Human exposure to airborne aldehydes in Chinese medicine clinics during moxibustion therapy and its impact on risks to health.

Many air toxicants, and especially aldehydes, are generated by moxibustion, which means burning Artemisia argyi. Our goal was to investigate indoor-air aldehyde emissions in Chinese medicine clinics (CMCs) during moxibustion to further evaluate the potential health risks, including cancer risk and non-cancer risk, to the medical staff and adult patients. First, the indoor-air-quality in 60 public sites, including 15 CMCs, was investigated. Four CMCs with frequent use of moxibustion were selected from the 15 CMCs to gather the indoor airborne aldehydes in the waiting and therapy rooms. The mean values of formaldehyde and acetaldehyde in the CMCs' indoor air were 654 and 4230 µg m(-3), respectively, in the therapy rooms, and 155 and 850 µg m(-3), respectively, in the waiting rooms. The average lifetime cancer risks (Rs) and non-cancer risks (hazard quotients: HQs) of airborne formaldehyde and acetaldehyde among the CMC medical staff exceeded the acceptable criteria (R < 1.00 × 10(-3) and HQ < 1.00) for occupational workers. The patients' Rs and HQs were also slightly higher than the critical values (R = 1.00 × 10(-6) and HQ = 1.00). Our results indicate that airborne aldehydes pose a significant threat to the health of medical staff, and slightly affected the patients' health, during moxibustion in the CMCs.

Emissions in the exhaust of fishing boats after adding viscous agents into fuel oils.

In order to avoid the illegal use of fishing boat fuel A (FBFA) by traveling diesel vehicles (TDVs) in Taiwan, alternatives that are easily distinguished from premium diesel fuel (PDF) were prepared to evaluate their suitability. Two new ingredients, pyrolysis fuel oil (PFO) and residue of desulfurization unit (RDS), were added into FBFA and formed PFO0.5 and RDS0.5, respectively. Along with FBFA, these three fuels were analyzed for their chemical and physical properties. Furthermore, they were used by three fishing boats with different sizes, output powers, and weights. The engine performances and pollutant emissions were examined and monitored. Experimental results show that there are significant differences in appearance between PDF and the two new blended fuels (PFO0.5 and RDS0.5), and thus misuse or illegal use of FBFA could be substantially reduced. The fuel consumption, which is negatively related to the heating value of fuels, is in order of FBFA

Uptake of polychlorinated dibenzo-p-dioxins and dibenzofurans in laying ducks.

Uptake of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in laying ducks was determined at different degree of feed contamination. To observe the extent of the transfer of 17 PCDD/Fs from feed to the duck eggs and duck meat, 18 ducks were divided into 3 groups (6 in each group) and fed feed with two different levels of PCDD/Fs. As a control, one group of ducks was fed with the non-contaminated feed for comparison, while the other 2 groups were exposed to the feed doped with EAF dusts (fly ash). The experiment lasted for 60 days, with an exposure duration of 41 days and the subsequent non-contaminated feed being given for an additional 19 days. PCDD/F levels in the eggs of the all 3 groups were observed to increase significantly on the 15th day. For the low contaminated group, PCDD/F levels reached 2.61 pg WHO-TEQ/g lipid at day 41, whereas those of the high contaminated group accounted exceeded 3 pg/g lipid on the 15th day. Furthermore, PCDD/Fs levels in the duck meat were analyzed before and after exposure duration, and at the end of the experiment. The results showed that the level of PCDD/F in the duck eggs and the duck meat may reach unacceptable levels due to the effect of accumulation, although the PCDD/Fs in the duck feed were at acceptable levels.

Assessment of polychlorinated dibenzo-p-dioxins and dibenzofurans contribution from different media to surrounding duck farms.

