Influence of a municipal solid waste incinerator on ambient air and soil PCDD/Fs levels

PCNs, PCBs, and PCDD/Fs in Soil around a Cement Kiln Co-Processing Municipal Wastes in Northwestern China: Levels, Distribution, and Potential Human Health Risks

To evaluate the impact of the first cement kiln co-processing municipal wastes in northwest China on the surrounding environment, the concentrations of polychlorinated naphthalenes (PCNs), polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined in 17 soil samples collected around the plant. The concentration ranges of PCNs, PCBs, and PCDD/Fs were 132-1288, 10.8-59.5, and 2.50-5.95 pg/g, and the ranges of toxic equivalents (TEQ) were 1.98-20.8, 2.36-48.0, and 73.2-418 fg/g, respectively. The concentrations of PCNs, PCBs, and PCDD/Fs in this study were generally lower than those in soil around municipal waste incinerators and industrial parks in other areas. An exponential function equation was applied for the relationship between the concentration of the target compounds and the distance from the cement kiln stack, the results showed that PCN and PCB concentrations declined with the increasing of distance from the stack. Furthermore, it was found that the effect of the cement kiln on surrounding soil contaminations with PCNs and PCBs was stronger than that of PCDD/Fs by comparing the PCN, PCB, and PCDD/F homologue profiles in the fly ash sample from the plant and soil samples at different distances. The total carcinogenic risks (CR) of PCNs, PCBs, and PCDD/Fs for children and adults in soil were 1.65 × 10^-8-8.93 × 10^-8 and 1.70 × 10^-8-9.16 × 10^-8, respectively, which was less than the risk threshold (CR = 1 × 10^-6), and there was no health risk.

Characteristics, correlations and health risks of PCDD/Fs and heavy metals in surface soil near municipal solid waste incineration plants in Southwest China

As primary anthropogenic emission source of toxic pollutants such as heavy metals and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), municipal solid waste (MSW) incineration has caused worldwide concern. However, a comprehensive analysis of the pollution characteristics and health risks of PCDD/Fs and heavy metals in soils around MSW incineration plants is lacking. In this study, 17 PCDD/Fs and 11 heavy metals in soil samples collected near MSW incineration plants in Sichuan province were investigated to evaluate their pollution characteristics and potential health risk. Sichuan was selected as the study area because the MSW incineration amount in this province ranks first among all inland provinces in China. The PCDD/Fs concentrations ranged from 0.30 to 7.50 ng I-TEQ/kg, which were significantly below risk screening and intervention thresholds. Regarding heavy metals, principal component analysis suggested that Hg, Pb and Zn were the primary metals emitted from the MSW incineration plants. Cluster analysis of PCDD/Fs and heavy metals showed that of PCDD/Fs homologs and heavy metals (e.g., Hg, Pb, Zn and Cd) were clustered into one group, indicating the coexistence and coaccumulation of heavy metals (especially Hg, Pb, Zn, and Cd) and PCDD/Fs in soil. These heavy metals are thus candidate tracers for PCDD/Fs in soil near MSW incineration plants. A health risk analysis found that the carcinogenic and non-carcinogenic risks of PCDD/Fs and heavy metals (except for Ni) in the soil samples were all within acceptable levels. This study provides new insights into correlations and health risks of PCDD/Fs and heavy metals in surface soil near MSW incineration plants. The findings have implications for future studies of environmental and human health risk analysis related to waste incineration.

Polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) in soil around municipal solid waste incinerator: A comparison with polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs)

Polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) share similar toxicities and thermal origins, e.g., municipal solid waste incinerator (MSWI). Recently, PBDD/Fs from MSWI attracted rising concern because their important precursors, i.e., brominated flame retardants (BFRs), were frequently found in various wastes for landfill or MSWI feedstock. So far, however, little is known about PBDD/Fs and their associated risks in the vicinal environments of MSWI. Here we analyzed PBDD/Fs and PCDD/Fs in 29 soil samples collected around a multiyear large-scale MSWI, and compared their spatial distributions, sources and risks. PBDD/Fs demonstrated comparable concentrations and toxic equivalent quantities (TEQs) to PCDD/Fs in these samples. Spatially, both the concentrations of PBDD/Fs and PCDD/Fs decreased outwards from the MSWI, and exhibited significant linear correlations with the distances from the MSWI in the southeast downwind soil, suggesting the influence of the MSWI on its vicinal soil environment. However, the existence of other dioxin sources concealed its influence beyond 6 km. PBDD/Fs in the soils were characterized by highly-brominated PBDFs, especially Octa-BDF, and their sources were diagnosed as the MSWI and diesel exhaust; PCDD/Fs, however, were dominated by highly-chlorinated PCDDs, particularly Octa-CDD, and were contributed individually or jointly by the MSWI, automobile exhaust and pentachlorophenol (PCP)/Na-PCP. The non-carcinogenic risks of dioxins in all the soil samples were acceptable, but their carcinogenic risks in 17% of the samples were unacceptable. These samples were all located close to the MSWI and highways, therefore, the land use of these two high-risk zones should be cautiously planed.

Evaluation of atmospheric sources of PCDD/Fs, PCBs and PBDEs around an MSWI plant using active and passive air samplers

This study evaluated the spatial distributions and concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in ambient air around a municipal solid waste incineration (MSWI) plant located in eastern China in two sampling campaigns within one year. Twenty high-volume samples and 27 passive air samples were collected from May 2012 to May 2013. The mean sampling rate of the passive sampler was estimated to be 3.8 ± 1.8 m³ d^-1 in summer and autumn, while the mean sampling rate was 2.8 ± 1.0 m³ d^-1 in winter and spring. Hence, the annual mean sampling rate was approximately 3.2 ± 1.4 m³ d^-1. The mean levels of PCDD/Fs, PCBs, PBDEs (excluding BDE-209) and BDE-209 in the passive air samples varied in the ranges of 0.086 ± 0.058-0.76 ± 0.51 pg TEQ m^-3, 39 ± 26-170 ± 120 pg m^-3, 3.3 ± 2.2-36 ± 24 pg m^-3 and 58 ± 39-300 ± 150 pg m^-3, respectively. The levels, congener profiles and spatial distributions of PCDD/Fs, PCBs and PBDEs were investigated. The results showed that the concentrations of PCDD/Fs and PCBs decreased with increasing distance from the emission source and that different sampling sites had slightly different effects. However, this trend was opposite to that observed for PBDEs. Moreover, principal component analysis (PCA) demonstrated that the MSWI emission source was the primary factor for PCDD/Fs in ambient air. Further monitoring should be conducted to evaluate the noticeable impact on the environment and human health due to exposure.

Twenty-year trends and exposure assessment of polychlorinated dibenzodioxins and dibenzofurans in human serum from the Seoul citizens

This study investigated polychlorinated dibenzodioxins and dibenzofurans (PCDD/Fs) in air (n = 108) and human serum (n = 1802) samples collected over 20 years to evaluate the long-term exposure to PCDD/Fs and health effects on the Korean general population. The serum PCDD/F levels were higher in males than in females and were significantly correlated with age, body mass index, and manifestation of diabetes mellitus. From 2000 to 2019, the PCDD/F levels declined by 96% in the air, but only by 36% in the serum, because PCDD/Fs are relatively stable in the human body and are exposed to humans after PCDD/Fs are distributed and migrated in various environmental matrices. The PCDD/F levels in other environmental matrices have also decreased at rates that differed among the matrices due to the different retention times and changes in continuous input of contaminants. As PCDD/Fs migrate from environmental matrices to the human body, the fraction of PCDDs increased whereas that of PCDFs decreased because of their relatively short half-lives. This study provides a concrete evidence that PCDD/F emissions by national regulations can achieve long-term reduction in human exposure. To the best of our knowledge, this is the longest and largest study to evaluate the long-term trends and annual changes of PCDD/Fs in the atmosphere and human serum, simultaneously.

