Measurement of PCDD/Fs emissions from a coal–fired power plant in Malaysia and establishment of emission factors

AbstractThis paper presents the PCDD/Fs emissions measured from a coal–fired power plant in Malaysia. The study discusses partitioning of PCDD/Fs in particle and gas phase, effects of coal quality to PCDD/Fs formation, effects of air pollution control device (APCD) configuration to PCDD/Fs formation and establishment of emission factors of PCDD/Fs from the studied coal–fired power plant. The results presented in this study were mostly in good agreement with the previous works on PCDD/Fs emissions conducted in other countries. Laboratory analysis results showed that PCDFs were the dominant congeners. The emissions of PCDD/Fs were low which most probably due to the high combustion efficiency. The PCDFs/PCDDs ratio was more than 1 and PCDD/Fs were detected in fly ash, hence speculating that the formation of PCDD/Fs during coal combustion was mainly through de novo synthesis. Analysis on partitioning of PCDD/Fs showed that the compounds were mainly emitted in gas phase. This study also indicated that type of coal influenced the formation of PCDD/Fs during coal combustion where bituminous coal with high sulfur (S) content resulted in slightly lower PCDD/Fs emissions compared to sub–bituminous coal. It was also found that operation of flue gas desulfurization (FGD) reduced the emission of PCDD/Fs. The established emission factors for PCDD/Fs were in the range of 0.08 to 0.11ng I–TEQ/kg

INFLUENCE OF LINEAR ALKYLBENZENE SULFONATE (LAS) AS ORGANIC COSOLVENT ON LEACHING BEHAVIOR OF PCDD/FS FROM FLY-ASH AND SOIL

The leaching of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) was measured in soil and standard fly ash column eluted with pure water and linear alkylbenzene sulfonate (LAS)- water. The data obtained were used to evaluate the leachability of PCDD/Fs from waste dump like incineration residual slag and fly ash deposition. The leaching rate was shown to be increased significantly by using LAS water. The leachate contents of PCDD/Fs were above their known water solubility. Concentration of PCDD/Fs in the leachates as well as the relative leaching (calculated on the fly ash content) increased with increasing chlorinating degree and decreasing water solubility. LAS above the critical micelle concentration (CMC) probably enhances PCDD/Fs solubility

The critical role of the operating conditions on the Fenton oxidation of 2-chlorophenol: assessment of PCDD/Fs formation

This work assesses the influence of the operating conditions H2O2dose (20 or 100% of the stoichiometric amount), temperature (20 or 70◦C), and the presence of chloride in the oxidation medium in the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) during Fenton treatment of aqueous samples of 2-chlorophenol, 2-CP, one of the strongest precursor of PCDD/Fs. After 4 h of oxidation in the experiments carried out with 20% H2O2chlorinated phenoxyphenols and biphenyls, which are intermediates in PCDD/Fs formation, as well as PCDD/Fs were observed, resulting in concentrations11 times higher than in the untreated sample. Additionally, when NaCl was also present in the reaction medium, PCDD/Fs were formed at higher extent, with a total concentration 74.4 times higher than in the untreated 2-CP solution. Results depicted a preferential formation of PCDFs over PCDDs, with dominance of lower chlorinated PCDD/Fs (tetra and penta-PCDD/Fs). Besides, the formation of the most toxic PCDD/Fs congeners (2,3,7,8-PCDD/Fs) was not favored under the operating conditions used in this work.Financial support from the projects CTQ2011-25262, CTQ2008-05545 and CTQ2008-00690 (Ministerio de Economía y Competitividad – MINECO (SPAIN) and Fondo Europeo de Desarrollo Regional – FEDER) is gratefully acknowledged

Oceanic Sink and Biogeochemical Controls on the Accumulation of Polychlorinated Dibenzo-p-dioxins, Dibenzofurans, and Biphenyls in Plankton.

Polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), and dioxin-like polychlorinated biphenyls (dl-PCBs) were measured in plankton samples from the Atlantic, Pacific and Indian Oceans collected during the Malaspina circumnavigation cruise. The concentrations of PCDD/Fs and dl-PCBs in plankton averaged 14 and 240 pg gdw-1, respectively, but concentrations were highly variable. The global distribution of PCDD/Fs and dl-PCBs was not driven by proximity to primary sources in continents, but significantly correlated with plankton biomass. These trends are consistent with the interactions between atmospheric deposition, biomass dilution, and settling fluxes of organic matter in the water column, as key processes driving the POPs plankton phase concentrations in the global oceans. The application of a model of the air-water-plankton diffusive exchange of PCDD/Fs and PCBs reproduce in part the influence of biomass on plankton phase concentrations, and suggest future modelling prioritiesThe estimated oceanic sink (Atlantic, Pacific and Indian Oceans) due to settling fluxes of organic matter bound PCDD/Fs and dl-PCBs is of 400 Kg y-1 and 10500 kg y-1, respectively. This oceanic sink is 3 and 8 times lower, for PCDD/Fs and dl-PCBs respectively, than the atmospheric inputs due to gross diffusive absorption and dry deposition. These important atmospheric inputs, among other observations, confirm that atmospheric deposition supports and drives the accumulation of dl-PCBs and PCDD/Fs in plankton from the oligotrophic oceans.MALASPINA (CSD2008 00077)Versión del editor5,228

