Evaluation of hexabromocyclododecane (HBCD), polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) outflows during the destruction of HBCD wastes in a hazardous waste incinerator.

This paper presents an evaluation of hexabromocyclododecane (HBCD), polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) outflows during the destruction of HBCD waste stockpiles in IZAYDAS Hazardous Waste Incinerator (HWI) in Kocaeli, Türkiye. HBCD wastes containing 100 % pure HBCD were in 25 kg packages with 63 % Br content were co-incinerated in a 3-day test burn with average feed rate of 26 kg/h. HBCD, PBDD/Fs and PCDD/Fs were measured in the outlet streams to quantify the amount of unintended POPs releases associated with the processing of HBCD waste and to observe the POP removal performance of air pollution control equipment (APCE) of the incinerator. Total mass outflow rate of HBCDs is calculated as 2.6 g/day, corresponding to destruction efficiency of 99.9996 %. Total toxicity of the brominated dioxins was measured as 0.00044 ng TEQ/Nm3 on average, while highly brominated congeners are dominant. PCDD/F concentrations in the outflow streams during HBCD test burns are produced similar congener distributions with those given in the previous studies, with the dominance of 7,8-chlorinated congeners. Mass flows in the outlet streams indicated that the efficiency of ESP and wet scrubbers for the removal of PCDD/Fs and HBCDs. Flue gas concentrations of PCDD/Fs, HBCDs and PBDD/Fs obtained in HBCD burn test indicated that burning HBCD wastes cause no significant emissions as operational parameters and total halogen content in the menu are kept within the incinerator limits.

Determination of PCDD/F and DL-PCB pollution levels, source appointment and risk assessment of surface sediments in dam lakes in Istanbul, Türkiye.

The current situation of the water resources of Istanbul, which is one of the important metropolises of Europe, should be known and constantly monitored by the reasons of the rapid increase in the city population, the acceleration of production-related industrial activities, the expansion of the city with construction activities, and the decrease in precipitation. The purpose of this study was to reveal the situations of surface sediments collected from Istanbul water reservoirs in terms of PCDD/Fs and DL-PCBs, to identify possible sources, and to conduct their ecological risk assessment. Total PCDD/Fs and DL-PCBs concentrations varied between 28.13 and 457.4 pg/g (average 136.8 pg/g) and 12.19-340.1 pg/g (average 72.09 pg/g). The corresponding TEQ values of PCDD/Fs and DL-PCBs were between 0.53 and 5.37 pg TEQ/g (average 2.23 pg TEQ/g) and 0.02-0.44 pg TEQ/g (average 0.12 pg TEQ/g), respectively. Octachlorodibenzo-p-dioxin (OCDD) is the dominant congener by constituting about 75% of the total PCDD/Fs on average, while congener distributions of DL-PCBs showed the dominance of PCB-118 and PCB-105. The sediments taken from Kazandere dam have the lowest pollution levels for both PCDD/Fs and DL-PCBs. The highest PCDD/F and DL-PCB amounts were measured in sediments of Alibey and Elmali dams (closest to highly populated settlements of Istanbul), which are most affected by the air pollution caused by the traffic, commercial/industrial combustion (like waste incineration facility) and combustion for residential heating. Almost all the sediments have total dioxin-like toxicity levels higher than the safe threshold level (with two exceptions) of 0.85 pg TEQ/g dw, proposed for ecological risk. Health risk assessment shows that levels of dioxin-like compounds would result in a total intake of 0.33 pg TEQ/kg bw/day even in the worst-case scenario, not exceeding the tolerable daily intake value of 1 pg TEQ/kg bw/day. Among exposure pathways, consumption of fish constitutes almost all the total intake, while contributions of other pathways are minimal.

Assessment of PCDD/F and dioxin-like PCB levels in environmental and food samples in the vicinity of IZAYDAS waste incinerator plant (WIP): from past to present.