Multiple classes of chemical contaminants in soil from an e-waste disposal site in China: Occurrence and spatial distribution

E-waste recycling is well known for releasing halogenated organic compounds (HOCs) and heavy metals. This study investigated the occurrence and distribution of traditional and novel classes of contaminants, including chlorinated, brominated, and mixed halogenated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs, PBDD/Fs, PXDD/Fs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and polyhalogenated carbazoles (PHCZs), in soil from an e-waste disposal site in Hangzhou. PBDEs were the most abundant, at 343-69306 ng kg^-1, followed by PHCZs (896-41,362 ng kg^-1), PCDD/Fs (349-19,396 ng kg^-1), PCBs (51.3-1834 ng kg^-1), PBDD/Fs (2.99-524 ng kg^-1) and PXDD/Fs (0.104-21.2 ng kg^-1). The detected target compound concentrations were generally lower than those reported in the literature for informal e-waste sites. Nevertheless, they can serve as a basis of information for evaluation and subsequent control. The toxic equivalent (TEQ) contributions from these contaminants (except PBDEs) decreased as follows: PCDD/Fs > PXDD/Fs > PHCZs > PCBs > PBDD/Fs. ΣDioxins (PCDD/Fs + PBDD/Fs + PXDD/Fs) accounted for 47.7%-97.2% of the total TEQs in the soil. OCDD, 1,2,3,4,6,7,8-HpBDF and OBDF were the dominant congeners, mainly derived from combustion and transport because of their low saturated vapor pressure. PXDFs were more abundant than PXDDs, and homologue profiles suggested a similar formation mechanism for PXDFs and PBDFs involving successive Br-to-Cl exchange. PHCZs were reported in soil from an e-waste disposal area for the first time, and their concentrations were several orders of magnitude higher than those of the other contaminants. Although the risk of human exposure in this study was estimated to be lower than the values recommended by the WHO (1-4 pg TEQ/kg bw/day), health implications still exist, and further investigations are necessary.

Long-term nationwide assessment of polychlorinated dibenzo-p-dioxins/dibenzofurans and dioxin-like polychlorinated biphenyls ambient air concentrations for ten years in South Korea

In this study, seasonal/regional variations of Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DFs) and dioxin like-polychlorinated biphenyls in the ambient air were monitored for ten years (2008-2017) using a high volume air sampler. As a result of strict regulation enforced by Korea Ministry of Environment in 2008, PCDD/DFs concentrations in the ambient air decreased from 0.051 pg I-TEQ Sm^-3 in 2009 to 0.014 pg I-TEQ Sm^-3 in 2017 which was comparably associated with cut-down of their emission sources from 880.2 g I-TEQ Sm^-3 in 2001 to 24.2 g I-TEQ Sm^-3 in 2015; revealing that it was only 2.7% against that of 2001. In 2017, mean TEQ concentration level of PCDD/DFs in the air of South Korea was quite low in comparison to its ambient environmental standards of 0.6 pg I-TEQ Sm^-3 for PCDD/DFs. Particularly, the sum of PCDD/DFs in the background revealed the lowest level, however, the fraction of octachlorodibenzodioxin among other isomers exposed at the highest level in this study, suggesting that the ambient air quality in the background being studied was severely and persistently impaired by inflowing unknown sources of any possible anthropogenic transboundary migratory air pollutants. Moreover, this study conducted the scientific analysis of the long-term variations in the ambient air and emission sources using principal component analysis. From this of 10 years long-term nationwide assessments for the PCDD/DFs and dl-PCBs in the ambient air, it is possible to prove that South Korean environmental policy to manage POPs has been successfully conducted for the last ten years.

Long-term monitoring of PCDD/Fs in soils in the vicinity of a hazardous waste incinerator in China: Temporal variations and environmental impacts

Campaigns from 2008 to 2016 are carried out to study temporal variations and environmental impacts of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/Fs) in soils in the vicinity of a new hazardous waste incinerator (HWI) in China. Results indicate that after 8-year operation of HWI, the geometrical means of both the total concentrations and the TEQ values of PCDD/Fs in soils decrease from 1280 ng·kg^-1 and 3.08 ng WHO-TEQ·kg^-1 to 568 ng·kg^-1 and 2.70 ng WHO-TEQ·kg^-1, respectively, showing generally limited impact on soils within 7.5 km. Temporal changes of PCDD/Fs congener profiles trend to profiles in combustion sources. Considering the whole studied area, results of principal component analysis between soils and emission sources show that instead of HWI, other sources including open burning, traffic, and cement plant are more responsible for PCDD/Fs accumulation. The modeling results of AERMOD indicate the dominant roles of wind velocities and directions on the deposition of PCDD/Fs emitted from HWI. The largest PCDD/Fs increase value in soils predicted by integrating AERMOD and a reservoir model is very limited after 25 years (2.03 × 10^-5 ng WHO-TEQ·kg^-1), indicating relatively minor impacts of HWI on surrounding soils, but the noticeable impact on area downwind from the stack in short distance (e.g., within 0.5 km) should be recognized.

Source apportionment of airborne PCDD/F at industrial and urban sites in Busan, South Korea

Long-term atmospheric measurement of 17 total (gaseous and particulate) polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) has been made from 2007 to 2016 at five industrial and urban sites in Busan, South Korea, based on their persistence, bioaccumulation, and toxicity. In the present study, two pooled datasets covering a combination of 2 industry sites and 3 urban sites have been subjected to positive matrix factorization (PMF) to identify and quantify the major sources of PCDD/Fs. Additionally, PMF has been applied to the industrial urban dataset consisting of both polycyclic aromatic hydrocarbons (PAHs) and PCDD/Fs. The results show that the sum of PCDD/F mass (Σ17PCDD/Fs) at the industrial sites is determined by five major sources: non-ferrous metal production (33.7%), diesel vehicle emissions (30.2%), ferrous metal production (22.4%), other industrial emissions (11.1%), and traffic emissions (2.6%), while the PAH mass (Σ16PAHs) is predominantly associated with emissions from coal combustion, followed by traffic emissions. At the urban sites, the largest contribution to the Σ17PCDD/Fs was observed from transported emissions being emitted from metallurgical industry (75.5%), followed by diesel vehicle emissions (24.5%). The application of congener-specific toxicity to PCDD/F mass (Σ₁₇fg I-TEQ Sm^-3) indicates enhanced contributions from the ferrous metallurgical emission factor associated with penta- and hexa-chlorinated furans across the study sites.

Spatial and temporal variation, source profile of PCDD/Fs in the atmosphere of a municipal waste incinerator in China

The mass concentrations, toxic equivalent quantity (TEQ) concentrations and congener profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the stack flue gas and ambient air of municipal solid waste incinerator (MSWI) were monitored in this study to evaluate the levels, emission characteristics, seasonal variation and emission sources of PCDD/Fs. Thirty-one ambient air samples were collected from four sites around MSWI during 2016-2017, and twelve stack flue gas samples were collected from one MSWI. Results showed that the PCDD/Fs concentrations of the stack flue gas ranged from 0.0077 to 0.021 ng I-TEQ/Nm³, with an average value of 0.016 ng I-TEQ/Nm³. The ambient air samples collected in 2016 and 2017 ranged from 0.017 to 0.27, and 0.035-0.27 pg I-TEQ/Nm³, with an average value of 0.078 and 0.10 pg I-TEQ/Nm³, respectively. The 2, 3, 4, 7, 8-PCDF always contributes most to toxicity both in stack flue gas and ambient air samples. PCDD/Fs in the ambient air of the study area showed significant seasonal differences, and the total concentration of PCDD/Fs was highest in winter, which was about 3.5-7.5 times that of summer. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to determine the correlation between MSWI emissions and PCDD/Fs in ambient air. It is worth mentioning that MSWI is not the main source of PCDD/Fs in ambient air.

Associations between polychlorinated dibenzo-dioxins and polychlorinated dibenzo-furans exposure and oxidatively generated damage to DNA and lipid

Polychlorinated dibenzo-dioxins and polychlorinated dibenzo-furans (PCDD/Fs) have been reported to induce reactive oxygen species and oxidative stress, but the dose-response relationships have not been explored in molecular epidemiological studies. In this study, a total of 602 participants were recruited, comprising of 215 foundry workers, 171 incineration workers and 216 residents living more than 5 km away from the plants as the reference group. Individual PCDD/Fs exposures were estimated according to PCDD/Fs levels of working and living ambient air and daily foods. Urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-iso-prostaglandin-F2α (8-isoPGF2α) were determined to reflect oxidatively generated damage to DNA and lipid. Generalized linear models were used to access the associations between PCDD/Fs exposure and oxidative stress biomarkers. We found that PCDD/Fs exposure and urinary oxidative stress biomarkers of workers were all higher than those of the reference group. Significantly positive exposure-response relationships between individual PCDD/Fs exposures and urinary 8-oxodG and 8-iso-PGF2α were found. Each 1-unit increase in ln-transformed levels of PCDD/Fs exposure generated a 0.78 nmol/mmol creatinine increase in ln-transformed 8-oxodG and a 0.50 ng/mmol creatinine increase in ln-transformed 8-isoPGF2α in foundry workers, a 0.49 nmol/mmol creatinine increase in ln-transformed 8-oxodG and a 0.26 ng/mmol creatinine increase in ln-transformed 8-isoPGF2α in incineration workers, compared with the reference group. And such associations were not modified by tobacco use. Our findings could help to understand the dose-response relationships between PCDD/Fs and oxidatively generated damage to DNA and lipid, and provide an epidemiologic basis for conducting research on the carcinogenesis and other toxicity mechanisms of PCDD/Fs.

