Formation and emission status of PCDDs/PCDFs in municipal solid waste incinerators in Korea

This study was carried out to examine the formation and the emission status of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDDs/PCDFs) in the flue gases of commercial-scale municipal solid waste (MSW) incinerators, and thus to provide the engineering data for the reduction of PCDDs/PCDFs emitted from MSW incinerators. The formation concentrations of the PCDDs/PCDFs generated at the outlet of waste heat boilers (WHB) were in the range of 1.18-29.61 ng-TEQ/N m3 (average 5.75 ng-TEQ/N m3), while the emission concentrations at the stacks were in the range of 0.026-4.548 ng-TEQ/N m3 (average 0.924 ng-TEQ/N m3). Two major 2,3,7,8-substituted congeners were 2,3,4,7,8-PeCDF and 2,3,4,6,7,8-HxCDF, and their concentrations were up to 50% and 64% of total TEQ values at the outlet of WHB and the stack, respectively. From the results of multi-regression analysis, the formation concentration of PCDDs/PCDFs could be predicted as follows with the correlation factor of r2 = 0.962: PCDDs/PCDFs (ng-TEQ/N m3) = 3.036 (Cl) + 0.094 (T1) - 0.472 (Combustibles) + 0.059 (CO) - 0.039 (THC) - 3.366 (H) + 22.157, where T1 (degrees C) is the temperature at the outlet of the WHB. Cl, Combustibles and H are given as percentages and the others are in parts per million.     

Determination of PCDDs and PCDFs in PCB oil from a hazardous waste site

This paper describes the analysis of hazardous waste oil samples with procedures that were developed primarily to clean up and analyze biological samples. Details of the cleanup procedure and the results from the analysis of several waste PCB oil samples are presented.     

Removal efficiencies of PCDDs/PCDFs by air pollution control devices in municipal solid waste incinerators

Removal efficiencies of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDDs/PCDFs) by air pollution control devices (APCDs) in the commercial-scale municipal solid waste (MSW) incinerators with a capacity of above 200 ton/day were evaluated. The removal efficiencies of PCDDs/PCDFs were up to 95% when the activated carbon (AC) was injected in front of electrostatic precipitator (EP). Spray dryer absorber/bag filter (SDA/BF) had high removal efficiency (99%)) of PCDDs/PCDFs when a mixture of lime and AC was sprayed into the SDA. When the AC was not added in scrubbing solution, the whole congeners of PCDDs/PCDFs were enriched in the wet scrubber (WS) with negative removal efficiencies of -25% to -5731%. Discharge of PCDDs/PCDFs was decreased with increasing the proportions of AC added in scrubbing solution. Selective catalytic reduction (SCR) system had the removal efficiencies of up to 93% during the test operation.     

Dechlorination and destruction of PCDDs/PCDFs in fly ashes from municipal solid waste incinerators by low temperature thermal treatment

Dechlorination and destruction characteristics of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs) in fly ashes from commercial-scale municipal solid waste incinerators by low temperature thermal treatment using a laboratory-scale heating system were investigated. Experiments were carried out in reducing atmosphere at temperatures of 300 degrees C, 450 degrees C and 600 degrees C respectively, for the treatment time of 1h and 3h. Concentrations of PCDDs/PCDFs in raw fly ashes ranged from 35.5 to 107.3 microg kg(-1) (1.5-3.4 microg TEQ kg(-1)) and treated fly ashes ranged from 0.34 to 45.3 microg kg(-1) (0.012-1.63 microg TEQ kg(-1)). Concentrations of PCDDs/PCDFs in fly ashes treated at the different temperatures and times were observed to decrease with increase of treatment temperature and time by dechlorination or destruction. The distribution of octa- and hepta-chlorinated congeners were decreased and tetra-, penta- and hexa-chlorinated congeners were increased at 300 degrees C and 450 degrees C, but the distribution of octa- and hepta-chlorinated congeners were increased and tetra-, penta- and hexa-chlorinated congeners were again decreased at 600 degrees C. Total destruction efficiencies of PCDDs/PCDFs in fly ashes showed above 95% at the treatment temperature of 450 degrees C for 3h. However, removal efficiency of each congener in fly ashes varied, especially, 2,3,7,8-TeCDD and 1,2,3,7,8-PeCDD in fly ash A increased. And the dechlorination and destruction characteristics of PCDDs/PCDFs in fly ash A and B was different due to difference in contents of Ca-compounds and metal oxides such as CuO and PbO in fly ashes.     

