Total Toxic Equivalents Research Articles

Dioxin-metabolizing genes in relation to effects of prenatal dioxin levels and reduced birth size: The Hokkaido study

ObjectivesWe investigated the effects of maternal polymorphisms in 3 genes encoding dioxin-metabolizing enzymes in relation to prenatal dioxin levels on infant birth size in Japan. MethodsWe examined the relationship between dioxin exposure and birth size in relation to the polymorphisms in the genes encoding aromatic hydrocarbon receptor (AHR [G>A, Arg554Lys]), cytochrome P450 (CYP) 1A1 (T6235C), and glutathione S-transferase mu 1 (GSTM1; Non-null/null) in 421 participants using multiple linear regression models. ResultsIn mothers carrying the GSTM1 null genotype, a ten-fold increase in total dioxin toxic equivalency was correlated with a decrease in birth weight of −345g (95% confidence interval: −584, −105). ConclusionsWe observed adverse effects of maternal GSTM1 null genotype on birth weight in the presence of dioxins exposure during pregnancy.

Application of microwave energy in the destruction of dioxins in the froth product after flotation of hospital solid waste incinerator fly ash

Most of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) and powder-activated carbon (PAC) in hospital solid waste incinerator fly ash are enriched in the froths produced through flotation. Because PAC is an excellent microwave absorber, microwave treatment was performed on the froths in this study to decompose PCDD/Fs. The results showed that the destruction efficiency of PCDD/Fs increased with increasing microwave incident power and processing time, particularly for highly chlorinated PCDD/Fs. With a microwave incident power of 2100W at 7min, the total mass destruction efficiency of the PCDD/Fs in the froths reached 99.6wt.% and the total toxic equivalent (TEQ) of PCDD/F was substantially reduced from 29.0 to 0.08 ng–I-TEQ/g. PCDD/Fs in the froths were mostly decomposed and evaporated very little into exhaust gas under microwave treatment, especially at 2100W. The treated froths displayed good porous structures, enabling the potential recovery of PAC for reuse. Microwave treatment of the froths could promote the rapid decomposition of PCDD/Fs and the recovery of a typical waste resource; also it could present a viable alternative to combustion treatment for the froths.

Characterization of particulate-phase polycyclic aromatic hydrocarbons emitted from incense burning and their bioreactivity in RAW264.7 macrophage

This study investigated the effects of particle-bound polycyclic aromatic hydrocarbons (PAHs) produced from burning three incense types on and their bioreactivity in the RAW 264.7 murine macrophage cell line. Gas chromatography/mass spectrometry was used to determine the levels of 16 identified PAHs. Macrophages were exposed to incense particle extracts at concentrations of 0, 3.125, 6.25, 12.5, 25, 50, and 100 μg/mL for 24 h. After exposure, cell viability and nitric oxide (NO) and inflammatory mediator [tumor necrosis factor (TNF)-α] production of the cells were examined. The mean atomic hydrogen (H) to carbon (C) ratios in the environmentally friendly, binchotan charcoal, and lao shan incenses were 0.69, 1.13, and 1.71, respectively. PAH and total toxic equivalent (TEQ) mass fraction in the incenses ranged from 137.84 to 231.00 and 6.73–26.30 pg/μg, respectively. The exposure of RAW 264.7 macrophages to incense particles significantly increased TNF-α and NO production and reduced cell viability. The cells treated with particles collected from smoldering the environmentally friendly incense produced more NO and TNF-α compared to other incenses. Additionally, the TEQ of fluoranthene (FL), pyrene (Pyr), benzo[a]anthracene (BaA), chrysene (Chr), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), indeno[1,2,3-cd]pyrene (INP), dibenz[a,h]anthracene (DBA), and benzo[g,h,i]perylene [B(ghi)P] had a significant correlation (R2 = 0.64–0.98, P < 0.05) with NO and TNF-α production. The current findings indicate that incense particle-bound PAHs are biologically active and that burning an incense with a lower H/C ratio caused higher bioreactivity. The stimulatory effect of PAH-containing particles on molecular mechanisms of inflammation are critical for future study.

