The emission inventory of PCDD/PCDF in Taiwan

Human biomonitoring of PCDDs, PCDFs, and PCBs in women living in a Northern Italy industrial area

In Brescia , a highly industrialized city in the Lombardy Region (Northern Italy) classified as a SIN (Contaminated Site of National Interest), a human biomonitoring study was carried out on breast milk of two groups of women residing in areas with presumably different levels of exposure to polychlorodibenzo-p-dioxins, polychlorodibenzofurans, and polychlorobiphenyls. This study was aimed at evaluating the possible difference between women living in Brescia and women living far from it but in the same Region. Between 2016 and 2018, 82 women were enrolled (41 "exposed" subjects and 41 "not exposed"), breast milk samples were collected, and a specific questionnaire was administered to the donors. Data obtained were processed by robust regression and Principal Component Factor Analysis. The differences in concentration between the two groups were significant for all the classes of analytes (except for PCDDs). The concentration increase rates from the not exposed to the exposed group resulted highly significant: some PCB congeners showed increase rates more than 1000 ng/g lb per one-unit change of the independent variable. Among the variables significantly associated with the observed concentrations, age showed the greatest influence, while BMI showed a counteracting effect. Consumption of vegetable oil and fruit resulted to possibly influence the chemicals body burden. For the not exposed group, the levels appear to be in line with the decreasing trend (2001-2018) observed for these contaminants in Italy.

Concentrations, congener patterns, and correlations of unintentional persistent organic pollutants in cement kilns co-processing hazardous waste

Emissions from two typical cement kilns co-processing different kind of hazardous waste were analyzed for 143 congeners of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls, polychlorinated naphthalenes, polybrominated dibenzo-p-dioxins and dibenzofurans, and polybrominated diphenyl ethers. The congener distributions in different process stages were investigated. One of the plants co-processed waste chemical reagents from laboratories. The emission factor (TEQ basis) for the plant was 2.09 ng WHO2005 TEQ/t, with the kiln head and the kiln back end contributing 1.18, 0.91 ng WHO2005 TEQ/t, respectively. The other plant co-processed municipal waste incineration fly ash. The emission factor for the plant was 0.12 ng WHO2005 TEQ/t, with the kiln head and the kiln back end contributing 0.022, and 0.10 ng WHO2005 TEQ/t. These results indicate that co-processing of waste containing reagents from laboratories may lead to higher emission levels than co-processing of other types of waste. The congener patterns of persistent organic pollutants (POPs) in ash samples from the humidifier tower were similar to those in samples from the bag filter at the kiln back end. The correlation coefficients of five pollutants between the humidifier and bag filters samples were generally high, which indicated that conditions in those two stages similarly favored the formation of these POPs. Comparison of the concentrations for different process stages suggested that the main stage for formation of unintentional POPs was the humidifier tower. These results improve our understanding of emission characteristics and could be used for simultaneous control of multiple POPs.

National and provincial dioxin emissions from municipal solid waste incineration in China

China presently lacks an up-to-date regional inventory of dioxin emissions from municipal solid waste incineration (MSWI), although MSWI has grown rapidly in recent decades. Based on dioxin concentrations from the official website for governments and enterprises, we created an inventory of dioxin emissions from 29 areas in mainland China. MSWI released a total of 22.56 g I-TEQ of dioxins in 2020. According to Monte Carlo simulation, the dioxin emissions with 95 %, 75 %, and 50 % certainty are 17.03-31.62, 19.24-27.71, and 20.43-25.96 g I-TEQ, respectively. Notably, Guangdong, Zhejiang, and Jiangsu provinces accounted for 38.8 %. The primary regions with considerable dioxin emission per capita and density are Zhejiang and Shanghai. Furthermore, Jilin and Heilongjiang provinces are the top two regions in terms of dioxin emissions per unit of billion gross domestic product. These indicators were affected significantly by the quantity of MSW generated and incinerated (MSWGI), capacity and operating years of incinerators, and degrees of air pollution control devices (APCDs). Dioxin emission factors (EFs) were about 100 times lower in 2020 than in 2004. Note, however, that there is a gap in dioxin EFs between China and European nations. We have proposed that MSW source classification, stable operation conditions of incinerators and APCDs, categories of incinerators selection, and technological upgrading should be China's major measures to curb dioxin emissions. Moreover, with the future increment in the quantity of MSWGI, it is essential to completely reinvent the dioxin monitoring program.

Atmospheric emissions of PCDDs and PCDFs in China from 1960 to 2014

Quantification of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) is a requirement of the Stockholm Convention on persistent organic pollutants (POPs), and essential to evaluate and understand their environmental fate and associated health risks. Unfortunately, works estimating the emission of PCDD/Fs in China are limited, especially in terms of historical trends and information on spatial distribution. In this study, provincial emissions of 17 toxic PCDD/Fs congeners from 79 sources were quantified from 1960 to 2014, and 0.1º × 0.1º gridded emissions for 2014 were obtained by applying a source-specific, annually varying emission factor (EF) dataset with similar time trends as measurements for China. Historical national PCDD/F emissions showed an increasing trend until around 1980, and then plateaued due to decreased emissions from cement production and waste burning. Decreased emissions from cement production and waste burning in northeast, east, and south China, and Taiwan province were the main causes for the stabilized national emissions after 1980. Spatially, highly positive correlations of emission densities with population and GDP densities were identified, but no clear temporal patterns were observed. Emission densities showed a decreasing trend in the order of cities, towns and rural areas, while the opposite was seen for per capita emissions.

Characteristics of Particles Emitted from Waste Fires-A Construction Materials Case Study

This study aimed to determine the relative densities of populations of particles emitted in fire experiments of selected materials through direct measurement and parametrization of size distribution as number (NSD), volume (VSD), and mass (MSD). As objects of investigation, four typical materials used in construction and furniture were chosen: pinewood (PINE), laminated particle board (LPB), polyurethane (PUR), and poly(methyl methacrylate) (PMMA). The NSD and VSD were measured using an electric low-pressure impactor, while MSD was measured by weighing filters from the impactor using a microbalance. The parametrization of distributions was made assuming that each distribution can be expressed as the sum of an arbitrary number of log-normal distributions. In all materials, except PINE, the distributions of the particles emitted in fire experiments were the sum of two log-normal distributions; in PINE, the distribution was accounted for by only one log-normal distribution. The parametrization facilitated the determination of volume and mass abundances, and therefore, the relative density. The VSDs of particles generated in PINE, LPB, and PUR fires have similar location parameters, with a median volume diameter of 0.2-0.3 µm, whereas that of particles generated during PMMA burning is 0.7 µm. To validate the presented method, we burned samples made of the four materials in similar proportions and compared the measured VSD with the VSD predicted based on the weighted sum of VSD of raw materials. The measured VSD shifted toward smaller diameters than the predicted ones due to thermal decomposition at higher temperatures.