The study includes the determination of the general background PCDD/F and dl-PCB levels in environmental (ambient air and soil) and food (meat, milk, egg, leafy vegetable, root vegetable and fruit samples) samples collected in four sampling sites in the vicinity of IZAYDAS WIP and its possible health risks. The local and meteorological conditions (prevailing wind direction, season, raining, and soil structure) were taken into account in the selection of sampling sites. The concentrations of PCDD/F and dl-PCB in ambient air ranged from 0.00841 to 0.05881 pg I-TEQ/m3. These results are quite low and it showed that there is no significant PCDD/F pollution in the vicinity of the plant. The results of PCDD/F and dl-PCB in eight soil samples (four in the range of 0-1.2 km, four in the range of 1.2-5 km) taken from the vicinity of IZAYDAS varied between 0.12681 and 0.4353 pg TEQ/g. The levels of PCDD/F and dl-PCBs measured in food samples were found to be significantly lower than both the limit values given by the Turkish Food Codex and the levels measured in the previous studies (between 2008 and 2009). In the health risk assessment, carcinogenic risk was calculated for PCDD/F and dl-PCBs made according to the exposure scenarios established for the study. The total intake values for the sum of PCDD/F and dl-PCB were found between 0.08 and 0.37 pg TEQ/kg.day for adults. These values are well below the limit value, which is considered as 2 pg WHO-TEQ/kg body weight.day. In this context, it was concluded that carcinogenic risk due to PCDD/F and dl-PCB intake is significantly low in the vicinity of the plant.

Did we choose the best one? A new site selection approach based on exposure and uptake potential for waste incineration.

Ecological problems arising after the construction and operation of a waste incineration plant generally originate from incorrect decisions made during the selection of the location of the plant. The main objective of this study is to investigate how the selection method for the location of a new municipal waste incineration plant can be improved by using a dispersion modelling approach supported by geographical information systems and multi-criteria decision analysis. Considering this aim, the appropriateness of the current location of an existent plant was assessed by applying a pollution dispersion model. Using this procedure, the site ranking for a total of 90 candidate locations and the site of the existing incinerator were determined by a new location selection practice and the current place of the plant was evaluated by ANOVA and Tukey tests. This ranking, made without the use of modelling approaches, was re-evaluated based on the modelling of various variables, including the concentration of pollutants, population and population density, demography, temporality of meteorological data, pollutant type, risk formation type by CALPUFF and re-ranking the results. The findings clearly indicate the impropriety of the location of the current plant, as the pollution distribution model showed that its location was the fourth-worst choice among 91 possibilities. It was concluded that the location selection procedures for waste incinerators should benefit from the improvements obtained by the articulation of pollution dispersion studies combined with the population density data to obtain the most suitable location.

Inventory development for perfluorooctane sulfonic acid (PFOS) in Turkey: challenges to control chemicals in articles and products.

Perfluorooctane sulfonic acid (PFOS) and related substances have been listed as persistent organic pollutants (POPs) in the Stockholm Convention. Countries which have ratified the Convention need to take appropriate actions to control PFOS use and release. This study compiles and enhances the findings of the first inventory of PFOS and related substances use in Turkey conducted within the frame of the Stockholm Convention National Implementation Plan (NIP) update. The specific Harmonized Commodity Description and Coding System (Harmonized System (HS)) codes of imported and exported goods that possibly contain PFOS and 165 of Chemical Abstracts Service (CAS) numbers of PFOS-related substances were assessed for acquiring information from customs and other authorities. However, with the current approaches available, no useful information could be compiled since HS codes are not specific enough and CAS numbers are not used by customs. Furthermore, the cut-off volume in chemical databases in Turkey and the reporting limit in the HS system (0.1 %) are too high for controlling PFOS. The attempt of modeling imported volumes by a Monte Carlo simulation did not also result in a satisfactory estimate, giving an upper-bound estimate above the global production volumes. The replies to questionnaires were not satisfactory, highlighting that an elaborated approach is needed in the communication with potentially PFOS-using stakeholders. The experience of the challenges of gathering information on PFOS in articles and products revealed the gaps of controlling highly hazardous substances in products and articles and the need of improvements.

Possibility of the most cost efficient choice: a divided process approach to method and location selection for municipal solid waste management.

As studies on municipal solid waste management increased in recent years, many new mathematical models and approaches with a focus on determining the best treatment and disposal scenario were developed and applied. In this study, a mixed integer linear programming model was developed to be used as a facilitative tool for the cost minimisation of municipal solid waste management practices. Since municipal solid waste mass is a mixed composition of various types of waste components with different physical and chemical properties, the model was designed to include all the suitable treatment and disposal methods for these different waste components. The method alternatives with multiple waste inputs, such as aerobic biological treatment and the thermal processes, were divided into a number of inputs to remove their non-linear structures. This way, linear programming could be used, and the linear cost function could be minimised over a set of linear constraints with integer variables. The model was applied to the city of Kocaeli, which will require a new waste management application in the future, beginning from 2015. The results obtained for different haul distance constraints in the study area were presented and assessed. The results showed that all the information required for a comprehensive management task could be modelled by a linear optimisation model with a divided processes approach easily.