Widespread Distribution of Dehalococcoides mccartyi in the Houston Ship Channel and Galveston Bay, Texas, Sediments and the Potential for Reductive Dechlorination of PCDD/F in an Estuarine Environment.

Sediments in the Houston Ship Channel and upper Galveston Bay, Texas, USA, are polluted with polychlorinated dibenzo-p-dioxins/furans (PCDD/F; ≤46,000ng/kg dry weight (wt.)) with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic congener, contributing >50% of the total toxic equivalents (TEQ) at most locations. We measured PCDD/F concentrations in sediments and evaluated the potential for enhanced in situ biodegradation by surveying for Dehalococcoides mccartyi, an obligate organohalide respiring bacterium. Dehalococcoides spp. (98% similar to D. mccartyi) and 22 other members of the class Dehalococcoidia were predominant 16S ribosomal RNA (rRNA) phylotypes. Dehalococcoides spp. were also present in the active fraction of the bacterial community. Presence/absence PCR screening detected D. mccartyi in sediment cores and sediment grab samples having at least 1ng/kg dry wt. TEQ at salinities ranging from 0.6 to 19.5 PSU, indicating that they are widespread in the estuarine environment. Organic carbon-only and organic carbon+sulfate-amended sediment microcosm experiments resulted in ∼60% reduction of ambient 2,3,7,8-TCDD in just 24months leading to reductions in total TEQs by 38.4 and 45.0%, respectively, indicating that 2,3,7,8-TCDD degradation is occurring at appreciable rates.

A Longitudinal Study of Peripubertal Serum Organochlorine Concentrations and Semen Parameters in Young Men: The Russian Children's Study.

Background:Exposures to endocrine-disrupting chemicals during critical phases of testicular development may be related to poorer semen parameters. However, few studies have assessed the association between childhood organochlorine (OC) exposure and adult semen parameters.Objective:We examined whether peripubertal serum OC concentrations are associated with semen parameters among young Russian men.Methods:From 2003 through 2005, 516 boys were enrolled at age 8–9 years and followed for up to 10 years. Serum OCs were measured in the enrollment samples using high-resolution mass spectrometry. At 18–19 years, 133 young men provided 1 or 2 semen samples (256 samples) collected approximately 1 week apart, which were analyzed for volume, sperm concentration, and motility. Unadjusted and adjusted linear mixed models were used to examine the associations of quartiles of lipid-standardized concentrations of dioxins [2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), polychlorinated dibenzo-p-dioxins (PCDDs)], furans, polychlorinated biphenyls (PCBs), and corresponding toxic equivalents (TEQs) with semen parameters.Results:The median (range) for TCDD was 2.9 (0.4–12.1) pg/g lipid and PCDD TEQ was 8.7 (1.0–36.0) pg TEQ/g lipid. Higher quartiles of TCDD and PCDD TEQs were associated with lower sperm concentration, total sperm count, and total motile sperm count (p-trends ≤ 0.05). The highest quartile of peripubertal serum TCDD concentrations was associated with a decrease (95% CI) of 40% (18, 66%), 29% (3, 64%), and 30% (2, 70%) in sperm concentration, total sperm count, and total motile sperm count, respectively, compared with the lowest quartile. Similar associations were observed for serum PCDD TEQs with semen parameters. Serum PCBs, furans, and total TEQs were not associated with semen parameters.Conclusion:Higher peripubertal serum TCDD concentrations and PCDD TEQs were associated with poorer semen parameters.Citation:Mínguez-Alarcón L, Sergeyev O, Burns JS, Williams PL, Lee MM, Korrick SA, Smigulina L, Revich B, Hauser R. 2017. A longitudinal study of peripubertal serum organochlorine concentrations and semen parameters in young men: the Russian Children’s Study. Environ Health Perspect 125:460–466; http://dx.doi.org/10.1289/EHP25

Number of Persistent Organic Pollutants Detected at High Concentrations in Blood Samples of the United States Population.