Abundance of diet-derived polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in the bodies and nests of the yellow-legged hornet Vespa velutina nigrithorax and risks to human health in South Korea

Detecting polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in an organism's environment is ecologically significant. In particular, the detection of PCDD/Fs in organisms consumed as food suggests the possibility of human health risks. In South Korea, there is a unique custom in which social wasps, such as hornets, have been used as ingredients in traditional liquor. Thus, we investigated the concentrations and patterns of PCDD/Fs for the most common social wasps, the yellow-legged hornet (Vespa velutina nigrithorax), and estimated human health risks based on potential dietary exposure in traditional liquor made from the polluted wasps and their nests. The mean concentration of ∑₁₇ PCDD/Fs in the wasps and nests of V. v. nigrithorax was 33.59 pg/g (median 25.31 pg/g), corresponding to 0.65 pg World Health Organization - Toxic equivalency factor (WHO-TEQ/g) (median 0.49 pg WHO-TEQ/g). The levels of ∑₁₇ PCDD/Fs from the nests of V. v. nigrithorax were higher than those in the adults and larvae. As a result of this risk assessment, the daily intake of traditional liquor made with these wasps and their nests was found to be below safety levels; however, there could still be a possibility for health risks due to the detection of PCDD/Fs from organism. Therefore, continuous monitoring of environmental contaminants, including PCDD/Fs in wasps and nests, is required in order to evaluate human health risks associated with the consumption of traditional liquor made with these biological substances. In addition, the results of this study can be used to calculate dietary exposure to PCDD/Fs and the extent of risk to food in which the organism is consumed.

Preliminary investigation of polychlorinated dibenzo-p-dioxin and dibenzofuran, polychlorinated naphthalene, and dioxin-like polychlorinated biphenyl concentrations in ambient air in an industrial park at the northeastern edge of the Tibet-Qinghai Plateau, China

Ambient air samples collected in an industrial park at the northeastern edge of the Tibet-Qinghai Plateau (China) were analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated naphthalenes (PCNs), and dioxin-like (dl) polychlorinated biphenyls (PCBs). The PCDD/F, PCN, and dl-PCB concentrations were 1.18-2.18, 21.9-75.1, and 0.49-0.90 pg/m³, respectively. The concentrations of these compounds were clearly higher than that observed at a remote site and were comparable with those found in ambient air in industrial areas in other locations. A principal component analysis indicated that emissions from local industrial sites (a secondary aluminum smelter, a cement kiln, and a lead-zinc smelter) at which thermal processes are performed were the sources of PCDD/Fs to the air. The combustion-related PCN congener profiles suggested that industrial thermal processes strongly affect PCN concentrations in ambient air at the industrial park. The results clearly indicated that the industrial park is a source of environmental PCDD/Fs and PCNs at the northeastern edge of the Tibet-Qinghai Plateau.

Concentrations, spatial distributions, and congener profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans around original plastic solid waste recovery sites in China

The concentrations, profiles, and spatial distributions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in soil and sediment samples from several typical plastic solid waste (PSW) recovery sites (particularly from areas in which PSW is burned openly) in China were investigated. The results showed that burning PSW directly influenced PCDD/F concentrations immediately around the burning area. All of the samples in which soil contained black burning residue, collected from immediately around burning areas, had PCDD/F concentrations (mean 21708 ng kg^-1) and toxic equivalent (TEQ) concentrations (mean 2140 ng I-TEQ kg^-1 or 1877 ng WHO₂₀₀₆-TEQ kg^-1) more than 100 times higher than the concentrations in samples collected away from burning areas (mean 222 ng kg^-1, 8.75 ng I-TEQ kg^-1, 7.96 ng WHO₂₀₀₆-TEQ kg^-1). Principal component analysis and hierarchical cluster analysis indicated that the PCDD/F concentrations in seven soil samples from near PSW burning areas were influenced by PSW burning but that the PCDD/Fs in these soil samples may have had other or multiple sources. PCDD/F distributions at PSW recovery sites have been investigated in few previous studies. The results presented here indicate that appropriate measures should be taken to decrease the ecological risks posed by PSW recovery and to prevent, control, and remediate PCDD/F and other chemical contamination caused by PSW recovery.

PAHs and heavy metals in the surrounding soil of a cement plant Co-Processing hazardous waste

The Chinese government is encouraging domestic cement producers to move from traditional coal power sources to the co-processing of waste as the primary energy source for the industry. In this study, 32 samples collected from the soil surrounding a cement plant in Beijing were analyzed for the presence of 16 U.S. EPA priority polycyclic aromatic hydrocarbons (PAHs) and 12 heavy metals. Ten samples were selected for polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) analysis. The pollution distribution patterns, sources, and potential risks to human health and the environment were investigated and evaluated. The highest concentrations of PCDD/Fs occurred 1200 m downwind from the cement plant. The levels of ∑16 PAHs ranged from 130.6 to 1134.3 μg kg^-1 in the sampled soils. Source identification analysis suggested that the cement plant was the most likely source of PAH contamination. The concentrations of most of the heavy metals detected in the sampled soils were close to background levels, except for the levels of cadmium (Cd) and mercury (Hg), which were, on average, two times and six times higher than background values, respectively. The co-incineration of sludge, coal, and hazardous waste in the cement plant is a major contributing cause for the high levels of Hg in the surrounding soil. Risk assessment models, both the incremental lifetime cancer risks (ILCRs) for PAHs and the potential ecological risk index (RI) for heavy metals, indicate potential risks to the population and the environment surrounding the cement plant.

Sources identification of PCDD/Fs in soil and atmospheric deposition in Taiwan

PCDD/Fs are among pollutants, which gain major concern from Taiwan government and citizens during industrialization. PCDD/Fs can be emitted into the atmosphere, soil, and water environment in either vapor or solid forms. Atmospheric deposition is the main pathways for atmospheric PCDD/Fs to precipitate on surface soil. In this study, a simultaneous analysis of both soil and deposition PCDD/Fs was done to investigate the relationship between in-soil and deposited PCDD/Fs in Taiwan. Soil samples (n = 84) and atmospheric deposition samples (n = 57) were collected within overlapped periods of time. Geometric mean of 10.4 pg WHO-TEQ/g was found in the soil samples when the geometric mean of atmospheric deposited PCDD/F concentrations was found to be 7.39 pg WHO-TEQ/m²/day. Concentration of PCDD/Fs in samples collected in industrial location were higher than those collected in other locations in all sampling areas. OCDD, OCDF, HpCDD, HpCDF, were the predominant congeners in PCDD/F profile in both soil and atmospheric deposited samples, when 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF were major contributors for PCDD/F fingerprint with WHO-TEQ transformation. Positive Matrix Factorization (PMF) analysis showed that 83% of soil PCDD/Fs correlate with atmospheric deposition process originated from industrial activities (44%) and long range transport activities (39%). Furthermore, the PMF analysis found long range transport, municipal solid water incinerators (MSWIs), industrial waste incinerators (IWIs), electric arc furnace, recycling process of aluminum, sintering plants to be the main sources contributing to atmospheric deposited PCDD/Fs.

Concentrations of trace elements and PCDD/Fs around a municipal solid waste incinerator in Girona (Catalonia, Spain). Human health risks for the population living in the neighborhood

Previously to the modernization of the municipal solid waste incinerator (MSWI) of Campdorà (Girona, Catalonia, Spain) two sampling campaigns (2015 and 2016) were conducted. In each campaign, 8 soil and 4 air samples (PM₁₀ and total particle phase and gas phase) were collected. The levels of As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Sn, Tl and V, and PCDD/Fs were analysed at different distances and wind directions around the MSWI. Environmental levels of trace elements and PCDD/Fs were used to assess exposure and health risks (carcinogenic and non-carcinogenic) for the population living around the facility. In soils, no significant differences were observed for trace elements and PCDD/Fs between both campaigns. In air, significant higher levels of As, Cd, Co, Mn, Ni, Pb, Tl and V were detected in 2016. Regarding soil levels, only Cd (distances) and As, Cu, Mn, and Ni (wind directions) showed significant differences. No differences were noted in the concentrations of trace elements and PCDD/Fs in air levels with respect to distances and directions to the MSWI. No differences were registered in air levels (elements and PCDD/Fs) between points influenced by MSWI emissions and background point. However some differences in congener profile were noted regarding from where back-trajectories come from (HYSPLIT model results), pointing some influence of Barcelona metropolitan area. The concentrations of trace elements and PCDD/Fs were similar -or even lower- than those reported around other MSWIs in Catalonia and various countries. Non-carcinogenic risks were below the safety limit (HQ<1). In turn, carcinogenic risks due to exposure to trace elements and PCDD/Fs were in acceptable ranges, according to national and international standard regulations.