Global status of dioxin emission and China's role in reducing the emission

The global status of dioxin emissions across 150 countries/regions were compiled in this study. China, the major emitter of dioxin and the largest developing country, was chosen as an example to illustrate its emission reductions. The global dioxin emissions were about 97.0 kg TEQ/year, Asia and Africa emitted the most dioxins among the continents. Globally, open burning processes were the most important sources of dioxins. Dioxin emissions in developed countries have remained at low and stable level, while those in developing countries have remained at relatively high level or have continued to increase in recent years. It can be speculated that the global dioxin emissions will increase first and then decrease in the future. Chinese dioxin emissions were stable around 9 kg toxic equivalent (TEQ) in recent years, while 17 subcategories are the key sources of dioxin control in the future. Moreover, according to analysis toward China's dioxin emission trend and sources, there is a large space for dioxins reduction in industries such as metal production, waste incineration and disposal. The results indicated that there is at least 30-70% of reduction scope in China based on three scenarios, and this will reduce the world's annual dioxin emissions by 2.7-6.8%.

Industrial disposal processes for treatment of polychlorinated dibenzo-p-dioxins and dibenzofurans in municipal solid waste incineration fly ash

Hazardous waste disposal is a serious environmental concern in China. Therefore, in this study, industrial trials were conducted in a low-temperature thermal degradation facility, a tunnel kiln, and a shaft kiln to effectively treat dioxins in municipal solid waste incineration (MSWI) fly ash. The results indicated that the low-temperature thermal degradation facility efficiently decomposed polychlorinated dibenzo-p-dioxins and dibenzofurans in the MSWI fly ash. Additionally, the concentrations of dioxins in the treated fly ash and exhaust gas were lower than the suggested standard limits and the degradation ratio of dioxins was ∼99%. Therefore, treated fly ash characterized by acceptable dioxin risks could be utilized for the production of non-fired building materials. The results from the tunnel kiln indicated complete decomposition of the dioxins in the firing and insulating sections. However, the addition of fly ash in the tunnel kiln increased the concentration of dioxins in the flue gas. This can be primarily attributed to the heterogeneous catalytic synthesis reaction in the low-temperature section of the tunnel kiln. The results from the shaft kiln indicated degradation of at least 22% of the dioxins in the ash. The dioxin concentration in the flue gas was lower than the national standard while that in the clinker was within a reasonable limit. Furthermore, the environmental risks were significantly reduced at fly ash addition ratios lower than 3%.

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.

Measurement of Dioxin Emissions from a Small-Scale Waste Incinerator in the Absence of Air Pollution Controls

Polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/Fs) emissions from basic small-scale waste incinerators (SWI) may cause health risks in nearby people and are thus subject to stringent regulations. The aim of this study was to evaluate PCDD/F emission and reduction of a basic SWI in the absence of air pollution controls (APCs). The results indicated that the stack gas and fly ash presented average PCDD/F levels and emission factors of 3.6 ng international toxic equivalent (I-TEQ)/Nm³ and 189.31µg I-TEQ/t and 6.89 ng I-TEQ/g and 137.85µg I-TEQ/t, respectively, much higher than those from large municipal solid waste incinerators (MSWI). PCDD/Fs congener fingerprints indicated that de novo synthesis played a dominant role in the low-temperature post-combustion zone and increased the presence of high-chlorine substituted congeners. On the basis of the emission factor 327.24 µg I-TEQ/t-waste, approximately 3000 g I-TEQ dioxins might be generated in total through basic SWIs and open burning. After refitting an SWI by adding activated carbon injection with a bag filter (ACI+BG), the PCDD/F emissions decreased to mean values of 0.042 ng I-TEQ/Nm³, far below the standard of 0.1 ng I-TEQ/Nm³, and the removal efficiency reached 99.13% in terms of I-TEQ. Therefore, it is entirely feasible to considerably reduce PCDD/F emissions by refitting basic SWI, which is positive for the future development of rural solid waste (RSW (RSW) disposal by SWI.

Concentrations, Sources, and TEQ of PCDD/Fs in Sediments from the Liaohe River Protected Areas

A preliminary study was conducted to examine the contamination of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in surface sediments collected from the Liaohe River. The contamination levels of PCDD/Fs ranged from 317.3 to 509.3 pg/g dw. According to the calculated WHO-TEQ (Toxic Equivalent Quantity of World Health Organization), the range of PCDD/Fs is 13.87-40.88 pg/g dw. A principal component analysis and a cluster analysis suggested that PCDD/Fs in the sediments were mainly from gasoline/diesel vehicle emissions and solid waste incineration. The study revealed that the establishment of protected areas did not markedly reduced the ecological risk caused by PCDD/Fs in the Liaohe River protected areas sediments. It is necessary to study further the environmental impact of PCDD/Fs on the environment.

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.

Spatial variation of PCDD/F and PCB emissions and their composition profiles in stack flue gas from the typical cement plants in China

Cement production processes are important sources of unintentionally produced persistent organic pollutants (UP-POPs), such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polychlorinated biphenyls (PCBs). The emissions of PCDD/Fs and PCBs in the stack flue gases from eight typical cement plants in China were investigated in this study, including one wet process rotary kiln, three dry process rotary kilns and four vertical shaft kilns. PCBs exhibited relatively higher mass concentrations with the dioxin-like (dl) and indicator PCBs of 0.14-17.36 and 0.42-12.90 ng/Nm³, respectively. However, PCDD/Fs contributed most to the total toxic equivalent concentrations, with the proportions exceeding 90%. The international toxicity equivalency (I-TEQ) concentrations of PCDD/Fs varied greatly from 0.01 to 0.46 ng I-TEQ/Nm³ in stack gases, two of which exceeded the exhaust gas concentration limit of 0.1 ng I-TEQ/Nm³ established by the European Union Directive. In weight units, 1,2,3,4,6,7,8-HpCDF was the most abundant congener in the stack gases from various types of cement kilns, with the factions of 17.0-27.8%. TCDFs and PeCDFs were the first two most abundant homologue groups. 2,3,4,7,8-PeCDF was the largest contributor to the total I-TEQ. The emission factors of PCDD/Fs and PCBs in the eight cement kilns were estimated to be 0.01-1.35 μg I-TEQ/t clinker and 8.20 × 10^-4∼8.23 × 10^-2 μg World Health Organization TEQ (W-TEQ)/t clinker, respectively. No obvious differences of the PCDD/F and PCB emission factors were found among the varied cement production technologies.