Human exposure to environmental chemicals as persistent organic pollutants (POPs) is usually assessed considering each pollutant individually, with little attention to concentrations of mixtures in individuals or social groups. Yet, it may be relatively common for humans to have low and high concentrations of numerous POPs. The study objectives were to analyze the number of POPs detected per person at high concentrations in the U.S. population, and the associations between such type of indicators and socioeconomic factors as gender, race / ethnicity, education, and poverty level. From 91 POPs analyzed in serum samples of 4,739 individuals in three subsamples of the National Health and Nutrition Examination Survey (NHANES) 2003–2004 (the last period with valid updated individual data for the compounds considered in the present study), we computed the number of POPs whose serum concentrations were above selected cutoff points. POPs included were 13 organochlorine compounds (OCs), 10 polybrominated diphenyl ethers (PBDEs), the polybrominated biphenyl (PBB) 153, 38 polychlorinated biphenyls (PCBs), 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/Fs), and 12 perfluorinated compounds (PFCs). Over 13% of participants had ≥10 of the 37 most detected POPs each at a concentration in the top decile (P90). Over 30% of subjects with total toxic equivalency (TEQ) ≥P75, had ≥10 of 24 POPs not included in TEQ calculations at concentrations ≥P90. Compared to non-Hispanic whites, the adjusted odds ratio of having ≥10 of the 37 POPs at P90 was 9.2 for non-Hispanic blacks and 0.18 for Mexican Americans. Poverty, body mass index, age, and gender were also independently associated with having ≥10 POPs in the top decile. More than one tenth of the US population may have ≥10 POPs each at concentrations in the top decile. Such pattern is nine times more frequent in Non-Hispanic blacks and four times less frequent in Mexican Americans than in non-Hispanic whites.

Congener-specific levels and patterns of polychlorinated biphenyls in edible fish tissue from the central Red Sea coast of Saudi Arabia

All 209 congeners of polychlorinated biphenyls (PCBs) in edible fish tissue from the central Red Sea coast (Jeddah region) of Saudi Arabia were analyzed by isotope dilution high-resolution gas chromatography–mass spectrometry. The upper-bound total PCB (ΣPCB) levels in nine commonly consumed fish species from three areas were 0.2–82.5ng/g wet weight (17–8450ng/g lipid weight), which were at the lower end of reported global range and far below international tolerance limits (500–3000ng/g ww). Dioxin-like congeners contributed up to 12.8% (mean 6.5%) to ΣPCB in tissue samples, with the total PCB toxic equivalencies (TEQs) at a tolerable range (0.05–2.6pgTEQ/g ww or 2–238pgTEQ/g lw) for all species. PCB profiles were dominated by moderately chlorinated homologs, mainly hexachlorobiphenyls, but less chlorinated congeners were also consistently elevated, notably in Siganus rivulatus (Area III) and Mugil cephalus (Area I). It remains to be ascertained if the latter were breakdown products or due to fresh inputs. The top congeners based on dominance by both occurrence and abundance were identified as potential markers of ΣPCB in fish tissue, which can be used for future selective biomonitoring in case of reasonable constraints on full congener approach.

The influence of maternal dietary exposure to dioxins and PCBs during pregnancy on ADHD symptoms and cognitive functions in Norwegian preschool children

