results consistent with human expert observation. This software also provided the advantage of reliably evaluating an increased sample lot which increased overall efficiency.
... The EDI of PCDD/DFs was used to assess whether infants are at risk of exposure to dioxin through breastfeeding as mentioned by numerous previous studies (Chan et al., 2007;Chao et al., 2005;Costopoulou et al., 2013;Deng et al., 2012;Huang et al., 2019;Li et al., 2009;Lu et al., 2015;Xu et al., 2019;Zhang et al., 2016). In this study, the infant EDI level was 54.21 pg TEQ/kg body wt/day in the exposed group, which was 13.5 times higher than the tolerable daily intake mentioned by the WHO (1-4 pg TEQ/kg body wt/day) (Van Leeuwen et al., 2000). Moreover, the infant EDI (54.21 pg TEQ/kg body wt/day) in our study was approximately two times higher than that in the Chinese National Survey (28.0 pg TEQ/kg body wt/day) (Li et al., 2009). ...
In the past two decades, numerous studies on dioxin concentrations in breast milk have been conducted in China. However, information concerning dioxin concentrations in breast milk from women living in e-waste recycling sites remains limited. Thus, this study aimed to evaluate health risk owing dioxin intake in e-waste recycling areas in China. In 2015, 42 mothers were recruited from an e-waste recycling site, and the same number of mothers were recruited from a reference site. We collected 10-mL breast milk samples from each participant. Breast milk concentrations of polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs) were significantly higher in the exposed group than in the reference group. The total toxic equivalents (TEQ) of PCDDs/DFs were 9.68 pg/g lipid in the exposed group, a value two times higher than those in the reference group (4.18 pg/g lipid). The estimated daily intake (EDI) of PCDD/DFs was calculated to assess the risk of dioxins through breastfeeding. The infant EDI level was two times higher in the exposed group (54.21 pg TEQ/kg body wt/day) than in the reference group (23.41 pg TEQ/kg body wt/day). Our findings suggest that mothers and their breastfeeding infants living in an e-waste recycling site were exposed to higher dioxin concentrations than those living in a reference site.
... Moreover, the occurrence of dioxin in the blood of younger residents <25 years old (35 pg TEQ g − 1 in male blood and 17 pg TEQ g − 1 in female blood), who were born after the end of the Vietnam war, supports ongoing human uptake of dioxins. In addition, the average daily intake of TCDD by infants of primiparous (first child) and multiparous (> 5 child) in the town of Dong Son was estimated to be 80-85 pg TEQ kg − 1 bw d − 1 and 153-167 pg TEQ kg − 1 bw d − 1 , respectively, values much higher than the WHO-TDI acceptance level of 1-4 pg TEQ kg − 1 bw d − 1 (Van Leeuwen et al., 2000). High residues of PCDD/Fs have also been found in animal tissues with concentrations of 87 pg TEQ g − 1 in duck fat and 35 pg TEQ g − 1 in carp fat (Hatfield Consultants Ltd., 2000). ...
In this study, an AhR-responsive reporter-gene cell-based bioassay CALUX was used to assess the biological potency of dioxins and dioxin-like PCBs (dl-PCBs) in top soil samples collected from a former airbase (A-So) and remote regions from urban and agricultural areas in Thua Thien Hue, Vietnam. In top soil collected from A-So airbase, Bioanalytical EQuivalent (BEQ) concentrations of up to 2700 pg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) per g dry weight (pg BEQ-TCDD g − 1 dw) were assessed. Interestingly, while BEQ values for dl-PCBs were found to be up to 13 pg BEQ-TCDD g − 1 dw, the dl-PCB activity was not detected in all the hotspot sample extracts. In contrasts, BEQ values for dioxin like compounds from remote regions were much lower and occasionally below the quantification limits of the method. The BEQ activities obtained in this study have a similar trend to the WHO-TEQ results for the samples collected in the A-So airbase. However, BEQ values were higher than those of TEQ, probably reflecting the presence of additional AhR ligands and/or possible non-additive interactions in the sample mixture. This study confirms that after more than 60 years, a strong residual pollution of PCDD/Fs remains on this former air base following the use and storage of Agent Orange during the Vietnam War, raising a health risk for populations exposed in this area because livestock animals graze there.
... In the latter study, the authors assumed a constant birthweight of 7 kg and a low milk consumption rate (600 mL per day) which greatly reduced the EDIs calculated. However, the mean EDI for total dioxins (23.9 pg TEQ/ kg bw per day) in the present study was still several times higher than the WHO tolerable intake (1-4 pg TEQ/kg bw per day) (van Leeuwen et al., 2000) suggesting that the breastmilk in Uganda might pose some health risks to the nursing infants with respect to PCDD/Fs and dl-PCBs. This conclusion must, however, be interpreted with caution since the WHO tolerable levels are meant for chronic exposure and not just during lactation as this covers a short period of time (van den Berg et al., 2017). ...