Tracing the sources of PCDD/Fs in Baltic Sea air by using metals as source markers

The atmosphere is the major contributor of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Baltic Sea environment. In this study, we investigated the potential of using metals along with PCDD/Fs as markers of important emission sources of PCDD/Fs in air. The air concentrations of PCDD/F congeners (n = 17), other persistent organic pollutants (n = 8) and metals (n = 16) were determined in summer and winter air using high volume samplers at a rural field station (Aspvreten, Sweden) located close to the Baltic Sea coast. During winter, PCDD/F levels were on average 20 times higher than in summer (5.1 ± 5.8 fg toxicity equivalents (TEQ) m^-3 and 0.26 ± 0.18 fg TEQ m^-3, respectively) mostly due to a higher fraction of PCDFs. The increased levels of PCDD/Fs were pronounced mainly in air masses that had travelled from southern (S) and eastern (E) compass sectors. A principal component analysis (PCA) of metal levels in Scots pine (Pinus sylvestris) needles sampled to reflect various air emission source types helped to identify potential marker metals for selected known atmospheric emission sources of PCDD/Fs and to rank among the candidate source types. Brown coal burning, domestic burning and heavy oil burning appeared to be the source types that contribute most of the PCDD/Fs in Baltic Sea air. The current study demonstrates a successful approach for source tracing of PCDD/Fs in air, where integrated indices from seasonal and spatial patterns of PCDD/Fs as well as metal source markers were used to trace and rank sources.

Characterization of polycyclic aromatic hydrocarbons in soil close to secondary copper and aluminum smelters

A total of 35 surface soil samples around two secondary copper smelters and one secondary aluminum smelter were collected and analyzed for 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs). The concentrations of PAHs were highest when the soil sample sites were closest to the secondary copper smelters. And, a level gradient of PAHs was observed in soil samples according to the distance from two secondary copper smelters, respectively. The results suggested that PAH concentrations in surrounding soils may be influenced by secondary copper smelters investigated, whereas no such gradient was observed in soils around the secondary aluminum smelter. Further analysis revealed that PAH patterns in soil samples also showed some difference between secondary copper and aluminum smelter, which may be attributed to the difference in their fuel and smelting process. PAH patterns and diagnostic ratios indicated that biomass burning may be also an important source of PAHs in the surrounding soil in addition to the emissions from the plants investigated.

Comparison of industrial emissions and carpet dust concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in a multi-center U.S. study

Proximity to facilities emitting polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) has been associated with increased risk of non-Hodgkin lymphoma (NHL). There is limited information about whether proximity to industrial sources leads to indoor PCDD/F contamination of homes. We measured carpet dust concentrations (pg/g) of 17 toxic PCDD/F congeners and calculated their toxic equivalence (TEQ) in 100 homes in a population-based case-control study of NHL in Detroit, Los Angeles, Seattle, and Iowa (1998-2000). We took global positioning system readings at residences and obtained coordinates and PCDD/F emissions (ng TEQ/yr) from an Environmental Protection Agency database for 6 facility types: coal-fired electricity generating plants, cement kilns burning non-hazardous waste, hazardous waste incinerators, medical waste incinerators, municipal solid waste incinerators, and sewage sludge incinerators. For each residence, we computed an inverse distance-squared weighted average emission index (AEI [pg TEQ/km2/yr]) for all facilities within 5km from 1983 to 2000. We also computed AEIs for each of the 6 facility types. We evaluated relationships between PCDD/F dust concentrations and the all-facility AEI or categories of facility-type AEIs using multivariable linear regression, adjusting for study center, demographics, and home characteristics. A doubling of the all-facility AEI was associated with a 4-8% increase in PCDD/F dust concentrations of 7 of 17 PCDD/F congeners and the TEQ (p-value<0.1). We also observed positive associations between PCDD/F dust concentrations and facility-type AEIs (highest vs. lowest exposure category) for municipal solid waste incinerators (9 PCDD/F, TEQ), and medical waste incinerators (7 PCDD/F, TEQ) (p<0.1). Our results from diverse geographical areas suggest that industrial PCDD/F emission sources contribute to residential PCDD/F dust concentrations. Our emissions index could be improved by incorporating local meteorological data and terrain characteristics. Future research is needed to better understand the links between nearby emission sources, human exposure pathways, and health risks.

PCDD/F contamination on surface soil in the vicinity of a hazardous waste incinerator: is it possible a different trend?

This study is the first to investigate the contamination of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) on surface soils in the vicinity of the first hazardous waste incinerator of Turkey. In the study, 24 soil samples were taken from a 1625-m-radius circle whose center is the stack of the incinerator. This process was repeated 1 year later. Since the acquired average PCDD/F concentrations of the two sampling campaigns (0.05 and 0.02 ng WHO-toxic equivalent (TEQ)/kg) were meaningfully low compared to the related literatures, a new sampling campaign was carried out to control this inconsistency, but this time in a foreign laboratory (0.56 ng WHO-TEQ/kg). In the same period, eight gas samples were taken from the stack under different operational conditions of the facility. According to the evaluations of the findings, the geographical-meteorological data of the study area and the specific operational conditions of the facility corroborate the concentrations of the first and the second soil samplings rather than the third one. The major underlying reason for the inconsistency of the soil concentrations may be the fact that the data analysis procedures used by the laboratories are different. The author suggests a hypothesis which argues that the soils in the vicinity of a hazardous waste incinerator may have significantly lower concentration levels than in related literatures.

Source apportionment of mass concentration and inhalation risk with long-term ambient PCDD/Fs measurements in an urban area

This study applies a receptor model to quantify source contributions to ambient concentration of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and inhalation cancer risk in Taipei from 2003 through 2009. Seventeen PCDD/F congeners were used in the effective variance solution to the Chemical Mass Balance equations to estimate source-specific mass contributions and inhalation risks. The average total PCDD/F concentration was 0.611pg/Nm(3) (0.036pg I-TEQ/Nm(3)). Traffic emissions contributed the most to the PCDD/F concentration (55.7%), followed by waste incinerators (18.6%) and joss stick burning (9.6%). For the inhalation cancer risk, the average was 1.1×10(-6) with traffic, waste incinerators, and joss paper burning as the main contributors (67.3%, 19.4%, and 6.3%, respectively). The mass and risk contributions of waste incinerators decreased significantly from 2003 to 2009 and were higher at downwind sites than at upwind sites. Reducing PCDD/F emissions from traffic and waste incinerators would provide the greatest health benefit. Policies that reduce the uncontrolled burning of joss stick and joss paper also need to be implemented.

Lung cancer risk assessment at receptor site of a waste-to-energy plant

The toxicity of particulate matter emitted from waste-to-energy plants, is associated to the compounds attached to the particles, several of which have been classified by the International Agency for Research on Cancer (IARC) in the Group 1 carcinogens. In this paper a modified risk-assessment model, deriving from an existing one, was applied to estimate the lung cancer risk related to both ultrafine and coarse particles emitted from an incinerator whose people living nearby are exposed to. To this end, the measured values of Polycyclic Aromatic Hydrocarbons (PAHs), heavy metals (As, Cd, Ni) and PCDD/Fs (Polychlorinated dibenzodioxins/furans) emitted from an incinerator placed in Italy were used to calculate the Excess Lifetime Cancer Risk (ELCR) at the stack of the plant. The estimated ELCR was then used as input data in a numerical CFD (Computational Fluid Dynamics) model that solves the mass, momentum, turbulence and species transport equations to study the influence of wind speed and chimney height on the ELCR at receptor sites. Furthermore, combining meteorological data (wind speed and direction), and hypothesizing different exposure scenarios on the basis of time-activity patterns of people living nearby the plant, specific risk maps were obtained by evaluating ELCR around the incinerator. Results show that with the increasing of wind speed, the ELCR value downwind at the plant decreases and its point of maximum risk becomes closer to the stack. On the other hand, increasing the stack height decreases the ELCR, moving away from the stack the point of maximum risk. Finally, the risk maps for people living or working nearby the plant have highlighted that the excess risk of lung cancer due to the presence of the incinerator is below the WHO target (1×10(-5)).

