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551.
The expression levels of cytochrome P450 1A, p53 and vitellogenin were investigated in three different tissues of male medaka fish after exposure to diclofenac that is one of the main concerns among pharmaceuticals frequently found in sewage treatment plant (STP) effluents. The results showed that cytochrome P450 1A, p53 and vitellogenin were highly expressed in tissue-specific gene expression patterns after exposure to 8 mg/l and 1 μg/l of diclofenac. These elevated expression levels of three biomarkers suggested that diclofenac has potential to cause cellular toxicity, p53-related genotoxicity and estrogenic effects. It is also noteworthy that diclofenac has the potential to cause these effects even at an environmentally relevant concentration of diclofenac, 1 μg/l. 相似文献
552.
Kinetics of the reduction of hexavalent chromium with the brown seaweed Ecklonia biomass 总被引:1,自引:0,他引:1
The dead biomass of the brown seaweed, Ecklonia sp., is capable of reducing toxic Cr(VI) into less toxic or nontoxic Cr(III). However, little is known about the mechanism of Cr(VI) reduction by the biomass. The objective of this work was to develop a kinetic model for Cr(VI) biosorption, for supporting our mechanism. The reduction rate of Cr(VI) increased with increasing total chromate concentration, [Cr(VI)], and equivalent concentration of organic compounds, [OCs], and decreasing solution pH. It was found that the reduction rate of Cr(VI) was proportional to [Cr(VI)] and [OCs], suggesting the simple kinetic equation -d[Cr(VI)]/dt=k[Cr(VI)][OCs]. When considering the consumption of organic compounds due to the oxidation by Cr(VI), an average rate coefficient of 9.33 (+/-0.65)microM(-1)h(-1) was determined, at pH 2. Although the function of the pH could not be expressed in a mechanistic manner, an empirical model able to describe the pH dependence was obtained. It is expected that the developed rate equation could likely be used for design and performance predictions of biosorption processes for treating chromate wastewaters. 相似文献
553.
To analyze polycyclic aromatic hydrocarbons (PAHs) at an urban site in Seoul, South Korea, 24-hr ambient air PM2.5 samples were collected during five intensive sampling periods between November 1998 and December 1999. To determine the PAH
size distribution, 3-day size-segregated aerosol samples were also collected in December 1999. Concentrations of the 16 PAHs
in the PM2.5 particles ranged from 3.9 to 119.9 ng m−3 with a mean of 24.3 ng m−3.An exceptionally high concentration of PAHs(∼120 ng m−3) observed during a haze event in December 1999 was likely influenced more by diesel vehicle exhaust than by gasoline exhaust,
as well as air stagnation, as evidenced by the low carbon monoxide/elemental carbon (CO/EC) ratio of 205 found in this study
and results reported by previous studies.
The total PAHs associated with the size-segregated particles showed unimodal distributions. Compared to the unimodal size
distributions of PAHs with modal peaks at < 0.12 μm measured in highway tunnels in Los Angeles (Venkataraman and Friedlander,
1994), four- to six-ring PAHs in our study had unimodal size distributions, peaking at the larger size range of 0.28–0.53
μm, suggesting the coagulation of freshly emitted ultrafine particles during transport to the sampling site. Further, the
fraction of PAHs associated with coarse particles(> 1.8 μm) increased as the molecular weight of the PAHs decreased due to
volatilization of fine particles followed by condensation onto coarse particles. 相似文献
554.