Persistent organic pollutants (POPs) are ubiquitous contaminants with adverse health effects in the ecosystem. One of such effects is endocrine disruption in humans and wildlife even at background exposure concentrations. This study assessed maternal breastmilk concentrations of POPs; brominated flame retardants (BFRs), polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), and the potential health risks posed to the nursing infants. We also evaluated the association of these POPs with total 3,3′,5-triiodo-L-thyronine (T3), L-thyroxine (T4), and 3,3′,5′-triiodo-L-thyronine (rT3) levels measured in human breast milk. Thirty breastmilk samples were collected from Kampala, Uganda between August and December, 2018. Hexabromobenzene was not detected while the maximum level of 2,2',4,4',5,5'-hexabrombiphenyl was 64.7 pg/g lw. The median levels of total indicator PCBs, PBDEs, dioxin-like PCBs, and PCDD/Fs in the samples were 159 pg/g lw, 511 pg/g lw, 1.16 pg TEQ/g lw, and 0.4 pg TEQ/g lw, respectively. These levels were lower than those reported in other countries. Owing to their bio accumulative nature, PCBs -81, -169, and ∑PCDD/Fs increased with increase in maternal age. Estimated dietary intakes for dioxin-like PCBs and PCDD/Fs were lower than those reported elsewhere but were higher than the WHO tolerable daily intakes suggesting potential health risks to nursing infants. In adjusted single pollutant models, PCB-126, PCB-169, and ∑PCBTEQ were negatively associated with T3, while 1,2,3,4,5,7,8-HpCDF was positively associated with rT3. Although these associations did not persist in multipollutant models, our findings suggest potential thyroid hormone disruption by POPs in mothers. This may reduce the levels of thyroid hormones transferred from the mother to the neonates and, hence, adversely influence infant growth. A temporal study with a bigger sample size is required to corroborate these findings.
... Specifically, mice were exposed to 20 pg TCDD/kg bw/day, 200 ng PCB153/kg bw/day, 500 mg DEHP/kg bw/day and 40 mg BPA/ kg bw/day (Supplementary Table 1). These doses were at least 10 times lower than the NoAEL (No-observed Adverse Effect Level) dose for each pollutant when taken individually (DEHP, BPA) or representative congener (TCDD, PCB153) (Beausoleil et al., 2018;Van leeuwen et al., 2000;WHO, 2003). To ensure that animals ingested the correct amount of polluted food/kg bw/day and were fed ad libitum, the calculations of intake of pollutants in the diet were based on 1 g of contaminated food/17 g of body weight/day, and pollutant-free food was provided to the animals at libitum. ...
Environmental pollutants suspected of disrupting the endocrine system are considered etiologic factors in the epidemic of metabolic disorders. As regulation of energy metabolism relies on the integrated action of a large number of hormones, we hypothesized that certain chemicals could trigger changes in glucocorticoid signaling. To this end, we exposed C57Bl6/J female and male mice between 5 and 20 weeks of age to a mixture of 2,3,7,8- tetrachlorodibenzo-p-dioxin (20 pg/kg body weight/day [bw/d]), polychlorobiphenyl 153 (200 ng/kg bw/d), di-[2-ethylhexyl]-phthalate (500μg/kg bw/d) and bisphenol A (40μg/kg bw/d). In female mice fed a standard diet (ST), we observed a decrease in plasma levels of leptin as well as a reduced expression of corticoid receptors Nr3c1 and Nr3c2, of leptin and of various canonical genes related to the circadian clock machinery in visceral (VAT) but not subcutaneous (SAT) adipose tissue. However, Nr3c1 and Nr3c2 mRNA levels did not change in high-fat-fed females exposed to pollutants. In ST-fed males, pollutants caused the same decrease of Nr3c1 mRNA levels in VAT observed in ST-fed females but levels of Nr3c2 and other clock-related genes found to be down-regulated in female VAT were enhanced in male SAT and not affected in male VAT. The expression of corticoid receptors was not affected in the livers of both sexes in response to pollutants. In summary, exposure to a mixture of pollutants at doses lower than the no-observed adverse effect levels (NoAELs) resulted in sex-dependent glucocorticoid signaling disturbances and clock-related gene expression modifications in the adipose tissue of ST-fed mice.
The concentrations and potential human health risks through dietary ingestion of PCBs in canned sardines collected from the Nigerian market were determined. The results shows that the total PCBs concentrations varied from <LOD to 668 ng g⁻¹. The composition of PCBs in the canned sardines followed the order: Penta-PCBs > Hexa-PCBs > Tetra-PCBs > Di-PCB > Deca-PCB > Tri-PCBs > Hepta-PCBs > Octa-PCB. The estimated daily intake for total PCBs ranged from <LOD to 926 ng kg⁻¹ bw day⁻¹ and < LOD to 232 ng kg⁻¹ bw day⁻¹ for child and adult exposures respectively. The TEQs values of the dl-PCBs indicated that these canned sardines are unsafe for consumption. The hazard index and total cancer risk values in 53% of the canned sardines were greater than 1 and 1 × 10⁻⁶ respectively indicating that there are adverse non-carcinogenic and carcinogenic risks associated with human consumption of these canned sardines.