Status and perspectives of municipal solid waste incineration in China: A comparison with developed regions

With the rapid expansion of municipal solid waste (MSW) incineration, the applicability, technical status, and future improvement of MSW incineration attract much attention in China. This paper aims to be a sensible response, with the aid of a comparison between China and some representative developed regions including the EU, the U.S., Japan, South Korea, and Taiwan area. A large number of up-to-date data and information are collected to quantitatively and impartially support the comparison, which covers a wider range of key points including spatial distribution, temporal evolution, technologies, emissions, and perspectives. Analysis results show that MSW incineration is not an outdated choice; however, policy making should prevent the potentially insufficient utilization of MSW incinerators. The structure of MSW incineration technologies is changing in China. The ratio of plants using fluidized bed is decreasing due to various realistic reasons. Decision-makers would select suitable combustion technologies by comprehensive assessments, rather than just by costs. Air pollution control systems are improved with the implementation of China's new emission standard. However, MSW incineration in China is currently blamed for substandard emissions. The reasons include the particular elemental compositions of Chinese MSW, the lack of operating experience, deficient fund for compliance with the emission standard, and the lack of reliable supervisory measures. Some perspectives and suggestions from both technical and managerial aspects are given for the compliance with the emission standard. This paper can provide strategic enlightenments for MSW management in China and other developing countries.

PCDD/Fs and dl-PCBs concentrations in water samples of Taiwan

Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (dioxin-like PCBs) have received much public concern worldwide due to their persistence and toxicity. The presence of these compounds in environmental matrices, especially in water bodies, enhances the risk of human exposure to these toxic pollutants. In this study, seventeen 2,3,7,8 chlorinated PCDD/Fs and twelve dl-PCBs were measured in 11 groundwater samples collected throughout Taiwan and 2 surface water samples collected in northern Taiwan. PCDD/F and PCB concentrations in two surface water samples are relatively low, with the average concentrations of 0.038 and 0.001 pg WHO-TEQ/L (7.474 and 1.862 pg L^-1), respectively. As for groundwater samples, PCDD/F concentrations measured range from 0.005 to 3.963 pg WHO-TEQ/L, while dl-PCB concentrations range from 2.5 × 10^-5 to 0.189 pg WHO-TEQ/L. Total WHO-TEQ concentrations range from 0.005 to 3.963 pg WHO-TEQ/L, reflecting serious contamination of PCDD/Fs and PCBs in groundwater at some sampling sites. In term of total PCDD/Fs, PCDDs constitute a significant fraction (77.3%), and OCDD is most abundant, followed by HpCDD/Fs and HxCDD/Fs. PCB 118 is dominant among 12 dl-PCBs measured, followed by PCB 105 and PCB 77. Solid-phase PCDD/Fs generally predominate in water samples and PCDFs are of slightly lower distribution in solid phase in comparison with PCDDs, while PCBs are mainly distributed in dissolved phase. Results of principal component analysis (PCA) indicate that use of PCP and Na-PCP, thermal processes and PCBs-containing products might be the major sources of PCDD/Fs and PCBs in water samples measured.

Field study and theoretical evidence for the profiles and underlying mechanisms of PCDD/F formation in cement kilns co-incinerating municipal solid waste and sewage sludge

A field study and theoretical calculations on the profile and formation mechanism of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from two cement kilns co-incinerating municipal solid waste and sewage sludge were performed, and the PCDFs were mainly focused. The back-end areas of the cement kilns were identified to be the major sites of PCDD/F formation according to their distributions in particulate samples from different process stages. The proportions of tetra- to hexa-chlorinated dibenzofurans (∑Cl_4-6CDFs) at the kiln back-end areas were in the range of 50-80% of the total PCDD/Fs in mass concentrations and 62-87% in toxic equivalent concentrations. These results indicated that ∑Cl_4-6CDFs are the dominant homologs that should be the focus for reducing PCDD/F emissions in cement kilns that co-incinerate municipal solid waste and sewage sludge. It is speculated that the low contents of oxygen and copper compounds, as well as the alkaline conditions, may contribute to the dominance of ∑Cl_4-6CDFs in the PCDD/Fs formed. Chlorination was assumed to be the mechanism of formation of PCDFs. The results from model predictions and thermodynamic calculations used to test this assumption were consistent with the PCDF profiles observed from the field study.

Recycling ash into the first stage of cyclone pre-heater of cement kiln

Fly ash collected from the bag filter could be recycled into the first stage of the cyclone pre-heater of the cement kiln, resulting in the possible enrichment of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). In this study, soxhlet fly ash (SFA) and raw meal (RM) were selected as the basis for the PCDD/F formation experiments. The levels of 2,3,7,8-PCDD/Fs formed on the SFA and RM were observed to be 2550pg/g (157pg I-TEQ/g) and 1142pg/g (55pg I-TEQ/g), respectively. While less 2,3,7,8-PCDD/Fs was detected when SFA was mixed with RM, suggesting that recycling cement kiln ash would not largely increase the concentration of PCDD/Fs in flue gas. Furthermore, the possible influencing factors on the PCDD/F formation were also investigated. The formation of 2,3,7,8-PCDD/Fs was up to 10,871pg/g (380pg I-TEQ/g) with the adding of CuCl2, which was much higher than the results of CuO and activated carbon. Most importantly, the homologue, congener and gas/particle distribution of PCDD/Fs indicated that de novo synthesis was the dominant PCDD/F formation pathway for SFA. Lastly, principal component analysis (PCA) was also conducted to identify the relationship between the compositions of reactant and the properties of PCDD/Fs produced.

Emission and distribution of PCDD/Fs and CBzs from two co-processing RDF cement plants in China

An analysis of the emission and distribution characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and chlorobenzenes (CBzs) from two cement kilns (CK1 and CK2) is done. Six measurements in CK1 showed an increase of PCDD/F emission from 76 to 97 pg I-TEQ/Nm(3) after feeding 10 ton/h RDF (refuse derived fuel). For CK2, the effect of increasing the RDF substitution rates from 0 to 21 t/h on the emission of PCDD/Fs was investigated. The correlation analysis indicated that replacing parts of the conventional fuel with RDF could not increase the emission of PCDD/Fs. Furthermore, the gas/particle partitions of PCDD/Fs and CBzs in stack gas were investigated, indicating that PCDD/Fs and CBzs were more associated in gas phase, especially for the lower chlorinated ones. Moreover, the bag filter fly ash was characterized by its particle distribution, XRD- and EDS-analysis. Additionally, the level of PCDD/Fs in outflowing fly ash escalates for smaller particle size. In order to evaluate the environmental effect on inhabitants, the levels of PCDD/Fs were also determined in samples of ambient air collected in the vicinity of CK2 (~200 m).

Review of the current state and main sources of dioxins around the world

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are a group of dangerous compounds, emitted mostly from anthropogenic sources, that have negative effects on human health. Therefore, it is interesting to analyze the emission patterns of dioxins proceeding from different sources around the world, to observe the actual trend of the transmission of dioxins and furans into the atmosphere.For that reason, the main objective of the present document is to provide a general assessment about the dioxin problematic, analyzing the main parameters that influence the ambient concentration of dioxins worldwide, and describing the most characteristic features of the fingerprint from different sources, while making emphasis in the importance that non-industrial sources are gaining over the last years in front of the decreasing tendency of industrial sources. The description of the most important abatement technologies for dioxins is also included in this review.