BackgroundPolychlorinated dibenzo-p-dioxins/dibenzofurans (dioxins) and polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) with potentially adverse impact on child neurodevelopment. Whether the potential detrimental effects of dioxins and PCBs on neurodevelopment are of specific or unspecific character is not clear. ObjectivesThe purpose of the current study was to examine the influence of maternal dietary exposure to dioxins and PCBs on ADHD symptoms and cognitive functioning in preschoolers. We aimed to investigate a range of functions, in particular IQ, expressive language, and executive functions. Material and methodsThis study includes n=1024 children enrolled in a longitudinal prospective study of ADHD (the ADHD Study), with participants recruited from The Norwegian Mother and Child Cohort Study (MoBa). Boys and girls aged 3.5years participated in extensive clinical assessments using well-validated tools; The Preschool Age Psychiatric Assessment interview (PAPA), Stanford-Binet 5th revision (SB-5), Child Development Inventory (CDI), and Behavior Rating Inventory of Executive Function, Preschool version (BRIEF-P). Maternal dietary exposure to dioxins and PCBs was estimated based on a validated food frequency questionnaire (FFQ) answered mid-pregnancy and a database of dioxin and PCB concentrations in Norwegian foods. Exposure to dioxins and dioxin-like PCBs (dl-compounds) was expressed in total toxic equivalents (TEQ), and PCB-153 was used as marker for non-dioxin-like PCBs (ndl-PCBs). Generalized linear and additive models adjusted for confounders were used to examine exposure-outcome associations. ResultsExposure to PCB-153 or dl-compound was not significantly associated with any of the outcome measures when analyses were performed for boys and girls together. After stratifying by sex, adjusted analyses indicated a small inverse association with language in girls. An increase in the exposure variables of 1 SD was associated with a reduction in language score of −0.2 [CI −0.4, −0.1] for PCB-153 and −0.2 [CI −0.5, −0.1] for dl-compounds in girls. For boys, exposure to PCB-153 or dl-compounds was not associated with language skills. The difference between sex-specific associations was not statistically significant (p-value=0.13). No sex-specific effects were observed for ADHD-symptoms, IQ scores, or executive functions. ConclusionsWe found no indications that variation in current low-level exposure to PCB-153 or dl-compounds in Norway is associated with variation ADHD-symptoms, verbal/non-verbal IQ, or executive functions including working memory in preschoolers. However, our findings indicated that maternal dietary exposure to PCB-153 or dl-compounds during pregnancy was significantly associated with poorer expressive language skills in preschool girls, although the sex-specific associations were not significantly different.

Airborne PCDD/F profiles in rural and urban areas of Buenos Aires Province, Argentina

Passive air samplers were deployed in 18 rural and urban locations in the densely populated Buenos Aires district to investigate airborne polychlorinated dibenzo-p-dioxin and polychlorinated-dibenzofuran (PCDD/Fs) profiles, sources and spatial patterns. Atmospheric concentrations reported as total toxic equivalents (TEQs), 2378-substituted (∑17PCDD/F) and 4–8 homologous groups (∑4–8PCDD/F) were highly variable and significantly correlated to urban scale. The rural average (3.0±2.7fgTEQm−3) was thirty times less than metropolitan values (90±51fgTEQm−3), with urban cluster (5.4±4.0fgTEQm−3) and urbanized area (33±50fgTEQm−3) in an intermediate position. A rural outlier exhibited the highest TEQ values (295–296fgTEQm−3) suggesting a local source. Principal component analyses (PCA) performed for ∑17PCDD/F and ∑4-8PCDD/F to identify source contributions showed more significant results for homologue groups compared to 17 congeners (83 and 45% of total variability explained, respectively) pointing to dominant diesel emissions enriched in TeCDF in rural areas, and open burning and industrial sources characterized by TeCDD, PeCDD contributing most in urbanized and metropolitan areas. Homologue group PCA also performed better clustering samples according to sources and TEQ concentrations. The PCDD/Fs profile of the rural outlier dominated by HxCDF and HpCDD/F showed a typical municipal incineration signature confirming the presence of local source.

Monitoring and risk assessment of polychlorinated biphenyls (PCBs) in agricultural soil collected in the vicinity of an industrialized area

Samples of agricultural soils possibly contaminated by polychlorinated biphenyls (PCBs) were collected from Anseong, Korea. The agricultural areas chosen have possibly been contaminated by nearby factories, either directly or via atmospheric deposition, and require monitoring. The concentrations of 29 out of 209 PCB congeners were determined at five sites using high-resolution gas chromatography/high-resolution mass spectrometry. Total concentrations of the 29 PCB congeners in soil samples obtained from each study site were 106.65, 149.15, 222.67, 166.15, and 118.28 pg g−1 dry weight, respectively, with pentaCBs and hexaCBs giving the highest concentrations of the congeners studied. The total toxic equivalent (TEQ) for 12 PCBs from each site was 0.05, 0.11, 0.08, 0.05, and 0.04 ng kg−1 dry weight, respectively. These values were mainly due to high TEQ values for PCB 126 (3,3′,4,4′,5-pentachlorobiphenyl) from each site (at 0.05, 0.10, 0.07, 0.04, and 0.03 ng kg−1 dry weight, respectively). The TEQ values are much lower than the action level of 20 ng WHO–TEQ kg−1 recommended by the World Health Organization, but PCB concentrations in this area should be monitored nonetheless, since these manmade compounds bioaccumulate, thus threatening the ecosystem and human health.