Total diet samples collected from seven regions throughout Japan in 2016 were analysed for polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and dioxin-like polychlorinated biphenyls (DL-PCBs), known collectively as dioxins. This led to estimates of the latest dietary intake of these contaminants for the general Japanese population (≥ 1 year old). The average daily intake of dioxins for a person weighing 50 kg, calculated at non-detected congener concentrations assumed to be equal to zero, was estimated to be 0.54 pg TEQ (toxic equivalents) kg⁻¹ body weight (bw) day⁻¹. This value is well below the tolerable daily intake of 4 pg TEQ kg⁻¹ bw day⁻¹ for dioxins in Japan. The average intake was highest from fish and shellfish, followed by meat and eggs. The TEQ contribution of the fish and shellfish group to the total dietary TEQs was significant (89%). The DL-PCBs accounted for about 67% of the dioxin intake. The latest dioxin intake level was compared with previous estimates from total diet study results obtained annually since 1998 to determine the time trends in the dietary intake of dioxins in Japan. Overall, the average dioxin intake appeared to be decreasing gradually during the period of study. The previous average intakes of dioxins ranged from 0.58 to 1.9 pg TEQ kg⁻¹ bw day⁻¹. The latest average intake was the lowest since 1998 and was about one-third of the average intake in 1998. This decreasing trend in the dietary intake of dioxins was mainly influenced by the decreased dioxin intakes from two food groups, fish and shellfish, and meat and eggs.
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.
The levels and accumulation characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) were investigated in nine pools of representative plant-origin foodstuffs randomly collected from markets located in five regions of the Chinese mainland during 2018–2019. The collected foodstuffs consisted of cereals, beans, potatoes, leafy vegetables, root and stem vegetables, melon vegetables, legume vegetables, edible fungi, and mixed vegetable oil. In the fresh plant food pools, the concentrations of toxic equivalency (WHO-TEQ) were in the ranges of 0.9–14.5 pg/kg in upperbound (UB) scenario and 0.002–7.3 pg/kg in lowerbound (LB) scenario on a fresh weight basis; and TriCDFs and TeCBs were the predominant PCDD/F and PCB homologues, respectively. In the mixed vegetable oil, the WHO-TEQ concentrations were 129.4 pg/kg and 103.6 pg/kg on a lipid weight basis in UB and LB scenarios, respectively; and high-chlorinated PCDD/F and PCB homologues were much more abundant. The estimated plant food-borne dietary intakes of WHO-TEQ by a standard adult in the five surveyed regions were in the ranges of 3.39–4.20 and 1.57–2.13 pg WHO-TEQ/kg body weight/month in UB and LB scenarios, respectively. Among all surveyed regions, consumption of cereals and vegetable oil made up the primary contributions to the estimated dietary intakes of WHO-TEQ. TriCDFs accounted for 41.1–83.9% of the PCDD/Fs dietary intakes via consumption of plant foods, and TeCBs made up 61.2–73.0% of the PCBs dietary intakes via consumption of plant foods, suggesting that the potential toxic effects of TriCDFs and TeCBs on human health should be concerned.
Among the diverse wastewater treatment routes, photoelectrocatalysis (PEC) developed by hybridization of photocatalyst with electrocatalyst has been demonstrated for a high potential in waste-to-energy applications. Here, we provide a comprehensive review to assess the technical readiness level of PEC techniques for both wastewater treatment and energy recovery, with a particular emphasis on the pulp and paper industry. The effects of various experminetal parameters on the removal of organic substances from wastewater and the simultaneous recovery of energy (using various electrodes, reactor types, and experimental conditions) have been discussed in relation to the PEC performance metrics (e.g., quantum yield (QY), space-time yield (STY) and figure of merit (FoM) metrics). Critical challenges in the augmentation of PEC are also summarized in terms of cost analysis, energy consumption, and durability. At last, future research prospects of the PEC system under the real-world conditions are discussed.
The distribution and toxic equivalents (TEQs) of brominated, chlorinated dibenzo-p-dioxins/dibenzofurans (PBDD/Fs and PCDD/Fs) in soils from Agbogbloshie e-waste site (Ghana) were investigated. The composition of brominated/chlorinated dibenzofurans (PXDFs) and diphenyl ethers (PBDEs, PCDEs and PXDEs) were examined using two-dimensional gas chromatography–time-of-flight mass spectrometry to elucidate possible formation pathways of dioxins from e-waste recycling. The highest concentrations of PCDD/Fs and PBDD/Fs were found respectively in the open burning (1.3–380 ng/g dry weight) and dismantling areas (11–1000 ng/g dry weight), and were comparable to the highest reported for informal e-waste sites. PXDFs and PXDEs were detected at up to the range of hundreds of nanogram per gram. The homologue profiles suggest that PXDFs were formed mainly from PBDFs through successive Br-to-Cl exchange. However, monobromo-PCDFs were also derived from de novo-generated PCDFs in open burning areas. PBDFs contributed similar or higher TEQs (7.9–5400 pg/g dry weight) compared with PCDD/Fs (6.8–5200 pg/g dry weight), whereas PXDFs were also substantial TEQ contributors in open burning areas. The high TEQs of PBDFs in the dismantling area (120–5200 pg/g dry weight) indicate the need to consider brominated dioxins besides chlorinated dioxins in future studies on health implications for e-waste workers and local residents.