Siting a municipal solid waste disposal facility, part II: the effects of external criteria on the final decision.

The procedure of a multi-criteria decision analysis supported by the geographic information systems was applied to the site selection process of a planning municipal solid waste management practice based on twelve different scenarios. The scenarios included two different decision tree modes and two different weighting models for three different area requirements. The suitability rankings of the suitable sites obtained from the application of the decision procedure for the scenarios were assessed by a factorial experimental design concerning the effect of some external criteria on the final decision of the site selection process. The external criteria used in the factorial experimental design were defined as "Risk perception and approval of stakeholders" and "Visibility". The effects of the presence of these criteria in the decision trees were evaluated in detail. For a quantitative expression of the differentiations observed in the suitability rankings, the ranking data were subjected to ANOVA test after a normalization process. Then the results of these tests were evaluated by Tukey test to measure the effects of external criteria on the final decision. The results of Tukey tests indicated that the involvement of the external criteria into the decision trees produced statistically meaningful differentiations in the suitability rankings. Since the external criteria could cause considerable external costs during the operation of the disposal facilities, the presence of these criteria in the decision tree in addition to the other criteria related to environmental and legislative requisites could prevent subsequent external costs in the first place.

Siting a municipal solid waste disposal facility, Part One: An evaluation of different scenarios for a site selection procedure.

UNLABELLED: This study includes an application of the first two phases of a new three-phased decision-making structure that was developed to overcome the problems related to ecological safety and social justice in site selection applications. It was conducted on a current site selection problem related to the municipal solid waste disposal facilities in Kocaeli, the most industrialized region of Turkey. In order to assess the deficiencies of the legal site selection procedures related to ecological safety, two different decision tree modes were applied separately. The first mode ("Legislation") concerns the current buffer zone applications given in the regulations, while the second one ("Proposed") includes the applications of the new decision-making structure proposed in this study. Since it was assumed that the subjective tendencies of the decision makers on the weightings would have a significant effect on the final decision, these two modes were assessed by employing two different weighting models. The results were obtained from all of the scenarios related to selection of suitable sites with three different area requirements (15, 250, and 500 acres) for the solid wastes generated in the Kocaeli region. The results showed that the possible changes in the decision structure could cause significant differences in the final decision related to selection of the most suitable sites. The most highest and lowest differences were at the "Legislation" mode for 15 acres and 500 acres, respectively. Furthermore, the results obtained in the study showed that the possible differentiations in the criteria weightings could also cause significant differences in the suitability ranking. Therefore, to get a reliable final decision, a statistical assessment of these differentiations should be made. IMPLICATIONS: The results showed that the possible changes in the decision structure could cause significant differences in the final decision related to selection of the most suitable sites. Furthermore, the results obtained in the study showed that the possible differentiations in the criteria weightings could also cause significant differences in the suitability ranking. Therefore, to get a reliable final decision, a statistical assessment of these differentiations should be made.

Assessment of emissions and removal of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) at start-up periods in a hazardous waste incinerator.

UNLABELLED: A study was conducted to observe the changes in polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) levels and congener profiles in the flue gas of a hazardous waste incinerator during two start-up periods. Flue gas samplings were performed simultaneously through Air Pollution Control Devices (APCDs) (including boiler outlet, electrostatic precipitator (ESP) outlet, wet scrubbers (WS) outlet, and activated carbon (AC) filter outlet) in different combustion temperatures during a planned cold (long) start-up and an unplanned warm (short) start-up. The results showed that PCDD/F concentrations could be elevated during the start-up periods up to levels 3-4 times higher than those observed in the normal operation. Especially lower combustion temperatures in the short start-ups may cause high PCDD/F concentrations in the raw flue gas. Assessment of combustion temperatures and Furans/Dioxins values indicated that surface-catalyzed de novo synthesis was the dominant pathway in the formation of PCDD/Fs in the combustion units. PCDD/F removal efficiencies of Air Pollution Control Devices suggested that formation by de novo synthesis existed in ESP also when in operation, leading to increase of gaseous phase PCDD/Fs in ESP Particle-bound PCDD/Fs were removed mainly by ESP and WS, while gaseous phase PCDD/Fs were removed by WS, and more efficiently by AC filter. IMPLICATIONS: This paper evaluates PCDD/F emissions and removal performances of APCDs (ESP, wet scrubbers, and activated carbon) during two start-up periods in an incinerator. The main implications are the following: (1) start-up periods increase PCDD/F emissions up to 2-3 times in the incinerator; (2) low combustion temperatures in start-ups cause high PCDD/F emissions in raw gas; (3) formation of PCDD/Fs by de novo synthesis occurs in ESP; (4) AC is efficient in removing gaseous PCDD/Fs, but may increase particle-bound ones; and (5) scrubbers remove both gaseous and particle-bound PCDD/Fs efficiently.

