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Study Design: Retrospective cohort. Objective: Billing and coding-related administrative tasks are a major source of healthcare expenditure in the United States. We aim to show that a second-iteration Natural Language Processing (NLP) machine learning algorithm, XLNet, can automate the generation of CPT codes from operative notes in ACDF, PCDF, and CDA procedures. Methods: We collected 922 operative notes from patients who underwent ACDF, PCDF, or CDA from 2015 to 2020 and included CPT codes generated by the billing code department. We trained XLNet, a generalized autoregressive pretraining method, on this dataset and tested its performance by calculating AUROC and AUPRC. Results: The performance of the model approached human accuracy. Trial 1 (ACDF) achieved an AUROC of.82 (range:.48-.93), an AUPRC of.81 (range:.45-.97), and class-by-class accuracy of 77% (range: 34%-91%); trial 2 (PCDF) achieved an AUROC of.83 (.44-.94), an AUPRC of.70 (.45-.96), and class-by-class accuracy of 71% (42%-93%); trial 3 (ACDF and CDA) achieved an AUROC of.95 (.68-.99), an AUPRC of.91 (.56-.98), and class-by-class accuracy of 87% (63%-99%); trial 4 (ACDF, PCDF, CDA) achieved an AUROC of.95 (.76-.99), an AUPRC of.84 (.49-.99), and class-by-class accuracy of 88% (70%-99%). Conclusions: We show that the XLNet model can be successfully applied to orthopedic surgeon's operative notes to generate CPT billing codes. As NLP models as a whole continue to improve, billing can be greatly augmented with artificial intelligence assisted generation of CPT billing codes which will help minimize error and promote standardization in the process. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the impact of racial disparities on surgical outcomes for cervical spondylotic myelopathy (CSM). Adult patients undergoing anterior cervical discectomy and fusion (ACDF) or posterior cervical decompression and fusion (PCDF) for CSM were identified from the 2016 to 019 National Inpatient Sample Database using the International Classification of Diseases codes. Patients were categorized based on approach (ACDF or PCDF) and race/ethnicity (White, Black, Hispanic). Patient demographics, comorbidities, operative characteristics, adverse events, and health care resource utilization were assessed. Multivariate logistic regression analyses were used to identify independent predictors of extended length of stay (LOS), nonroutine discharge (NRD), and exorbitant costs. A total of 46,500 patients were identified, of which 36,015 (77.5%) were White, 7465 (16.0%) were Black, and 3020 (6.5%) were Hispanic. Black and Hispanic patients had a greater comorbidity burden compared to White patients (P = 0.001) and a greater incidence of any postoperative complication (P = 0.001). Healthcare resource utilization were greater in the PCDF cohort than the ACDF cohort and greater in Black and Hispanic patients compared to White patients (P < 0.001). Black and Hispanic patient race were significantly associated with extended hospital LOS ([Black] odds ratio [OR]: 2.24, P < 0.001; [Hispanic] OR: 1.64, P < 0.001) and NRD ([Black] OR: 2.33, P < 0.001; [Hispanic] OR: 1.49, P = 0.016). Among patients who underwent PCDF, Black race was independently associated with extended hospital LOS ([Black] OR: 1.77, P < 0.001; [Hispanic] OR: 1.47, P = 0.167) and NRD ([Black] OR: 1.82, P < 0.001; [Hispanic] OR: 1.38, P = 0.052). Our study suggests that patient race may influence patient outcomes and healthcare resource utilization following ACDF or PCDF for CSM. [ABSTRACT FROM AUTHOR]

Introduction: Frailty has been shown to negatively influence patient outcomes across many disease processes, including in the cervical spondylotic myelopathy (CSM) population. The aim of this study was to assess the impact that frailty has on patients with CSM who undergo anterior cervical discectomy and fusion (ACDF) or posterior cervical decompression and fusion (PCDF). Materials and Methods: A retrospective cohort study was performed using the 2016–2019 national inpatient sample. Adult patients (≥18 years old) undergoing ACDF only or PCDF only for CSM were identified using ICD codes. The patients were categorized based on receipt of ACDF or PCDF and pre-operative frailty status using the 11-item modified frailty index (mFI-11): pre-Frail (mFI = 1), frail (mFI = 2), or severely frail (mFI ≥ 3). Patient demographics, comorbidities, operative characteristics, perioperative adverse events (AEs), and healthcare resource utilization were assessed. Multivariate logistic regression analyses were used to identify independent predictors of extended length of stay (LOS) and non-routine discharge (NRD). Results: A total of 37,990 patients were identified, of which 16,665 (43.9%) were in the pre-frail cohort, 12,985 (34.2%) were in the frail cohort, and 8340 (22.0%) were in the severely frail cohort. The prevalence of many comorbidities varied significantly between frailty cohorts. Across all three frailty cohorts, the incidence of AEs was greater in patients who underwent PCDF, with dysphagia being significantly more common in patients who underwent ACDF. Additionally, the rate of adverse events significantly increased between ACDF and PCDF with respect to increasing frailty (p < 0.001). Regarding healthcare resource utilization, LOS and rate of NRD were significantly greater in patients who underwent PCDF in all three frailty cohorts, with these metrics increasing with frailty in both ACDF and PCDF cohorts (LOS: p < 0.001); NRD: p < 0.001). On a multivariate analysis of patients who underwent ACDF, frailty and severe frailty were found to be independent predictors of extended LOS [(frail) OR: 1.39, p < 0.001; (severely frail) OR: 2.25, p < 0.001] and NRD [(frail) OR: 1.49, p < 0.001; (severely frail) OR: 2.22, p < 0.001]. Similarly, in patients who underwent PCDF, frailty and severe frailty were found to be independent predictors of extended LOS [(frail) OR: 1.58, p < 0.001; (severely frail) OR: 2.45, p < 0.001] and NRD [(frail) OR: 1.55, p < 0.001; (severely frail) OR: 1.63, p < 0.001]. Conclusions: Our study suggests that preoperative frailty may impact outcomes after surgical treatment for CSM, with more frail patients having greater health care utilization and a higher rate of adverse events. The patients undergoing PCDF ensued increased health care utilization, compared to ACDF, whereas severely frail patients undergoing PCDF tended to have the longest length of stay and highest rate of non-routine discharge. Additional prospective studies are necessary to directly compare ACDF and PCDF in frail patients with CSM. [ABSTRACT FROM AUTHOR]