Mono- to Octachlorinated Polychlorinated Dibenzo-p-dioxin and Dibenzofuran Emissions from Sintering Plants Synergistically Controlled by the Desulfurization Process.

The influence of desulfurization systems in sintering plants on polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) concentrations, profiles, and emission factors was studied. Mono- to tri-CDD/Fs and tetra- to octa-CDD/F concentrations were 4.4 ± 2.3 and 10.5 ± 8.3 ng m(-3), respectively, at the inlets and 0.87 ± 0.48 and 0.47 ± 0.22 ng m(-3), respectively, after desulfurization. The toxic equivalents (TEQs) were 0.95 ± 0.093 and 0.51 ± 0.040 ng of I-TEQ m(-3) at the inlets and after desulfurization, respectively. The congener profiles and homologue distributions were dominated by 2-MoCDF and MoCDF, respectively. The PCDD/F removal efficiencies achieved by desulfurization increased as the chlorination level increased. The PCDD/Fs became adsorbed to gypsum. Annual mono- to tri-CDD/Fs PCDD/F and TEQ (tetra- to octa-CDD/F) emission factors for flue gas and gypsum between 2003 and 2012 were determined. The total amounts of mono- to tri-CDD/Fs emitted in flue gas and gypsum between 2003 and 2012 were 10.7 and 10.2 kg, respectively. The total TEQs emitted in flue gas and gypsum between 2003 and 2012 were estimated to be 15486 and 1878 g of I-TEQ, respectively. PCDD/Fs adsorbed to gypsum are not effectively eliminated. The PCDD/F concentrations increased as the fly ash surface area increased moving through the electrostatic precipitator stages.

Determination of chlorinated polycyclic aromatic hydrocarbons in water by solid-phase extraction coupled with gas chromatography and mass spectrometry

Given the potential risks of chlorinated polycyclic aromatic hydrocarbons, the analysis of their presence in water is very urgent. We have developed a novel procedure for determining chlorinated polycyclic aromatic hydrocarbons in water based on solid-phase extraction coupled with gas chromatography and mass spectrometry. The extraction parameters of solid-phase extraction were optimized in detail. Under the optimal conditions, the proposed method showed wide linear ranges (1.0-1000 ng/L) with correlation coefficients ranging from 0.9952 to 0.9998. The limits of detection and the limits of quantification were in the range of 0.015-0.591 and 0.045-1.502 ng/L, respectively. Recoveries ranged from 82.5 to 102.6% with relative standard deviations below 9.2%. The obtained method was applied successfully to the determination of chlorinated polycyclic aromatic hydrocarbons in real water samples. Most of the chlorinated polycyclic aromatic hydrocarbons were detected and 1-monochloropyrene was predominant in the studied water samples. This is the first report of chlorinated polycyclic aromatic hydrocarbons in water samples in China. The toxic equivalency quotients of chlorinated polycyclic aromatic hydrocarbons in the studied tap water were 9.95 ng the toxic equivalency quotient m(-3) . 9,10-Dichloroanthracene and 1-monochloropyrene accounted for the majority of the total toxic equivalency quotients of chlorinated polycyclic aromatic hydrocarbons in tap water.

Gas-phase and particle-phase PCDD/F congener distributions in the flue gas from an iron ore sintering plant

The activated carbon injection-circulating fluidized bed (ACI-CFB)-bag filter coupling technique was studied in an iron ore sintering plant. For comparison, the removal efficiencies under the conditions without or with ACI technology were both evaluated. It was found that the polychlorinated dibenzo-p-dioxins and dibenzofuran (PCDD/F) removal efficiency for total international toxic equivalence quantity (I-TEQ) concentration was improved from 91.61% to 97.36% when ACI was employed, revealing that ACI was very conducive to further controlling the PCDD/F emissions. Detailed congener distributions of PCDD/Fs in the gas-phase and particle-phase of the Inlet and Outlet samples were determined. Additionally, the PCDD/F distribution for the Fly ash-with ACI sample of was also studied.

