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1.
Mehmet Ates James Daniels Zikri Arslan Ibrahim O. Farah 《Environmental monitoring and assessment》2013,185(4):3339-3348
Aquatic stability and impact of titanium dioxide nanoparticles (TiO2 NPs, 10–30 nm) were investigated using Artemia salina. Acute exposure was conducted on nauplii (larvae) and adults in seawater in a concentration range from 10 to 100 mg/L TiO2 NPs for 24 and 96 h. Rapid aggregation occurred in all suspensions of TiO2 NPs to form micrometer size particles. Yet, both nauplii and adults accumulated the aggregates significantly. Average TiO2 content in nauplii ranged from 0.47 to 3.19 and from 1.29 to 4.43 mg/g in 24 and 96 h, respectively. Accumulation in adults was higher ranging from 2.30 to 4.19 and from 4.38 to 6.20 mg/g in 24 and 96 h, respectively. Phase contrast microscopy images revealed that Artemia were unable to excrete the particles. Thus, the TiO2 aggregates filled inside the guts. No significant mortality or toxicity occurred within 24 h at any dose. Lipid peroxidation levels characterized with malondialdehyde concentrations were not statistically different from those of the controls (p?>?0.05). These results suggested that suspensions of the TiO2 NPs were nontoxic to Artemia, most likely due to the formation of benign TiO2 aggregates in water. In contrast, both mortality and lipid peroxidation increased in extended exposure to 96 h. Highest mortality occurred in 100 mg/L TiO2 NP suspensions; 18 % for nauplii and 14 % for adults (LC50?>?100 mg/L). These effects were attributed to the particle loading inside the guts leading to oxidative stress as a result of impaired food uptake for a long period of time. 相似文献
2.
Herbicide is indispensable for crop production. However, substantial usage of herbicide has led to its increasing accumulation in soils and crops. In addition, cadmium has become one of the widely occurring contaminants in soils due to its significant release into environment via anthropogenic activities. In this study, ecotoxicological investigations were made by exposing the food crop wheat to joint contaminations of Cd and metsulfuron-methyl, a sulfonylurea herbicide. We analyzed growth and physiological and molecular responses in wheat exposed to 0.5 mg kg?1 Cd and 0.02 mg kg?1 metsulfuron-methyl (MSM). Soils contaminated with Cd and MSM complex caused significantly detrimental effect on wheat growth and physiological process. Combinative treatments with Cd and MSM damage more severely the plant cells as compared with Cd or MSM treatment alone. Compared with the growth parameter, the biochemical and molecular responses of wheat appeared more pronounced to Cd and MSM complex. Furthermore, compared with control, wheat plants exposed to Cd?+?MSM generated more O2?.and H2O2, both of which were shown to be the cause of enhanced activity of several antioxidant enzymes. Native polyacrylamide gel eletrophoresis and molecular response analyses were performed to validate the results indicated above. Our results indicated that joint contamination with Cd and MSM was more toxic to wheat than a single contamination. These sensitive biological parameters can be used as biomarkers monitoring the ecotoxicological process in plants. 相似文献
3.
Hossein Tavallali Gohar Deilamy-Rad Pegah Peykarimah 《Environmental monitoring and assessment》2013,185(9):7723-7738
A novel nanomaterial has been developed for speciation of Cr(III) and Cr(VI) in water and soil samples. In this study, a new type of alumina-coated magnetite nanoparticles (Fe3O4/Al2O3 NPs) modified by the surfactant Triton X-114 has been successfully synthesized and used in magnetic mixed hemimicelles solid-phase extraction procedure. The procedure was based on the reaction of chromium(III) with 1-(2-pyridilazo)-2-naphtol as a ligand, yielding a complex, which was entrapped “in situ” in the surfactant hemimicelles. The concentration of chromium(III) was determined using flame atomic absorption spectrometry. After reduction of Cr(VI) to Cr(III) by ascorbic acid, the system was applied to the total chromium. Cr(VI) was then calculated as the difference between the total Cr and the Cr(III) content. This method can also be used for complicated matrices such as soil samples without any special pretreatment. Under the optimum conditions of parameters, the recoveries of Cr(III) by analyzing the spiked water and soil samples were between 98.6 and 100.8 % and between 96.5 and 100.7 %, respectively. Detection limits of Cr(III) were between 1.4 and 3.6 ng?mL?1 for water samples and 5.6 ng?mg?1 for soil samples. 相似文献
4.
The toxicological evaluations of crude oil, xylene, toluene and benzene were carried out against juvenile stages of Clarias gariepinus. On the basis of LC(50) value, benzene (0.017 ml/l) was found to be the most toxic followed by xylene (0.086 ml/l), toluene (0.398 ml/l) and crude oil (2.219 ml/l) was the least toxic. The results of the lipid peroxidation assay showed that the level of malonaldehyde (MDA) in liver and gills of fish exposed to all the test chemicals increased significantly (P < 0.05) when compared to control. Measurement of activities of antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) in liver and gill of fishes exposed to sublethal concentration of the test chemicals over a 28-day period was found to decrease significantly (P < 0.05) when compared to control. The observed reduction in the activities of antioxidant defense enzymes such as SOD, CAT and GST in conjunction with an increase in MDA levels in the gill and liver tissues of test animals exposed to aromatic hydrocarbon compounds were recommended as a good battery of biomarkers for early detection of pollution during biomonitoring programmes. 相似文献
5.