Identification, Quantification, and Toxicity of PCDDs and PCDFs in Soils from Industrial Areas in the Central and Eastern Regions of Saudi Arabia

This study was conducted to identify and quantify polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in soil samples collected from selected industrial areas in the central and eastern regions of Saudi Arabia. All the investigated compounds of PCDDs/PCDFs were identified in the studied locations. The average concentrations of PCDDs (sum of seven congeners measured) ranged from 11.5 to 59.6 pg g(-1), with a maximum concentration of 125.7 pg g(-1) at an oil refinery station followed by 100.9 pg g(-1) at a cement factory. The average concentrations of PCDFs (sum of 10 congeners measured) accounted for 11.68-19.35 pg g(-1), with a maximum concentration of 38.67 pg g(-1) at the cement factory. It was generally observed that the soil samples collected from industrial areas have substantially high toxicity equivalence (TEQ) values of PCDDs/PCDFs compared to soils of remote areas. Principal component analysis revealed that the cement factories and oil refineries were the primary sources of PCDDs and PCDFs.

Human dietary exposure and levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (DL-PCBs) and non-dioxin-like polychlorinated biphenyls (NDL-PCBs) in free-range eggs close to a secondary aluminum smelter, Northern Italy

PCDD/Fs and PCBs are environmentally persistent substances that have been associated with adverse effects on human health. Contamination of soils, animal feed and pastures leads to their bioaccumulation of in food products of animal origin, which are considered the major source of intake of these contaminants in humans. We analyzed eggs from free-range hens, sampled from small farms, located within a distance of 4.5 km from a secondary aluminum smelter in Northern Italy. The concentrations of PCDD/Fs, DL-PCBs and NDL-PCBs were higher in eggs from locations close to the plant, and strongly exceeded the limits set by EU Regulation 1259/2011 (2.5 pg WHO TEQ fat g(-1) for PCDD/Fs, 5.0 pg WHO TEQ g(-1) for PCDD/Fs and DL-PCBs L, 40 ng g(-1) for NDL-PCBs). Without the prompt and immediately applied control strategies, the consumption of contaminated eggs may have posed [corrected] a risk for human health, especially for children (≤9 years) and infants (≤3 years), due to the 2-fold excess of the current exposure limits.

Distribution of PCDD/Fs in the fly ash and atmospheric air of two typical hazardous waste incinerators in eastern China

Distribution of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) in the fly ash and atmospheric air of one medical waste incinerator (MWI) and one industrial hazardous waste incinerator (IHWI) plants were characterized. The PCDD/F concentrations of the stack gas (fly ash) produced from MWI and IHWI were 17.7 and 0.7 ng international toxic equivalent (I-TEQ)/Nm(3) (4.1 and 2.5 ng I-TEQ/g), respectively. For workplace air, the total concentrations of PCDD/Fs were 11.32 and 0.28 pg I-TEQ/Nm(3) (819.5 and 15.3 pg/Nm(3)). We assumed that the large differences of PCDD/F concentrations in workplace air were due to the differences in chlorine content of the waste, combustion conditions, and other contamination sources. With respect to the homologue profiles, the concentrations of PCDFs decreased with the increase of the substituted chlorine number for each site. Among all of the PCDD/F congeners, 2,3,4,7,8-PeCDF was the most important contributor to the I-TEQ value accounting for ca. 43 % of two sites. The gas/particle partition of PCDD/Fs in the atmosphere of the workplace in the MWI was also investigated, indicating that PCDD/Fs were more associated in the particle phase, especially for the higher chlorinated ones. Moreover, the ratio of the I-TEQ values in particle and gas phase of workplace air was 11.0. At last, the relationship between the distribution of PCDD/Fs in the workplace air and that from stack gas and fly ash was also analyzed and discussed. The high correlation coefficient might be a sign for diffuse gas emissions at transient periods of fumes escaping from the incinerator.

Spatial and seasonal distributions of polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls around a municipal solid waste incinerator, determined using polyurethane foam passive air samplers

Twenty-six ambient air samples were collected around a municipal solid waste incinerator (MSWI) in the summer and winter using polyurethane foam passive air samplers, and analyzed to assess the spatial and seasonal distributions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs). Three stack gas samples were also collected and analyzed to determine PCDD/F (971 pg m(-3) in average) and PCB (2,671 pg m(-3) in average) emissions from the MSWI and to help identify the sources of the pollutants in the ambient air. The total PCDD/F concentrations in the ambient air samples were lower in the summer (472-1,223 fg m(-3)) than the winter (561-3913 fg m(-3)). In contrast, the atmospheric total PCB concentrations were higher in the summer (716-4,902 fg m(-3)) than the winter (489-2,298 fg m(-3)). Principal component analysis showed that, besides emissions from the MSWI, the domestic burning of coal and wood also contributed to the presence of PCDD/Fs and PCBs in the ambient air. The PCDD/F and PCB spatial distributions were analyzed using ordinary Kriging Interpolation and limited effect was found to be caused by emissions from the MSWI. Higher PCDD/F and PCB concentrations were observed downwind of the MSWI than in the other directions, but the highest concentrations were not to be found in the direction with the greatest wind frequency which might be caused by emissions from domestic coal and wood burning. We used a systemic method including sampling and data analysis method which can provide pioneering information for characterizing risks and assessing uncertainty of PCDD/Fs and PCBs in the ambient air around MSWIs in China.

Maldives: an archipelago that burns. A first survey of PCDD/Fs and DL-PCBs from human activities

Due to its geographical peculiarities, the Republic of Maldives represents a case study of great interest for the investigation of persistent organic pollutants, from both a socio-economic and an ecological perspective. Thus, we conducted a first survey to assess the current status of polychlorinated dibenzo-p-dioxin (PCDD), polychlorinated dibenzofuran (PCDF) and dioxin-like polychlorinated biphenyl (DL-PCB) concentrations in Maldivian soils. The range for PCDD/F and DL-PCB soil concentrations was 0.01-49.3 pg WHO2005-TEQ g(-1) and 0.01-3.69 pg WHO2005-TEQ g(-1) dw respectively. PCDD/F concentrations exceeding several international soil guidelines were found in samples from locations in the proximity of local waste combustion sources. DL-PCB concentrations were lower than PCDD/Fs and comparable to those in previous reports from background areas and in areas with developing industrial and agricultural activities. PCDD/F and DL-PCB levels (expressed as WHO2005-TEQ) in soils were strongly correlated (r=0.89), which suggests that, in most of the sites, they are originated from the same emission sources. Results indicate that PCDD/F soil concentrations (expressed as WHO2005-TEQ) tend to decrease with the distance from the local pollution sources. Principal component analysis (PCA) showed that PCDD/Fs in the most polluted locations are mainly generated by waste combustion. These findings highlight the need for immediate changes in waste management policies in the Archipelago, in order to reduce the release of Persistent Organic Pollutants (POPs) in the fragile local environment.

Congener profiles and source-wise phase partitioning analysis of PCDDs/Fs and PCBs in Gyeonggi-do ambient air, South Korea

The atmospheric concentrations and gas-particle partitioning of polychlorinated dibenzo-p-dioxins and furans (PCDDs/Fs) and polychlorinated biphenyls (PCBs) were investigated at two sites (Suwon and Ansan) in Gyeonggi-do, a heavily industrialized area of Korea, during the year 2010. The sum level (Σ17) of PCDDs/Fs and dioxin-like PCBs (dl-PCBs) in the ambient air at Suwon and Ansan ranged from 0.04 to 0.30 pg-TEQ·m(-3) (geometric mean: 0.09 pg-TEQ·m(-3)) and 0.17 to 0.63 pg-TEQ·m(-3) (geometric mean: 0.36 pg-TEQ·m(-3)), respectively. Moreover, the geometric mean concentrations of Σ180 PCBs at Suwon and Ansan were 233.6 pg·m(-3) and 274.2 pg·m(-3), respectively, and di-chlorinated biphenyls and tri-chlorinated biphenyls were the predominant homologs. Among the PCB congeners, 3,3'-dichlorobiphenyl (PCB-11) was the dominant species at both sites during all sampling periods, comprising up to 15.1% of Σ180 PCBs at Ansan and 24.6% at Suwon. We evaluated their gas-to-particle equilibriums by conducting regression between the particle-gas partition coefficient Kp (m(3)·ug(-1)) and the corresponding subcooled liquid vapor pressure (PL°). The slope (m) values for log-log plots of Kp vs. PL° were steeper in industrial areas owing to local source proximity. Moreover, owing to enhanced emissions from combustion-related sources at low temperatures, PCDD/Fs exhibited the largest deviation from the regression line of the particle-gas partition coefficient. Incinerators were found to be the primary emission source of atmospheric PCDDs/Fs, whereas re-evaporation from pre-existing environmental loads (e.g., storage areas or spilled soil and water bodies) was the dominant source for PCBs.