Md. Humayun Kabir A. M. Abd El-Aty Md. Musfiqur Rahman Hyung Suk Chung Han Sol Lee Sun-Hyang Park Fazil Hacımüftüoğlu Byung-Joon Chang Ho-Chul Shin Jae-Han Shim 《Environmental monitoring and assessment》2017,189(6):302
Amisulbrom formulated as suspension concentrate was applied at the rate recommended for Korean melon to determine the dissipation pattern (at two different sites), the pre-harvest residue limit (PHRL), and risk assessments. Samples collected over 10 days were extracted using liquid-liquid extraction (LLE) and cleaned up with solid-phase extraction (SPE) Florisil cartridge. Residual concentrations were determined using liquid chromatography-ultraviolet detector (LC-UVD) and confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The standard showed good instrument response linearity with a correlation coefficient (R 2) = 0.9999, and the recovery ranged from 87.5 to 93.7%. The dissipation half-life calculated from two different sites were found to be 7.0 and 8.8 days for sites 1 and 2, respectively. A PHRL graph constructed from the data indicated that if the residue levels were less than 0.55–0.59 mg/kg 3 days before harvest or less than 0.61–0.74 mg/kg 7 days before harvest, then they would be lower than the maximum residue limits (MRLs) at harvest. Risk assessments showed that the risk quotient (RQ) was 4.39–3.47% at 0 day, declined to 1.53–1.63% at 10 days. Therefore, the current data indicate that the amisulbrom can be applied safely to Korean melon; hence, it is unlikely to induce adverse health effects in consumers. 相似文献
555.
Monitoring of ambient particles and heavy metals in a residential area of Seoul, Korea 总被引:2,自引:0,他引:2
In this study, ambient TSP, PM10, and PM2.5 in a residential area located in the northern part of Seoul were monitored every
other month for 1 year from April 2005 to February 2006. The monthly average levels of TSP, PM10, and PM2.5 had ranges of
71∼158, 40∼106, and 28∼43 μg/m3, respectively. TSP and PM10 showed highest concentration in April; this seems to be due to Asian dust from China and/or Mongolia.
However, the fine particle of PM2.5 showed a relatively constant level during the monitoring period. Heavy metals in PM 10
and PM2.5, such as Cr, As, Cd, Mn, Zn and Pb, were also analysed during the same period. The monthly average concentrations
of heavy metal in PM2.5 were Cr:1.9∼22.7 ng/m3; As:0.9∼2.5 ng/m3; Cd: 0.6∼7 ng/m3; Mn:6.1∼22.6 ng/m3; Zn: 38.9∼204.8 ng/m3, and Pb: 21.6∼201.1 ng/m3. For the health risk assessment of heavy metals in ambient particles, excess cancer risks were calculated using IRIS unit
risk. As a result, the excess cancer risks of chromium, cadmium, and arsenic were shown to be more than one per million based
on the annual concentration of heavy metals, and chromium showed the highest excess cancer risk in ambient particles in Seoul. 相似文献
556.
Metallic elements (As, Be, Ca, Cd, Co, Cr, Fe, K, Mn, Ni, Pb, Sb, Se, and Zn) in PM10 aerosols were determined at urban and industrial sites, which are affected by traffic and residential sources, metallurgical activity, and petrochemical and steel works. The effect of the long-range transported Asian Dust on the metal content of aerosols was also examined. At the urban sampling site, concentrations of As, Cd, Pb, Se, and Zn were assigned to road traffic and combustion sources, Ca and Fe to soil dust sources from long-range transported Asian Dusts, and Cr and Ni to metallurgical sources transported from the nearby industrial complex, based on Principal Component Analysis (PCA). Enhanced Cr and Ni concentrations at the metallurgical industrial site suggest that local emissions from metal-assembly facilities and manufacture of alloys contributed to elevated levels of those metals. We also observed that petrochemical activities contributed to increased levels of Sb and Zn. When Asian Dust events occurred, Ca, Fe, K, and Zn concentrations dramatically increased compared to values without the Asian Dust. Two different types of Asian Dust events were observed. For the Asian Dust event 1 (4/1/2007), the Fe and K concentrations were much higher by a factor of 2–3 than those for the Asian Dust event 2 (3/2/2008), while As, Mn, and Zn concentrations were significantly higher on the Asian Dust event 2. Backward trajectory analysis showed that for the Asian Dust event 2, the air mass had passed over the heavily industrialized zones in China during long-range transport to the current sampling site, suggesting that the As, Mn, and Zn may have originated from industrial sources. 相似文献
557.