A pilot and field investigation on mobility of PCDDs/PCDFs in landfill site with municipal solid waste incineration residue

A field investigation by boring was carried out in a landfill site primarily with municipal solid waste incineration residue. From the collected core samples, vertical profiles of homologous content of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs) in the landfill layer were traced and the behavior of PCDDs/PCDFs was examined. In addition, a pilot-scale study was conducted on the PCDDs/PCDFs leached from incineration fly ash and the treated one using large landfill simulation columns (lysimeters) and the leaching behavior of PCDDs/PCDFs was examined. As a result, it was found that the coexistence of dissolved coloring constituents (DCCs), which might be composed of constituents like dissolved humic matters having strong affinity for hydrophobic organic pollutants, could enhance the leachability of PCDDs/PCDFs, thus contributing to the vertical movement and leaching behavior of PCDDs/PCDFs in the landfill layers of the incineration residue. Moreover, it is highly probable that DCCs derive from the unburned carbon in the bottom ash mixed and buried with the fly ash containing a high content of PCDDs/PCDFs.     

PCDDs & PCDFs from the MSW incinerator

In the range 670 to 900°C furnace temperature, dioxin concentrations strongly depended upon the oxygen concentration in the flue gas. In keeping the oxygen concentration at apploximately 12 percent, dioxin was reduced in the flue gas. For further dioxin reduction from the flue gas, it was the most effective process to treat the flue gas with bag filter system with 120 C operation.     

PCDDs, PCDFs emission control by dry scrubbing system

Presently, in Japan there are no limitations on the emission of PCDDs or PCDFs, but in order to study the feasibility of dry type air pollution control, a pilot plant was constructed in 1988 and the removal efficiencies for PCDDs, acid gas and heavy metals were measured.At the same time PCDDs concentration was compared with that of a previously installed electrostatic precipitator (ESP) plus wet scrubber line.In this paper, the following two items are reported.

1. (1) The difference in the amounts of PCDDs and PCDFs produced due to differences in gas temperature and retention time in ESP and fabric filter (FF).

2. (2) Removal efficiencies of PCDDs and PCDFs of fabric filter.

PCDDs concentration, generally 100–200 ng/Nm³ at the boiler outlet (ESP inlet and/or Quench Reactor (QR) inlet), increased several times at the ESP outlet, but it showed almost no increase at the QR outlet due to a sudden temperature drop. The temperature was 280–310°C, and the gas retention time was 12 sec. during passage through ESP so that it is thought that PCDD was formed under these conditions.On the other hand, a removal efficiency of approx. 90% was obtained with the fabric filter, and the PCDD at the bag outlet was at a sufficiently low level.     

PCDDs, PCDFs, PCBs and DDE in edible marine species from the Adriatic Sea

Edible marine species from several areas of the Adriatic sea were analyzed for their content in persistent organic pollutants (POPs), such as polychlorinated dibenzodioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), and pp'-DDE (dichlorodiphenyldichloroethylene), a metabolite of the organochlorine pesticide dichlorodiphenyltrichloroethane (DDT). On the whole, PCDD/F contamination levels were low. In general, I-TEQ findings were greater for those species at higher levels in the trophic web (mackerel > red mullet > anchovy). Contamination levels were within 0.23 and 1.07 pg TEQ/g fw (fresh weight) in the aforesaid species, while all remaining species exhibited contamination levels ranging from approximately 0.07 to 0.25 pg TEQ/g fw. Besides, TEQ cumulative findings in species from the northern area were in general greater than those from the central and southern areas. PCB cumulative findings in the samples also revealed a detectable difference in contamination levels in species obtained from the northern, central, and southern sampling sites, between 7.6 and 177, 2.3 and 157, and 4.5 and 94 ng/g fw, respectively. The greatest PCB concentrations were found in mackerel (94-177 ng/g fw). Finally, DDE concentration levels varied from 0.7 to 32.4 ng/g fw. The highest levels of contamination were found in mackerel, red mullet and anchovy (17.7-32.4 ng/g fw, 8.1-9.8 ng/g fw, and 6.4-11.9 ng/g fw, respectively).     