Polychlorinated biphenyls (PCBs) in sediments/soils of different wetlands along 100-year coastal reclamation chronosequence in the Pearl River Estuary, China

PCBs (polychlorinated biphenyls) were determined in sediment/soil profiles to a depth of 30 cm from three different wetlands (i.e., ditch wetlands, riparian wetlands and reclaimed wetlands) of the Pearl River Estuary to elucidate their levels, distribution and toxic risks along a 100-year chronosequence of reclamation. All detected PCB congeners and the total 15 PCBs (∑15 PCBs) decreased with depth along sediment/soil profiles in these three wetlands. The ∑15 PCBs concentrations ranged from 17.68 to 169.26 ng/g in surface sediments/soils. Generally, old wetlands tended to have higher PCB concentrations than younger ones. The dominant PCB congeners at all sampling sites were light PCB homologues (i.e., tetra-CBs and tri-CBs). According to the sediment quality guideline, the average PCB concentrations exceeded the threshold effects level (TEL, 21.6 ng/g) at most of the sampling sites, exhibiting possible adverse biological effects, which were dominantly caused by light PCB congeners. The total toxic equivalent (TEQ) concentrations of 10 dioxin-like PCBs (DL-PCBs) detected at all sampling sites ranged from 0.04 to 852.7 (10−3 ng/g), mainly affected by PCB126. Only DL-PCB concentrations in ditch and riparian wetland sediments with 40-year reclamation histories (i.e., D40 and Ri40) exhibited moderate adverse biological effects according to SQGQ values. Principal component analysis indicated that PCBs in three wetland sediments/soils mainly originated from Aroclor 1016, 1242, and 1248. Correlation analysis showed that sediment/soil organic carbon content had a significant correlation with the concentrations of several PCB congeners (P < 0.05), whereas no significant correlations were observed between any PCBs congeners and grain size or aggregate content (P > 0.05).

Persistent Organohalogens in Paired Fish Fillet and Eggs: Implications for Fish Consumption Advisories.

Fish consumption is associated with both health benefits from high-quality proteins, minerals, vitamins, and fatty acids and risks from contaminants in fish. Fish consumption advisories are issued by many government agencies to keep exposure to contaminants at a safe level. Such advisories are typically based on fillets and neglect consumption of other fish parts such as eggs by certain subpopulations. To evaluate potential for dietary exposure to toxic organic chemicals via fish eggs, we analyzed polybrominated diphenyl ethers (PBDEs), polychlorinated naphthalenes (PCNs), dioxin-like polychlorinated biphenyls (dlPCBs), and polychlorinated dibenzodioxins/furans (PCDD/Fs) in paired fillet and eggs of fish from a tributary to Lake Ontario, one of the North American Great Lakes. All wet weight based concentrations in fish eggs were statistically higher than in the paired fillet samples. In fish eggs, concentrations of Σ14PBDEs, Σ14PCNs, and Σ12dlPCBs were 41-118, 0.3-1.7, and 30-128 ng/g wet weight (ww), respectively; Σ3PCDD/Fs and total (dlPCB+ PCDD/Fs) toxic equivalents (TEQs) were 4-22 and 9-54 pg/g ww, respectively. In fillet samples, Σ14PBDEs, Σ14PCNs, and Σ12dlPCBs were 4-116, 0.05-0.66, and 6-85 ng/g, respectively; Σ3PCDD/Fs and TEQs were 2-10 and 3.4-31 pg/g ww, respectively. In contrast, the fillets had higher lipid normalized concentrations than the paired egg samples, suggesting that these chemicals did not reach equilibrium between the fillets and eggs. Accordingly, measured concentrations in eggs or empirical relationship with fillet rather than prediction from equilibrium partitioning model should be used to evaluate contaminant exposure via consumption of fish eggs. For fatty fish from the lower Great Lakes area, we suggest one fillet meal be reduced from the advised fish consumption frequency for consumptions of 207 ± 37, 39 ± 2, 105 ± 51, and 119 ± 9 g fish eggs of brown trout, Chinook salmon, Coho salmon, and rainbow trout, respectively.