Since the "Toxic Egg Event" broke out in central Taiwan, the possible sources of the high content of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in eggs have been a serious concern. In this study, the PCDD/F contents in different media (feed, soil and ambient air) were measured. Evaluation of the impact from electric arc furnace dust treatment plant (abbreviated as EAFDT plant), which is site-specific to the "Toxic Egg Event", on the duck total-PCDD/F daily intake was conducted by both Industrial Source Complex Short Term model (ISCST) and dry and wet deposition models. After different scenario simulations, the worst case was at farm A and at 200 g feed and 5 g soil for duck intake, and the highest PCDD/F contributions from the feed, original soil and stack flue gas were 44.92, 47.81, and 6.58%, respectively. Considering different uncertainty factors, such as the flow rate variation of stack flue gas and errors from modelling and measurement, the PCDD/F contribution fraction from the stack flue gas of EAFDT plant may increase up to twice as that for the worst case (6.58%) and become 13.2%, which was still much lower than that from the total contribution fraction (86.8%) of both feed and original soil. Fly ashes contained purposely in duck feed by the farmers was a potential major source for the duck daily intake. While the impact from EAFDT plant has been proven very minor, the PCDD/F content in the feed and soil, which was contaminated by illegal fly ash landfills, requires more attention.

Atmospheric deposition of polychlorinated dibenzo-p-dioxins and dibenzofurans on the soils in the vicinity of municipal solid waste incinerators.

This study focuses on the atmospheric deposition of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) on the soils in the vicinity of two municipal solid waste incinerators (MSWIs), which were located in the Gangshan (GS) and the Renwu (RW) Townships of southern Taiwan. PCDD/Fs in the soils were sampled simultaneously with those in the ambient air and analyzed for 17 2,3,7,8-substituted PCDD/Fs. The results show that the mean contents of PCDD/Fs in the soils near MSWI-GS and MSWI-RW were 2.65 and 1.20 ng I-TEQ/kg dry weight, respectively. Annual wet deposition fluxes of total PCDD/Fs were 119 and 113 ng/m(2)-year in the ambient air near MSWI-GS and MSWI-RW, respectively. The results obtained in this study are much higher than those estimated for the Atlantic Ocean, where the average wet deposition was only 45 ng/m(2)-year. The annual dry deposition fluxes accounted for 58.2 and 66.7%, respectively, indicating that dry deposition was more dominant than wet deposition in the atmospheric deposition processes. The congener profiles of 17 2,3,7,8-substituted PCDD/Fs showed that OCDD dominates in the soils. The contributions of OCDD in the soils near MSWI-GS and MSWI-RW were 73.4 and 67.1%, respectively, while they were only 41.4 and 31.2% in the atmospheric deposition, respectively. These results imply that OCDD is more persistent in the environment than other congeners. The results of the present study strongly suggest that exposure to PCDD/Fs in these areas should be reduced.

Reduction of carbon content in waste-tire combustion ashes by bio-thermal treatment.

Application of bio-catalyst (NOE-7F) in thermal treatment can adequately dispose dark-black fly ashes from co-combustion of both waste tires and coal. After thermal treatment of fly ashes by adding 10% NOE-7F, the carbon contents reduced by 37.6% and the weight losses increased by 405%, compared with the fly ashes without mixing with NOE-7F. The combustion behaviors of wasted tires combustion fly ashes with NOE-7F were also investigated by both thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The results verify that NOE-7F has positive effects on the combustion of residual carbon and toxic polycyclic aromatic hydrocarbons (PAHs) enhance the energy release and reduce the toxicity during the process of thermal treatment. Furthermore, using NOE-7F to dispose high-carbon content fly ashes did improve the compressive strength of fly ashes and concrete mixtures. Therefore, NOE-7F is a promising additive which could decrease treatment cost of high-carbon content fly ashes and reduce the amount of survival toxic PAHs.

Thermal treatment of polychlorinated dibenzo-p-dioxins and dibenzofurans from contaminated soils.