PCDD and PCDF concentrations in a traffic tunnel environment

In an effort to understand the fundamental aspects of air quality in traffic tunnel environments, field campaigns were conducted to measure polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and other important pollutants within two traffic tunnels in Nam San (NS) and Hong Ji (HJ) in Korea in 2009 and 2010. The mean concentrations of ∑PCDD/Fs (in fg/m(3)) at the two tunnel sites were 1270 (± 880) and 1200 (± 810), respectively. These values were moderately lower than those measured at a non-tunnel urban background site (1350 (± 780) fg/m(3))--selected as a reference in this study. In addition, seasonal patterns of dioxin concentrations were clearly evident at the traffic tunnels like the urban reference site, showing higher levels during the winter (and spring) than the summer (and fall). The observed seasonal variations were driven by changes in the concentrations of ∑PCDF congeners, while ∑PCDD concentrations showed little seasonality. The results of our study suggest that there is no significant difference in source characteristics between the two investigated tunnel sites and urban location, although the role of gasoline and diesel fueled vehicles are considered as the major source in determining the PCDDs and PCDF levels in a tunnel environment. However, given the relative increase in other important ambient pollutant (e.g. PM10) concentrations over ∑PCDD/Fs in tunnel air (compared to urban background air), the balance of sources in tunnels is clearly different from those in urban air overall.

Long-term monitoring and modeling of polychlorinated dibenzo-p-dioxins and dibenzofurans from municipal solid waste incinerators and surrounding area in northern Taiwan

Municipal solid waste incinerators (MSWIs) have long been the major contributors of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) to ambient air in Taiwan. After stringent MSWI emission standards were introduced in 2001, the long-term continuous monitoring of flue gas and ambient air quality became necessary to ensure the effectiveness of the related control strategies. Three MSWIs and the surrounding ambient air were investigated in the current study for PCDD/F characteristics during 2006 to 2011. The average concentrations in the flue gas ranged from 0.008 ~ 0.0488 ng I-TEQ/Nm(3), which is much less than the emission standard in Taiwan (0.1 ng I-TEQ/Nm(3)) (I-TEQ is the abbreviation of International Toxic Equivalent). This led to extremely low levels in the ambient air, 0.0255 pg I-TEQ/Nm(3), much less than the levels seen in most urban areas around the world. Additionally, the results obtained using the Industrial Source Complex Short-Term Dispersion Model (ISCST3) indicate that the PCDD/F contributions from the three MSWIs to the ambient air were only in the range from 0.164 ~ 0.723 %. Principal component analysis (PCA) showed that the PCDD/Fs in the air samples had very similar characteristics to those from mobile sources. The results thus show that stringent regulations have been an effective control strategy, especially for urban areas, such as Taipei City.

Influence of a municipal solid waste incinerator on ambient air PCDD/F levels: a comparison of running and non-running periods

The concentration of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the ambient air of a municipal solid waste incinerator (MSWI) during its running and non-running periods was monitored in this study to investigate the contribution of the MSWI to PCDD/F pollution in the vicinal environment. Results show that the PCDD/F levels for the normal MSWI running period and after shut-down ranged 0.156-1.44 pg I-TEQ/m(3) (0.514 pg I-TEQ/m(3)) and 0.158-0.648 pg I-TEQ/m(3) (0.345 pg I-TEQ/m(3)), respectively. Significant differences were found between the results of the two surveys in 2011 and 2012. High PCDD/F levels were observed in two of the seven study sites in 2011, and these levels directly declined in 2012. A dramatic increase in PCDD/F concentrations was observed in two sites in 2012. Comparison of congener and homologue fingerprint characteristics in the two surveys, together with principal component analysis, revealed that the PCDD/F levels in all of the samples collected in 2012 and in three of the samples collected in 2011 are mainly influenced by heavy traffic. MSWI is the primary PCDD/F emission sources of the PCDD/Fs detected in the remaining samples collected in 2011.

Field-measured uptake rates of PCDDs/Fs and dl-PCBs using PUF-disk passive air samplers in Gyeonggi-do, South Korea

The collection of 2,3,7,8-substituted polychlorinated dibenzo-ρ-dioxins and dibenzo furans (PCDDs/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) using a polyurethane form (PUF)-disk passive air sampler (PAS) was investigated in urban-residential and industrial areas. This was performed to assess the feasibility of using this method as an alternative to an active air sampler (AAS). The PUF-disk PAS was exposed to ambient air over a period of 37-370 and 57-173 days in urban and industrial areas, respectively, together with AASs. The sum of total toxic equivalent quantity (TEQ) ΣPCDDs/Fs and Σdl-PCB was typically high in the industrial area, with values within the range 0.171-0.635 pg-TEQ/m(3), and 0.037-0.300 pg-TEQ/m(3) in the urban-residential area. To derive the time-weighted average (TWA) concentration from the PAS data accurately, it was estimated that the PAS deployed for less than 80 days was adequate to maintain linear accumulation conditions. PCDDs/Fs are mainly particle bound and showed low average uptake rates of 1.4m(3)d(-1), while dl-PCBs were slightly higher with 2.0m(3)d(-1) because of its high vapor pressure. Most of the congener concentrations measured using the PAS and AAS were within a factor of two, indicating that PASs can be used to monitor spatial and temporal variations in the concentrations of persistent organic pollutants (POPs) in the atmosphere.

Spatial distribution of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in soil around a municipal solid waste incinerator

Municipal solid waste incinerators (MSWIs) are usually considered to be important sources of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). To examine the influence of PCDD/Fs emissions from a MSWI on the surrounding environment, 21 soil samples were collected from various sampling sites distributed at distances of 300-1,700 m away from the stack of a MSWI. International Toxic Equivalent (I-TEQ) concentrations ranged from 0.47 to 2.07 pg I-TEQ g(-1), with average and median concentrations of 1.08 and 1.05 pg I-TEQ g(-1), respectively. Comparison of the results presented herein with other worldwide studies suggested that the concentrations of PCDD/Fs in the ambient soil were relatively low, indicating a limited impact on the surrounding environment. The emission concentrations from the incinerator were the critical factor in generating an environmental impact on the surrounding environment. An exponential function was developed, indicating a slight decline in TEQs of PCDD/Fs with increasing distance from the MSWI stack. The ordinary kriging interpolation technique was selected to create a contour map, which intuitively showed that a limited surrounding area (≤1,000 m from the stack) was obviously influenced by the MSWI.

Pollution characteristics and potential health risk of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in soil/sediment from Baiyin City, North West, China

In order to better understand the environmental behaviors of persistent organic pollutants, the characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were investigated in twenty-three soil/sediment samples from Baiying City, Northwest China, in 2008. The possible sources and potential health risk of PCDD/Fs were also discussed. The concentrations of PCDD/Fs in nineteen soil samples varied between 20.13 and 496.26 pg/g dry weight (dw.), with an average value of 125.59 pg/g dw. The highest International Toxic Equivalent (I-TEQ) of PCDD/Fs (8.34 pg/g dw.) in soil was found at sample S1 collected from proximity to a copper metallurgy plant. The concentrations of PCDD/Fs in four sediment samples ranged from 37.69 to 491.49 pg/g dw., with an average value of 169.95 pg/g dw. The highest I-TEQ of PCDD/Fs (8.56 pg/g dw.) in sediment was found at sample S12 collected from the East big ditch with waste water discharged into the Yellow River. The results indicated that PCDD/Fs contamination of soil/sediment is originated from three sources: chlorine-containing chemicals, non-ferrous metal industrial PCDD/Fs emission and coal burning. The health risk exposure to PCDD/Fs through soil, dust ingestion and dermal absorption ranged from 0.0006 to 0.0134 pg/kg/day Word Health Organization's toxic equivalent in 1998 (WHO1998-TEQ) with mean values 0.0032 pg WHO1998-TEQ for adults and varied between 0.0012 and 0.0256 pg/kg/day WHO1998-TEQ with mean values 0.006 pg/kg/day WHO1998-TEQ for children, respectively. These results indicated that health risk of PCDD/Fs for children should be paid more attention.

Simple and rapid yeast reporter bioassay for dioxin screening: evaluation of the dioxin-like compounds in industrial and municipal waste incineration plants

The CROMIS AhR kit, a simple and rapid yeast bioassay kit, was developed and used to detect dioxins and dioxin-like compounds in 20 gas and solid samples collected from refuse incineration plants in Japan. The World Health Organization toxic equivalent (WHO-TEQ) values of the samples were also calculated using high-resolution gas chromatography/high--resolution mass spectrometry. The WHO-TEQ values of the samples varied greatly, ranging from 0.0021-6.3 ng/g to 0.00013-16 ng/m(3)N (normal cubic meter) in the solid and gas samples, respectively. 2,3,4,7,8-Pentachlorodibenzofuran (23478-PeCDF) and 1,2,3,7,8-pentachlorodibenzo-p-dioxin (12378-PeCDD) were the major contributors to the samples' WHO-TEQ values. The yeast in the bioassay responded to these congeners, and the EC50 values of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2378-TeCDD), 12378-PeCDD, and 2,3,4,7,8-PeCDF were 490, 560, and 590 nM, respectively. The incinerator samples were subjected to the bioassay to obtain 2378-TeCDD equivalent values (CROMIS-TEQ values). The CROMIS-TEQ values of the solid and gas samples ranged from 0.0019 to 5.64 ng/g and from 0.14 to 20 ng/m(3)N, respectively. The CROMIS-TEQ and WHO-TEQ values displayed good correlations (r (2) = 0.94 and 0.95 in the solid and gas samples, respectively), except for those of the samples with low dioxin concentrations (below the Japanese emission standards). Therefore, the CROMIS AhR kit is a useful tool for the initial screening of samples containing dioxin-like compounds.