The concentrations and distribution profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) were measured in representative animal origin foodstuffs randomly collected from markets located in five regions of the Chinese mainland during 2018–2019. The collected foodstuffs were classified into 11 pools consisting of pork, beef, mutton, poultry meat, chicken eggs, pure milk, mixed animal fat, fish, shrimp, shellfish, and cephalopods. The levels of tri-to octa-CDD/Fs (∑PCDD/Fs), tri-to deca-CBs (∑PCBs), and WHO-TEQ in the collected animal foods were found to be in the ranges of 0.4–14.3 pg/g, 0.04–2.8 ng/g, and 0.013–0.75 pg/g on a fresh weight basis, respectively. The concentrations of PCDD/Fs and PCBs in most of the animal food groups from coastal regions were obviously higher than those from inland regions. Remarkable differences in the homologue and congener distribution of PCDD/Fs and PCBs were observed between terrestrial and aquatic animal foods. The dietary intakes of WHO-TEQ via consumption of animal foods by a standard adult in the five regions were estimated to be in the range of 3.57–19.63 pg WHO-TEQ/kg body weight/month. Consumption of the aquatic animal food and pork categories contributed most of the estimated dietary intakes of WHO-TEQ in the coastal regions, whereas consumption of beef, mutton, and milk made up the primary contributions in Northwest region.
To monitor the body burden of persistent organic pollutants in mothers and infants living in proximity to a 10-year-old municipal waste incinerator (MWI), levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in the breast milk of mothers were evaluated, and the estimated daily intake (EDI) level of these pollutants in infants was assessed. In total, 14 mothers from the exposure area and 18 mothers from a control area were recruited for this study. In addition, the levels of 17 PCDD/F congeners and 18 PCB congeners in the breast milk of the mothers were estimated, and risk assessment for their infants by calculating their EDI levels was performed. The mean levels of ΣPCDD/Fs and TEQ-ΣPCDD/Fs in the breast milk of the exposure group were significantly greater than those of the control group (3.36 vs. 1.47 pg/g wet weight; and 0.24 vs. 0.12 pg TEQ/g wet weight, respectively; p < 0.05). With respect to PCBs, the mean levels of the total PCBs (ΣPCBs) and non-dioxin like-PCBs (ΣNDL-PCBs) in the exposure group were significantly greater than those in the control group (269 vs. 141 pg/g wet weight; 230 vs. 115 pg/g wet weight, respectively; p < 0.05). The mean levels of ΣPCDD/Fs and TEQ-ΣPCDD/Fs were positively correlated with the inhabit time of the exposure group (r = 0.636, r = 0.629, p < 0.05, respectively). The mean EDI level of the exposure group in infants was significantly greater than that of the control group (22.0 vs. 13.0 pg TEQ/kg bw day; p < 0.05). In conclusion, mothers and their breast-fed infants living in proximity to the 10-year-old MWI located in the Zhejiang Province of China exhibited a significantly higher body burden of PCDD/Fs and PCBs compared to those living in the control area.
This study investigated POPs contamination at a total of six sites: the world’s largest e-waste scrap yard in Agbogbloshie (Ghana); medical waste incinerators in Accra (Ghana), Kumasi (Ghana) and Yaoundé (Cameroon); and two open-burning waste dump sites in Yaoundé (Cameroon). The study measured POPs in eggs because free-range chickens are “active samplers” of materials on the ground. Eggs also represent an important human exposure pathway through consumption. To our knowledge, this is the first study to measure POPs in free-range chicken eggs from hens foraging at the Agbogbloshie e-waste scrap yard, as well as in Yaoundé.
The key findings of this study are:
High levels of POPs were found at all six sites
The sampling revealed very high levels of chlorinated dioxins, brominated dioxins, PCBs, PBDEs, and SCCPs in the eggs of chickens that had foraged in areas at the e-waste scrap yard, open burning dump sites and medical waste incinerators.
Some of the highest levels of POPs ever measured in eggs were found in samples collected at the Agbogbloshie e-waste scrap yard in Ghana Eggs sampled at the Agbogbloshie scrap yard in Ghana contained the highest level of brominated dioxins ever measured in eggs and one of the highest ever measured levels of the flame retardant chemical, HBCD. These eggs also contained the second highest level of chlorinated dioxins ever measured in poultry eggs. An adult eating just one egg from a free-range chicken foraging in Agbogbloshie area would exceed the European Food Safety Authority (EFSA) tolerable daily intake (TDI) for chlorinated dioxins by 220-fold. Indicator PCBs in these eggs were four-fold higher than the EU standard and dioxins and dioxin-like PCBs were 171-fold higher than the standard. These eggs also contained very high levels of SCCPs and PBDEs and relatively high levels of other POPs such as PeCB and HCB.
Eggs sampled near medical waste incinerators exceeded EU dioxin standards
Eggs near the medical waste incinerator in Accra, Ghana exceeded the EU dioxin limit by 13-fold and eggs sampled near the facility in Yaoundé exceeded the limit by more than two-fold. PCBs did not exceed limits, but significant levels were also found. High levels of HBCD were also found in eggs from the vicinity of the Yaoundé waste incinerator and one of the dumpsites.
Stockholm and Basel Convention provisions need strengthening
Hazardous waste limits in the Stockholm Convention should prevent the export of POPs waste, including e-waste. Currently the existing and proposed limits for POPs found in e-waste and generated by its ‘recycling’ in Africa and other developing regions is far too weak and allows the trade to continue. This includes limits for chlorinated dioxins/furans, flame retardant chemicals such as PBDEs and HBCD, and short chain chlorinated paraffins. These stricter limits (defined as Low POP Content in the Stockholm Convention) should be 50 mg/kg for PBDEs, 100 mg/kg for HBCD and SCCPs and 1 μg TEQ/kg for PCDD/Fs at a maximum. The Stockholm Convention could be further strengthened by listing brominated dioxins. The current provisional e-waste guidelines under the Basel Convention contain a loophole that allows for e-waste export under the guise of ‘export for repair’. This industry-promoted loophole makes the guidelines contradictory to the Convention because electronic products at end-of-life are hazardous waste. This loophole should be closed to preserve the integrity of the treaty.