Concentrations of Polychlorinated Biphenyls (PCBs), Polychlorinated Dibenzo-p-dioxins and Furans (PCDD/Fs), and Polybrominated Diphenyl Ethers (PBDEs) as Functions of Sample Depth in Killer Whale (Orcinus orca) Blubber

Concentrations of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polybrominated diphenyl ethers (PBDEs) were examined as a function of depth in killer whale (Orcinus orca) blubber samples. Lipid-normalized concentrations of PCBs, PCDD/Fs, and PBDEs did not display significant variation with depth in three distinct blubber layers (outer, central, and inner). Significantly more variation in contaminant concentrations were observed with depth on a wet weight basis for the killer whale sample. The current study indicates that non-invasive microdart biopsy sampling methods commonly used for monitoring contaminants in marine mammals yield representative details on contaminant burdens for chlorinated and brominated aromatic compounds in marine mammal blubber, regardless of the quantity and type of blubber sampled, provided that lipid normalization is performed on resulting analytical determinations

Polykloorattujen dibentso-p-dioksiinien ja dibentsofuraanien anaerobinen mikrobiologinen kloorinpoisto Kymijoen sedimenteissä

Highly toxic polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) accumulate in the environment in sediments and soils. PCDD/Fs may pose considerable environmental and health risks because of their persistence in the environment. PCDD/Fs can be degraded slowly by microbial reductive dechlorination under anaerobic conditions which produces less chlorinated PCDD/Fs. Sediments of the Kymijoki River located in South-Eastern Finland are highly contaminated with PCDD/Fs and other chlorinated compounds. PCDD/Fs in sediments of the river mainly originate as unwanted byproducts from the production of the chlorophenol wood preservative Ky-5 between 1939 and 1984. The total volume of the most toxic 2,3,7,8-substituted PCDD/Fs contaminated sediments in the Kymijoki River, from Kuusankoski to the Baltic Sea, are estimated to be five million cubic meters of wet sediment. The Kymijoki River is the largest known source of PCDD/Fs to the Baltic Sea. The objective of this thesis was to gain knowledge on the sediment PCDD/Fs and the dechlorinating bacterial community at the Kymijoki River. We aimed to determine the potential for anaerobic microbial dechlorination of weathered PCDD/Fs in river sediments. Sediment samples were collected from the Kymijoki River located at 0, 20, 30, and 60 km downstream from the main source of contamination, and at a reference site. An anaerobic microcosm study was conducted to determine dechlorination potential and the effect of temperature on the reductive dechlorination process for spiked 1,2,3,4-tetrachlorodibenzofuran (1,2,3,4-TeCDF). Concentrations of weathered PCDD/Fs and activity of the indigenous dechlorinating microbial community were determined in sediment samples. The measured mean total concentrations for 2,3,7,8-PCDD/Fs were high in sediments at all study sites of the river. The predominant PCDD/F congeners were 1,2,3,4,6,7,8-HpCDF, 1,2,3,4,6,8,9-HpCDF, and OCDF at all sites. The sediment PCDD/F congener profiles were similar to that of the Ky-5 wood preservative. Dechlorination of spiked 1,2,3,4-TeCDF to less chlorinated dibenzofurans was detected after 10 and 29 months in sediment microcosms from the all studied sites. The pathway of 1,2,3,4-TeCDF dechlorination was mainly via 1,3,4-TrCDF to 1,3-DiCDF. The low temperature decreased the dechlorination rate of spiked TeCDF which suggests that dechlorination of weathered PCDD/Fs is limited at the in situ temperature of the river sediments. A native dechlorinating Dehalococcoides-like Chloroflexi community was present in sediment samples at all studied sites. The dechlorination pathway of 1,2,3,4-TeCDF suggests that dechlorination of aged PCDD/F congeners could generate non-2,3,7,8-substituted and hence less toxic PCDD/Fs. However, concentrations of 2,3,7,8-substituted PCDD/Fs have remained at approximately the same levels over the last few decades at each sampling location of the Kymijoki River. Furthermore, no