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

Assessment of receptor-mediated activity (AhR and ERα), mutagenicity, and teratogenicity of metal shredder wastes in Wallonia, Belgium

In this study, hazardous wastes including fluff, dust, and scrubbing sludge were sampled in 2019 from two metal shredding facilities located in Wallonia, Belgium. To assess the extent of the contamination, a global approach combining chemical and biological techniques was used, to better reflect the risks to health and the environment. The samples investigated induced significant in vitro aryl hydrocarbon receptor (AhR) agonistic bioactivities and estrogenic receptor (ERα) (ant)agonistic bioactivities in the respective CALUX (chemical activated luciferase gene expression) bioassays. The mutagenicity of the samples was investigated with the bacterial reverse gene mutation test using the Salmonella typhimurium TA98 and TA100 strains. Except for the sludge sample (site 3), all samples induced a mutagenic response in the TA98 strain (± S9 metabolic fraction) whereas in the TA100 strain (+ S9 metabolic fraction), only the sludge sample (site 2) showed a clear mutagenic effect. The in vivo toxicity/teratogenicity of the shredder wastes was further evaluated with zebrafish embryos. Except for the dust sample (site 2), all samples were found to be teratogenic as they returned teratogenic indexes (TIs) > 1. The high levels of contamination, the mutagenicity, and the teratogenicity of these shredder wastes raise significant concerns about their potential negative impacts on both human health and environment.

Passive Air Sampling of PCDD/Fs, PCBs, PAEs, DEHA, and PAHs from Informal Electronic Waste Recycling and Allied Sectors in Indian Megacities

Xenobiotic chemical emissions from the informal electronic waste recycling (EW) sector are emerging problem for developing countries, with scale and impacts that are yet to be evaluated. We report an intensive polyurethane foam disk passive air sampling study in four megacities in India to investigate atmospheric organic pollutants along five transects viz., EW, information technology (IT), industrial, residential, and dumpsites. Intraurban emission sources were estimated and attributed by trajectory modeling and positive matrix factorization (PMF). ∑₁₇PCDD/Fs, ∑₂₅PCBs, ∑₇plasticizers, and ∑₁₅PAHs concentrations ranged from 3.1 to 26 pg/m³ (14 ± 7; Avg ± SD), 0.5-52 ng/m³ (9 ± 12); 7.5-520 ng/m³, (63 ± 107) and 6-33 ng/m³ (17 ± 6), respectively. EW contributed 45% of total PCB concentrations in this study and was evidenced as a major factor by PMF. The dominance of dioxin-like PCBs (dl-PCBs), particularly PCB-126, reflects combustion as the possible primary emission source. PCDD/Fs, PCBs and plasticizers were consistently highest at EW transect, while PAHs were maximum in industrial transect followed by EW. Concentrations of marker plasticizers (DnBP and DEHP) released during EW activities were significantly higher (p < 0.05) in Bangalore than in other cities. Toxic equivalents (TEQs) due to dl-PCBs was maximum in the EW transect and PCB-126 was the major contributor. For both youth and adult, the highest estimated inhalation risks for dl-PCBs and plasticizers were seen at the EW transect in Bangalore, followed by Chennai and New Delhi.

Evaluation of the dioxin-like toxicity in soil samples from Thua Thien Hue province using the AhR-CALUX bioassay - An update of Agent Orange contamination in Vietnam

In this study, an AhR-responsive reporter-gene cell-based bioassay CALUX was used to assess the biological potency of dioxins and dioxin-like PCBs (dl-PCBs) in top soil samples collected from a former airbase (A-So) and remote regions from urban and agricultural areas in Thua Thien Hue, Vietnam. In top soil collected from A-So airbase, Bioanalytical EQuivalent (BEQ) concentrations of up to 2700 pg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) per g dry weight (pg BEQ-TCDD g^-1 dw) were assessed. Interestingly, while BEQ values for dl-PCBs were found to be up to 13 pg BEQ-TCDD g^-1 dw, the dl-PCB activity was not detected in all the hotspot sample extracts. In contrasts, BEQ values for dioxin like compounds from remote regions were much lower and occasionally below the quantification limits of the method. The BEQ activities obtained in this study have a similar trend to the WHO-TEQ results for the samples collected in the A-So airbase. However, BEQ values were higher than those of TEQ, probably reflecting the presence of additional AhR ligands and/or possible non-additive interactions in the sample mixture. This study confirms that after more than 60 years, a strong residual pollution of PCDD/Fs remains on this former air base following the use and storage of Agent Orange during the Vietnam War, raising a health risk for populations exposed in this area because livestock animals graze there.