Greater attention is needed to fully implement sustainable healthcare waste management
The data obtained from egg samples near medical waste incinerators in this study reinforce concerns over the inadequate healthcare waste management including the use of small incinerators. None of the medical waste incinerators in this study could be considered to employ Best Available Techniques / Best Environmental Practices due to their design, operation, lack of pollution control and lack of waste management for the waste incineration residues. Changing the hospital waste stream by moving away from PVC products, source reduction, segregation, recycling, training, and use of autoclaves and other non-combustion methods should be prioritized. A hospital facility designed for healing should not pollute the food chain or cause adverse impacts on human health and the environment.
Polybrominated diphenyl ethers (PBDEs) are a group of flame retardants which are frequently detected in the aquatic environment. PBDEs would convert into intermediates during some natural or artificial processes. A simple PBDEs congener, 2-bromodiphenyl ether (BDE-1), was targeted, and its transformation characteristics during combined UV-chlorine treatment were investigated in this study. It was found that BDE-1 could rapidly transform in combined UV-chlorine process, and HO was the predominant radical that contributed to BDE-1 degradation in ultrapure water system. The formation of toxic dibenzofuran (DF) and 2-hydroxydibenzofuran (2-OH-DF) was significantly promoted in combined UV-chlorine treatment, whose total yield (2.78%) was 1.46 times to that in UV treatment alone. Radical scavenger tests revealed that enhanced formation of DF-type products in combined UV-chlorine treatment was attributed to radical reactions. Cl or HO generated from free available chlorine photolysis reacted with ortho-carbon radicals generated from BDE-1 photolysis, and produced intermediates 2-chlorodiphenyl ether (2-Cl-DE) or 2-phenoxyphenol (2-OH-DE), which underwent intramolecular elimination of HCl or H2O and formed DF and 2-OH-DF. The treatment with alkaline conditions, high chlorine doses and strong irradiation would be beneficial to the less formation of DF-type products. Besides, the matrix effects of ambient water also inhibited the formation of DF-type products. Overall, this work would provide an insight into the role of free radicals in dibenzofuran formation during combined UV-chlorine treatment on PBDEs and a scientific reference for optimizing operational parameters in the water treatment.
Cleft lip and cleft palate also known as orofacial cleft is a congenital malformation involving the partial or total lack of anatomical continuity of craniofacial tissue. The most common environmental factors that may cause orofacial clefts include pharmaceuticals, alcohol, addictive drugs, and tobacco smoke. Living in the area of industrial factories, garbage, ironworks, crematoria, wastewater treatment plants, and plastic waste landfills also has a significant impact on the development of the craniofacial defects. Some of the main factors causing the formation of congenital craniofacial defects are dioxins, of which emission to the environment is an important environmental and health problem. Dioxins are a diverse group of organic chemical compounds, derivatives of oxanthrene and fumarates, which are organoleptically imperceptible. Acting mainly through induction of inflammation, they influence a number of metabolic processes, including the process of bone mineralization and embryonic development. In this work, we highlight the problem of orofacial cleft including the impact of dioxin on development of this defect and the recommended prevention.
Feeding during the first two years of life is very important for nutrition and
growth of an infant. It has a great effect on early morbidity and mortality and long-term effects on health. Breastfeeding has many benefits for both the infant and mother,
whereas formula feeding, although associated with disadvantages and problems, can
be life-saving for infants who need it. This book examines many aspects of infant
feeding and nutrition with chapters covering such topics as the impact of the first 1000
days of nutrition on child health and development, breastfeeding, factors behind the
the decision to breastfeed or formula feed, and the relationship between breastfeeding and
gut microbiota, among others.
Polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexabromobiphenyl (BB-153), novel brominated flame retardants (NBFRs), and unsubstituted/methylated polycyclic aromatic hydrocarbons (PAHs/Me-PAHs) were simultaneously monitored in the air samples collected from Vietnamese urban and vehicular waste processing areas by using polyurethane foam-based passive air sampling (PUF-PAS) method. Concentrations (pg m-3) of organic pollutants decreased in the order: PAHs (median 29,000; range 5100-100,000) > Me-PAHs (6000; 1000-33,000) > PCBs (480; 170-1100) > PBDEs (11; 5.3-86) > NBFRs (0.20; n. d. - 51) > BB-153 (n.d.). The difference in total PCB and PBDE concentrations between the urban and waste processing air samples was not statistically significant. Meanwhile, levels of PAHs, Me-PAHs, benzo [a]pyrene equivalents (BaP-EQs), and toxic equivalents of dioxin-like PCBs (WHO-TEQs) were much higher in the waste processing sites. This is the first report on the abundance of mono- and di-CBs (notably CB-11) in the air from a developing country, suggesting their roles as emerging and ubiquitous air pollutants. Our results have indicated potential sources of specific organic pollutants such as dioxin-like PCBs, PAHs, and Me-PAHs from improper treatment of end-of-life vehicles and other vehicle related materials (e.g., waste oils and rubber tires), as well as current emission of PCBs and PBDEs in the urban area in Vietnam. Further atmospheric monitoring studies should be conducted in this developing country that cover both legacy and emerging contaminants with a focus on areas affected by rapid urbanization and informal waste processing activities.