The Southwest Nigeria has witnessed tremendous increase in the output of municipal wastes in the recent years. Non availability of government policy on solid wastes management or its lack of effectiveness where it exists makes unabated open burning the predominant means of municipal solid waste disposal in the region. Open burning of municipal wastes being a major source of anthropogenic air emissions was investigated for atmospheric loading of some hazardous organic pollutants using the emission inventory method. The specific pollutants considered in this study were volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo -p-dioxin (PCDDs) and polychlorinated dibenzo furan (PCDF). The estimated release of VOCs, PAHs, PCBs, PCDD and PCDF from open burning of municipal wastes in the region over the 5-year period investigated were 64000 tonnes, 988 tonnes, 43 tonnes, 0.56 tonnes and 0.2 tonnes respectively. Given the serious human health implications associated with these hazardous organic pollutants, the study suggested conversion of wastes to energy as a possible solution since the region also faces energy challenges. [ABSTRACT FROM AUTHOR]

This study reports the data of polychlorinated dibenzo-p-dioxins (PCDDs), -furans (PCDFs), and polychlorinated biphenyls dioxin-like (dl PCBs) measured in a total of 260 samples of the dairy supply chain collected over a period of 7 years (2011–2017) in the Latium region (Italy). Levels and average profiles of congeners were reported for each group of the analyzed dairy matrices, and any differences between different sampling strategies were considered (around likely pollutant sources or casual sampling). Of the samples, 95.4% resulted compliant with the regulated levels; only samples belonging to the "sheep bulk milk" matrix were found to be above either the action levels or the maximum levels (tot. 12 samples). Raw milk of the sheep species showed the highest averages (PCDD/F 0.248 and dl PCB 0.966 WHO TEQ pg/g of fat) compared to the milk of other species. The buffalo milk showed a content of dl PCB significantly lower (dl PCB: 0.371 WHO TEQ pg/g of fat) than the sheep milk (p<0.05). Dioxins were found to be superior to furans in almost all dairy products, except in the noncompliant samples where furans were higher. The OCDD was found to be the most abundant congener in almost all dairy products. This study provides a first list of reference values for background contamination of the dairy supply chain in the Latium region. These pre-existing values will be useful in all cases of environmental pollution to identify critical situations. [ABSTRACT FROM AUTHOR]

Increased posterior cervical decompression and fusion (PCDF) procedures over the past decade have raised the prospect of bundled payment plans. The American Society of Anesthesiologists (ASA) Physical Status Classification system may enable accurate estimation of health care costs, length of stay (LOS), and other postoperative outcomes in patients undergoing PCDF. Low (I and II) versus high (III and IV) ASA class was used to evaluate 971 patients who underwent PCDF between 2008 and 2016 at a single institution. Demographics were compared using univariate analysis. Cost of care, LOS, and postoperative complications were compared using multivariable logistic and linear regression, controlling for sex, age, length of surgery, and number of segments fused. The high ASA class cohort was older (mean age 62 years vs. 55 years, P < 0.0001) and had higher Elixhauser comorbidity index scores (P < 0.0001). ASA class was independently associated with longer LOS (2.1 days, 95% confidence interval [CI] 1.3–2.9, P < 0.0001) and higher cost ($2936, 95% CI $1457–$4415, P < 0.0001). Patients with high ASA class were more likely to have a nonhome discharge (3.9, 95% CI 2.8–5.6, P < 0.0001), delayed extubation (3.2, 95% CI 1.4–7.3, P = 0.006), intensive care unit stay (2.4, 95% CI 1.5 3.7, P = 0.0001), in-hospital complications (1.5, 95% CI 1.0–2.2, P = 0.03), and 30-day (3.2, 95% CI 1.5–6.8, P = 0.003) and 90-day (3.2, 95% CI 1.8–5.7, P = 0.0001) readmission. High ASA class is strongly associated with increased costs, LOS, and adverse outcomes following PCDF and could be useful for preoperative prediction of these outcomes. [ABSTRACT FROM AUTHOR]

The Seveso Women's Health Study (SWHS) is a historical cohort study of the female population residing near Seveso, Italy, on 10 July 1976, when a chemical explosion resulted in the highest known residential exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Individual TCDD concentration was measured in serum collected near the time of the explosion, and in 1996, we collected adequate blood for TCDD and total dioxin toxic equivalent (TEQ) measurement. Polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls were measured in 1996 serum for a sample (n=225, 23%) of the SWHS cohort and WHO 2005 TEQs were calculated. We examined characteristics that predict 1996 TCDD concentrations and estimated TCDD elimination half-life over the 20-year period since the explosion. Median lipid-adjusted TCDD and total TEQ concentrations in 1996 serum were 7.3 and 26.2 p.p.t., respectively. Initial 1976 TCDD and age at explosion were the strongest predictors of 1996 TCDD. The TCDD elimination half-life was 7.1 years for women older than 10 years in 1976, but was shorter in those who were younger. Twenty years after the explosion, TCDD concentrations in this SWHS sample, the majority of who were children in 1976, remain elevated relative to background. These data add to the limited data available on TCDD elimination half-life in children.

Animal evidence suggests an association between exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and adverse pregnancy outcomes. Epidemiologic studies report inconsistent results, but are limited by narrow range of exposure, small sample size, and lack of a biologic measure of highest lifetime exposure. On July 10, 1976, a chemical explosion in Seveso, Italy resulted in the highest known residential exposure to TCDD. In 1996, we initiated the Seveso Women's Health Study (SWHS), a retrospective cohort of TCDD exposure and reproductive health. Individual-level TCDD was measured in serum collected soon after the explosion. After 20years of follow-up, we found no association between maternal TCDD in 1976 serum or estimated at pregnancy and spontaneous abortion (SAB), fetal growth, or gestational length. Here, we present an updated analysis of TCDD exposure and adverse pregnancy outcomes from a subsequent follow-up of the SWHS cohort in 2008-2009. SWHS women had 1211 post-explosion pregnancies through the 2008-2009 follow-up. We found no association between TCDD estimated at pregnancy and SAB, fetal growth, or gestational length. However, we found a non-significant inverse association between maternal 1976 serum TCDD and birthweight (adjusted β=-22.8, 95% CI: -80.1, 34.6). The association was stronger among first post-explosion births, but remained non-significant (adjusted β=-47.7, 95% CI: -107.3, 11.9). SWHS is the first study to be able to consider two potentially relevant measures of TCDD exposure: highest lifetime dose and in utero. Our results, although non-significant, suggest that highest dose may be more relevant in epidemiologic studies of TCDD and pregnancy outcomes.