Thermal treatment technology was used to remove polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from heavily contaminated soil. For a soil with an original PCDD/F content of 35,970ng International Toxic Equivalents (I-TEQ)/kg, >99.99% PCDD/F removal efficiency was obtained with a primary furnace at two different treatment temperatures (750 degrees C and 850 degrees C), while a secondary furnace at 1200 degrees C gave >98% decomposition efficiency. The total PCDD/F I-TEQ contents in treated soils at 750 degrees C and 850 degrees C were 1.56ngI-TEQ/kg and 2.15ngI-TEQ/kg, respectively, which were far below the soil pollution standard of Taiwan (1000ngI-TEQ/kg soil). Although air pollution control devices had significant effects on the removal of PCDD/Fs, the total I-TEQ concentrations in the upstream flue gas of PUF cartridge at 750 degrees C and 850 degrees C (2.61ngI-TEQ/Nm(3) and 2.38ngI-TEQ/Nm(3), respectively) were still higher than the stationary emission limit of the Taiwan EPA (0.5ngI-TEQ/Nm(3)). The above results also suggested that additional APCDs, such as activated carbon injection in front of the filter are needed to enhance PCDD/F removal efficiency.

Significance of biomass open burning on the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans in the ambient air.

In southern Taiwan, two areas (L- and Y-) with/without biomass open burning were selected to compare the PCDD/F concentrations and their congener profiles in the ambient air. The results of this study indicate that biomass (rice straw) open burning exhibited a significant impact on the PCDD/F concentration level in the ambient air. During the biomass burning season, the total PCDD/F I-TEQ concentrations in the ambient air of L- and Y-areas were approximately 4 and 17 times higher than those without biomass open burning, respectively. When 10% mass fraction of rice straw was burned, the contribution fraction of biomass burning on annual total PCDD/F I-TEQ emission was 3.28 and 8.11% for KC County and for Taiwan, respectively; however, when the calculation was on a weekly basis, the contribution fraction of biomass burning on weekly total PCDD/F I-TEQ emission was 30.6 and 53.4% for KC County and for Taiwan, respectively. The results of this study imply that during the week of biomass burning, it appears to be the most significant source of total I-TEQ PCDD emission. The results of this research can be applied to the study of other agricultural areas.

Comparisons of levels of polychlorinated dibenzo-p-dioxins/dibenzofurans in the surrounding environment and workplace of two municipal solid waste incinerators.

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the surrounding environment (outdoor) and workplace air of two municipal solid waste incinerators (MSWIs, T and M) were characterized and compared. T and M represented two typical municipal solid waste incinerators in the north of Taiwan, which have different processes for controlling the PCDD/F emissions. The results of this study are summarized as follows. (1) The total PCDD/F and the total PCDD/F WHO-TEQ concentrations in the workplace air were 5-13 and 5-15 times higher than those in the outdoor air, respectively. Obviously, it is worthwhile to explore more on health risk assessment for exposure of PCDD/Fs emitted from MSWIs, particularly in the workplace air. (2) Mean total PCDD/F I-TEQ concentrations in the outdoor air ranged between 0.0216 and 0.155 pg I-TEQ/Nm(3) and averaged 0.0783 pg I-TEQ/Nm(3) (0.0828 pg WHO-TEQ/Nm(3)) during two seasons for two MSWIs, which were 6.5-fold higher than that of a remote site (0.0119 pg I-TEQ/Nm(3) or 0.0132 pg WHO-TEQ/Nm(3)) in Taiwan. However, the above outdoor air concentration levels in the MSWIs were still much lower than the air quality limitation of PCDD/Fs (0.6 pg I-TEQ/Nm(3)) in Japan []. (3) PCDFs were the primary toxicity distributors for PCDD/Fs in the outdoor air, since the ratios of PCDDs/PCDFs (I-TEQ) at all sampling sites ranged from 0.180 to 0.492 and were less than unity. (4) The OCDD, OCDF, 1,2,3,4,6,7,8-HpCDD and 1,2,3,4,6,7,8-HpCDF were the four dominant species in both workplace and outdoor air near MSWIs. (5) By spraying water on and wetting both the fly and bottom ashes, the mean total PCDD/F I-TEQ concentration in the workplace air was reduced 86.9% in the T MSWI. The above results indicate an appropriate improving action did inhibit the fugitive emission of PCDD/Fs and reduce the health risk of workers during work handling ashes in MSWIs.