substantial changes in the relative abundances of weathered PCDD/Fs were observed over 2.5 years in laboratory microcosm studies, indicating that anaerobic dechlorination of weathered PCDD/Fs was limited over the course of the experiment. Results of this study indicates that no or only minimal biodegradation of PCDD/F congeners has occurred in the river sediments over the last few decades since the contamination events. Therefore, concentrations of weathered PCDD/Fs in the sediments of the Kymijoki River are expected to remain at the same level for decades or centuries with further migration towards the Baltic Sea.Polyklooratut dibentso-p-dioksiinit ja dibentsofuraanit (PCDD/F) ovat erittäin myrkyllisiä, sedimentteihin ja maaperään kertyviä yhdisteitä. PCDD/F-yhdisteet ovat merkittävä ympäristö- ja terveysriski, koska ne ovat pysyviä ympäristössä ja voivat kertyä eliöihin. PCDD/F-yhdisteiden on mahdollista hajota mikrobiologisella kloorinpoistolla anaerobisissa olosuhteissa hitaassa reaktiossa, jossa muodostuu klooria vähemmän sisältäviä yhdisteitä. Kymijoen pohjasedimenteissä esiintyy PCDD/F-yhdisteitä ja muita orgaanisia klooriyhdisteitä laajalla alueella korkeissa pitoisuuksissa. Suurimpana lähteenä joen PCDD/F-yhdisteille on ollut vuosina 1940-1984 puunsuoja-aineena käytetyn kloorifenolituote Ky-5:n valmistusprosessi, jossa nämä yhdisteet ovat syntyneet sivutuotteena. Haitallisimmilla 2,3,7,8-PCDD/F-yhdisteillä saastuneiden jokisedimenttien kokonaismäärän Kuusankosken ja Suomenlahden välillä on arvioitu olevan noin 5 000 000 m3 sedimenttiä. Kymijoki on suurin yksittäinen PCDD/F-yhdisteiden päästölähde Itämereen. Työn tavoitteena oli lisätä tietoutta Kymijoen sedimenttien sisältämistä PCDD/F-yhdisteistä. Tarkoituksena oli tutkia joen sedimentteihin kertyneiden PCDD/F-yhdisteiden mahdollista hajoamista anaerobisella mikrobiologisella kloorinpoistoreaktiolla. Sedimenttinäytteet kerättiin Kymijoelta 0 km:n, 20 km:n, 30 km:n ja 60 km:n etäisyydellä saastuneimmasta paikasta Kuusankoskelta sekä vertailupaikalta. Anaerobiset mikrokosmoskokeet suoritettiin kloorinpoistopotentiaalin sekä lämpötilan vaikutuksen tutkimiseksi malliaineeksi lisätyllä 1,2,3,4-tetraklooridibentsofuraanilla (1,2,3,4-TeCDF). Näytteistä määritettiin joen sedimentteihin kertyneiden 2,3,7,8-PCDD/F-yhdisteiden pitoisuudet sekä klooriyhdisteitä hajottavien mikrobien esiintyvyyttä sedimentissä. Kymijoen kaikilta tutkimusalueilta määritetyissä näytteissä 2,3,7,8-PCDD/F-yhdisteitä esiintyi huomattavan korkeissa keskiarvopitoisuuksissa. Kaikilla tutkimusalueilla suurimpina pitoisuuksina PCDD/F-yhdisteistä esiintyivät 1,2,3,4,6,7,8-HpCDF, 1,2,3,4,6,8,9-HpCDF ja OCDF. Joen sedimenteistä määritetty PCDD/F-yhdisteiden pitoisuusprofiili oli samanlainen kuin Ky-5-tuotteessa. Tutkimuksessa havaittiin 1,2,3,4-TeCDF-yhdisteen kloorinpoistoa sekä samanaikaisesti tri-, di- ja monokloorattujen furaanien muodostumista mikrokosmoksissa. 1,2,3,4-TeCDF:sta muodostui hajoamistuotteena eniten 1,3,4-TrCDF:a, josta muodostui edelleen 1,3-DiCDF:a. Huoneenlämpötilaa (21 ○C) viileämpi lämpötila hidasti merkittävästi 1,2,3,4-TeCDF:n kloorinpoistoa, minkä perusteella voidaan arvioida PCDD/F-yhdisteiden hajoamisen hidastuvan joen sedimenttien in situ lämpötiloissa. Kloorinpoistoon kykeneviä Dehalococcoides-ryhmään kuuluvia Chloroflexi mikrobeja tunnistettiin kaikilla tutkimus- ja vertailupaikoilla. Tutkimuksessa määritetyn 1,2,3,4-TeCDF:n hajoamisreitin perusteella voidaan päätellä, ettei mahdollinen kloorinpoistoreaktio tuota haitallisimpia 2,3,7,8-substituoituja yhdisteitä. Tulokset osoittivat, että joen sedimenttien 2,3,7,8-PCDD/F-yhdisteiden pitoisuudet ovat säilyneet samalla tasolla useiden vuosikymmenten ajan. Lisäksi tutkimuksen aikana ei tapahtunut merkittäviä muutoksia PCDD/F-yhdisteiden suhteellisissa osuuksissa 2,5 vuoden aikana mikrokosmoksissa. Näiden tulosten perusteella tutkimuksessa ei havaittu sedimentteihin kertyneiden PCDD/F-yhdisteiden mikrobiologista hajoamista kloorinpoistoreaktiolla Kymijoen sedimenteissä. Pitoisuuksien voidaan olettaa säilyvän ennallaan sedimenteissä useiden vuosikymmenten ajan sekä mahdollisesti vähitellen kulkeutuvan sedimentin mukana Itämereen

