Ya-Fen Wang

Distribution of polybrominated diphenyl ethers (PBDEs) and polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) in municipal solid waste incinerators.

The stack flue gases and the ashes in different units of two municipal solid waste incinerators (MSWIs) are sampled to investigate the characteristics of polybrominated diphenyl ethers (PBDEs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Bottom ashes (BA) exhibited much higher PBDD/F (8.11-52.2 pg TEQ/g) and PBDE contents (20.4-186 ng/g) than those of fly ashes (0.0932-2.02 pg TEQ/g and 0.332-25.5 ng/g), revealing that the PBDD/Fs and PBDEs in the feeding waste may not be completely destroyed. The PBDE concentrations/contents in the stack flue gases (26.1-109 ng/Nm(3)) and in the BA (20.4-186 ng/g) of the MSWIs could reach three orders higher than those in the atmosphere and reference soils. PBDE contributions to the environment from the stack flue gases or the reutilization of BA of MSWIs should not be ignored from the developing PBDE inventory.

Characterizing the emissions of polybrominated diphenyl ethers (PBDEs) and polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) from metallurgical processes.

This study investigated the characteristics of polybrominated diphenyl ethers (PBDEs) and polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) in the stack flue gases of the metallurgical processes. An examination of the PBDEs existing in the stack flue gases of sinter plants revealed that PBDEs can form during the combustion processes through the similar formation conditions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). The PBDD/F and PBDE emission rates of the metallurgical facilities were 0.446-3.19 microg TEQ/h and 4470-27000 microg/h, correspondingly. Both emission rates could reach several orders higher than those of the reported sources, revealing that the metallurgical facilities are not only important PCDD/F but also significant PBDD/F and PBDE emission sources to the environment. BDE-209 is the most abundant PBDE congener in the emissions of metallurgical facilities and is found to be dominant in the atmosphere and soils. However, few studies have considered metallurgical facilities as potential PBDE contributors to the environment. Because PBDEs could form or not be completely destroyed in the feeding materials in the combustion system, PBDE contributions from combustion emission sources to the atmosphere should not be ignored and need further investigation.

A recombinant peroxisome proliferator response element-driven luciferase assay for evaluation of potential environmental obesogens

A recombinant Huh7-PPRE-Luc cell line for analyzing the peroxisome proliferator response element (PPRE)-driven luciferase activity was established. The cells exhibited a good dose–response induction in PPRE-driven luciferase activity by three subtypes of peroxisome proliferator-activated receptor (PPAR) agonists as well as by a retinoid X receptor agonist, 9-cis-retinoic acid. Among five environmental chemicals tested, benzyl butyl phthalate and bisphenol induced PPRE-driven luciferase activation in Huh7-PPRE-Luc cells and caused adipogenic differentiation of 3T3-L1 cells. This recombinant Huh7-PPRE-Luc cell line would be useful for screening potential environmental obesogens with PPAR activity.

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.

Effect of NaOH on the vitrification process of waste Ni–Cr sludge

This study investigated the effect of NaOH on the vitrification of electroplating sludge. Ni, the major metal in the electroplating sludge, is the target for recovery in the vitrification. Sludge and encapsulation materials (dolomite, limestone, and cullet) were mixed and various amounts of NaOH were added to serve as a glass modifier and a flux. A vitrification process at 1450 °C separated the molten specimens into slag and ingot. The composition, crystalline characteristics, and leaching characteristics of samples were measured. The results indicate that the recovery of Ni is optimal with a 10% NaOH mass ratio; the recoveries of Fe, Cr, Zn, Cu, and Mn all exhibited similar trends. The results of the toxicity characteristic leaching procedure (TCLP) show that leaching characteristics of the slag meet the requirements of regulation in Taiwan. In addition, a semi-quantitative X-ray diffraction analysis revealed that the main crystalline phase of slag changed from Ca(3)(Si(3)O(9)) to Na(4)Ca(4)(Si(6)O(18)) with a NaOH mass ratio of over 15%, because the Ca(2+) ions were replaced with Na(+) ions during the vitrification process. Na(4)Ca(4)(Si(6)O(18)), a complex mineral which hinders the mobility of metals, accounts for the decrease of metal recovery.

Size distribution of airborne fungi in vehicles under various driving conditions.

ABSTRACT Circulation or air conditioning (AC) system was proven to improve the air quality inside the vehicles; however, the quantified study was limited. In this study, fungal concentration under various driving mode inside the vehicle was proposed. The driving conditions were classified into 4 states: (1) window closed without AC and circulation, (2) window open without AC and circulation, (3) window closed with only circulation on, and (4) window closed with only AC on. Results show that at state 4, the mean respirable fraction was 83.3%, with a number median diameter of the fungi being 1.73 μm. More attention should be paid for these smaller fungi easily penetrating into the alveoli and probably lead to allergic alveolitis. Turning on AC for reducing the normalized concentration for each size range of fungi was suggested; however, the respirable fraction increased. Those who are prone to allergies or asthma are suggested to switch between AC and the circulation mode while driving a long time.