Decomposition of benzene in the RF plasma environment. Part II. Formation of polycyclic aromatic hydrocarbons.

This study investigated the characteristics of polycyclic aromatic hydrocarbons (PAHs) formed during the decomposition of benzene (C(6)H(6)) in radio-frequency (RF) plasma environments. The identification and quantification were accomplished by using a GC/MS for PAHs and an on-line Fourier transform infrared (FT-IR) spectrometer for the reactants and gaseous products. The analytical results show that PAHs were formed in both C(6)H(6)/Ar and C(6)H(6)/H(2)/Ar systems. In terms of individual PAHs, naphthalene (C(10)H(8)) was the predominant species found among the 21 PAHs under all operational conditions, phenanthrene and chrysene are the next. High-ring PAHs did not form easily in the C(6)H(6)/Ar and C(6)H(6)/H(2)/Ar system, especially at high input power and high C(6)H(6) feed concentration (C(C(6)H(6))) for the former system. Yields of PAHs with different ring numbers decreased with increasing ring number. At low input power, increasing C(C(6)H(6)) would promote yields of PAHs, while adding hydrogen as the auxiliary gas suppressed PAHs formation. Higher input power or addition of oxygen not only effectively suppresses PAHs formation but also completely destroys C(6)H(6). Owing to the absence of the principal intermediate species, phenol (C(6)H(5)OH), from the gas products of C(6)H(6)/O(2)/Ar system, H-abstraction-C(2)H(2)-addition (HACA) pathway is proposed as the primary mechanism for PAHs formation in the present study. Gas phase distribution of total-PAHs accounts for 20-95.3% at 2% of C(C(6)H(6)) among C(6)H(6)/Ar, C(6)H(6)/H(2)/Ar and C(6)H(6)/O(2)/Ar systems. This study suggests that gas-phase PAHs should not be ignored, particularly in C(6)H(6)/Ar systems under high input power and high C(C(6)H(6)) , or in C(6)H(6)/O(2)/Ar systems.

Decomposition of benzene in the RF plasma environment. Part I. Formation of gaseous products and carbon depositions.

This study employed radio-frequency (RF) plasma for decomposing benzene (C6H6) gas, and examined both gaseous products and solid depositions after reaction. The reactants and products were analyzed mainly by using both an on-line Fourier transform infrared (FT-IR) spectrometer and a gas chromatography. The analyses for solid deposition included electron spectroscopy for chemical analysis (ESCA), element analysis and heat value analysis. The C2H2, C2H4, C2H6, CH4, CO2 and CO were detected and discussed. The analytical results demonstrate that in the C6H6/Ar plasma, C2H2 is the sole gaseous product being detected. The fraction of total carbon input converted into C2H2 YC2H2 increased with increasing C6H6 feed concentration, but decreased with increasing input power. In the C6H6/H2/Ar system, besides C2H2, CH4, C2H4 and C2H6 were also detected, and their yields increased with increasing H2/C6H6 ratio. The above results indicated that the addition of H2 (auxiliary gas) achieves the benefit of creating hydrogen-rich species like CH4, C2H4 and C2H6. In the C6H6/O2/Ar system, C6H6 could be totally oxidized into CO2, CO and H2O, and no measurable phenol was found. Analyses of solid depositions revealed that the carbon depositions were similar to those of Anthracite. The carbon deposition has a heat value of 7000 kcal/kg. Additionally, the possible reaction pathways were also built up and discussed.