Formation of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) in the electrochemical oxidation of polluted waters with pharmaceuticals used against COVID-19

The COVID-19 pandemic has produced a huge impact on our lives, increasing the consumption of certain pharmaceuticals, and with this, contributing to the intensification of their presence in wastewater and in the environment. This situation demands the implementation of efficient remediation technologies, among them, electrochemical oxidation (ELOX) is one the most applied. This work studies the application of ELOX with the aim of eliminate pharmaceuticals used in the fight against COVID-19, assessing its degradation rate, as well as the risk of formation of toxic trace by-products, such as unintentional POPs like polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). To this end, model solutions containing 10 mg L-1 of dexamethasone (DEX), paracetamol (PAR), amoxicillin (AMX), and sertraline (STR) with two different electrolytes (NaCl and Na2SO4) have been evaluated. However, electrochemical systems that contain chloride ions in solution together with PCDD/Fs precursor molecules may lead to the formation of these highly toxic by-products. So, PCDD/Fs were quantified under conditions of complete degradation of the drugs. Furthermore, the presence of PCDD/Fs precursors such as chlorophenols was determined, as well as the role of Cl-, Cl- and radicals in the formation of the by-products and PCDD/Fs. The maximum measured concentration of PCDD/Fs was around 2700-pg-L-1 for the amoxicillin case in NaCl medium. The obtained results emphasise the importance of not underestimating the potential formation of these highly toxic trace by-products, in addition to the correct selection of oxidation processes and operation variables, in order to avoid final higher toxicity in the medium.This research was developed in the framework of the project PID2020–115409RB-I00 (MCIN/AEI) financed by the Spanish Ministry of Science and Innovation. Sophie Schroder is also grateful to MCIN for the FPI grant PRE2018–83526

Dietary intake of polychlorinated dibenzo-p-dioxins and furans, adiposity and obesity status

Introduction: The principal source of exposure to Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans (PCDD/Fs) in humans comes from food intake. PCDD/Fs, are a family of potential endocrine disruptors and have been associated with different chronic diseases such as diabetes and hypertension. However, studies assessing the relationship between dietary exposure to PCDD/Fs and adiposity or obesity status in a middle-aged population are limited. Objective: To assess cross-sectionally and longitudinally the associations between estimated dietary intake (DI) of PCDD/Fs and body mass index (BMI), waist circumference, and the prevalence/incidence of obesity and abdominal obesity in a middle-aged population. Methods: In 5899 participants aged 55-75 years (48% women) living with overweight/obesity from the PREDIMED-plus cohort, PCDD/Fs DI was estimated using a 143-item validated food-frequency questionnaire, and the levels of food PCDD/F expressed as Toxic Equivalents (TEQ). Consequently, cross-sectional and prospective associations between baseline PCDD/Fs DI (in pgTEQ/week) and adiposity or obesity status were assessed at baseline and after 1-year follow-up using multivariable cox, logistic or linear regression models. Results: Compared to participants in the first PCDD/F DI tertile, those in the highest tertile presented a higher BMI (β-coefficient [confidence interval]) (0.43kg/m2 [0.22; 0.64]; P-trend <0.001), a higher waist circumference (1.11 cm [0.55; 1.66]; P-trend <0.001), and a higher prevalence of obesity and abdominal obesity (1.05 [1.01; 1.09] and 1.02 [1.00; 1.03]; P-trend = 0.09 and 0.027, respectively). In the prospective analysis, participants in the top PCDD/F DI baseline tertile showed an increase in waist circumference compared with those in the first tertile after 1-year of follow-up (β-coefficient 0.37 cm [0.06; 0.70]; P-trend = 0.015). Conclusion: Higher DI of PCDD/Fs was positively associated with adiposity parameters and obesity status at baseline and with changes in waist circumference after 1-year of follow-up in subjects living with overweight/obesity. Further large prospective studies using a different population with longer follow-up periods are warranted in the future to strengthen our results. Keywords: Abdominal obesity; Adiposity; Endocrine disrupting chemicals; Obesity; Polychlorinated dibenzo-p-furans (PCDD/F)