Reductive dechlorination of octachlorodibenzo-p-dioxin by nanosized zero-valent zinc: modeling of rate kinetics and congener profile

Polychlorinated dibenzo-p-dioxins (PCDDs), a group of recalcitrant toxic compounds, are ubiquitous in nature. Amongst them, octachlorodibenzo-p-dioxin (OCDD) is not only prevalent in soil and sediment due to its high lipophilicity and hydrophobicity, but also detected in ground water and surface water. The present study examined the degradation of OCDD in aqueous solutions using four different zero-valent metal nanoparticles; zero-valent aluminum (nZVAL), zero-valent zinc (nZVZ), zero-valent iron (nZVI) and zero-valent nickel (nZVN). Only nZVZ was found to efficiently degrade OCDD into lower chlorinated congeners [OCDD → 1,2,3,4,6,7,9-HxCDD (63%)→ 1,2,3,6,8,9-HpCDD (21%) → 1,2,4,7,8-PeCDD (46%) → 1,2,4,7-TeCDD (19%)] under ambient conditions. Simulations were also performed to predict the OCDD dechlorination pathway using a linear free energy relationship (LFER) model. Additionally, toxic equivalent quantity (TEQ) and homologue patterns were calculated by LFER modeling. The experimentally observed congener profiles were in excellent agreement with the model-predicted results, especially considering the complexity of the OCDD dechlorination pathway (256 theoretically possible reactions). This study proposes nZVZ as a suitable candidate for OCDD dechlorination and constitutes the first report on OCDD degradation using zero-valent metal nanoparticles under ambient conditions.

Prevalence of low chlorinated dibenzo-p-dioxin/dibenzofurans in human serum

Mono- to tri-chlorinated dibenzo-p-dioxin/dibenzofurans (DD/Fs) have not been studied as extensively as the 17 toxic 2,3,7,8-substituted congeners. In this study for the first time, mono- to octa-chlorinated DD/Fs were analyzed for seventy one human serum samples collected from incinerator workers as well as residents living near and far from the facility. The mean concentrations of ∑Cl(1-8)DD/Fs and 17-toxic congeners were 1890 and 398 pg g(-1) lipid (11.9 TEQ pg g(-1) lipid), respectively. 2,3,4,7,8-PeCDF, 1,2,3,7,8-PeCDD, and 1,2,3,6,7,8-HxCDD were predominant congeners that accounted for more than 78% of the TEQ concentrations. The profile for polychlorinated dibenzo-p-dioxins (PCDDs) was dominated by the most chlorinated congener, OCDD (>58%), while decreasing concentrations with increasing degree of chlorination were seen for polychlorinated dibenzofurans (PCDFs); MoCDFs (>83%) and DiCDFs (>6%). ∑Cl(1-3)DD/Fs accounted for 77% of the serum concentrations of ∑Cl(1-8)DD/Fs. These findings confirm that human beings are exposed to a large amount of ∑Cl(1-3)DD/Fs. Moreover, MoCDFs contributed more than 60% of the ∑Cl(1-8)DD/Fs and was highly correlated with ∑Cl(1-8)DD/Fs. Thus, 2-MoCDF could be a predictive indicator for ∑Cl(1-8)DD/Fs (r(s)=0.96), and the combination of 2-MoCDF and OCDD could explain the 95.9% variation in the serum of ∑Cl(1-8)DD/Fs. These results suggest that low chlorinated DD/Fs should be studied extensively until these low chlorinated congeners will have been elucidated for their toxicities.

Health risk assessment of PCDD/F emissions from municipal solid waste incinerators (MSWIs) in China

The objectives of this study were to determine the environmental impacts of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD/Fs) emitted from two typical municipal solid-waste incinerators (MSWIs), named M and L, in China. The main differences between the two MSWIs relate to incineration technologies, treatment capacities, emission standards and meteorological conditions. The distribution of PCDD/Fs in the surrounding ambient air and soils of the MWSIs were monitored and compared. In addition, air dispersion models and health risk assessments were combined to determine the behaviour and transport of PCDD/Fs. The results indicated that higher PCDD/F emission levels resulted in higher concentrations in the surrounding environment. The average PCDD/F levels emitted from the M MSWI was about seven times higher than those emitted from the L MSWI and about 10 times and 2 times higher in air and soils, respectively. The simulation results were similar to the trend of the monitored results. Both the observed and the simulation results suggested that the atmospheric pollution by PCDD/F surrounding the M MSWI was relatively serious; the environmental impact of the L MSWI was not significant.

A pilot study for determining the optimal operation condition for simultaneously controlling the emissions of PCDD/Fs and PAHs from the iron ore sintering process

In this study, the cost-benefit analysis technique was developed and incorporated into the Taguchi experimental design to determine the optimal operation combination for the purpose of providing a technique solution for controlling both emissions of PCDD/Fs and PAHs, and increasing both the sinter productivity (SP) and sinter strength (SS) simultaneously. Four operating parameters, including the water content, suction pressure, bed height, and type of hearth layer, were selected and all experimental campaigns were conducted on a pilot-scale sinter pot to simulate various sintering operating conditions of a real-scale sinter plant. The resultant optimal combination could reduce the total carcinogenic emissions arising from both emissions of PCDD/Fs and PAHs by 49.8%, and increase the sinter benefit associated with the increase in both SP and SS by 10.1%, as in comparison with the operation condition currently used in the real plant. The ANOVA results indicate that the suction pressure was the most dominant parameter in determining the optimal operation combination. The above result was theoretically plausible since the higher suction pressure provided more oxygen contents leading to the decrease in both PCDD/F and PAH emissions. But it should be noted that the results obtained from the present study were based on pilot scale experiments, conducting confirmation tests in a real scale plant are still necessary in the future.

Assessment of characteristic distribution of PCDD/Fs and BFRs in sludge generated at municipal and industrial wastewater treatment plants

The presence of polychlorinated dibenzo-p-dioxins and furan (PCDD/Fs) and brominated flame retardants (BFRs) in sludge generated at municipal wastewater treatment plants (MWTPs) and industrial wastewater treatment plants (IWTPs) was investigated. The concentrations of these pollutants were in the following ranges: 5.38-7947ngkg(-1)dw (0.02-49.9ngWHO-TEQkg(-1) dw) for 17 PCDD/Fs, 17.5-66761μgkg(-1)dw for 27 polybrominated diphenyl ethers (PBDEs), 1.55-29604μgkg(-1)dw for hexabromocyclododecanes (HBCDs) (α-, β-, and γ-diastereomers), and 4.01-618μgkg(-1)dw for tetrabromobisphenol A (TBBPA). Generally, the levels of each compound in the sewage-sludge samples were higher than those in the industrial-sludge samples with some exceptions. The characteristic distribution profiles of target compounds were observed for different types of sludge and different sources of wastewater. High-chlorinated PCDD/Fs were dominant in all samples except those from the textile industry. The distribution of the BFRs in industrial-sludge samples varied, whereas that of the BFRs in sewage-sludge samples was consistent. The proportion of penta-BDEs in sewage sludge was higher than that in industrial sludge, even though BDE-209 was the most dominant congener in all the samples. For HBCDs, the distribution of diastereomers (α-, β-, and γ-HBCD) was similar across sludge samples that had the same source of wastewater and treatment processes.

Baseline soil levels of PCDD/Fs established prior to the construction of municipal solid waste incinerators in China

In order to determine the baseline contamination by polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in different areas in China, prior to the construction of municipal solid waste incinerators (MSWIs), a total of 32 representative soil samples was collected near 16 incinerators and analyzed for their PCDD/F concentrations. The PCDD/F baseline concentrations in the soil samples ranged from 0.32 to 11.4 ng I-TEQ kg(-1) (dry matter), with average and median value of 2.73 and 2.24 ng I-TEQ kg(-1) (dry matter), respectively, and a span between maximum and minimum recorded value of 36. The PCDD homologues predominated in 26 out of 32 soil samples, with the ratio (PCDDs)/(PCDFs) ranging from 1.1 to 164; however in the other 6 samples, PCDF homologues were larger, with the same ratio varying from 0.04 to 0.8. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to examine PCDD/F amount and profile in these soil samples, and their possible associations with known emission sources: in this process 6 really distinct isomer fingerprints were identified. Background PCDD/F levels and profiles were comparable to those found in soils from China and other countries and indicate a rather low baseline PCDD/F contamination of soils. The present data provide the tools for future assessment of a possible impact of these MSWIs.