Maternal dietary exposure to dioxins and polychlorinated biphenyls (PCBs) is associated with language delay in 3 year old Norwegian children

BackgroundPrenatal exposure to dioxins and PCBs is potentially harmful to the developing fetus and may increase the risk of delayed or impaired neurodevelopment. Several studies have reported negative associations between prenatal exposure to these compounds and aspects of cognition related to language in early childhood. ObjectivesThe aim was to examine the association between maternal low level dietary exposure to dioxins and PCB during pregnancy and language development in 3year old children in a large group of mother-child pairs participating in the Norwegian Mother and Child Cohort Study (MoBa). MethodsThis study includes 44,092 children of women who were recruited to the Norwegian Mother and Child Cohort Study (MoBa) during the years 2002–2009. Maternal dietary exposure to dioxins and PCBs was estimated based on a validated food frequency questionnaire (FFQ) answered mid-pregnancy and a database of dioxin and PCB concentrations in Norwegian foods. Exposure to dioxins and dioxin-like PCBs (dl-compounds) was expressed in total toxic equivalents (TEQ), and PCB-153 was used as marker for non-dioxin-like PCBs (ndlPCBs). Children's language skills at age 3 were assessed by parental report including a Dale and Bishop grammar rating and questions about communication skills from the Ages and Stages Questionnaire (ASQ). Logistic regression models adjusted for confounders were used to examine the association between maternal dietary exposure to dl-compounds or PCB-153 and language development in children. ResultsThe maternal dietary exposure to dl-compounds and PCB-153 was generally low, and 98% of women had intakes of dl-compounds ≤14pg TEQ/kg bw/week, which is the tolerable weekly intake set by EU's Scientific Committee for Food (SCF). High maternal exposure (>14pg TEQ/kg bw/week of dl-compounds (median 2.6pg/kg bw/day, range 2–16) or >97.5-percentile intake of PCB-153 (median 11ng/kg bw/day, range 5–28) was associated with higher odds of incomplete grammar (in boys and girls, adjusted ORs 1.1 to 1.3) and severe language delay in girls, adjusted ORs 2.8 [95% CI 1.1, 7.1] for PCB-153 and 2.9 [95% CI 1.4, 5.9] for dl-compounds. Furthermore, high exposure to dl-compounds was associated with moderate language delay 1.4 [95% CI 1.0, 2.0] and lower communication score (ASQ), adjusted OR 1.4 [95% CI 1.1, 1.9] in girls. ConclusionsThe main findings of this study were: 1) Girls born to mothers who exceeded the tolerable weekly intake for dl-compounds or had a PCB-153 intake above the 97.5 percentile in early pregnancy may have increased risk of language delay at age 3years. 2) Negative associations with maternal exposure to dl-compounds or PCB-153 were observed for both boys and girls having incomplete grammar, which is a subtle reduction in language skills. This interesting finding should not be considered as deviant at this age.

Inverse association of highly chlorinated dioxin congeners in maternal breast milk with dehydroepiandrosterone levels in three-year-old Vietnamese children

This study aims to evaluate the endocrine-disrupting effect of dioxin congeners on adrenal steroid hormones in mother–child pairs. In our previous study, we found that cortisol and cortisone levels were higher in the blood and the saliva of mothers living in a dioxin hotspot area than in mothers from a non-exposed region in Vietnam. In this follow-up study, we determined the salivary steroid hormone levels in 49 and 55 three-year-old children of these mothers in the hotspot and non-exposed region, respectively. Steroid hormones were determined by liquid chromatography–tandem mass spectrometry, and dioxin in the maternal breast milk was determined by gas chromatography–mass spectrometry. Dioxin levels in the breast milk of mothers from the hotspot (median total toxic equivalents polychlorinated dibenzodioxins/polychlorinated dibenzofurans; (TEQ PCDD/Fs) of 11pg/g lipid) were three to four times higher than those of mothers in the non-exposed region (median TEQ PCDD/Fs of 3.07pg/g lipid). Salivary dehydroepiandrosterone (DHEA) levels in children were found to be significantly lower in the hotspot than in the non-exposed region, while cortisol and cortisone levels were not different between the two regions. Highly chlorinated dioxin congeners, such as octacholorodibenzodioxin (OCDD), 1,2,3,4,6,7,8-heptacholorodibenzodioxin (HpCDD) and 1,2,3,4 (or 6), 7,8-hexachlorodibenzodioxin Hx(CDD), showed stronger inverse associations with the children's salivary DHEA than other lowly chlorinated dioxin congeners. Glucocorticoid levels in the mothers exhibited a significantly positive correlation with OCDD and HpCDD/F (polychlorinated dibenzofurans). In conclusion, highly chlorinated dioxin congeners are more strongly correlated with endocrine-disrupting effects on adrenal hormones, resulting in high cortisol levels in the mothers and low DHEA levels in their three-year-old children.