Update of daily intake of PCDDs, PCDFs, and dioxin-like PCBs from food in Japan

Total diet study (TDS) samples of 14 food groups from 16 locations in Japan, collected in 1999 and 2000, were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (dioxin-like PCBs) to estimate the update of daily intake of these contaminants from food. The mean daily intake of toxic equivalency (TEQ) for an adult weighing 50 kg, calculated at non-detected isomer concentrations equal to zero (ND=0), was estimated to be 2.25 pg TEQ/kg b.w./day. When non-detected isomer concentrations are assumed to be equal to half of the limits of detection (ND=1/2 LOD), the mean daily intake was estimated to be 3.22 pg TEQ/kg b.w./day. These values were below the tolerable daily intake (TDI) of 4 pg TEQ/kg b.w. for PCDD/Fs and dioxin-like PCBs set in Japan. In both the estimates, the mean daily intakes were highest from fish and shellfish (76.9% at ND=0 and 53.9% at ND=1/2 LOD of the total TEQs), followed by those from meat and eggs (15.5% at ND=0 and 11.7% at ND=1/2 LOD of the total TEQs). Congener specific data revealed that these total TEQ levels were dominated by 1,2,3,7,8-PeCDD, 2,3,4,7,8-PeCDF and 3,3^′,4,4^′,5-PeCB in each case (71.7% at ND=0 and 63.1% at ND=1/2 LOD of the total TEQs). The dioxin-like PCBs (non-ortho and mono-ortho PCBs) accounted for about 50% of these total TEQs. These data will be very useful in the risk assessment of PCDD/Fs and dioxin-like PCBs from food in Japan.     

PCDDs, PCDFs, PCBs and HCB in marine and estuarine sediments from Queensland, Australia.

Concentrations of 2,3,7,8-chlorine substituted PCDDs, PCDFs, selected PCB congeners and HCB were determined in sediment samples collected from sites along the east coast of Queensland in northern Australia. PCDDs were detectable in all sediment samples while PCDFs, PCBs and HCB were mainly found in sediment samples collected from sites in the Brisbane metropolitan area. The results provide evidence that an unidentified source for higher chlorinated PCDDs exists along the Queensland coast.     

Determination of PCDDs,PCDFs, PCBs and HCB emissions from the metallurgical sector in Poland

Background The aim of the project was to measure the actual emissions of PCDD/F, PCBs and HCB from 20 selected metallurgical installations in Poland, in order to update the national inventory of dioxin emission from metallurgical industry for developing a strategy for dioxins and furans emission abatement from the subject facilities (UNEP 2005). Methods Sampling methodology used in this work was developed at the Cracow University of Technology because of the complexity of simultaneous sampling and determining PCDFs, PCDDs, PCB and HCB. For the determination a GC-MS/MS system was used. Results and Discussion Results from the work indicate that the highest dioxins and PCB concentrations were recorded for iron ore sintering plants at 1.10–1.32 ng total¹ TEQ/Nm³ followed by aluminium scrap melting at 0.03–0.66 ng total TEQ/Nm³. The highest HCB concentrations at 613–1491 ng/Nm³ were also recorded for iron ore sintering plants, whereas at aluminium plants the HCB concentrations were in the range of only 10.1–22.7 ng/Nm³. Conclusions The above investigations indicate that secondary aluminium production is the most significant dioxins source, if calculated as emission factor values. However, iron ore sintering plants are operating at much higher production capacity, causing this process to become the major source of dioxins, PCB and HCB pollution to the atmosphere in Poland. Recommendations and Perspectives Based on the performed tests and the environmental reviews of selected plants several recommendations were formulated for the reduction of generation or of emission of these pollutants from iron ore sintering plants, electric arc furnace steel production processes, hot-blast furnace operations, secondary aluminium smelting and primary zinc production from zinc cathodes.     