The need and potential of biosensors to detect dioxins and dioxin-like polychlorinated biphenyls along the milk, eggs and meat food chain

Dioxins and dioxin-like polychlorinated biphenyls (DL-PCBs) are hazardous toxic, ubiquitous and persistent chemical compounds, which can enter the food chain and accumulate up to higher trophic levels. Their determination requires sophisticated methods, expensive facilities and instruments, well-trained personnel and expensive chemical reagents. Ideally, real-time monitoring using rapid detection methods should be applied to detect possible contamination along the food chain in order to prevent human exposure. Sensor technology may be promising in this respect. This review gives the state of the art for detecting possible contamination with dioxins and DL-PCBs along the food chain of animal-source foods. The main detection methods applied (i.e., high resolution gas-chromatography combined with high resolution mass-spectrometry (HRGC/HRMS) and the chemical activated luciferase gene expression method (CALUX bioassay)), each have their limitations. Biosensors for detecting dioxins and related compounds, although still under development, show potential to overcome these limitations. Immunosensors and biomimetic-based biosensors potentially offer increased selectivity and sensitivity for dioxin and DL-PCB detection, while whole cell-based biosensors present interpretable biological results. The main shortcoming of current biosensors, however, is their detection level: this may be insufficient as limits for dioxins and DL-PCBs for food and feedstuffs are in pg per gram level. In addition, these contaminants are normally present in fat, a difficult matrix for biosensor detection. Therefore, simple and efficient extraction and clean-up procedures are required which may enable biosensors to detect dioxins and DL-PCBs contamination along the food chain.

Comparative analysis of PCDD/Fs in soil around waste incineration plants in China using CALUX bioassay and HRGC/HRMS

In this study, the contamination of soil by PCDD/Fs and other dioxin-like chemicals in the vicinity of Municipal Solid Waste Incinerators (MSWIs) and Hazardous Waste Incinerators (HWIs) is estimated by the XDS-CALUX bioassay. The resulting CALUX-TEQ value is compared with the WHO-TEQ value obtained from HRGC/HRMS analysis, in order to validate the CALUX bioassay as suitable screening method for PCDD/Fs determination of soil samples. The results show that the CALUX-TEQ and the WHO-TEQ values are significantly correlated (R = 0.87). The WHO-TEQ and CALUX-TEQ of soil samples collected from four waste incineration plants in China were in the range from 1.72 to 31.4 pg-TEQ/g and 1.71 to 44.2 pg-TEQ/g respectively, with a mean value of 6.09 pg-TEQ/g and 11.0 pg-TEQ/g. Considering the homologue patterns, a principal component analysis (PCA) and a hierarchical cluster analysis (HCA) of the PCDD/Fs in the soil samples, the emissions of MSWIs and HWIs were probably not the only source of PCDD/Fs.

Sources and distribution of polychlorinated-dibenzo-p-dioxins and -dibenzofurans in soil and sediment from the Yellow Sea region of China and Korea

Polychlorinated-dibenzo-p-dioxins and -dibenzofurans (PCDD/Fs) were measured in soils and sediments from the Yellow Sea region. Korean soils and sediments mostly contained detectable PCDD/Fs and showed a widespread distribution among locations. Soil and sedimentary PCDD/Fs from China were comparable to or less than those in Korea. The patterns of relative concentrations of individual congeners in soils were different between the two countries, but similar in sediments. Sources of PCDD/Fs in China and Korea were found to be independent of each other and their distributions reflected matrix-dependent accumulation. Spatial distribution indicated some point sources in Korea while Chinese sources were more widespread and diffuse. PCDD/Fs measured in the coastal areas of the Yellow Sea were comparable to or less than those previously reported in for eastern Asia. However, ∑TEQs in soils and sediments were near to or, in some cases exceeded environmental quality guidelines.

Levels of PCDD/Fs in agricultural soils near two municipal waste incinerators in Shanghai, China

A study was conducted on polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) in agricultural soils at 41 sites within a radius of 3 km from two municipal solid waste incinerators in Shanghai. The PCDD/F concentrations ranged from 71.32 to 3,881.44 pg g⁻¹ (0.64-61.15 pg I-TEQ g⁻¹). The highest PCDD/F concentrations were found approximately 1,000 m from the municipal solid waste incinerators. The PCDD/F homologue profiles of all soil samples were compared with the profiles from suspected PCDD/F sources by multivariate statistical analysis. The results showed that, the PCDD/F pollutions in some soil samples can be attributed to emissions from the municipal solid waste incinerators.

Levels of PCDD/Fs in soil in the vicinity of a medical waste incinerator in China: the temporal variation during 2007-2009

In 2004, it is estimated that 1.18 kg I-TEQ of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) emitted from medical waste incinerators (MWIs) in China, accounting for 11.5% of the total PCDD/Fs emissions. So it is essential to assess the environmental impact of MWIs. A new MWI of China was started operation in May 2007, and implemented an advanced technology in the combustion and air pollution control system by the BAT/BEP guideline in August 2008. From 2007 to 2009, levels of PCDD/Fs were determined in soil collected in the vicinity of this MWI. The blank survey (2007) was conducted before the start-up operation of this plant. After the operation, soil samples were collected again at the same sampling sites as the blank survey. The average concentration of PCDD/Fs in soil increased from 1.13 pg I-TEQ g(-1) to 2.29 pg I-TEQ g(-1) after 1 year operation of the MWI (2007-2008), and a marked decrease (0.50 pg I-TEQ g(-1)) was observed during 2008-2009. In addition, the current level (2009) was still higher than the blank value (2007). The composited analysis of the experimental results indicated levels of PCDD/Fs were still comparative lower and a limited neighbourhood of the MWI was slightly affected by the emission from this incinerator, meanwhile other un-known PCDD/Fs sources and potential influenced factors could not be neglected in this investigated region.

An integrated approach for identification of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) pollutant sources based on human blood contents

BACKGROUND, AIM, AND SCOPE

This study developed an integrated approach to identify pollutant sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) of workers based on their blood contents.

MATERIALS AND METHODS

We first measured blood PCDD/F contents of sinter plant workers and residents living near the plant. By comparing those blood indicatory PCDD/Fs found for residents with those for sinter plant workers, exposure-related blood indicatory PCDD/Fs were identified for each selected worker. We then measured PCDD/F concentrations of four different sinter plant workplaces and three different ambient environments of the background. By comparing those airborne indicatory PCDD/Fs found for ambient environments with those for sinter plant workplaces, exposure-related airborne indicatory PCDD/Fs for each workplace were obtained. Finally, by matching exposure-related blood indicatory PCDD/Fs with exposure-related airborne indicatory PCDD/Fs, all suspected pollutant sources were identified for each selected worker.

RESULTS

Poor Pearson correlations were found between workers' blood contents and their corresponding PCDD/F exposures. Significant differences were found in the top three blood indicatory PCDD/Fs among the selected workers. By matching exposure-related blood indicatory PCDD/Fs with exposure-related airborne indicatory PCDD/Fs, two to three suspected pollutant sources were identified for each selected worker.

DISCUSSION

The poor Pearson correlation found between workers' airborne PCDD/Fs exposures and their blood contents was because workers' blood PCDD/Fs contents were contributed not only by workers' occupational exposures, but also by other exposure sources and exposure routes. The difference in blood indicatory PCDD/Fs among the selected workers were obviously due to the intrinsic differences in their time/activity patterns in the involved workplaces. While workers used a dust respirator to perform their jobs, gas phase exposure-related airborne indicatory PCDD/Fs played an important role on identifying suspected pollutant sources. But if a dust respirator was not used, the gas + particle phase exposure-related airborne indicatory PCDD/Fs would become the key factor for identifying suspected pollutant sources.

CONCLUSIONS

The developed integrated approach could identify all suspected pollutant sources effectively for selected workers based on their blood contents. The identified pollutant sources were theoretically plausible since they could be verified by examining workers' time/activity patterns, their status in using dust respirators, and the concentrations of PCDD/Fs found in the selected workplace atmospheres.

RECOMMENDATIONS AND PERSPECTIVES

The developed technique can be used to identify possible pollutant sources not only for workers but also for many other exposure groups associated with various emission sources and exposure routes in the future.