IMPLICATIONS

Given the negative effects of dioxins in human health, it is important to depict and locate the main sources of these dangerous compounds. Emissions proceeding from industrial facilities have decreased over the last years; however, other zones where nonindustrial sources used to be relevant contributors do not show the same decreasing tendency because it is more difficult to control this type of emissions. For that reason, future studies should focus on measuring and regulating this highly uncontrolled source of dioxins.

Refractory organic pollutants and toxicity in pulp and paper mill wastewaters

This review describes medium and high molecular weight organic material found in wastewaters from pulp and paper industry. The aim is to review the versatile pollutants and the analysis methods for their determination. Among other pollutants, biocides, extractives, and lignin-derived compounds are major contributors to harmful effects, such as toxicity, of industrial wastewaters. Toxicity of wastewaters from pulp and paper mills is briefly evaluated including the methods for toxicity analyses. Traditionally, wastewater purification includes mechanical treatment followed by chemical and/or biological treatment processes. A variety of methods are available for the purification of industrial wastewaters, including aerobic and anaerobic processes. However, some fractions of organic material, such as lignin and its derivatives, are difficult to degrade. Therefore, novel chemical methods, including electrochemical and oxidation processes, have been developed for separate use or in combination with biological treatment processes.

Human health risk assessment of soil dioxin/furans contamination and dioxin-like activity determined by ethoxyresorufin-O-deethylase bioassay

The major objective of this study was to evaluate the human health risks of agricultural land use conversion to other purposes in Hong Kong, based on the levels of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD/Fs) and determined dioxin-like activity in soil using ethoxyresorufin-O-deethylase (EROD) bioassay. Hazard quotient showed soils of open burning site (OBS) and electronic waste open burning site (EW (OBS)) exert a relatively higher non-cancer risk on adults (50.9 and 8.00) and children (407 and 64.0) via the pathway of accidental ingestion of soil particles than other types of land use. In addition, the levels of 17 PCDD/Fs congeners in OBS and EW (OBS) soils indicated high and moderate (1654 and 260 in one million people) cancer risks through the above pathway. Furthermore, the biologically derived TCDD concentrations (TEQbio) were also significantly correlated to the chemically derived toxic equivalent concentrations of dioxin-like chemicals (TEQcal (sum of chemically derived 2,3,7,8-TeCDD toxic equivalent concentrations (TEQPCDD/F) and chemically derived dioxin-like PAHs toxic equivalent concentrations (TEQPAH)) (r = 0.770, p <0.05). PCDD/Fs (95.4 to 99.9%) were the major stressor to the TEQcal in the soil samples, indicating higher concentrations of PCDD/Fs derived from chemical analyses may reflect a higher potency of inducing EROD activity.

Characteristics of PCDD/F emissions from secondary copper smelting industry

Characteristics and mechanisms of PCDD/F formation with different feed materials in secondary copper smelting industry are investigated. The results indicate that PCDD/Fs are significantly formed even with the reaction time less than 0.1s, especially when the material containing high residues (Cu3) is fed. High copper content (65±2%) in the feed material enhances PCDD/F formation rate. Memory effect and de novo synthesis are two important mechanisms leading to PCDD/F formation. PCDD/F concentrations at the cyclone's inlet are between 2.92 and 12.4ng-TEQNm(-3) and increase with increasing residue content in the feed material. Two regions are identified for high potential of PCDD/F formation including the brass melt surface of the induction furnace and piping before the induced draft fan of the inlet hood. PCDD/Fs in flue gas are effectively removed with a cyclone and bag filter at low operating temperatures (<60°C) to meet the emission limit of 1.0ng-TEQNm(-3). 1,2,3,4,6,7,8-HpCDF has the largest mass fraction of PCDD/Fs and can serve as a fingerprint for emissions from secondary copper smelting processes. The total emission factor of PCDD/Fs from flue gas, residual and fly ash in the secondary copper smelting process investigated is 22.01μg-TEQtonne(-1).

Destruction of DDT wastes in two preheater/precalciner cement kilns in China

The destruction of DDT formulations and DDT contaminated soil was conducted by feeding wastes into the flue gas chamber at the kiln inlet of two different preheater/precalciner cement kilns in China. The concentration of DDT, PCDD/PCDFs and HCB were measured in the flue gas of the main stack, in the solid material under baseline conditions and when feeding DDT-wastes. The destruction efficiency and the destruction and removal efficiency for DDT were in the range of 99.9335%-99.9998% and 99.9984%-99.9999%, respectively. The emissions of PCDD/PCDFs and HCB in the flue gas varied in the range of 0.0019-0.0171 ng I-TEQ/Nm(3) and 0.0064-0.0404 μg/Nm(3), respectively. The emission factor for PCDD/PCDF and HCB varied from 0.0137 to 0.0281 μg/ton and from 17.32 to 109.34 μg/ton of clinker, respectively. The concentration of PCDD/PCDFs and HCB in solid samples decreased as follows: cement kiln dust, 4.1-5 ng I-TEQ/kg and 0.70-0.71 μg/kg, respectively; >raw meal, 0.82-0.97 ng I-TEQ/kg and 0.18 μg/kg, respectively; >cement clinker, 0.09-0.22 ng I-TEQ/kg and 0.14-0.18 μg/kg, respectively. This study indicates that the feeding of DDT and POPs-wastes to the lower temperature part of a cement kiln system possibly to create a buildup of trace not-destroyed compounds in the system and might cause emissions; the technical feasibility and the environmental acceptability of this practice need to be investigated thoroughly.

Ten-year time trend of dioxins in human serum obtained from metropolitan populations in Seoul, Korea

Polychlorinated dibenzo-p-dioxin/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) were measured in 954 and 539 human serum samples obtained, respectively, from incinerator workers and residents living near and far from municipal solid waste incinerators (MSWIs) during a 10-year period from 2001 to 2011 in Seoul, Korea. The mean toxic equivalent (TEQ) concentrations of PCDD/Fs and DL-PCBs were 9.29 and 5.39 pg TEQ/g lipid, respectively. All populations exhibited similar concentrations and profiles, and 2,3,4,7,8-PeCDF, 1,2,3,7,8-PeCDD, and PCB126 were identified as major contributors to TEQs. However, the levels of PCDD/Fs and DL-PCBs were found to have positive associations with age when considering stratified age groups and showed a slight trend toward reduction. Differences in concentrations of these compounds among age groups slightly but continuously decreased from 2001 to 2011. The measured PCDD/F levels were compared to the predicted concentrations by using a single-compartment pharmacokinetic model on the basis of the daily intake of PCDD/Fs. The predicted concentration was 5.24 pg TEQ/g lipid, which was approximately half of the measured concentration, reflecting the present exposures. These results suggest that current data on the levels of PCDD/Fs in foodstuffs might be useful to predict the future levels of dioxins in humans, which are expected to decline with time.