Evaluation of PCDD/F pollution in surface sediments of Izmit Bay.

This study evaluates PCDD/F pollution in the surface sediments of Izmit Bay (Turkey) and assesses the possible sources of PCDD/F inputs to the bay. The results showed that concentrations of toxic PCDD/F congeners in the sediments varied between 0.45 and 255 ng WHO2005-TEQ/kg dry weight. Pollution mapping shows that PCDD/F levels in the central section of Izmit Bay are much higher than those in the eastern and the western sections. Sediments collected from the northern part of the central section showed very high PCDD/F concentrations. The samples reveal three different congener profiles dominated by OCDF, 1,2,3,4,6,7,8-HpCDF, and OCDD respectively. The dominance of OCDF in the sediment samples taken from the central section was attributed to the former production of vinyl chloride monomer in the area, while that of 1,2,3,4,6,7,8-HpCDF was attributed to the (previously unknown) use of a chlorophenol-based fungicide in the region. The OCDD dominated group was explained by the use of pentachlorophenol. The results indicate that historic industrial discharges are the main contributor to the PCDD/F pollution in the sediments.

Levels of PCDD/Fs in local and non-local food samples collected from a highly polluted area in Turkey.

A sampling and analysis program were conducted to determine the PCDD/F levels in various food samples collected in Kocaeli, one of the highly polluted areas in Turkey. Several food samples including animal (egg, chicken, meat and cow's milk) and plant (fruits, leafy vegetables, fruiting vegetables, rooty vegetables and flour) products were collected from both local and non-local (commercial) sources. The local food samples were taken from 20 sampling points selected by taking into account the location of the possible PCDD/F sources, dominant wind directions and representing the major part of the Turkish daily diet The PCDD/F concentrations in local eggs and milk samples were ranged from <1.16 to 10.94 pg TEQ g(-1) fat and from <0.43 to 3.29 pg TEQ g(-1) fat, respectively. On the other hand, the PCDD/F concentrations were measured between 0.28-1.81 pg EQ g(-1) fat in local meat samples and 0.15-2.92 pg TEQ g(-1) fat in local chicken samples. The PCDD/F concentrations in the plant products were relatively low and most of the congeners were measured below the detection limits except for the leafy vegetables. In addition, several commercial samples were analyzed in order to evaluate the differences of PCDD/F levels in samples collected from both the local and non-local sources. The results showed that the local animal products have higher PCDD/F concentrations than the non-local ones. Moreover, the commercial plant products showed undetectable concentrations for most of the congeners. Finally, the PCDD/F levels in some animal products were found to be higher than the national limit values.

Health risk assessment of BTEX emissions in the landfill environment.

This study focuses on a health risk assessment related to benzene, toluene, ethylbenzene, and m,p,o-xylene (xylenes) (BTEX) exposure via inhalation for workers at a landfill (LF) site. First, the landfill gas (LFG) samples were collected and analyzed accordance with US EPA method TO-17. The mean concentrations of benzene, toluene, ethylbenzene, and xylenes were determined as 140.3, 1271.7, 239.9, and 341.3 microg/m(3), respectively. Then, a risk assessment methodology was employed to evaluate the potential adverse health effects of the individual BTEX compounds according to their carcinogenicities. The corresponding mean cancer risk for benzene was estimated to be 6.75E-05 that is lower than the designated acceptable risk level of 1.0E-04. With respect to mean non-carcinogenic risks for toluene, ethylbenzene, and xylenes, both individually and cumulatively, they were lower than the specified level of 1.0. These findings reveal that landfill BTEX emissions do not pose a health threat to workers at the landfill site. In addition, as far as the risks are concerned for the population in the neighborhood area of the landfill, air dilution of BTEX emitted from LF site is widely sufficient to guarantee their protection.

The prevalence of molar incisor hypomineralization (MIH) in a group of children in a highly polluted urban region and a windfarm-green energy island.