Widely used as wood preservatives for the last century, Pentachlorophenol (PCP) and chromated copper arsenate (CCA) have been shown to leach from treated surfaces and contaminate soil of wood storage sites. We performed a four-year field phytoremediation trial in southern Quebec (Canada) on a site contaminated with PCP and CCA with the following objectives: (1) assess the potential of willow, fescue, alfalfa and Indian mustard to tolerate and translocate CCA and PCP residues in their aerial tissues, (2) investigate the possibility of phytoextraction of dioxins and furans, and (3) test the effect of nitrogen fertilizer on phytoremediation performance. We showed that while nitrogen fertilization increased the chlorophyll content of plants, it did not result in a significantly greater plant biomass. We also showed that plants grown in the presence of PCP/CCA residues were able to translocate and concentrate trace elements in their aerial tissues, but also dioxins and furans (PCDD/F). This suggests that plants grown on sites polluted by PCP might contain dioxins and furans and should be treated as contaminated by these toxic chemicals. Finally, the reduction of soil contaminants at the end of the trial suggests that phytoremediation is a promising approach for decontaminating such sites. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective study of a surgical cohort from a single, large academic institution.Objective: The aim of this study was to investigate associations between surgical start time, length of stay, cost, perioperative outcomes, and readmission.Summary Of Background Data: One retrospective study with a smaller cohort investigated associations between surgical start time and outcomes in spine surgery and found that early start times were correlated with shorter length of stay. No examinations of perioperative outcomes or cost have been performed.Methods: All patients undergoing anterior cervical discectomy and fusion (ACDF) and posterior cervical decompression and fusion (PCDF) were queried from a single institution from January 1, 2008 to November 30, 2016. Patients undergoing surgery that started between 12:00 AM and 6:00 AM were excluded due to their likely emergent nature. Cases starting before and after 2:00 PM were compared on the basis of length of stay and cost as the primary outcomes using multivariable logistic regression.Result: The patients undergoing ACDF and PCDF were both similar on the basis of comorbidity burden, preoperative diagnosis, and number of segments fused. The patients undergoing ACDF starting after 2 PM had longer LOS values (adjusted difference of 0.65 days; 95% confidence interval [CI]: 0.28-1.03; P = 0.0006) and higher costs of hospitalization (adjusted difference of $1177; 95% CI: $549-$1806; P = 0.0002). Patients undergoing PCDF starting after 2 PM also had longer LOS values (adjusted difference of 1.19 days; 95% CI: 0.46-1.91; P = 0.001) and higher costs of hospitalization (adjusted difference of $2305; 95% CI: $826-$3785; P = 0.002).Conclusion: Later surgical start time is associated with longer LOS and higher cost. These findings should be further confirmed in the spine surgical literature to investigate surgical start time as a potential cost-saving measure.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

Torrefaction constitutes one of the promising technologies for the management of waste biomass and the production of high-carbon products for combustion, gasification, adsorption of pollutants or soil treatment. Unfortunately, waste biomass may be contaminated with toxic persistent organic pollutants, such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF) and dioxin-like biphenyls (dl-PCB). Literature does not provide consistent measurements on how the low-temperature thermochemical processing, such as torrefaction, affects the toxicity of biomass. This contribution assesses how a torrefaction treatment, conducted at 200 °C, modifies the toxicity due to PCDD/PCDF/dl-PCB in biomass. We deploy the XDS-CALUX biotest on five types of waste biomass (sewage sludge, tree bark, cattle manure, spent coffee ground, common reed), before and after treatment. The content of total dioxin- & biphenyl fraction compounds in the raw biomass, investigated in this study, varies from 0.14 to 3.67 pg BEQ·g−1 d.m. , and in the torrefied biomass between 0.17 and 6.00 pg BEQ·g−1 d.m. ; BEQ stands for bioanalytical equivalent. This increase is statistically insignificant at p = 0.05, taking into account all types of examined biomass. This proves that low-temperature torrefaction cannot detoxify biomass, i.e., chars, produced from biomass characterized by elevated concentration of PCDD/PCDF/dl-PCB, will reflect the contamination of the feedstocks. With respect to heavy metals, we conclude that only the content of Cd in biomass, and, to a lesser extent, the abundance of Cu and Fe, modify the toxicity of this material during its thermochemical treatment at low temperature. [Display omitted] • Torrefaction at 200 °C cannot remove PCDD/PCDF/dl-PCB and metals from biomass. • Toxicity of PCDD/PCDF/dl-PCB is similar before and after treatment. • Cd, Fe, and Cu alter the toxicity of biomass. [ABSTRACT FROM AUTHOR]

Concentrations of polychlorinated dibenzo- para -dioxins and dibenzofurans (PCDD/Fs) were measured in sediment and bivalves at 25 locations along the Korean coasts during 2001–2012. Concentrations of PCDD/Fs in sediment and bivalves ranged from 0.15 to 18.9 pg TEQ/g dry weight and from 0.06 to 7.70 pg TEQ/g wet weight, respectively. Elevated PCDD/F concentrations were found at locations close to largest industrial complexes and commercial harbors. A significant decreasing trend of PCDD/Fs in sediment was associated with strong regulation of PCDD/Fs, whereas levels in bivalves did not show a decreasing trend. Octachlorinated dibenzo- p -dioxin (OCDD) was predominant in sediment, while tetrachlorinated dibenzofuran and OCDD were predominant in bivalves. Almost half (46%) of sediment samples exceeded the threshold effect level suggested by the US National Oceanic and Atmospheric Administration, implying ecotoxicological risks to benthic organisms. Our findings support the effectiveness of legislative action on PCDD/Fs for coastal environments of Korea. Unlabelled Image • Nationwide and long-term monitoring of PCDD/Fs was conducted for coastal environment of Korea. • Highest PCDD/F concentrations were found at locations close to industrial complexes and commercial harbors. • A significant declining trend was observed for PCDD/Fs in coastal sediments. • Approximately 46% of sediment samples exceeded the NOAA threshold guideline. [ABSTRACT FROM AUTHOR]