Reduction of Polycyclic Aromatic Hydrocarbon Emission by Porous Alumina Bed Material during Sewage Sludge Incineration

In this paper, porous alumina was used as an alternative bed material to reduce polycyclic aromatic hydrocarbon (PAH) emission and improve the combustion efficiency during sewage sludge combustion in a fluidized bed combustor (FBC). To discover the reduction mechanism, the Brunauer–Emmett–Teller (BET) surface area, critical fluidized velocity, and heat-transfer coefficient of three bed materials (silica sand, alumina sand, and porous alumina sand) were characterized. In comparison to the conventional silica bed material, the reduction efficiencies of PAH emission and PAH total toxic equivalent (TEQ) by porous alumina bed material under 850 °C were 52.0 and 97.7%, respectively. Porous alumina bed material had more BET surface area than that of the conventional silica sand, which could adsorb gaseous hydrocarbon and prolong the residence time of hydrocarbon in the diluted zone of the FBC. At the same time, it was well-known that gaseous hydrocarbons were a precursor of PAHs. Thus, PAH formation was suppress...

PCDD/Fs and PCBs in Soils: a Study of Case in the City of Belo Horizonte‑MG

Dioxins (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs)) are substances that represent a global concern due to their ubiquitous presence and toxicity. Industrial processes and other human activities as well as uncontrollable accidents are the main sources that release these pollutants into the environment. The presence of these compounds has been reported in soils from Europe, Asia and Africa, but currently, there is not much information of dioxin levels in soils from Brazil. This paper presents the levels of PCDD/Fs, dioxin-like PCBs (dl-PCBs) and non-dioxin-like PCBs (ndl-PCBs) in soils collected from urban areas of Belo Horizonte city, Minas Gerais State, Brazil. Total toxic equivalents (TEQ) observed ranged from 0.43 to 4.54 ng TEQ kg-1 d.m. The highest concentration TEQ found was 2.68 (± 1.63) ng TEQ kg-1 d.m. The low total TEQ achieved suggests that the locations evaluated are not being affected by possible sources of dioxin emissions, although Belo Horizonte is surrounded by a number of them.

Mass Concentrations of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans (PCDD/Fs) and Heavy Metals in Different Size Fractions of Hospital Solid Waste Incinerator Fly Ash Particles

ABSTRACTHospital solid waste incinerator (HSWI) fly ash is an extremely complex mixture because it contains carbon constituents, toxic heavy metals, and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). We investigated the distribution of carbon constituents, PCDD/Fs, and heavy metals in the five different particle size fractions (+106 µm, –106 + 75 µm, –75 + 38 µm, –38 + 25 µm, and –25 µm) of HSWI fly ash. The loss on ignition (LOI) in the particle size fraction of –25 µm was higher than that in the particle size fractions of other sizes. Moreover, 82.63% of the fly ash particles were in the size range of –75 + 25 µm, and this particle size range was suitable for direct flotation treatment. Because powder-activated carbon adsorbed a higher amount of low-chlorinated PCDD/Fs in the gaseous phase, the concentration of each PCDD/F congener, particularly of low-chlorinated PCDD/Fs, generally increased with a decrease in the particle size. The total toxic equivalent (TEQ) of the fraction of –75 µm did not satisfy the landfill site standard (3 ng-TEQ g–1). The highest concentration of Pb, Zn, and Cd was observed in the fraction of –38 + 25 µm rather than in the fraction of –25 µm. The exchangeable speciation of Zn, Pb, and Cd was relatively high in the particle size fraction of –75 µm. The carbonate speciation of Pb and Zn was the highest in the particle size fraction of –38 + 25 µm. The leaching concentrations of Pb and Cd in all particle size fractions exceeded landfill allowable thresholds.