Insights into PCDD/Fs and PAHs in biomass boilers envisaging risks of ash use as fertilizers

ABSTRACT: Since ashes are a possible source of Persistent Organic Pollutants (POPs) contamination, their application in soils must be subject to more study and control. In this scope, feed residual forest biomasses and biomass ashes, collected along one year in four biomass power stations, were characterized mainly for their polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) and Polycyclic Aromatic Hydrocarbons (PAHs) contents. The biomasses present concerning levels of Cl (0.04-0.28%) that may lead to PCDD/Fs formation. The biomasses also contain OCDD (29-260 ng/kg) and 1,2,3,4,6,7,8-HpCDD (35 ng/kg) that may contribute to increased Toxic Equivalents (TEQs) of ashes, possibly involving dechlorination and ash enrichment mechanisms. While the WHO2005-TEQs in bottom ashes (14-20 ng TEQ/kg) reaches the proposed limit (20 ng TEQ/kg) for ash use as fertilizers, in fly ashes (35-1139 ng TEQ/kg) the limit is exceeded. PAHs are below 0.02 mg/kg in bottom ashes and 1.5-2.5 mg/kg in fly ashes, complying with the proposed limit of 6 mg/kg. As bottom and fly ash streams may contain different ash flows, a clear definition of ash mixes is required. Correlations between unburned carbon (C), PAHs and PCDD/Fs were not found, which highlights the need for compulsory PCDD/Fs analysis in ashes, independently of their origin, burnout degree or levels of other contaminants. A sensitivity analysis was performed to evaluate the impact of handling non-detected values, which showed more impact for TEQs values close to the proposed regulatory limit of PCDD/Fs. These findings highlight the need to define reporting protocols of analytical results for risk assessments and conformity evaluation.info:eu-repo/semantics/publishedVersio

The Contribution of Fly Ash Components to PCDD/F Formation

Chlorinated aromatics undergo surface-mediated reactions with metal oxides to form environmentally persistent free radicals (EPFRs) which can further react to produce polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Previous work using laboratory-made fly ash surrogates composed of transition metal oxides deposited on silica powder has confirmed their ability to mimic fly ash in the production of PCDD/Fs. However, little is known about the propensity of alumina and aluminosilicates to form PCDD/Fs. Cooperative catalysis between transition metals in the formation of PCDD/Fs has also seen little research. A fly ash sample containing both alumina and mullite, an aluminosilicate, was tested for PCDD/F formation ability and compared to PCDD/F yields from the thermal degradation of 2-monochlorophenol (2-MCP) precursor over γ-alumina, α-alumina, and mullite. A series of fly ash surrogates with varying amounts of co-deposited iron (III) oxide and copper (II) oxide, both known to increase PCDD/F formation individually, were also investigated. A packed-bed flow reactor was used to investigate the thermal degradation of 2-MCP over the various catalysts at 200-600 ⁰C. Fly ash gave similar PCDD/F yields to surrogates made with similar transition metal content. γ-alumina, which is thermodynamically unfavorable, was very catalytically active and gave low PCDD/F yields despite a high destruction of 2-MCP. Mullite and α-alumina, the thermodynamically favorable form of alumina, yielded higher concentrations of dioxins and products with a higher degree of chlorine substitution than γ-alumina. The data suggests that certain aluminas and aluminosilicates, commonly found in fly ash, are active in the formation of PCDD/Fs in the post-flame cool zones of combustion systems and should be considered as additional catalytic surfaces active in the process. The bimetallic surrogates were found to be extremely catalytically active, suggesting synergistic effects between Fe and Cu in real incineration systems. Under oxidative conditions, the bimetallic surrogates completely catalytically oxidize the 2-MCP precursor and exhibit low yields of PCDD/Fs. Under pyrolytic conditions, the bimetallic surrogates give extremely high yields of PCDD/Fs. The comparisons between transition metal and non-transition metal effects on PCDD/F formation represents a new step forward in our understanding of PCDD/F emissions from incineration systems