E-waste recycling is well known for releasing halogenated organic compounds (HOCs) and heavy metals. This study investigated the occurrence and distribution of traditional and novel classes of contaminants, including chlorinated, brominated, and mixed halogenated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs, PBDD/Fs, PXDD/Fs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and polyhalogenated carbazoles (PHCZs), in soil from an e-waste disposal site in Hangzhou. PBDEs were the most abundant, at 343–69306 ng kg⁻¹, followed by PHCZs (896–41,362 ng kg⁻¹), PCDD/Fs (349–19,396 ng kg⁻¹), PCBs (51.3–1834 ng kg⁻¹), PBDD/Fs (2.99–524 ng kg⁻¹) and PXDD/Fs (0.104–21.2 ng kg⁻¹). The detected target compound concentrations were generally lower than those reported in the literature for informal e-waste sites. Nevertheless, they can serve as a basis of information for evaluation and subsequent control. The toxic equivalent (TEQ) contributions from these contaminants (except PBDEs) decreased as follows: PCDD/Fs > PXDD/Fs > PHCZs > PCBs > PBDD/Fs. ΣDioxins (PCDD/Fs + PBDD/Fs + PXDD/Fs) accounted for 47.7%–97.2% of the total TEQs in the soil. OCDD, 1,2,3,4,6,7,8-HpBDF and OBDF were the dominant congeners, mainly derived from combustion and transport because of their low saturated vapor pressure. PXDFs were more abundant than PXDDs, and homologue profiles suggested a similar formation mechanism for PXDFs and PBDFs involving successive Br-to-Cl exchange. PHCZs were reported in soil from an e-waste disposal area for the first time, and their concentrations were several orders of magnitude higher than those of the other contaminants. Although the risk of human exposure in this study was estimated to be lower than the values recommended by the WHO (1–4 pg TEQ/kg bw/day), health implications still exist, and further investigations are necessary.
While terrestrial organisms such as livestock are consumed regularly, studies of internal distribution and bioaccumulation of persistent organic pollutants (POPs) have been focused more on aquatic organisms. In this study, we have assessed the internal distribution and fate of legacy (PCDD/Fs and PCBs) and emerging POPs (HBCDs and PFASs), and TBBPA in 42 tissues of a Bos Taurus. PCDD/Fs, DL-PCBs, and HBCDs were found 3, 4, and 4-fold higher in the lipid-rich organs (subcutaneous fat, visceral fat, large intestine) compared to the remaining organs and muscles, owing to their hydrophobic properties. The TBBPA concentration in the excrement was 36-fold higher compared to the average tissues, suggesting a short internal half-life of TBBPA. Among PFASs, PFUnDA displayed 98% contribution from all ionic PFASs in the tissues due to its strong binding affinity, high exposure via feed and water, and increasing emergence of PFUnDA and its precursors in the Southeast Asian countries. While our study suggests that, at the moment, there is no significant health risks to the general Korean population, the future changes in environmental exposure as well as the internal dynamics and fate of various POPs species should be kept in mind when consuming various parts of livestock.
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.
Endometriosis in Rhesus Monkeys (Macaca mulatta) Following Chronic Exposure to 2,3,7,8-Tetrachlorodibenzo-p-dioxin. RIER, S. E., MARTIN, D. C., BOWMAN, R. E., DMOWSKI, W. P., AND BECKER, J. L. (1993). Fundam. Appl. Toxicol. 21, 433–441.
The incidence of the reproductive disease endometriosis was determined in a colony of rhesus monkeys chronically exposed to
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD or dioxin) for a period of 4 years. Ten years after termination of dioxin treatment, the presence of endometriosis
was documented by surgical laparoscopy and the severity of disease was assessed. The incidence of endometriosis was directly
correlated with dioxin exposure and the severity of disease was dependent upon the dose administered (p < 0.001). Three of 7 animals exposed to 5 ppt dioxin (43%) and 5 of 7 animals exposed to 25 ppt dioxin (71%) had moderate
to severe endometriosis. In contrast, the frequency of disease in the control group was 33%, similar to an overall prevalence
of 30% in 304 rhesus monkeys housed at The Harlow Primate Center with no dioxin exposure. This 15-year study indicates that
latent female reproductive abnormalities may be associated with dioxin exposure in the rhesus. Therefore, the effects of this
toxin may be more diverse than previously recognized.
An expert meeting was organized by the World Health Organization (WHO) and held in Stockholm on 15-18 June 1997. The objective of this meeting was to derive consensus toxic equivalency factors (TEFs) for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and dioxinlike polychlorinated biphenyls (PCBs) for both human, fish, and wildlife risk assessment. Based on existing literature data, TEFs were (re)evaluated and either revised (mammals) or established (fish and birds). A few mammalian WHO-TEFs were revised, including 1,2,3,7,8-pentachlorinated DD, octachlorinated DD, octachlorinated DF, and PCB 77. These mammalian TEFs are also considered applicable for humans and wild mammalian species. Furthermore, it was concluded that there was insufficient in vivo evidence to continue the use of TEFs for some di-ortho PCBs, as suggested earlier by Ahlborg et al. [Chemosphere 28:1049-1067 (1994)]. In addition, TEFs for fish and birds were determined. The WHO working group attempted to harmonize TEFs across different taxa to the extent possible. However, total synchronization of TEFs was not feasible, as there were orders of a magnitude difference in TEFs between taxa for some compounds. In this respect, the absent or very low response of fish to mono-ortho PCBs is most noticeable compared to mammals and birds. Uncertainties that could compromise the TEF concept were also reviewed, including nonadditive interactions, differences in shape of the dose-response curve, and species responsiveness. In spite of these uncertainties, it was concluded that the TEF concept is still the most plausible and feasible approach for risk assessment of halogenated aromatic hydrocarbons with dioxinlike properties.