Portuguese inventory of dioxins and furans atmospheric emissions

This article presents the results of the most recent estimation of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) atmospheric emissions in Portugal, which has covered the period 2004-2009 and includes 27 emission sources types. The results are compared with previous emissions inventories published for Portugal. The main objective of this work is to provide relevant information about the amounts of the compounds that are released into the atmosphere in Portugal, and identify their major sources and trends. The methodology involved the identification of relevant sources, the collection of information to characterize these sources, the selection of appropriate emission factors and their application to estimate the emissions. Furthermore, several studies conducted in Portugal were considered, namely reports from PCDD/PCDF measurements performed in some industrial facilities. The inventory covered 27 emission sources types. However the results show that only 8 were relevant, i.e. with emission amounts greater than 1 g I-TEQ year(-1). The total emissions of PCDD/PCDF in Portugal reached between 40 and 105 g I-TEQ year(-1), for the period of 2004-2009. The largest emission source and at same time with greater variation is forest fires, with emissions between 3 g I-TEQ year(-1) and 67 g I-TEQ year(-1) in 2008 and 2005, respectively. Excluding the emissions from forest fires, the total emission is more or less constant over the years and around 37 g I-TEQ year(-1).

QSPR modeling of n-octanol/air partition coefficients and liquid vapor pressures of polychlorinated dibenzo-p-dioxins

The molecular geometries of 75 polychlorinated dibenzo-p-dioxins (PCDDs) were optimized using B3LYP/6-31G(*) method. The calculated structural parameters were taken as theoretical descriptors to establish two new novel QSPR models for n-octanol/air partition coefficients (log K(OA)) and subcooled liquid vapor pressure (log P(L)) of PCDDs. The R(2) values of the two models are 0.983 and 0.985 respectively. Their standard deviations of prediction in modeling (SD) are 0.174 and 0.230 respectively. The results of leave-one-out (LOO) cross-validation for training set show that the two models exhibited optimum stability and good predictive power.

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.

Occupational exposure to PCDDs, PCDFs, and PCBs of metallurgical workers in some industrial plants of the Brescia area, northern Italy

BACKGROUND

The study was carried out in order to respond to public concern on the occupational exposure of metallurgical workers to highly toxic PCDDs, PCDFs, and PCBs in the area of the city of Brescia, northern Italy.

OBJECTIVES

The study investigated the effects on the haematic burden of occupational exposures to the aforesaid contaminants in different work environments, attempting to establish causal relationships and providing indications for occupational health preventive measures.

METHODS

Chemical concentrations were measured in blood serum of "professionally exposed" (PE) and "not professionally exposed" (NPE) subjects. NPE subjects included industrial administrative employees, Brescia inhabitants, and remote rural people.

RESULTS

The central tendency indexes of contaminant cumulative concentrations were higher in PE than in NPE samples (for the mean values: PCDDs+PCDFs, 22.9 vs. 19.5 pgWHO-TEQ(1997)/g lb; DL-PCBs, 26.0 vs. 23.6 pgWHO-TEQ(1997)/g lb; PCDDs+PCDFs+DL-PCBs (TEQ(TOT)), 48.9 vs. 43.1 pgWHO-TEQ(1997)/g lb; Σ(6)[NDL-PCBs], 427 vs. 401 ng g(-1)lb); however, no statistical differences were detected at P=0.05. A significant difference for PCDDs+PCDFs and TEQ(TOT) was observed as the NPE data were progressively reduced to those of the remote rural people. The existence of a differential occupational exposure due to different environments was detected by applying the factor analysis to congener-specific data (analytical profiles).

CONCLUSIONS

Findings indicate that metallurgical workers may be exposed to PCDD, PCDF, and PCB more than the general population, in particular due to non-negligible contributions to exposure from workplace ambient air. Findings also suggest that an improvement of preventive measures may be required to avoid chemical overexposure in certain metallurgical workplaces. To identify exposure groups, the DL- and NDL-PCB analytical profiles seemed to be more sensitive to environmental exposure sources/pathways than those of PCDDs and PCDFs.

Polychlorinated dibenzo-p-dioxin and dibenzofuran and polychlorinated biphenyl emissions from different smelting stages in secondary copper metallurgy

Secondary copper production has received much attention for its high emissions of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) reported in previous studies. These studies focused on the estimation of total PCDD/F and polychlorinated biphenyl (PCB) emissions from secondary copper smelters. However, large variations in PCDD/F and PCB emissions reported in these studies were not analyzed and discussed further. In this study, stack gas samples at different smelting stages (feeding-fusion, oxidation and deoxidization) were collected from four plants to investigate variations in PCDD/F and PCB emissions and characteristics during the secondary copper smelting process. The results indicate that PCDD/F emissions occur mainly at the feeding-fusion stage and these emissions contribute to 54-88% of the total emissions from the secondary copper smelting process. The variation in feed material and operating conditions at different smelting stages leads to the variation in PCDD/F emissions during the secondary copper smelting process. The total PCDD/F and PCB discharge (stack gas emission+fly ash discharge) is consistent with the copper scrap content in the raw material in the secondary copper smelters investigated. On a production basis of 1 ton copper, the total PCDD/F and dl-PCB discharge was 102, 24.8 and 5.88 μg TEQ t(-1) for the three plants that contained 100%, 30% and 0% copper scrap in their raw material feed, respectively.

Emissions of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) to air from waste incinerators and high thermal processes in India

This study investigated dioxins and dioxin-like polychlorinated biphenyls in gasses emitted from waste incinerators and thermal processes in central and western parts of India. The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/DFs) ranged from 0.0070 to 26.8140 ng toxicity equivalent (TEQ)/Nm(3), and those of dioxin-like polychlorinated biphenyls (PCBs) ranged from 0.0001 × 10(-1) to 0.0295 ng TEQ/Nm(3). The characteristics of mean PCDD/F I-TEQ concentration and congener profiles were studied over all the samples of air. In particular, a pattern consisting of a low proportion of dioxin-like PCBs and high proportion of PCDDs/DFs was common for all the samples from incinerators and high-temperature processes.

Emission profiles of polychlorinated dibenzodioxins, polychlorinated dibenzofurans (PCDD/Fs), dioxin-like PCBs and hexachlorobenzene (HCB) from secondary metallurgy industries in Portugal

This paper reports, for the first time, a study of dioxin emissions from 10 siderurgies and metallurgies, secondary copper, aluminum and lead metallurgies, in Portugal. The study reports the emission factors and total emission amounts of PCDD/Fs, dioxin-like PCBs and hexachlorobenzene (HCB). The congener patterns were characterized and are discussed. The results showed that the total amount of PCDFs is higher than PCDDs in flue gas of each industrial unit. The toxic equivalent emission factors of pollutants emitted are 3098-3338 ngI-TEQt(-1) for PCDD/Fs and 597-659 ng I-TEQt(-1) for dioxin-like PCBs in siderurgies production (total estimated emission amounts released to atmosphere of 3.9-4.5 g I-TEQyr(-1)), 50-152 ng I-TEQt(-1) for PCDD/Fs and 24-121 ng I-TEQt(-1) for dioxin-like PCBs in ferrous foundries production (total estimated emission amounts released to atmosphere of 0.0010-0.0016 g I-TEQyr(-1)) and 5.8-5715 ng I-TEQt(-1) for PCDD/Fs and 0.49-259 ng I-TEQt(-1) for dioxin-like PCBs in non-ferrous foundries production (total estimated emission amounts released to atmosphere of 0.00014-0.12 g I-TEQyr(-1)). The HCB emission from siderurgies production is 0.94-3.2 mg t(-1) (total estimated emission amounts released 0.94-3.8 g yr(-1)), being much smaller, residual, in the emissions of the other types of plants (0.0012-0.026 mg t(-1) production and total estimated emission amounts released to atmosphere of 0.013-1.7 mg yr(-1)).