Introduction : Frailty has been shown to negatively influence patient outcomes across many disease processes, including in the cervical spondylotic myelopathy (CSM) population. The aim of this study was to assess the impact that frailty has on patients with CSM who undergo anterior cervical discectomy and fusion (ACDF) or posterior cervical decompression and fusion (PCDF). Materials and Methods : A retrospective cohort study was performed using the 2016-2019 national inpatient sample. Adult patients (≥18 years old) undergoing ACDF only or PCDF only for CSM were identified using ICD codes. The patients were categorized based on receipt of ACDF or PCDF and pre-operative frailty status using the 11-item modified frailty index (mFI-11): pre-Frail (mFI = 1), frail (mFI = 2), or severely frail (mFI ≥ 3). Patient demographics, comorbidities, operative characteristics, perioperative adverse events (AEs), and healthcare resource utilization were assessed. Multivariate logistic regression analyses were used to identify independent predictors of extended length of stay (LOS) and non-routine discharge (NRD). Results : A total of 37,990 patients were identified, of which 16,665 (43.9%) were in the pre-frail cohort, 12,985 (34.2%) were in the frail cohort, and 8340 (22.0%) were in the severely frail cohort. The prevalence of many comorbidities varied significantly between frailty cohorts. Across all three frailty cohorts, the incidence of AEs was greater in patients who underwent PCDF, with dysphagia being significantly more common in patients who underwent ACDF. Additionally, the rate of adverse events significantly increased between ACDF and PCDF with respect to increasing frailty ( p < 0.001). Regarding healthcare resource utilization, LOS and rate of NRD were significantly greater in patients who underwent PCDF in all three frailty cohorts, with these metrics increasing with frailty in both ACDF and PCDF cohorts (LOS: p < 0.001); NRD: p < 0.001). On a multivariate analysis of patients who underwent ACDF, frailty and severe frailty were found to be independent predictors of extended LOS [(frail) OR: 1.39, p < 0.001; (severely frail) OR: 2.25, p < 0.001] and NRD [(frail) OR: 1.49, p < 0.001; (severely frail) OR: 2.22, p < 0.001]. Similarly, in patients who underwent PCDF, frailty and severe frailty were found to be independent predictors of extended LOS [(frail) OR: 1.58, p < 0.001; (severely frail) OR: 2.45, p < 0.001] and NRD [(frail) OR: 1.55, p < 0.001; (severely frail) OR: 1.63, p < 0.001]. Conclusions : Our study suggests that preoperative frailty may impact outcomes after surgical treatment for CSM, with more frail patients having greater health care utilization and a higher rate of adverse events. The patients undergoing PCDF ensued increased health care utilization, compared to ACDF, whereas severely frail patients undergoing PCDF tended to have the longest length of stay and highest rate of non-routine discharge. Additional prospective studies are necessary to directly compare ACDF and PCDF in frail patients with CSM.

The levels of PCDDs, PCDFs and DL-PCBs were analyzed both in milk and adipose tissues sampled "in vivo" from lactating, drying off and heifer buffaloes from a Campania farm which had been impounded by the competent authority owing to the high dioxin levels found in bulk milk. The chemical determination was carried out by HRGC-HRMS using US EPA Method 1613b. The range of WHO-TEQ values for the PCDDs/PCDFs in adipose tissues was 1.79 to 68.64 pg g−1 fat and in milk was 8.33 to 13.95 pg g−1 fat. The contamination profile for dioxins and furans was given by 1,2,3,7,8-PeCDD; 2,3,4,7,8-PeCDF; 1,2,3,6,7,8-HxCDD and 2,3,7,8-TCDD. The levels of DL-PCBs in adipose tissue varied from 1.38 to 20.13 pg g−1 fat while ranged from 8.33 to 13.95 pg g−1 fat in milk. The pattern of DL-PCBs in both matrices was dominated by congeners PCB 126 and PCB 169. [ABSTRACT FROM AUTHOR]

Reductions in concentrations of persistent organic pollutants were observed for polychlorinated dibenzo- p -dioxins and dibenzofurans (PCDD/Fs) in a comparison of two consecutive decades ending in December 31, 2015 (n = 413) and compiled from a 48-station long-term air-monitoring network in Catalonia, Spain. Reductions were observed in geometric mean concentration of total PCDD/Fs, decreasing at a rate of 11% yr −1 . Results reflect the relative success of improved pollution control measures at industry and traffic locations. At traffic and industrial locations, PCDD/Fs were reduced by around 68% (from 70 to 22 fg I-TEQ/m 3 ) and 66% (from 57 to 19 fg I-TEQ/m 3 ), respectively. The highest concentration of 1196 fg I-TEQ/m 3 was observed during the first decade at an industrial location. The highest concentration over the second decade was at a background location during winter (674 fg I-TEQ/m 3 ). Winter observations are generally higher than those recorded in summer, as evident in an 8-year period of moderate PCDD/F levels (<250 fg I-TEQ/m 3 , n = 143). PCDD/F congener profiles were identified has having less chlorinated PCDD/F, indicating the presence of nearby combustion sources at selected locations. More long-term sampling campaigns, combined with network optimization and integration into a meteorological model, can offer a tool for future PCDD/Fs control measures in not only Catalonia – but also applicable to other areas. [ABSTRACT FROM AUTHOR]

Toxic polychlorinated dibenzo- p -dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in 45 stack gas samples were measured from 19 medical waste incinerators in South Korea using high-resolution gas chromatography equipped with a high-resolution mass spectrometer. The average concentrations of the sum of 17 toxic PCDD/PCDF congeners emitted from the medical waste incinerators ranged from 0.153 to 101.9 ng/Sm 3 . Based on the World Health Organization toxic equivalency factor, they ranged from 0.007 to 5.437 ng-TEQ/Sm 3 . The congener patterns of PCDDs/PCDFs were described using principal component analysis and presented four patterns. In the evaluation of annual average total TEQ concentrations, outlying stack gas samples were excluded. In this study, the number of chlorine substitutions was evaluated as an important factor in congener patterns. Coefficient of determination values were employed for evaluation of correlation between PCDDs and PCDFs. 1,2,3,4,6,7,8-HpCDF was measured as the most emitted congener, while 2,3,4,7,8-PeCDF was the greatest TEQ contributor. [ABSTRACT FROM AUTHOR]

Torrefaction of municipal solid waste (MSW), refuse-derived fuel (RDF), and demolition and construction wood (DC) was performed at 220 °C and a residence time of 90 min in a bench-scale reactor. The levels of toxic polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) contained in emission from the torrefaction process were evaluated. In addition, main ash-forming elements and trace metals in the raw feedstock and char were determined. The use of MSW in fuel blends with DC resulted in lower PCDD and PCDF emissions after torrefaction, compared with the RDF blends. The migration of chlorine from the feedstock to the gas phase reduces the chlorine content of the char which may reduce the risk of alkali chloride-corrosion in char combustion. However, trace metals catalytically active in the formation of PCDD and PCDF remain in the char, thereby may promote PCDD and PCDF formation during subsequent char combustion for energy recovery; this formation is less extensive than when the feedstock is used. [ABSTRACT FROM AUTHOR]