BACKGROUND: Children's developing teeth may be sensitive to environmental pollutants such as polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans. The term molar incisor hypomineralization (MIH) was introduced to describe the clinical appearance of enamel hypomineralization of systemic origin affecting one or more permanent first molars (PFMs) that are associated frequently with affected incisors. AIM: The aim of this study was to determine the prevalance of MIH in children from the most industrialized and polluted region and the most green-energy island of Turkey. DESIGN: In September 2007, a retrospective study was initiated in two elementary schools: one, a group of children (N = 153) who fitted the criteria from Tavsancil, Kocaeli (N = 109) and the other from Bozcaada island, Canakkale (N = 44). The soil samples were collected from selected regions in order to determine the contamination levels in a heavily industrialized area and a non-industrialized area. RESULTS: Prevalance of MIH in children in Bozcaada island was 9.1%, while prevalance of MIH was 9.2% in Tavsancil. The PCDD/F levels in soil samples collected from Bozcaada and Tavsancil were determined as 1,12 and 8,4 I-TEQ ng/kg dry soil, respectively (P < 0.001). CONCLUSIONS: In this preliminary study with a small study population, prevalence of MIH did not seem to be associated with the levels of PCDD/Fs in the environment.

Health risk assessment of background PCDD/F exposure levels in Kocaeli, Turkey.

An estimation and assessment of the polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo furans (PCDD/Fs) exposure levels for the people living in Kocaeli, the most industrialized area of Turkey, are presented. The information is based on the results of PCDD/F analyses in the samples collected from various environmental media and the multimedia exposure assessment methodology. Exposure scenarios were constructed on a site-specific basis by combining the exposure pathways appropriate to the area, and the activity patterns of the people living in Kocaeli. The model showed that the exposure levels of PCDD/Fs were in the range of 3.7-13.1 pg I-TEQ.kg-1 bw for adult receptors, which are higher than the recommended TDI value of 2 pg TEQ.kg-1 bw. The PCDD/F intakes for rural receptors were estimated to be three times higher than those for urban and semi-urban receptors due mainly to the consumption of locally grown foods. The assessment of the contributions of various exposure pathways to the total exposure and the sensitivity analysis performed based on a probabilistic approach indicated that PCDD/F intakes for adult receptors are directly proportional to the locally grown fraction of plant groups consumed.

Inventory of emissions of primary air pollutants in the city of Kocaeli, Turkey.

This study aims to obtain a reliable inventory of the emission rates of the principal air pollutants including PM, SO2, NOx) and CO in Kocaeli, Turkey. In the first stage, the pollutant sources classified as point, area and line sources are determined in the area. Then the annual emission rates of the pollutants released from these sources are estimated by the emission factors given by USEPA and CORINAIR. Results show that the annual emission rates for PM, SO2, NOx) and CO are 2195 tons, 5342 tons, 14632 tons and 23095 tons, respectively. On the other hand, the pollutant group with the highest contribution to total emission rate is determined as the point sources for NOx, which is responsible for 73% of total NOx emission, while it is the area sources for PM, SO2 and CO with the contribution percentages of 75, 76 and 69, respectively.

Adsorbable organic halogens (AOXs) in solid residues from hazardous and clinical waste incineration.

Trace concentrations of a variety of chemicals remain in solid residues following combustion even in properly designed and operated incinerators. In the present study, the adsorbable organic halogen (AOX) levels of the solid residues, i.e., bottom ash, fly ash, and filter cake, were investigated during a 82-day of continuous operation of a Hazardous and Clinical Waste Incinerator. The distribution of halogens in the waste input prior to the incineration was also determined. The AOX levels measured in bottom ash, fly ash and filter cake were in the range of 0.014-1.879, 0.012-0.263, and 0.004-0.062 mg-Cl(-)/kg, respectively. The AOX levels are significantly low in the fly ash and filter cake due to the post-combustion process in the incinerator. At the end of the 82 days, the total AOX output in the bottom ash, fly ash, and filter cake were 571, 3.71, and 6.26 g, respectively. The partitioning of the total AOX in solid residues was 98.28, 0.64, and 1.08% for the bottom ash, fly ash and filter cake, respectively. This shows that the bottom ash is more contaminated with AOX than the other two residues.

Evaluation of PCDD/F levels in ambient air and soils and estimation of deposition rates in Kocaeli, Turkey.