Pal R Kim KH Jeon EC Song SK Shon ZH Park SY Lee KH Hwang SJ Oh JM Koo YS 《Environmental monitoring and assessment》2009,148(1-4):109-125
The atmospheric concentrations of several reduced sulfur compounds (RSCs) including H(2)S, CH(3)SH, DMS, CS(2), and DMDS were measured concurrently from a series of field campaigns covering multiple locations in the surroundings of a large industrial region (August 2004 to September 2005). These field studies have been designed and undertaken to inspect the concentrations of RSCs in ambient air. The RSC concentrations were found to occur in a highly variable range. H(2)S (1.06 +/- 2.07 ppb) was found to be the most abundant RSC followed by CS(2) (0.84 +/- 0.54 ppb), DMDS (0.36 +/- 1.21 ppb), DMS (0.24 +/- 0.83 ppb), and CH(3)SH (0.11 +/- 0.23 ppb). The RSC levels measured at the study area were comparable to those observed previously from other polluted environmental settings. When these RSC data were examined further in terms of spatial (industrial vs. non-industrial sites) and seasonal (summer vs. winter seasons) grouping schemes, differences in their concentration levels were statistically insignificant in most cases. In contrast, there were fairly strong variations in temporal patterns over a diurnal cycle. If these RSC concentration data were converted to diagnose the malodor strengths, their effects were in most cases insignificant with minor contribution towards odor nuisances. 相似文献
558.
Eun-Jin Yoo Jung-A Lee Jae-Seon Park Khanghyun Lee Won-Seok Lee Jin-Seok Han Jong-Woo Choi 《Environmental monitoring and assessment》2014,186(2):781-789
This study focused on Pb isotope ratios of sediments in areas around an abandoned mine to determine if the ratios can be used as a source tracer. For pretreatment, sediment samples were dissolved with mixed acids, and a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS, Nu plasma II) was used to investigate the Pb isotopic composition of the samples. The measured isotope ratios were then corrected for instrumental mass fractionation by measuring the 203Tl/205Tl ratio. Repeated measurements with the NIST SRM 981 reference material showed that the precision of all ratios was below 104 ppm (±2σ) for 50 ng/g. The isotope ratios (207Pb/206Pb) found were 0.85073?±?0.0004~0.85373?±?0.0003 for the main stream, while they were 0.83736?±?0.0010 for the tributary and 0.84393?±?0.0002 for the confluence. A binary mixing equation for isotope ratios showed that the contributions of mine lead to neighboring areas were up to 60 %. Therefore, Pb isotope ratios can be a good source tracer for areas around abandoned mines. 相似文献
559.
Bong-San Baek Ji-Won Park Byoung-Ho Lee Hyun-Joong Kim 《Journal of Polymers and the Environment》2013,21(3):702-709
Environmental degradation and global warming are increasing as a result of the use of petroleum. Therefore, many industries are seeking more eco-friendly materials that will decrease the level of environmental contamination and economic cost. Recently, the level of coffee consumption has increased rapidly. Therefore, the amount of coffee grounds discarded is increasing. In this study, polylactic acid, coffee grounds and bamboo flour were compounded for green composites. Coffee grounds are used in the recycling of food waste. In addition, 4,4-methylene diphenyl diisocyanate (MDI) was used as a coupling agent. The mechanical strength of green composites decreased with increasing natural filler content. However, mechanical and thermal properties were increased by the addition of MDI as a coupling agent. The hydroxyl groups of natural fillers reacted with the isocyanate group of MDI, and a urethane linkage was created between the polymer and natural fillers. 相似文献
560.
Jong Jin Park Ho-Jun Song Jin-Won Park 《Journal of Material Cycles and Waste Management》2013,15(1):37-41
The purpose of this study was to investigate the possibility of light gases produced from polypropylene, specifically hydrogen. In particular, we examined the effect of operating conditions on gaseous product and compositions in the catalytic cracking of polypropylene. We also characterized the gaseous product generated from polypropylene cracking. The feedstock (2.0 g) mixed with NiO/SiO2–Al2O3 (Si–Al) was used, under non-isothermal conditions at low temperature range between 380 and 500 °C. Argon gas was used to carry the pyrolyzed gas, and the gas collected in a tedlar bag was analyzed for its behavior. We observed the behavior of major gases (H2, CH4, C2H4 and C3H6, etc.) according to reaction time and temperature. Finally, the effect of reaction conditions on evolved gases from catalytic cracking of polypropylene was analyzed. 相似文献