Currently used analytical techniques for halogenated aromatic environmental contaminants such as polychlorinated dibenzo- p -dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs), also known as legacy persistent organic pollutants, are based on gas chromatographic separation of target analytes and detection by mass spectrometry. The coupling of packed column supercritical fluid chromatography (SFC) to atmospheric pressure ionization mass spectrometry (API/MS) could allow for the concurrent analysis of thermally labile and legacy halogenated environmental contaminants if ionization can be sufficiently optimized. The evaluation of positive ion atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) as well as possible charge transfer dopants for the generation of molecular ion isotopomeric clusters of halogenated environmental contaminants with minimal fragmentation has been completed. Using the investigated parameters, positive ion APPI was found to be the more sensitive technique. Of the aromatic and cycloalkane dopants investigated, only fluorobenzene and trifluorotoluene were found to be effective dopants for the halogenated aromatic target analytes (PCDDs, PCDFs, and PCBs). Experiments involving deuterated dopants confirmed that reactive species generated by cycloalkanes were quenched by the SFC eluent rendering them unusable in conjunction with the investigated separation technique. Alternatively, aromatic dopants were found to be less susceptible to quenching by the SFC eluent and fluorobenzene was determined to be the most effective charge transfer dopant for PCDDs, PCDFs, and PCBs. To demonstrate the applicability of the optimized ionization conditions, SFC-API/MS has been used for the concurrent analysis of legacy halogenated aromatic environmental contaminants (PCDDs, PCDFs, and PCBs) and thermally labile analytes (α, β, and γ isomers of hexabromocyclododecane). [ABSTRACT FROM AUTHOR]

In 2006, new maximum levels for the concentration of dioxins (PCDD/F) and dioxin-like PCB (dl-PCB) in food entered into force in the European Union [Regulation (EC) No 199/2006]. The Swiss Confederation decided to adopt these values from the 1 January 2009 on (RS 817.021.23). A previous appraisal showed that beef from extensive production systems in Switzerland may exceed the new maximum level of 4.5 pg WHO97-TEQ·g-1 fat. In order to identify the reasons of the presence of dioxins (PCDD/F) and dioxin-like PCB in Swiss beef, a detailed survey was conducted on eight farms in 2008. Depending on the production system, on each farm several suckler cows and their calves or fattening bulls and heifers were selected and followed over several months. Samples of soil, milk, forages, concentrates and meat were taken and analyzed according to standard protocols. The sum of PCDD/F and dl-PCBs in soil averaged 1.4 pg WHO97-TEQ·g-1 dry matter (DM) across all farms. The mean value found in feed samples was 0.25 pg WHO97-TEQ·g-1 feed (88% DM), which is considerably lower than the legal maximum level of 1.25 pg WHO97-TEQ·g-1 feed. The mean value of milk from suckler cows was 2.75 pg, and the one of milk from dairy cows was 2 pg WHO97-TEQ·g-1 fat. Although two individual beef samples (out of 36) slightly exceeded the legal limit of 4.5 pg WHO97-TEQ·g-1 fat, the mean value of all beef samples was 2.3 pg WHO97-TEQ·g-1 fat. The results did not allow to establish direct relationships between the presence of contaminants in feeds and milk or beef and they showed that variation in PCDD/F and dl-PCB contamination of meat within the same farm was very high. It can be concluded that the situation in Switzerland seems not to be alarming and that no particular measures have to be taken. Nevertheless farmers should be aware that extensive production coupled with absence of delay between weaning and slaughtering may induce some risk for producing non compliant beef.

Crude fish oil is an important ingredient in fish feed for fish farming; it can be used as functional food or neutraceutical (cod liver oil, EPA/DHA concentrates) or incorporated in healthy foods after refining. Major components of fish oil have positive nutritional properties. Polyunsaturated fatty acids can go up to 40% with variable proportions of EPA (C20:5) and DHA (C22-6) [ω-3 fatty acids]. Content of fat soluble vitamins is usually high. Unfortunately, fish oil is also sensitive to degradation products (polymeric and oxidized fat, increased polar content, off-flavor problems…). The beneficial nutritional properties of fish oil are in great contrast with the presence of heavy metals and persistent organic pollutants (POPs) such as polychlorinated dibenzo-dioxins and -furans (PCDDs/PCDFs) and polychlorinated biphenyls (PCBs), mainly originating from the environment. Usual steps for fish oil refining are neutralization, bleaching, winterization (optional) and deodorization. Processing difficulties consist in finding the best operating conditions for an effective removal of unwanted contaminants and a maximal preservation of the nutritional qualities (processing duality). In this work, different adsorbents (filter aid, silica powder, bleaching earth and active carbon) were tested for the best removal of PCDDs/PCDFs and PCBs; it was shown that filter aid, silica and bleaching earth have no significant effect on decontamination while removal of majority non ortho PCBs and PCDDs/PCDFs was possible with active carbon. Mono-ortho PCBs were significantly less absorbed by active carbon. Deodorization was further investigated. Processing temperature had a very pronounced effect on the reduction of PCDDs/PCDFs and PCBs. Already at 210 °C, all of them were removed efficiently to a level below the limit set by European Legislation. But temperature increase was limited by the risk of degradation of EPA/DHA (ω-3). Combination of active carbon treatment and deodorization was shown to be the best compromise to remove majority of the contaminants and to preserve the nutritional quality of fish oil. At low active carbon dosage and deodorization temperature below 200 °C, the total contamination level of PCDDs/PCDFs and PCBs can be reduced below level imposed by European Legislation.

The concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (DL-PCB) were determined in samples of Baltic herring (Clupea harengus membras) and sprat (Sprattus sprattus balticus) in 2006 from commercial catches in Estonian coastal waters, Baltic Sea. The dioxin content of the fish sampled in 2006 did not exceed the European Union's maximum permissible level for PCDD/Fs (4.0 pg WHO-TEQ/g fresh weight) and for the sum of PCDD/Fs and DL-PCBs (8.0 pg WHO-TEQ/g fresh weight). PCDD/Fs and the sum of PCDD/Fs and DL-PCBs content in herring were 2.12 and 3.84 pg WHO-TEQ/g of fresh weight respectively; the corresponding figures for sprat were 1.94 and 3.82 pg WHO-TEQ/g of fresh weight. Comparable with our earlier data on the content of dioxins in three to four year old herring and two to three year old sprat, these data show that two servings of fish per week are not at all harmful tothe health of the Estonian people; indeed, the opposite is more likely to be the case.