PCDDs and PCDFs in sewage sludges from two wastewater treatment plants in Beijing, China

The levels of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were analyzed by an isotope-dilution high-resolution mass spectrometric in 16 sewage sludges, sampled from 2004 to 2009, from two municipal wastewater treatment plants (WWTPs) in Beijing. Total toxicity equivalent (TEQ) values were evaluated using the toxicity equivalent factors proposed by International for PCDD/Fs. The I-TEQs for these sewage sludges were from 0.97 to 15.0 pg g⁻¹ dry weight (dw) with a mean value 4.43 pg g⁻¹ dw, indicating that all I-TEQs were below Chinese legislation limit value regulated for agricultural use in soils.The results from limited samples (16 samples) showed that the levels of PCDD/Fs might be correlated with the sludge age. Meanwhile, the temporal trends of PCD/Fs suggested that the I-TEQs may correlate with rainfall in the present study.     

PCDDs and PCDFs in sewage sludge, river and lake sediments from south west Germany

Sewage sludges and sediments of rivers and lakes are sinks for “persistent” organic compounds entering the environment. These matrices are therefore useful in the assessment of local and global pollution with certain compounds or classes of compounds. In recent years we have analyzed sediments of the rivers Neckar, Rhine, and Danube, from Lake Constance, and samples of sewage sludge from municipal waste water treatment plants of south-west Germany for PAH, phthalates, organochlorine pesticides, and PCBs. ¹ We have now analyzed a number of these samples for PCDDs and PCDFs. Isomer-specific analyses for 2,3,7,8-subsituted PCDDs/PCDFs were carried out in all cases.

In all samples PCDDs could be detected, and in most cases PCDFs as well. 2,3,7,8-TCDD was never detected at a detection limit of 0.01 ppb. In sediments (14 samples) the total PCDDs ranged from 0.1 to 2.9 ppb and PCDFs from “not detectable” to 1.2 ppb. The highest concentration for a 2,3,7,8-substituted PCDD^* was found for 1,2,3,6,7,8-hexaCDD with 0.06 ppb. In sewage sludges (15 samples) the total PCDDs ranged from 4 to 65 ppb and PCDFs from 1 to 7 ppb. The highest concentration for a 2,3,7,8-substituted PCDD^* was found for 1,2,3,6,7,8-hexaCDD with 0.57 ppb.

Comparison of PCDD/PCDF patterns of congeners and isomers for the sewage sludge and river sediment samples with those of stack gas emissions of waste incinerators and of pentachlorophenol allows the conclusion that the main source of PCDDs and PCDFs found in these samples is pentachlorophenol. Results of the Lake Constance sediment core indicate that here the atmospheric immission from waste incineration might be predominant.     

Formation of PCDDs and PCDFs by the chlorination of water

Two samples of tab water and double distilled water were chlorinated using chlorine gas. A series of PCDFs could be identified from these experiments, however no PCDDs could be found. The two water samples gave very similar isomeric patterns ( . . tetra-CDFs), however the congener profile (Cl₄ --- Cl₈) was different. These experiments indicate that all products formed by chlorination reactions are potentially contaminated by PCDFs by a specific “chlorine pattern”.     

The presence of PCDDs and PCDFs in human breast milk from the Netherlands

Sixteen individual and two pooled human milk samples were analyzed for PCDDs and PCDFs. All detected PCDD and PCDF congeners had a 2,3,7,8-chlorine substitution pattern.The PCDDs and PCDFs were associated with the lipid fraction of the milk. Major components were 2,3,4,7,8-PnCDF (0.2 – 2.6 ppt), 1,2,3,6,7,8-HxCDD (0.2 – 5.7 ppt), 1,2,3,4,6,7,8-HpCDD (1.3 – 19.1) and OCDD (1.7 – 37.8 ppt), with concentrations on total milk basis.Minor components were 1,2,3,7,8-PnCDD, 1,2,3,7,8,9- and 1,2,3,4,7,8- HxCDD (⩽ 1 ppt). Qualitatively and quantitatively the milk samples from the Netherlands strongly resemble those from Sweden and West-Germany. A linear relationship was found between some congeners. This correlation was highest for congeners having an equal number of chlorine atoms or those with a difference of one chlorine atom.By using a one compartment open model for multiple doses, a maximum liver concentration of approximately 200 ppt 2,3,4,7,8-PnCDF in the neonate was calculated after six months.     