A review of levels and profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans in different environmental media from China

This review provides a summary of the levels and profiles of PCDD/Fs throughout China, as reported in peer reviewed literatures since 1997. The literature shows that PCDD/Fs are widespread in various environmental media including air, water, sediment, and soil. PCDD/Fs concentrations in air were relatively low in most regions, with only a few areas considered polluted. Many studies reported seasonal trends, with higher and lower concentrations in winter and summer, respectively. We analyzed the factors affecting the concentrations of dioxins in air and summarized the causes of seasonal changes. As hydrophobic organic compounds, PCDD/Fs readily accumulate in sediments. The distribution of dioxins in sediment in Bohai Sea area was mainly introduced and the factors affecting concentrations of dioxins were studied. The levels of dioxins in soil in different regions varied greatly, with higher levels in areas close to pollution sources. We examined the dioxins concentrations in soil in places where the levels were very low (including the Tibet Plateau and other remote areas), contaminated areas, and other areas. Apart from the contaminated areas, the dioxins concentrations in soil were low. The results of the relatively low number of studies that have investigated PCDD/Fs in water have reported no obvious pollution in some waters, apart from Dongting Lake. PCDD/Fs levels across China are similar to those worldwide. Point sources, mainly related to local geographic, economic, and historical factors, were the most common source of contamination. E-waste dismantling and chemical production has the greatest impact on PCDD/Fs in different media.

Comprehensive diagnosis of PCDD/F emission from three hazardous waste incinerators

Comprehensive diagnosis of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) emissions was systematically conducted on three hazardous waste incinerators (HWIs). Results indicated that PCDD/F mainly existed in the solid phase before the bag filter. This was especially true for higher chlorinated dioxin and furan congeners (hexa-, hepta- and octa-). The aged bag filters tended to increase the gas-phase PCDD/F. Emissions also increased due to PCDD/F desorption from circulated scrubbing solution and plastic packing media used in the wet scrubber. The PCDD/F concentrations were elevated during the start-up process, reaching up to 5.4 times higher than those measured during the normal operating period. The ratios of PCDFs/PCDDs revealed that the surface-catalysed de novo synthesis was the dominant pathway of PCDD/F formation. Installation of more efficient fabric filters, intermittent replacement of circulated scrubbing solution will result in reduced PCDD/F emission. Additionally, 2,3,4,7,8-PeCDF correlated well with the international toxic equivalent quantity (I-TEQ) value, which suggests that 2,3,4,7,8-PeCDF could act as an I-TEQ indicator.

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.

An AhR-Luciferase Adenovirus Infection System for Rapid Screening of Dioxins in Soils

Our goal was to develop a fast-screening method for measuring dioxin levels in soils. The adenovirus (Ad)-dioxin-responsive (DR) bioassay system (AdEasy-6XDRE-TATA-Luc) combined with a fast-cleanup system was examined under conventional conditions (i.e., with incubation at 37°C) and three alternative conditions [incubation at 37°C with addition of phorbol-12-myristate-13-acetate (PMA), incubation at 33°C, and incubation at 33°C with addition of PMA]. The best conditions for carrying out the Ad-DR bioassay was 33°C and no addition of PMA. The background level of soil dioxins determined by the chemical assay [6.49 ng I-TEQ/kg dry weight (dw)] was well correlated (Pearson's r = 0.873, p < 0.001) with that by the Ad-DR bioassay [expressed in ng bioanalytical equivalents (BEQ) 81.1 ng BEQ/kg dw] (n = 17). When surveyed in contaminated soil samples (n = 114) from industrial areas by the Ad-DR bioassay, dioxin levels were 117, 102, 98.5, and 112 ng BEQ/kg dw, respectively, in northern, central, southern, and eastern Taiwan.

Distribution of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofurans in the Jukskei and Klip/Vaal catchment areas in South Africa

Comprehensive two dimensional gas chromatography (GCxGC)-μECD analysis was used to determine 2,3,7,8-substituted dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) distribution in the Jukskei and Klip/Vaal catchment areas from ten sites previously identified as persistent organic pollutant hotspots in major rivers in the Gauteng province of South Africa. Five sediment samples from the Jukskei River catchment area and five sediment samples from the Kilp/Vaal River catchment area were collected for analysis. The extracts were screened for dioxin-like activity using the DR-Luc bioassay prior to GCxGC-μECD analysis. All sediment samples tested positive for dioxin-like activity with total activity ranging from 16 to 37 pg toxic equivalents (TEQ) g(-1) dry weight (dw) for the Jukskei River catchment and 1.5-22 pg TEQ g(-1) dw for the Klip/Vaal River catchment, indicating that the Jukskei River catchment area had higher concentrations of total dioxin-like compounds. Confirmatory tests for the presence of the most potent seven PCDDs and ten PCDFs conducted using GCxGC-μECD revealed presence of 11 PCDD/Fs and 6 PCDD/Fs in the Jukskei and Klip/Vaal River catchments respectively. Total organic carbon (TOC) and particle size distribution analysis were conducted to understand the distribution of PCDD/Fs within the Jukskei and Klip/Vaal catchments.