An earlier demonstration that the relative concentrations of isomers of polychlorinated dibenzofuran do not vary as the flamefront of an iron ore sinter plant progresses through the bed, and profiles are similar for two sinter strands has been widened to include studies of the similarity or otherwise between full scale strand and sinter pot profiles, effect of addition of suppressants and of coke fuel substitution with other combustible materials. For dioxin suppressant addition, a study of the whole of the tetra- penta- and hexaCDF isomer range as separated by the DB5MS chromatography column, indicates no significant change in profile: examination of the ratios of the targeted penta- and hexaCDF isomers suggests the profile is similarly unaffected by coke fuel replacement. Addition of KCl at varied levels has also been shown to have no effect on the ‘fingerprint’ and there is no indication of any effect by the composition of the sinter mix. The recently published full elution sequence for the DB5MS column is applied to the results obtained using this column. It is confirmed that isomers with 1,9-substitution of chlorine atoms are invariably formed in low concentrations. This is consistent with strong interaction between the 1 and 9 substituted chlorine atoms predicted by DFT thermodynamic calculations. Non-1,9-substituted PCDF equilibrium isomer distributions based on DFT-derived thermodynamic data differ considerably from stack gas distributions obtained using SP2331 column separation. A brief preliminary study indicates the same conclusions (apart from the 1,9-interaction effect) hold for the much smaller content of PCDD. [ABSTRACT FROM AUTHOR]

Isomer distribution patterns of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and naphthalenes (PCNs) were investigated in microwave-assisted pyrolysis (MAP) products of woody biomass. The feedstocks included bark and impregnated wood. The results indicated that isomer distributions in MAP are more selective compared to those reported from wood burning and waste incineration. Favored formation of 4-MoCDF and highly selective chlorine substitution at the 2,4-position observed during MAP suggested a preferred formation pathway of PCDFs involving (chloro)phenol precursors followed by subsequent chlorination. The PCDD distribution was dominated by isomers typically formed from chlorophenol condensation at relatively low temperature. The PCN isomer distributions showed a tendency for sequential chlorination from non-substituted naphthalene at successive positions. The presence of isomers such as 1-MoCDD, 4-MoCDF, 1,2,3-TriCN with low thermodynamic stability indicates that kinetic factors may be important in the MAP process. [ABSTRACT FROM AUTHOR]

Fly ash and Air Pollution Control (APC) residues collected from three municipal solid waste incinerators in Denmark and Greenland were treated by electrodialytic remediation at pilot scale for 8–10 h. This work presents for the first time the effect of electrodialytic treatment on polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), and how these levels impact on the valorization options for fly ash and APC residue. PCDD/PCDF levels in the original residues ranged between 4.85 and 197 ng g −1 , being higher for the electrostatic precipitator fly ash. The toxic equivalent (TEQ) varied ten fold, ranging 0.18–2.0 ng g −1 I-TEQ, with penta and hexa-homologs being most significant for toxicity. After the electrodialytic treatment PCDD/PCDF levels increased in the residues (between 1.4 and 2.0 times). This does not mean PCDD/PCDF were synthesized, but else that soluble materials dissolve, leaving behind the non-water soluble compounds, such as PCDD/PCDF. According to the Basel Convention, PCDD/PCDF levels in these materials is low (<15 μg WHO-TEQ kg −1 ) and the fly ash and APC residue could eventually be valorized, for instance as construction material, provided end-of-waste criteria are set and that a risk assessment of individual options is carried out, including the end-of-life stage when the materials become waste again. [ABSTRACT FROM AUTHOR]

Este artículo contiene resultados del trabajo ejecutado para el esclarecimiento de los mecanismos de formación de los micropolutantes muy tóxicos, como dioxinas y dibenzofuranos, que son emitidos por los hornos de arco eléctrico utilizados en la producción de acero. Estos estudios han permitido relacionar las concentraciones de polutantes emitidos a la atmósfera con las condiciones operación del homo eléctrico. Utilizando el método normalizado CEN 1948 para captación y análisis de muestras de compuestos análogos a las dioxinas ha sido posible determinar el perfil característico de los micropolutantes emitidos por esta fuente

El objetivo de este estudio fue la evaluación de la influencia en los niveles de dioxinas emitidos a la atmósfera como resultado de la utilización de diferentes residuos, tales como neumáticos usados o harinas animales como combustible alternativo durante la producción de clínker. Con este propósito se seleccionaron tres instalaciones que operan en España que fueron evaluadas en diferentes campañas de muestreo. Además, los diferentes residuos fueron evaluados por separado en cada una de las instalaciones. Así, la primera instalación incluyó la adición de harinas animales en la producción de cemento. En la segunda instalación se evaluaron neumáticos fuera de uso y en la tercera planta fueron incorporados los dos tipos de residuos simultáneamente. En todos los casos, los valores de emisión se mantuvieron por debajo de lo establecido por la Directiva Europea de 0,1 ng I-TEQ/Nm3 con valores que se mantuvieron entre 0,001 y 0,042 ng I-TEQ/Nm3. Además, no se encontraron diferencias significativas entre los valores encontrados en el presente estudio y los determinados en instalaciones que operan habitualmente con combustible convencional.

Klorlanmış organik bileşiklerin endüstriyel üretiminin ve yanmanın olduğu kimyasal proseslerin bir ürünü olan poliklorlanmış dibenzodioksinler (PCDDs) ve furanlar (PCDFs), çevrede hemen hemen heryerde bulunmaktadır. Bu durum insan sağlığı için potansiyel bir risk teşkil etmektedir. PCDD ve PCDF bileşikleri özellikle yağlı gıdalarda (tam yağlı süt ve süt ürünleri, et yumurta) birikerek insan vücuduna transfer olmaktadır. Bu makalede PCDD ve PCDF bileşiklerinin yapıları, bulaşma kaynakları, toksik etkileri, kontaminasyon kaynağı olarak süt, süt ürünleri ve anne sütü ve alınması gereken önlemler üzerinde durulmuştur.