Endometriosis in Rhesus Monkeys (Macaca mulatta) Following Chronic Exposure to 2,3,7,8-Tetrachlorodibenzo-p-dioxin. Rier, S. E., Martin, D. C., Bowman, R. E., Dmowski, W. P., and Becker, J. L. (1993). Fundam. Appl. Toxicol. 21, 433-441.
The WHO-European Centre for Environment and Health (WHO-ECEH) and the International Programme on Chemical Safety (IPCS), have initiated a project to create a data base containing information relevant to the setting of Toxic Equivalency Factors (TEFs), and, based on the available information, to assess the relative potencies and to derive consensus TEFs for PCDDs, PCDFs and dioxin-like PCBs. Available data on the relative toxicities of dioxin-like PCBs with respect to a number of endpoints were collected and analyzed. A consultation was held at the WHO-European Centre for Environment and Health in Bilthoven, the Netherlands, at which the available data were discussed to derive TEFs for dioxin-like PCBs. TEFs were recommended for 3 non-ortho-, 8 mono-ortho- and 2 di-ortho-substituted PCBs. The consultation recommended that the project should be extended to include PCDDs and PCDFs and other dioxin-like halogenated environmental pollutants. It was also recommended that the possibilities of separate TEFs for body burdens and ecotoxicology should be explored.
Rats were maintained for 2 years on diets supplying 0.1, 0.01, and 0.001 μg of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)/kg/day. Analysis of these diets indicated 2200, 210, and 22 parts per trillion (ppt) of TCDD. Ingestion of 0.1 μg/kg/day caused an increased incidence of hepatocellular carcinomas and squamous cell carcinomas of the lung, hard palate/nasal turbinates, or tongue, whereas a reduced incidence of tumors of the pituitary, uterus, mammary glands, pancreas, and adrenal gland was noted. Other indications of toxicity at this dose level included increased mortality, decreased weight gain, slight depression of erythroid parameters, increased urinary excretion of porphyrins and δ-aminolevulinic acid, along with increased serum activities of alkaline phosphatase, γ-glutamyl transferase and glutamic-pyruvic transaminase. Gross and histopathologic changes were noted in the hepatic, lymphoid, respiratory, and vascular tissues. The primary hepatic ultrastructural change at this high dose level was proliferation of the rough endoplasmic reticulum. Terminal liver and fat samples from rats at this high dose level contained 24,000 and 8100 ppt of TCDD, respectively. Rats given 0.01 μg/kg/day for 2 years had a lesser degree of toxicity than that seen at the highest dose level. This included increased urinary excretion of porphyrins in females, liver lesions (including hepatocellular nodules), and lung lesions (including focal alveolar hyperplasia). Terminal liver and fat samples from rats of this dose level contained 5100 and 1700 ppt of TCDD, respectively. Ingestion of 0.001 μg of TCDD/kg/day (∼22 ppt in the diet) caused no effects considered to be of any toxicologic significance. At this lower dose level, terminal liver and fat samples each contained 540 ppt of TCDD. These data indicate that continuous doses of TCDD sufficient to induce severe toxicity increased the incidence of some types of tumors, while reducing other types. During the 2-year study in rats, no increase in tumors occurred in those rats receiving sufficient TCDD to induce slight or no manifestations of toxicity.
TCDD is an extremely toxic chemical pollutant which bioaccumulates in maternal adipose tissue, and is transferred to the developing organism during gestation and lactation. Long-term cognitive deficits have been reported following perinatal exposure to polychlorinated biphenyls, which are structurally and toxicologically similar to TCDD. In the current study, monkeys exposed to TCDD perinatally were later tested in two cognitive paradigms, discrimination-reversal learning (RL) and delayed spatial alternation (DSA). RL detected effects; whereas DSA, as analyzed, did not. RL consisted of a series of simple spatial reversals, followed by spatial reversals with color and shape as irrelevant cues, then by color reversals and finally by shape reversals. TCDD-exposed monkeys exhibited retarded learning of the shape reversals. The deficit was most pronounced on the first reversal following overtraining. There were no group differences on the spatial or color reversals. However, the number of trials the TCDD-exposed monkeys individually took to learn the spatial reversals was positively correlated with TCDD concentration in body fat. Conversely, the number of trials they took to learn the color reversals was negatively correlated with TCDD in body fat.