PCDD/F analyses were made in soil and ambient air samples taken from Kocaeli, an industrialized area of Turkey. Results showed that the levels of PCDD/F pollution are comparable to the levels observed in the various urban areas in the world. PCDD/F concentrations in surface soils ranged between 0.4 and 4.27 pg I-TEQ kg(-1) with a geometric mean of 0.76 pg I-TEQ kg(-1), while those in ambient air were between 23 and 563 f gm(-3), with geometric mean of 82.0 f gm(-3). Ambient air PCDD/F concentration in the city center was about 10 times higher than those in the rural area. Combustion activities present in the area were assessed to be the most significant source of the PCDD/F pollution based on the congener and homologue profiles and statistical analysis of the data. The deposition rate modeling of USEPA was applied and the deposition rates were determined in the range between 7.6 and 66.3 ng I-TEQ m(-2)year(-1) with a geometric mean of 15.9 ng I-TEQ m(-2)year(-1). The rates were higher than the recommended deposition rates in relation to the tolerable daily intake (TDI) range of PCDD/Fs for humans. The deposition velocities computed were also found to be high in both low and highly chlorinated PCDD/Fs, and this was attributed to the vapor phase deposition of volatile PCDD/Fs, and the scavenging effect of the precipitation on the particle-bound PCDD/Fs.

Health risk assessment of PCDD/F emissions from a hazardous and medical waste incinerator in Turkey.

A multimedia risk assessment procedure was conducted to determine the fate and transport of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD/F) emissions from the Izmit Hazardous and Medical Waste Incinerator (IZAYDAS) in Turkey and their potential health risks. Congener concentrations in ambient air and their deposition rates were determined by an air dispersion model (ISCST3). Their transfer to some plant groups and animal tissues was predicted by food chain modeling. Exposure scenarios were produced based on three receptor groups (urban, semiurban, and rural) and five subgroups determined according to ages. Daily intakes of PCDD/Fs via exposure pathways were determined based on three different emission scenarios for each group and subgroup. Estimated incremental PCDD/F doses caused by the incinerator emissions in central-tendency scenario were computed as between 2.31 x 10(-6) and 0.008 pg TEQ kg(-1) bodyweight (bw) day(-1) on average for all the receptors other than infants in all the settings, while the range was 3.01 x 10(-5)-0.081 pg TEQ kg(-1) bw day(-1) for infants. Sensitivity analysis showed that the consumption of vegetal products and their locally grown fractions are the most significant parameters in the exposure to PCDD/Fs in the area.

An evaluation of the occupational health risks to workers in a hazardous waste incinerator.

A study was conducted to evaluate the health impact of airborne pollutants on incinerator workers at IZAYDAS Incinerator, Turkey. Ambient air samples were taken from two sampling points in the incinerator area and analyzed for particulate matter, heavy metals, volatile and semi-volatile organic compounds (VOCs and SVOCs) and dioxins. The places where the maximum exposure was expected to occur were selected in determining the sampling points. The first point was placed in the front area of the rotary kiln, between the areas of barrel feeding, aqueous and liquid waste storage and solid waste feeding, and the second one was near the fly ash transfer line from the ash silo. Results were evaluated based on the regulations related to occupational health. Benzene, dibromochloropropane (DBCP) and hexachlorobutadiene (HCBD) concentrations in the ambient air of the plant were measured at levels higher than the occupational exposure limits. Dioxin concentrations were measured as 0.050 and 0.075 pg TEQ.m(-3), corresponding to a daily intake between 0.007 and 0.01 pg TEQ. kg body weight(-1).day (-1). An assessment of dioxin congener and homologue profiles suggested that gaseous fractions of dioxin congeners are higher in front of the rotary kiln, while most of them are in particle-bound phases near the ash conveyor. Finally, the necessity of further studies including occupational health and medical surveillance assessments on the health effects of the pollutants for the workers and the general population in such an industrialized area was emphasized.

Removal of PCDD/Fs from flue gas by a fixed-bed activated carbon filter in a hazardous waste incinerator.

The adsorption of polychlorinated dibenzodioxins and dibenzofurans (PCDD/Fs) by activated carbon (AC) was examined in a fixed-bed AC unit in a hazardous waste incinerator (IZAYDAS) in Turkey. Results showed that the removal efficiencies of PCDD/Fs decrease as the chlorination level increases, which was explained by the difference in gas/particle partitioning of the compounds. Since dioxins are tightly adsorbed by activated carbon, other flue gas constituents showed no clear effect on the dioxin removal. Adsorption kinetics indicated that the adsorption of volatile congeners and homologues fits well with Henry's law, possibly due to the higher gaseous fractions, while the correlation was lower for lowly volatile ones. PCDD/F congeners and homologues had a concentration value up to which no adsorption occurred, which could be attributed to the insufficient contact times at the low concentrations.