Cluster Analysis for Polychlorinated Dibenzo-p-Dioxins and Dibenzofurans Concentrations in Southern Taiwan

Abstract 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.

The inhibition effect of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin-induced aryl hydrocarbon receptor activation in human hepatoma cells with the treatment of cadmium chloride.

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), considered as endocrine disruptors, tend to accumulate in fatty tissues. Dioxin-responsive element chemical activated luciferase gene expression assay (DRE-luciferase assay) has been recognized as a semi-quantitative method for screening dioxins for its fast and low-cost as compared with HRGC/HRMS. However, some problems with the bioassay, including specificity, detection variation resulted from different cleanup strategies, and uncertainty of false-negative or false-positive results, remain to be overcome. Cadmium is a prevalent environmental contaminant around the world. This study was aimed to examine the effects of cadmium on the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced activation of aryl hydrocarbon receptor (AhR)-mediated gene expression in human hepatoma cells (Huh7-DRE-Luc cells and Huh7 cells). Ethoxyresorufin-O-deethylase (EROD) and DRE-luciferase assay were employed to determine the enzyme activity of cytochrome P450 1A1 (CYP1A1) and activation of AhR, respectively. The results showed that Cd(2+) levels significantly inhibited the induction of TCDD-induced CYP1A1 and DRE luciferase activation in hepatoma cells. The 50% inhibited concentrations (IC(50)) of CdCl(2) were 0.414 microM (95% confidence interval (C.I.): 0.230-0.602 microM) in Huh7-DRE-Luc cells and 23.2 microM (95% C.I.: 21.7-25.4 microM) in Huh7 cells. Accordingly, prevention of interference with non-dioxin-like compounds in a DRE-luciferase assay is of great importance in an extensive cleanup procedure.

Incorporation of zinc for fabrication of low-cost spinel-based composite ceramic membrane support to achieve its stabilization.

In order to reduce environment risk of zinc, a spinel-based porous membrane support was prepared by the high-temperature reaction of zinc and bauxite mineral. The phase evolution process, shrinkage, porosity, mechanical property, pore size distribution, gas permeation flux and microstructure were systematically studied. The XRD results, based on a Zn/Al stoichiometric composition of 1/2, show a formation of ZnAl2O4 structure starting from 1000°C and then accomplished at 1300°C. For spinel-based composite membrane, shrinkage and porosity are mainly influenced by a combination of an expansion induced by ZnAl2O4 formation and a general densification due to amorphous liquid SiO2. The highest porosity, as high as 44%, is observed in ZnAl4 membrane support among all the investigated compositions. Compared with pure bauxite (Al), ZnAl4 composite membrane support is reinforced by ZnAl2O4 phase and inter-locked mullite crystals, which is proved by the empirical strength-porosity relationships. Also, an increase in average pore diameter and gas flux can be observed in ZnAl4. A prolonged leaching experiment reveals the zinc can be successfully incorporated into ceramic membrane support via formation of ZnAl2O4, which has substantially better resistance toward acidic attack.

SnO2/TiO2 nanotube heterojunction: The first investigation of NO degradation by visible light-driven photocatalysis

Titania (TiO2) as a commercial photocatalyst has been continually struggling due to the limitation of ultraviolet light response and the high recombination rate of photoinduced carriers. The development of heterojunction nanostructures provides great promise to achieve the activation by visible light and suppress the photoinduced electron-hole pairs recombination. Herein, we synthesized a SnO2 and TiO2 nanotube heterojunction (SnO2/TNT) via a one-step hydrothermal strategy and systematically investigated NO photocatalytic degradation over the SnO2/TNTs heterojunction under visible light at the parts per billion level. Various physicochemical characterization techniques were conducted to verify the physical and chemical properties of the materials. For example, the morphology and lattice spacings of the materials were examined by high-resolution TEM (HR-TEM) images and selected area electron diffraction (SAED) pattern, X-ray photoelectron spectroscopy (XPS) was employed to study the oxidation states and propose the band alignment diagram of the SnO2/TNTs heterojunction, and photoluminescence spectroscopy was employed for understanding of carriers trapping, migration and transfer. The photocatalytic results show that the SnO2/TNTs heterojunction exhibits the superior photocatalytic performance, and the photocatalytic degradation efficiency of NO can reach 60% under visible light with effective inhibition of NO2 production. The excellent photocatalytic ability is due to the low recombination rate of the photoinduced electron-hole pairs. Furthermore, a trapping experiment was combined with electron spin resonance (ESR) and utilized to identify the involvement of reactive radicals in the photocatalysis process suggesting that and OH mediated pathways play a predominant role in NO removal.