Background: Exposure to PCDD/PCDF (dioxin and furan) through consumption of fish and shellfish is closely related to the occurrence of skin diseases, such as chloracne and hyperpigmentation. This study aimed to determine the exposure of PCDD/PCDF and its congeners in fish and shellfish obtained from different regions of the Straits of Malacca among the fishing community. Methods: The risk of fish and shellfish consumption and exposure to PCDD/PCDF among fishermen living in coastal areas of the Straits were evaluated based on a cross-sectional study involving face to face interviews, blood pressure and anthropometric measurements, and administration of food frequency questionnaires (FFQ). Skin examination was done by a dermatologist after the interview session. Determination of 17 congeners of PCDD/ PCDF in 48 composite samples of fish and shellfish was performed based on HRGC/HRMS analysis. Results: The total PCDD/PCDF in the seafood samples ranged from 0.12 to 1.24 pg WHO-TEQ/g fresh weight (4.6-21.8 pg WHO-TEQ/g fat). No significant difference found for the concentrations of PCDD/PCDF between the same types of seafood samples obtained from the three different regions. The concentrations of the most potent congener, 2,3,7,8-TCDD in the seafood samples ranged from 0.01 to 0.11 pg WHO-TEQ/g FW (1.9 pg WHO-TEQ/g fat). A positive moderate correlation was found between the fat contents and concentrations of PCDD/PCDF determined in the seafood samples. The total PCDD/PCDF in all seafood samples were below the 1 pg WHO-TEQ/g fresh weight, with the exception of grey eel-catfish. The respondents had consumed fish and shellfish with the amounts ranging between 2.02 g and 44.06 g per person per day. The total PCDD/PCDF exposures through consumption of fish and shellfish among the respondents were between 0.01 and 0.16 pg WHO-TEQ/kg BW/day. With regard to the two PCDD/PCDF-related skin diseases, no chloracne case was found among the respondents, but 2.2 % of the respondents were diagnosed to have hyperpigmentation. Conclusion: Intake of a moderate amount of fish and shellfish from the area is safe and does not pose a risk for skin diseases. An over-consumption of seafood from the potentially polluted area of the Straits should be monitored in future. [ABSTRACT FROM AUTHOR]

Research has made considerable attempt to decrease the emission of harmful gaseous pollutants to the atmosphere. This report reviews hazards due to foundry air pollution, measurement of pollution emission, pollution control devices and policies of pollution control. The pollutants discussed are polycyclic aromatic hydrocarbon, 1-hydroxypyrene, polychlorinated- p-dibenzodioxins and dibenzofurans and polychlorinated biphenyls. [ABSTRACT FROM AUTHOR]

This paper studies contamination by polychlorinated dibenzo- p-dioxins (PCDDs) and dibenzo furans (PCDFs) of eggs of poultry and wild birds (chicken, duck, Streakeared Bulbul ( Pycnonotus blanfordi), and Whiterumped Munia ( Lonchura striata)) from ten provinces in the north and south of Vietnam. The concentrations of PCDDs/PCDFs had values from 0.4 to 107.6 pg WHOTEQ/g lipid and in the eggs of birds from the southern part of Vietnam they mostly exceeded concentrations in the eggs from the northern part. [ABSTRACT FROM AUTHOR]

Gas/particle partitioning of polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) compounds in the ambient atmosphere were investigated at three different sites (urban-industrial, urban and sub-urban) in İstanbul. Average gas and particle phase concentrations were measured as 133 fg m −3 and 1605 fg m −3 , respectively. Gas phase concentrations of polychlorinated dibenzo-p-dioxin/furan (PCDD/F) compounds were determined to be 128 fg m −3 , 50 fg m −3 , 153 fg m −3 during summer season and 204 fg m −3 , 164 fg m −3 , 154 fg m −3 during winter season for the respective three sampling sites. Particle phase concentrations were determined to be 287 fg m −3 , 176 fg m −3 , 160 fg m −3 during summer and 6586 fg m −3 , 2570 fg m −3 and 1861 fg m −3 during winter season for those three sampling sites. Chlorination level and molecular weight of congeners affected gas/particle partitioning of PCDD/F compounds. Gas phase percentages of 2,3,7,8-TCDD and OCDD concentrations were determined to be 47% and 1% respectively. A relatively high correlation was found between total particle matter (TPM) and particle phase PCDD/F concentration during winter season. [ABSTRACT FROM AUTHOR]

In the marine food-webs, zooplankton is a key element in the transfer of persistent organic pollutants to higher trophic levels. We determined the congener-specific concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in offshore zooplankton (size from 0.2 to 20mm) collected in 2001, 2002 and 2010 in the northern and central Baltic Sea. Of the PCDD/Fs, the concentrations of 2378-TCDF were from 18 to 47 and of 23478-PeCDF from 7.9 to 29pgg−1fat and showed little temporal differences. However, 1234678-HpCDF and OCDF were abundant in 2001-2002 especially in the eastern Gulf of Finland (average concentrations 50 and 89pgg−1fat, respectively). In 2010 the concentrations of these two congeners were lower, 29 and 30pgg−1fat, respectively, but still substantially higher than in the other surveyed areas. The principal components analysis (PCA) supported that area-specific patterns in pollution strongly contributed to the congener profiles particularly in surface sediment and in sediment trap material, but even in zooplankton. The concentrations of the PCBs were highest in the Gulf of Finland and in the Bothnian Bay. The concentrations of most PCBs were somewhat lower in 2010 than in 2001-2002. Of the dioxin-like PCBs, the concentrations of PCB-77 were highest (271-572pgg−1fat) but PCB-126 (32-113pgg−1fat) contributed from 85% to 91% of the total toxicity of PCBs due to its higher toxic potency. Of the PBDEs, the BDE47 and BDE99 were the most abundant (concentrations from 1.2 to 4.6 and from 0.4 to 3.3ngg−1 fat, respectively). The concentrations of most PBDEs were lower in 2010 than in 2001/2002 except in the eastern Gulf of Finland. [ABSTRACT FROM AUTHOR]

Highlights: [•] Case study of remodeled MSWI with PCDD/F emission problems. [•] Analysis of all PCDD/F congeners before and after fabric filters in MSWI plant. [•] PCDD formation within the fabric filters at 220°C was observed. [•] PCDD/F TEQ concentrations and total PCDD/F are independent of each other. [ABSTRACT FROM AUTHOR]

Highlights: [•] The PCDD/Fs and PCBs concentration in people living in Campania. [•] The levels in blood serum were lower than the levels reported in other countries. [•] No difference in blood contamination was found in two areas of the region. [ABSTRACT FROM AUTHOR]