Effects of basin topography and monsoon conditions on transport and occurrence of atmospheric PCDD/Fs in the Taichung Basin

BACKGROUND, AIM, AND SCOPE

Topographical and meteorological factors, such as monsoons, can drastically affect ambient dioxin levels. In order to better understand these phenomena, four sampling lines (comprising 16 sampling sites) were selected in accordance with the topographical characteristics and the transport paths of the Taichung Basin.

MATERIALS AND METHODS

The ambient air samples were simultaneously collected according to US EPA TO-9A. Seventeen polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed by a high-resolution gas chromatograph/high-resolution mass spectrometer.

RESULTS

Field measurements indicated that, during monsoons, PCDD/Fs concentrations varied from 128 to 4,230 fg m(-3). Two locations, the pass between two tablelands and the valley in front of a mountain, had the highest PCDD/Fs concentrations; those concentrations were about two to five times greater than the average concentration. There were 189 analyses of 11 kinds of PCDD/Fs emission sources used to develop emission fingerprints for a CMB8.2 simulation. Chemical mass balance (CMB8.2) model simulation with PCDD/Fs and surface wind field measurements were performed. Results of CMB8.2 modeling indicated that the major source of most sites was secondary copper smelting.

CONCLUSIONS

The CMB8.2 model indicated the effects of hills and river valleys on pollutant transport. Results indicated that secondary copper smelting must be controlled to reduce the ambient concentrations of PCDD/Fs in the Taichung Basin.

The reduction of dioxin emissions from the processes of heat and power generation

The first reports that it is possible to emit dioxins from the heat and power generation sector are from the beginning of the 1980s. Detailed research proved that the emission of dioxins might occur during combustion of hard coal, brown coal, and furnace oil as well as coke-oven gas. The emission of dioxins occurs in wood incineration; wood that is clean and understood as biomass; or, in particular, wood waste (polluted). This paper thoroughly discusses the mechanism of dioxin formation in thermal processes, first and foremost in combustion processes. The parameters influencing the quantity of dioxins formed and the dependence of their quantity on the conditions of combustion are highlighted. Furthermore, the methods of reducing dioxin emissions from combustion processes (primary and secondary) are discussed. The most efficacious methods that may find application in the heat and power generation sector are proposed; this is relevant from the point of view of the implementation of the Stockholm Convention resolutions in Poland with regard to persistent organic pollutants.

Analysis of polychlorinated dibenzo-p-dioxins and furans in various aqueous samples in Taiwan

Twenty-one fresh water samples were taken from reservoirs, wells and drinking water treatment plants in Taiwan for measurement of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) concentrations. Due to low concentration of PCDD/Fs, water samples (400-1,000 L) were collected by using the on-site large volume pre-concentration system and analyzed by high resolution gas chromatography (HRGC)/high resolution mass spectrometer (HRMS). Different characteristics of dioxin profiles in surface water and groundwater are observed. The PCDD/F concentrations in fresh water samples varied from 0.001 to 0.265 pg WHO(98)-TEQ/L which are lower than the standard (12 pg WHO(98)-TEQ/L) set by the Taiwan Environmental Protection Administration (TEPA) for drinking water. Only a small fraction (<5%) of the total PCDD/F concentration in fresh water samples was water-soluble. As a result of their hydrophobicity, PCDD/Fs are effectively removed along with suspended solid via the water treatment process (average 98% removal efficiency).

"Dioxin releases in waste incinerations and thermal processes"

The releases of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from waste incinerators and thermal processes were investigated. The characteristics of mean PCDD/Fs I-TEQ concentrations and congener profiles were studied over the samples of water, soil, fly ash and bottom ash of individual source. The TEQ value for fly ash ranges from 0.013 to 17.01 pg-TEQ/g. Moreover, the TEQ value for bottom ash was 12.06 pg-TEQ/g and the TEQ values for the water samples were found to be in a consistent range from 0.41-0.56 ng-TEQ/L. In almost all the analyzed matrices the congener OCDD/OCDF was found in highest concentration raising the critical concerns over the overall PCDD/Fs emissions from incinerations and thermal processes.

Relationship of PCDD/F concentrations in duck-egg farmers and consumption of ranched duck eggs in central Taiwan

The 2004 food market-basket survey in Taiwan found high levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in duck eggs. A subsequent survey in Chang-Hua County, central Taiwan, found nine duck farms for egg production and duck eggs that were highly contaminated by PCDD/Fs in the secondary sampling and analysis during the years 2004 to 2005. Duck-egg farmers eat duck eggs rather than chicken eggs, and the aim of the current study was to evaluate how eating contaminated duck eggs affected serum PCDD/F accumulation and PCDD/F profiles in family members of duck-egg farmers. Forty-two family members of duck-egg farmers and 88 residents living nearby (control group) were recruited. Serum PCDD/F levels were significantly higher in duck-egg farmers than in the control group (28.1 vs 18.6 pg World Health Organization toxic equivalency [TEQ]/g lipid, WHO-TEQ). Significant differences in PCDD/F levels were found for most congeners, especially for 2,3,4,7,8-penta-chlorinated dibenzofurans. Elevated serum PCDD/F levels were positively associated with an increase in monthly duck-egg consumption after adjustments for fish consumption. The current result contradicted results of our previous study, which showed a positive association between fish intake and serum PCDD/F levels. The matter of cultivation in the contaminant area in Chang-Hua County should be considered more seriously.

Occurrence and characteristics of polybrominated dibenzo-p-dioxins and dibenzofurans in stack gas emissions from industrial thermal processes

The occurrence and characteristics of 2,3,7,8-substituted polybrominated and polychlorinated dibenzo-p-dioxins and dibenzofurans (PBDD/F and PCDD/F) from various combustion and metallurgic industrial thermal processes were investigated. PBDD/F levels from metallurgic processes (TEQ) concentrations from 0.14 to 1.5 ng Nm(-3), mass concentrations from 0.56 to 5.8 ng Nm(-3)) were markedly higher than those from combustion processes (TEQ) concentrations from 0.010 to 0.054 ng Nm(-3), mass concentrations from 0.025 to 0.15 ng Nm(-3)). This indicated that metallurgic processes could be important sources of PBDD/F. Consequently, more attention should be paid to the metallurgical emission sources in addition to combustion of brominated flame retardants (BFRs) and related products. Specific isomeric patterns for PCDD/F from various industrial sources were highly consistent, while PBDD/F patterns were not. This revealed that PCDD/F might form through a common mechanism such as de novo synthesis mechanism, while PBDD/F might form by different mechanisms in thermal processes such as precursor mechanisms. Finally, an approach to identify the PBDD/F sources in ambient air by using the PBDD/F to PCDD/F ratio was developed.