Male rats exposed in utero to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) display reduced fertility as a consequence of the direct action of TCDD on the epididymides, as well as delayed puberty and altered reproductive organ weights. The current study provides dose-response data for the reproductive effects of TCDD, administered during pregnancy, with an emphasis on the effects of TCDD on testicular, epididymal, and ejaculated sperm numbers. Long Evans Hooded rats were dosed by gavage with 0, 0.05, 0.20, or 0.80 microg TCDD/kg on Day 15 of gestation. After birth, growth, viability, and developmental landmarks were monitored in both male and female offspring. Shortly after puberty (49 and 63 days of age) and at 15 months of age, male offspring were necropsied. Growth and viability of the pups were reduced only at 0.80 microg TCDD/kg, eye opening was accelerated (all dosage groups), and puberty was delayed (at 0.20 and 0.80 microg TCDD/kg). Treated progeny displayed transient reductions in ventral prostate and seminal vesicle weights, while epididymal sperm reserves and glans penis size were permanently reduced. Ejaculated sperm numbers were reduced (45% in the 0.8 and by 25% in the 0.05 and 0.2 microg TCDD/kg dosage groups) to a greater degree than were cauda or caput/corpus epididymal or testicular (unaffected) sperm numbers. In conclusion, administration of TCDD on Day 15 of pregnancy at 0.05 microg/kg altered eye opening and reduced ejaculated sperm counts, while higher dosage levels also delayed puberty and permanently reduced cauda epididymal sperm reserves.
Perinatal exposure of rodents to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been shown to result in thymic atrophy and cell-mediated immune suppression at lower doses than are required to produce those effects following adult exposure. This study was designed to examine the effects that in utero TCDD exposure has on thymocyte development in the rat. Timed-bred pregnant F344 rats were given 0, 1.0, or 3.0 μg TCDD/kg body weight by gavage on gestational day 14 (GD14). On GD19 or GD22/postnatal day one (PD1), the dams were euthanized, and the dams and their offspring were examined for organ weight and thymus phenotypic alterations. GD19 fetuses from the 3.0 μg TCDD/kg maternal exposure group exhibited decreases in relative thymus weight and thymic cellularity. There were a decreased percentage of CD3⁻/CD4⁺CD8⁺ thymocytes and an increased percentage of CD3⁻/CD4⁻CD8⁺ thymocytes in these fetuses, but there were no alterations in the CD3⁺ subsets. No effects were seen in the GD19 fetuses from the 1.0 μg TCDD/kg dosage group. In the TCDD-exposed GD22/PD1 offspring thymic atrophy was no longer present, but there was an increase in the relative liver weight. In addition, there were decreased percentages of CD3⁻/CD4⁻CD8⁻, CD3⁺/CD4⁻CD8⁻, and CD3⁺/CD4⁺CD8⁺ thymocytes and an increased percentage of CD3⁺/CD4⁻CD8⁺ thymocytes. The CD3⁺/CD4⁻CD8⁻ and CD3⁺/CD4⁻CD8⁺ cell populations were the most sensitive, with changes appearing at both 1.0 and 3.0 μg TCDD/kg maternal exposures. The TCDD-exposed GD19 dams exhibited an increased relative liver weight, a decreased relative thymus weight, and alterations in thymic CD3⁺ populations. Three days later the relative organ weights had recovered in the dams, but the phenotypic alterations were seen in CD3⁻ as well as CD3⁺ thymocyte subsets. These results indicate that the developing rat fetal thymus is susceptible to the effects of TCDD. In addition, pregnant rats and their offspring showed similar alterations in thymocytic phenotypes.
Prenatal administration of a single dose of 1 microg TCDD/kg induces malformations of the external genitalia and subfertility in female offspring (L. E. Gray, Jr., and J. S. Ostby (1995) Toxicol. Appl. Pharmacol. 133, 285-294). A cross-fostering study indicated that in utero but not lactational TCDD exposure (1 microg TCDD/kg on gestational Day 15) induces cleft phallus, vaginal thread formation, and reduced ovarian weight. TCDD treatment on the 15th day of pregnancy at 0, 0.05, 0.20, or 0.80 microg TCDD/kg delayed vaginal opening at 0.80 microg/kg in the progeny. A persistent vaginal thread was displayed by 27% of the progeny at 0.20 and 92% at 0.80 microg TCDD/kg. These effects did not appear to result from abnormal ovarian function during prepubertal development; neither serum estradiol levels nor ovarian estradiol production were reduced in 21- or 28-day-old progeny of dams exposed to 1 microg TCDD/kg. In addition, partial to complete clefting of the phallus was displayed in TCDD-treated rats (10% at 0.20 and 60% at 0.80 microg TCDD/kg) and these dosage levels also increased the length of the urethral slit, increased distance from the urethral opening to the tip of the phallus, and decreased distance from the urethral opening to the vaginal orifice. Although fertility rates were normal, time-to-pregnancy was delayed by treatment with 0.80 microg TCDD/kg. When necropsied at 20 months of age, females from the TCDD-dose groups displayed histopathological alterations of the reproductive tract. In summary, administration of TCDD at dosage levels of 0.2, 0.8, and 1.0 microg/kg produces morphological reproductive alterations in female rat offspring as a consequence of in utero exposure.
Toxic equivalency factors for dioxin-like PCBs; report on a WHO-ECEH and IPCS consultation Alterations in the developing immune system of the F344 rat after perinatal exposure to 2,3,7,8-tetrachlorodi-benzo-p-dioxin. II. Eects on the pup and the adult
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Persistent suppression of delayed-type hypersensitivity (DTH) in rats perinatally exposed to TCDD
- Gehrs