Increasing amounts of sewage sludge are produced nowadays, which need to be disposed of in a safe and responsible manner. Likewise, bottom sediments from small urban water bodies undergo periodical dredging and need to be utilized. These deposits often contain Persistant Organic Pollutants (POPs) and other toxic substances. Plants can be used to reduce these pollutants during or before disposal to land (phytoremediation). Cucurbitaceae are known to accumulate high levels of POPs, including polychlorinated biphenyls (PCB), compared with other plant species but such accumulation may lead to secondary oxidative stress that may limit their value. This study examined the impact of sewage sludge and urban lake sediment on soil toxicity, measured as PCB concentration, and changes in the antioxidative system of cucumber plants grown in the soils. There was an average reduction of PCB by 38.63% and 27.38% in soil amended with sewage sludge and sediment, respectively after 5 weeks of cucumber plant cultivation. In the case of plants grown with sewage sludge, guaiacol peroxidase (POx) activity significantly decreased to 49% of the control at the highest dose given, while that of glutathione S-transferase (GST) increased to 172% of the control value in the same treatment. α-Tocopherol concentration was higher in the plants grown in the sewage sludge amended soil. [ABSTRACT FROM AUTHOR]

Abstract: Temporal trends of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in mothers' milk are still quite rare. Data are particularly scarce when it comes to concentrations from the last decade, 2000 and onwards. The aims of the present study were to assess temporal trends of PCDD, PCDF and DL-PCB in mothers' milk from Stockholm, 1972–2011 and to compare the results with previous analysis of some of the older samples. The samples were analyzed by high resolution GC/MS and results were statistically evaluated for the periods, 1972–2011 and 2002–2011. The rate of which ∑PCDDs, ∑DL-PCBs and the ∑TEQ are decreasing (on pg/g fat WHO-TEQ2005) is higher in the last decade compared to the 40year period, 1972–2011. A similar trend is indicated, but not confirmed, for ∑TEQ of PCDFs, probably due to too many PCDF congeners below LOQ in the period 2002–2011. Concentrations of ∑PCDDs, ∑PCDFs, ∑DLPCBs and ∑TEQ, all expressed as pg/g fat on TEQ-WHO2005-basis, show a statistically significant decline over time, 5.8–6.8% per year, 1972–2011. The last ten years the annual declines for ∑PCDDs, ∑DL-PCBs and ∑TEQ are 9.2–11% and for ∑PCDF, 5.4%. Congener specific trend analysis, 2002–2001, of PCDDs and DL-PCBs showed the same pattern, while the PCDF congeners showed no such general trend. The results from the re-analysis showed good agreement with slightly lower ∑TEQ1998 pg/g fat concentrations in six out of seven samples and mean difference of 13% in ∑TEQ1998. The study shows that time series can be elongated from previous studies, as long as the sample population remains the same. [Copyright &y& Elsevier]

Highlights: [•] Marine fish was analysed as bioindicators of POPs contamination. [•] Levels for PCDD/Fs and PCBs were below the limits established by EU legislation. [•] PCDD/F and DL-PCB concentrations decrease from 2006 to 2012. [Copyright &y& Elsevier]

The river environment is a highly complex system with a variety of processes continuously changing along its continuum (River Continuum Concept). Therefore identification of the threats that result from different elements of the river ecosystem is an intricate task, mainly because of the transportation and biological, geological and chemical processes occurring in such a system. The overall objective of the presented study was to examine the concentration and pattern of polychlorinated dibenzo-para-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dI-PCBs) in the five urban, cascade reservoirs. The obtained data demonstrated an increasing total concentration of toxic PCDDS/PCDFS and dI-PCBs along the studied reservoirs starting from 266 ng/kg d.w. in the first pond up to 11,400 ng/kg d.w. in the last pond, wherein the highest World Health Organization - Toxic Equivalent (WHO-TEQ) concentration (18.9 n TEq/kg d.w.) was also recorded. The exception from this rule, with the lowest total and WHO-TEQ concentrations (182 ng/kg d.w. and 1.31 ng TEq/kg d.w., respectively) was the middle newly constructed III reservoir, equipped with the sediment traps and sand separators at the stormwater outlets and ecotone zones around its catchment for enhancing the purification of inflowing stormwater. This situation may indicate the importance of such solutions for the reduction of PCDDS, PCDFS and dI-PCBs in the urban water ecosystems. [ABSTRACT FROM AUTHOR]

Abstract: The need for accurate thermodynamic data for the polychlorinated dibenzofuran family of isomers arises from the continued interest in the prediction of relative populations of these, and the lack of experimental data justifies the need for the calculation of these at a sufficiently accurate level. In order to add to the existing databases, specific heats have been calculated for the full 135 isomer set of PCDFs using B3LYP density functional theory calculations at the 6-31G(d) and 6-311+G(3df,p) basis set levels. These are calculated for temperatures up to 800K as well as the accompanying heats of formation and entropies at standard conditions. Knowledge of the specific heats up to this temperature gives greater confidence in the calculation of free energy values in the temperature ranges known to be important for PCDF formation and transformation. It is shown that a reduced set of quadratic functions can be used to represent the C p values for the eight isomer groups of the PCDF family and the methodology used is shown to predict the C p and entropy values with good accuracy for a number of other molecules for which experimental values are known. [Copyright &y& Elsevier]

Polychlorinated biphenyls (PCBs) are toxic and persistent chemicals produced between 1930s and 1980s primarily for insulating fluids in heavy-duty electrical equipment in power plants, industries, and large buildings. They persist in the environment and accumulate in plants and animals, and have been classified as probable carcinogens to humans. We performed a systematic review and meta-analysis of scientific literature on the relationship between PCB exposure and human cancer. Two cohorts of people highly exposed to PCBs through ingestion of contaminated rice oil and some cohorts of occupationally exposed workers failed to show a definite increase in total cancer mortality and provided inconsistent results regarding single cancers. Several cohort and case-control studies investigated the association between PCBs and specific cancers, showing an association between PCB serum levels and non-Hodgkin lymphomas (NHL), with a summary odds ratio of 1.5 (95% confidence interval: 1.1–1.7), but no consistent results for the other cancer sites and types. In conclusion, this review provides some evidence for the role of PCBs in the development of NHL, although the inconsistent results of studies performed on highly polluted people and occupationally exposed workers do not allow a firm conclusion to be drawn. [ABSTRACT FROM PUBLISHER]