Environmental and human exposure to persistent halogenated compounds derived from e-waste in China

Various classes of persistent halogenated compounds (PHCs) can be released into the environment due to improper handling and disposal of electronic waste (e-waste), which creates severe environmental problems and poses hazards to human health as well. In this review, polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), tetrabromobisphenol A (TBBPA), polybrominated phenols (PBPs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), and chlorinated polycyclic aromatic hydrocarbons (ClPAHs) are the main target contaminants for examination. As the world's largest importer and recycler of e-waste, China has been under tremendous pressure to deal with this huge e-waste situation. This review assesses the magnitude of the e-waste problems in China based on data obtained from the last several years, during which many significant investigations have been conducted. Comparative analyses of the concentrations of several classes of toxic compounds, in which e-waste recycling sites are compared with reference sites in China, have indicated that improper e-waste handling affects the environment of dismantling sites more than that of control sites. An assessment of the annual mass loadings of PBDEs, PBBs, TBBPA, PBPs, PCDD/Fs, and ClPAHs from e-waste in China has shown that PBDEs are the dominant components of PHCs in e-waste, followed by ClPAHs and PCDD/Fs. The annual loadings of PBDEs, ClPAHs, and PCDD/Fs emission were estimated to range from 76,200 to 182,000, 900 to 2,000 and 3 to 8 kg/year, respectively. However, PCDD/Fs and ClPAHs should not be neglected because they are also primarily released from e-waste recycling processes. Overall, the magnitude of human exposure to these toxics in e-waste sites in China is at the high end of the global range.

Assessment of dioxin-like soil contamination in Mexico by enzyme-linked immunosorbent assay

In this work, we describe the results of a preliminary soil assessment program for the detection of dioxins at different sites in Mexico performed by immunoassay. We studied five different sectors considered relevant sources of dioxins: Anaversa and Tekchem industrial areas where organochlorine pesticides were manufactured and released by accidental explosions, secondary smelters, brick kilns, and rural dwellings. In the context of the Agency for Toxic Substances and Disease Registry (ATSDR) guidelines, only the brick kilns sites can be considered as low-risk areas. The dioxin concentrations detected in the vicinity of the Anaversa and Tekchem chemical plants and secondary smelters exceed the screening level of 0.05 ppb set by the ATSDR, and therefore further site-specific studies are needed. The dioxin levels found in all soot samples from indigenous dwellings where wood is used for indoor cooking were above the evaluation level. Considering that the studied areas are representative examples of dioxin sources in less developed countries, our work demonstrates the useful application of dioxin immunoassays as a tool for dioxin screening for environmental assessment programs in developing countries.

Estimation and congener-specific characterization of polychlorinated naphthalene emissions from secondary nonferrous metallurgical facilities in China

Secondary nonferrous production is addressed as one of the potential sources of the unintentionally produced persistent organic pollutants (UP-POPs) due to the impurity of raw material. Although there are inventories of dioxin emissions from secondary nonferrous metallurgical facilities, release inventories of polychlorinated naphthalenes (PCNs) are scarce. This study selected typical secondary copper, aluminum, zinc, and lead plants to investigate the emissions of PCNs in secondary nonferrous production in China. The toxic equivalency (TEQ) emission factor for PCNs released to the environment is highest for secondary copper production, at 428.4 ng TEQ t(-1), followed by secondary aluminum, zinc, and lead production, at 142.8, 125.7, and 20.1 ng TEQ t(-1), respectively. PCNs released in secondary copper, aluminum, lead, and zinc production in China are estimated to be 0.86, 0.39, 0.009, and 0.01 g TEQ a(-1), respectively. Analysis of stack gas emission from secondary nonferrous production revealed that less-chlorinated PCNs are the dominant homologues, with mono- to tri-CNs making the most important contributions to the concentration. However, for fly ash, the more highly chlorinated PCNs such as octa-CN are the dominant homologues.

Toxic emissions from crematories: a review

In recent years, the cremation ratio of cadavers has increased dramatically in many countries. Crematories have been identified as sources of various environmental pollutants, being polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and mercury those raising most concern. In contrast to other incineration processes for which the number of studies on their toxic emissions is considerable, references related to PCDD/F and mercury emissions from crematories and their health risks are very limited. In this paper, the scientific information concerning these issues, using the databases PubMed, Scopus and Scirus, is reviewed. Results show that in comparison with PCDD/F emissions from other sources, those corresponding to crematories are significantly lower, while those of mercury should not be underrated.

The Possibilities of Reduction of Polychlorinated Dibenzo-P-Dioxins and Polychlorinated Dibenzofurans Emission

In the study the most important and known polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzo-furans (PCDFs) emission sources are presented and known methods of reduction of dioxin emission to the atmosphere are discussed in detail. It is indicated that the most relevant emission source is a combustion process. The mechanism of dioxin formation in thermal processes is presented in brief. The author characterized primary methods of reduction of PCDDs/PCDFs emission encompassing the interference into the combustion process to minimize their formation and discussed known secondary methods aimed at their removal from the stream of waste gases. It was attempted to make a critical assessment of PCDD/Fs reduction methods described in literature.

Polychlorinated biphenyls emission from a medical waste incinerator in China

Detailed polychlorinated biphenyls (PCBs) congener patterns were determined in the flue gas from a medical waste incinerator (MWI) using high-resolution gas chromatograph coupled to high-resolution mass spectrometer (HRGC/HRMS). The total PCBs concentration of all homologues (mono- to deca-chlorinated homologues) in the flue gas ranged from 138.01 to 855.35 ng/Nm(3) and the WHO-TEQ value varied from 0.046 to 0.549 ng/Nm(3) under the different operating conditions. PCB-77 concentration was the highest among dioxin-like PCBs and PCB-126 contributed mostly to the WHO-TEQ. The ratios of dioxin-like PCBs in the total PCB concentrations in the flue gas varied between 11.7% and 26.0% (the average value is 18.7%). Three inhibitors, sulfur, urea, and ammonium sulfate were tested to investigate the capacity for preventing PCBs formation. The decomposition efficiency for total PCBs and PCBs TEQ ranged from 38% to 84% and 69% to 92% respectively. It was shown that urea mixed with ammonium sulfate and more activated carbon was proved to be the most effective inhibitor for PCBs formation. The removal efficiencies (REs) of the total PCBs concentration and PCBs TEQ by the bag filter under two conditions were 69% and 85%, and 86% and 94% respectively.