Simultaneous removal of PCDD/Fs and NOx from the flue gas of a municipal solid waste incinerator with a pilot plant

The pilot-scale plant on the simultaneous removal of PCDD/Fs and NOx from the flue gas of a municipal solid waste incinerator is presented. In order to research the influence of temperature on the catalytic decomposition of PCDD/Fs and the selective catalytic reduction of NOx, the experiments were performed at 220 °C, 260 °C, and 300 °C, and the congener profiles of PCDD/Fs for the samples collected at the inlet and outlet were illustrated. Noteworthy, the detailed congener distributions of PCDD/Fs in the gas-phase and particle-phase of the inlet and 300-outlet (decomposition temperature = 300 °C) samples are presented, and the removal efficiencies η(g-I-TEQ) and η(p-I-TEQ) reached to 94.94% and 99.67%, respectively. The effect of the SCR process on the removal of PCDD/Fs was also studied at a relatively low temperature of 220 °C. Additionally, the NOx emissions and the SCR efficiencies were investigated.

Combination of a fast cleanup procedure and a DR-CALUX® bioassay for dioxin surveillance in Taiwanese soils

Our goal was to determine dioxin levels in 800 soil samples collected from Taiwan. An in vitro DR-CALUX^® assay was carried out with the help of an automated Soxhlet system and fast cleanup column. The mean dioxin level of 800 soil samples was 36.0 pg-bioanalytical equivalents (BEQs)/g dry weight (d.w.). Soil dioxin-BEQs were higher in northern Taiwan (61.8 pg-BEQ/g d.w.) than in central, southern, and eastern Taiwan (22.2, 24.9, and 7.80 pg-BEQ/g d.w., respectively). Analysis of multiple linear regression models identified four major predictors of dioxin-BEQs including soil sampling location (β = 0.097, p < 0.001), land use (β = 0.065, p < 0.001), soil brightness (β = 0.170, p < 0.001), and soil moisture (β = 0.051, p = 0.020), with adjusted R² = 0.947 (p < 0.001) (n = 662). An univariate logistic regression analysis with the cut-off point of 33.4 pg-BEQ/g d.w. showed significant odds ratios (ORs) for soil sampling location (OR = 2.43, p < 0.001), land use (OR = 1.47, p < 0.001), and soil brightness (OR = 2.83, p = 0.009). In conclusion, four variables, including soil sampling location, land use, soil brightness, and soil moisture, may be related to soil-dioxin contamination. Soil samples collected in northern Taiwan, and especially in Bade City, soils near industrial areas, and soils with darker color may contain higher dioxin-BEQ levels.

Occurrence of PCDD/PCDFs and PCBs in soil and comparison with CYP1A response in PLHC-1 cell line

The responsiveness of CYP1A (gene transcription and EROD enzyme activity) in the cell line Poeciliopsis lucida hepatoma (PLHC-1) upon exposure to extracts of contaminated soil samples was investigated and compared to levels of PCDD/PCDFs and PCBs including non-ortho obtained by GC/MS analysis. Soil samples A and B were collected in sites A and B. Two fractions, not purified (np) and purified (p), were obtained from each sample and analyzed for PCDD/PCDF and PCB content by GC/MS; in parallel they were tested for 24 h with PLHC-1. CYP1A response was investigated at gene (RT-qPCR) level and as 7-ethoxyresorufin-O-deethylase (EROD) enzyme activity. Chem-TEQs and Bio-TEQs were then calculated. ∑TEQ calculated for PCDD/Fs and PCBs was 0.081 pg/g and 20.32 pg/g for samples A and B, respectively. PLHC-1 showed less up-regulation of cyp1a gene on exposure to the two purified fractions (Ap 2.1-fold and Bp 1.8-fold) than to non-purified fractions (up to 15-fold for Anp and 13-fold for Bnp). EROD was also induced 2.38- and 9.44-fold in the two purified fractions (Ap and Bp) compared to model inducer 2,3,7,8-TCDD, and up to 16.03-fold for non-purified Anp and 33.79-fold for Bnp. The combination of CYP1A response, obtained in a PLHC-1 cell-based bioassay, with contaminant residue analysis provided a better description of the presence and toxicity of dioxin-like compounds in an environmental matrix.

Formation and contamination of PCDD/Fs, PCBs, PeCBz, HxCBz and polychlorophenols in the production of 2,4-D products

The concentrations and profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), pentachlorobenzene (PeCBz), hexachlorobenzene (HxCBz) and polychlorophenols in 2,4-D were investigated in this study. Two 2,4-D acid and three 2,4-D butyl ester enterprises were selected as typical 2,4-D producers. The total concentrations of 2,3,7,8-PCDD/Fs in the 2,4-D samples ranged from 355 to 35080ngkg(-1) and the corresponding TEQ values were in the range of 13.4 and 694.6ng WHO-TEQkg(-1). The concentrations of total PCBs in the 2,4-D were in the range of 16.1 and 8023ngkg(-1), and the WHO-TEQ values of the PCBs were between 0.057 and 108.3ng WHO-TEQkg(-1), while total PCBs were between 1486 and 47342ngkg(-1). The average emission factors were 414.4μg WHO-TEQt(-1) for PCDD/Fs and 21.9μg WHO-TEQt(-1) for PCBs. The polychlorobenzenes and polychlorophenols impurities may play a key role in the PCBs and PCDD/Fs formation. The impurities of PCDD/Fs and PCBs in 2,4-D may increase the risk for the human and environmental health.

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.