Levels of PBDEs, PCDDs, PCDFs, and coplanar PCBs in edible fish from California coastal waters

The levels of polychlorinated dibenzo-dioxins (PCDDs), polychlorinated dibenzo-furans (PCDFs), coplanar polychlorinated biphenyls (coPCBs), and polybrominated diphenyl ethers (PBDEs) were measured in fish collected from San Francisco Bay in 2000 and from the California coast in 2001. The samples were composites of only the edible portions of the fish (skin on, skin off, or whole body minus head and guts) of comparable size and from distinct geographical areas. Sixty-five composite samples were analyzed for PCDD/PCDF/coPCBs, and 43 composite samples were analyzed for PBDEs. For all fish of all species from all sampling areas, the mean concentration of the sum of BDEs 47, 99, 100, 153, and 154 was 302 ng/g lipid weight, with BDE 47>100>99 approximately 154>153. For all fish of all species from all sampling areas, the mean PCDD/PCDF International Toxic Equivalent (I-TEQ) was 33.1 pg/g lipid. For the three coPCBs (77, 126, 169), the mean I-TEQ for all fish of all species from all sampling areas was 109 pg/g lipid. The highest concentrations of both PCDD/PCDF/coPCBs and PBDEs were found in the highly populated areas of San Francisco Bay, the Los Angeles area, and San Diego Bay.     

A comparison of TEQ contributions from PCDDs,PCDFs and dioxin-like PCBs in sewage sludges from Catalonia,Spain

Eight sewage sludges from rural, urban and industrial wastewater treatment plants (WWTPs) in Catalonia (Spain) were analysed for polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) to determine the present levels of contamination. A method based on an automated cleanup system followed by an isotope-dilution high-resolution mass spectrometric analysis was employed. Total toxicity equivalent (WHO-TEQ) values were calculated using the toxicity equivalent factors (WHO-TEFs) proposed by WHO for dioxin-like PCBs, PCDDs and PCDFs. The WHO-TEQ(PCDD/F) values for these samples ranged from 4.9 to 20.8 pg/g dry weight (d.w.), with a mean value of 9.3 pg/g d.w., whereas WHO-TEQ(PCB) levels ranged between 1.9 and 6.6 pg/g d.w., with a mean value of 4.2 pg/g d.w. The WHO-TEQ(PCB) contribution varied from 13% to 50%, suggesting that PCB contribution on the toxicity of the samples must be taken into account. Moreover, these contemporary PCDD, PCDF and PCB concentrations were compared with previous data obtained from sewage sludge samples collected during the 80s. Our findings show that contemporary PCDD, PCDF and PCB levels have declined since the 80s.     

Spatial and temporal trends of PCDDs and PCDFs in bivalve mollusc coming from Galicia (2000-2005). Possible relationship between biometric parameters and PCDDs and PCDFs levels

Levels and specific profiles of PCDD/F congeners were determined in bivalve mollusc coming from several Rías (estuarine bays) in Galicia (Spanish northwest Atlantic coast). Three species of bivalve mollusc, Mytilus galloprovincialis, Cerstoderma edulis and Ostrea edulis, from several points of littoral collected in the period from 2000 to 2005 were analysed. WHO-TEQ concentrations ranged from 0.08 to 1.62pgg(-1) wet weight, values below the maximum concentration established by the EU. The PCDD/PCDF congeners profile in the studied samples was dominated by 2,3,7,8-TCDF and 2,3,4,7,8-PeCDF. The possible influence between biometric parameters (fat and condition index) and the culture type of mussel (wild or raft) on PCDDs and PCDFs levels were studied using statistical analysis. The coefficients of Pearson product-moment correlation indicated the existence of positive significant relationship between 2,3,7,8-TCDF and 2,3,4,7,8-PeCDF levels and fat content. There was not correlation between condition index and PCDD/Fs content. ANOVA also revealed there were significant differences between summation operatorPCDD/Fs, 2,3,7,8-TCDF and 2,3,4,7,8-PeCDF levels in raft and wild mussels. Spatial and temporal trends were supported by patterns in ANOVA, using a general linear model (GLM) showing a clear separation in the composition of these compounds in more and less contaminated Rías and a decrease of PCDD/FS levels along the years.