Distribution of air and serum PCDD/F levels of electric arc furnaces and secondary aluminum and copper smelters

Metallurgical processes, such as smelting, can generate organic impurities such as organic chloride chemicals, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). The objective of this study was to elucidate the serum PCDD/F levels of 134 workers and ambient air levels around electric arc furnaces (EAF), secondary copper smelters and secondary aluminum smelters (ALSs) in Taiwan. The highest serum PCDD/F levels were found in the ALSs workers (21.9 pg WHO-TEQ/g lipid), with lower levels in copper smelter workers (21.5 pg WHO-TEQ/g lipid), and the lowest in the EAF plant workers (18.8 pg WHO-TEQ/g lipid). This was still higher than the levels for residents living within 5 km of municipal waste incinerators (14.0 pg WHO-TEQ/g lipid). For ambient samples, the highest ambient air PCDD/F level was in the copper smelters (12.4 pg WHO-TEQ/Nm(3)), with lower levels in ALSs (7.2 pg WHO-TEQ/Nm(3)), and the lowest in the EAF industry (1.8 pg WHO-TEQ/Nm(3)). The congener profiles were consistent in serum and in air samples collected in the copper smelters, but not for ALSs and EAF. In secondary copper smelters, the air PCDD/Fs levels might be directly linked to the PCDD/Fs accumulated in the workers due to the exceedingly stable congener pattern of the PCDD/F emission.

Cluster analysis for polychlorinated dibenzo-p-dioxins and dibenzofurans concentrations in southern Taiwan

This study investigates the characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the ambient air of two municipal solid waste incinerators (MSWIs: GS and RW) and a coal-fired power plant (PW) in the Kaohsiung County (KC) area in Taiwan. The results show that the toxic equivalency (TEQ) concentration in the flue gas of GS and RW averaged 0.090 and 0.044 ng international toxic equivalents (I-TEQ)/N m3, respectively. The TEQ concentration in the flue gas of PW averaged 0.050 ng I-TEQ/N m3. All PCDD/Fs concentrations from the stack flue gas are lower than the Taiwan Environmental Protection Administration emission standard. Furthermore, the mean I-TEQ concentration in the ambient atmosphere ranged from approximately 0.019 to 0.165 pg I-TEQ/N m3, much lower than the environmental quality standards for dioxins in Japan (0.6 pg TEQ/ N m3). This work classified all sampling sites into three clusters according to k-means cluster analysis. The result shows a probable direct correlation between the GS incinerator and site C. Although the concentration from the PW plant did not exceed the emission standard, it was much higher than that in Fernández-Martínez's study. For proper environmental management of dioxins, establishing a complete emission inventory of PCDD/Fs is necessary. The government of Taiwan should particularly pay more attention to power plants to address the information shortage.

Emissions of PCDD/Fs from municipal solid waste incinerators in China

Gas emission of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) from 19 commercial municipal solid waste (MSW) incinerators in China are investigated. The emission concentrations of PCDD/Fs were 0.042-2.461 ng TEQ Nm(-3) with an average value of 0.423 ng TEQ Nm(-3). The emissions of PCDD/Fs from 16 MSW incinerators were below the MEP regulation level (1.0 ng I-TEQ Nm(-3)), while only six systems have the dioxin emission levels below the limit established by the European Union Directive of 0.1 ng I-TEQ Nm(-3). The emission factors of PCDD/Fs from 19 MSW incinerators were calculated to be 0.169-10.72 microg TEQ ton(-1) MSW with an average value of 1.728 microg I-TEQ ton(-1) MSW. The total amount of PCDD/Fs emitted from MSW incinerators to the atmosphere in China was estimated to 19.64 g TEQ year(-1) in 2006.

Estimation and characterization of PCDD/Fs and dioxin-like PCBs from secondary copper and aluminum metallurgies in China

The secondary metallurgy industry is considered as one source of polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs). This study investigated the emission factors and total emissions amounts of PCDD/Fs and dioxin-like polychlorinated biphenyls (dioxin-like PCBs) released from secondary aluminum and copper metallurgy industries in China. The congener patterns are shown and the formation mechanism is also discussed in this paper. The toxic equivalency (TEQ) emission factor of PCDD/Fs is higher for secondary copper production, at 14,802 ng TEQ t(-1) than for secondary aluminum production, at 2650 ng TEQ t(-1). However, the TEQ emission factor of dioxin-like PCBs of secondary aluminum production, with 193 ng TEQ t(-1), is higher than that of secondary copper production with 98.1 ng TEQ t(-1). The total estimated emission amount of PCDD/Fs released to air from the production of 2.75 million tons secondary aluminum and 2 million tons secondary copper in 2007 are 7.3 and 37.5 g TEQ yr(-1), respectively, the corresponding dioxin-like PCBs total emission amounts being 0.53 and 0.2 g TEQ yr(-1) respectively. In general, the emission factors and the total emission amounts of the secondary aluminum and copper metallurgies in China stay in the middle level compared to values reported for other countries. The most abundant congener of PCDD/Fs is 2,3,4,7,8-PeCDF and the most abundant congener of dioxin-like PCBs is CB-126 in samples collected from both secondary aluminum and copper metallurgies. According to the distribution of organochlorocompounds (PCDF>PCDD>PCB, PCDF/PCDD>>1) and the dominant contribution of higher chlorinated congeners, the de novo synthesis is assumed to be the main formation pathway of PCDD/Fs and PCBs in the secondary copper and aluminum metallurgies.

Emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans from a heavy oil-fueled power plant in northern Taiwan

We measured the concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from the flue gas and the ambient atmosphere of a power plant fueled by heavy oil in northern Taiwan. The mean emission concentration and I-TEQ concentration of total PCDD/Fs were 0.292 ng/Nm(3) and 0.016 ng I-TEQ/Nm(3), respectively. All PCDD/F emission concentrations in the flue gas were supposed to meet the Environmental Protection Administration Executive Yuan, R.O.C. standard (1.0 ng I-TEQ/Nm(3) from 2008). Furthermore, the mean I-TEQ concentration in the ambient atmosphere was 0.011 pg I-TEQ/Nm(3), which was much lower than the environmental quality standards for dioxins in Japan (0.6 pg TEQ/Nm(3)). Also, the PCDD/F emission factor was 0.188 ng I-TEQ/L fuel, which was comparable to the data issued in US EPA [EPA, Locating and estimating air emissions from sources of dioxins and furans, Office of Air Quality Planning and Standards, Research Triangle Park, NC, DCN No. 95-298130-54-01, 1997] (0.2 ng I-TEQ/L of fuel). Also, the result of the correlations of PCDD/Fs and operational parameters illustrated that the positively significant correlation (r=0.502, p=0.048) was found only between PCDD/Fs (I-TEQ) and the flue gas emission temperature (125-157 degrees C). However, PCDD-TEQ/PCDF-TEQ ratios were statistically significantly associated with the decreased flue gas flow (r=-0.659, p=0.006), moisture (r=-0.612, p=0.012) and flue gas temperature (r=-0.503, p=0.047). For proper environmental management of dioxins, it is necessary to establish a complete emission inventory of PCDD/Fs, and, in particular, the government should pay more attention to power plants to address the information shortage.