Juliana Janet M. Puzon Gilda C. Rivero Jocelyn E. Serrano 《Environmental monitoring and assessment》2014,186(10):6889-6901
Eichhornia crassipes (Mart.) Solms. plantlets were grown in 0.1 and 1.0 ppm treatment solutions of Hoagland’s hydroponic solutions modified with Hg(NO3)2 in order to examine the specific cellular and biochemical mechanisms involved in the tolerance of this plant exposed to mercury. This study assessed the responses of chloroplast pigments, i.e., carotenoids and chlorophylls, and evaluated the enzymatic and nonenzymatic antioxidant systems. Inductively coupled plasma-atomic emission spectrometry (ICP-AES) revealed varying Hg2+ levels in the young and mature leaf tissues, with greater amounts of Hg2+ found in the tissues of the young leaves. Total chlorophyll levels, notably those of chlorophyll a, chlorophyll b, and carotenoids, showed significant elevation in young leaf tissues, while a decrease in their levels was observed in mature leaf tissues in comparison to those of the control plants. These results lend support to the protective role of increased chlorophyll and carotenoid levels in the photosynthetic apparatus of young E. crassipes leaves in the presence of Hg2+. The antioxidant responses of Hg-treated E. crassipes plants were also measured, revealing a highly significant increase in catalase units, catalase and ascorbate peroxidase activities, and mercury-binding thiols in leaves from Hg-treated plants. Moreover, substantial differences in the degree of oxidative injury between the cells in leaves from the control and Hg-treated plants were evidenced by the lipid peroxidation activities monitored. The Hg-treatment-induced significant decrease in malondialdehyde (MDA) levels was observed in 0.1-ppm Hg(NO3)2-exposed plants, while a highly significant increase in MDA levels was noted in 1.0-ppm Hg(NO3)2-exposed plants. The high degree of lipid peroxidation at 1.0-ppm Hg treatment was evidently counteracted by the compensatory protective mechanism brought about by the increased levels in chloroplast pigments and the enhanced activities of the antioxidant systems. E. crassipes responded to mercury treatments by enhancing the synthesis of chlorophyll and carotenoid pigments, enzymatic, and nonenzymatic antioxidant substances, concomitantly increasing the antioxidative activities, thus rendering E. crassipes capable of tolerating Hg-induced stress. The potential of E. crassipes as a phytoremediator is evident. 相似文献
6.
Jianguo Jiang Changxiu Gong Sicong Tian Shihui Yang Yujing Zhang 《Environmental monitoring and assessment》2014,186(12):8081-8088
Fenton oxidation was compared with Fenton oxidation coupled with ultrasonication (Fenton?+?US) for sludge dewatering. Different Fenton reagent (H2O2, Fe2+) concentrations, pH, and reaction times were studied in different systems on the basis of the specific resistance to filtration (SRF) and capillary suction time (CST). It was found that Fenton?+?US can significantly reduce Fe2+ and H2O2 dosages and reaction times. After ultrasonication of the system at pH 3, with an ultrasonic frequency of 25 kHz and a sound energy density of 100 W/L, the Fe2+, H2O2 dosage, and reaction time were reduced by 66.7, 75.0, and 75.0 %, respectively, when compared with Fenton oxidation at the same dewaterability of sludge. The microstructure of sludge and hydroxyl radical (·OH) density in Fenton oxidation and Fenton?+?US was further examined. Fenton?+?US produced more?·?OH in a sludge system than did individual Fenton oxidation. The concentration of?·?OH in Fenton?+?US fell from 79.2 to 6 mg/L over 3.5 h, while the concentration of?·?OH in Fenton oxidation fell from 59.6 to 1 mg/L over 2 h, thus destroying the microstructure of sludge more effectively. Sludge treated using Fenton?+?US for 30 min showed a much thinner and looser microstructure. 相似文献
7.
Santosh Ranjan Mohanty Parul Rajput Bharati Kollah Dipanti Chourasiya Archana Tiwari Muneshwar Singh A Subba Rao 《Environmental monitoring and assessment》2014,186(6):3743-3753
There is worldwide concern over the increase use of nanoparticles (NPs) and their ecotoxicological effect. It is not known if the annual production of tons of industrial nanoparticles (NPs) has the potential to impact terrestrial microbial communities, which are so necessary for ecosystem functioning. Here, we have examined the consequences of adding the NPs particularly the metal oxide (CuO, ZnO) on CH4 oxidation activity in vertisol and the abundance of heterotrophs, methane oxidizers, and ammonium oxidizers. Soil samples collected from the agricultural field located at Madhya Pradesh, India, were incubated with either CuO and ZnO NPs or ionic heavy metals (CuCl2, ZnCl2) separately at 0, 10, and 20 μg g?1 soil. CH4 oxidation activity in the soil samples was estimated at 60 and 100 % moisture holding capacity (MHC) in order to link soil moisture regime with impact of NPs. NPs amended to soil were highly toxic for the microbial-mediated CH4 oxidation, compared with the ionic form. The trend of inhibition was Zn 20?>?Zn 10?>?Cu 20?>?Cu 10. NPs delayed the lag phase of CH4 oxidation to a maximum of 4-fold and also decreased the apparent rate constant k up to 50 % over control. ANOVA and Pearson correlation analysis (α?=?0.01) revealed significant impact of NPs on the CH4 oxidation activity and microbial abundance (p?<?0.0001, and high F statistics). Principal component analysis (PCA) revealed that PC1 (metal concentration) rendered 76.06 % of the total variance, while 18.17 % of variance accounted by second component (MHC). Biplot indicated negative impact of NPs on CH4 oxidation and microbial abundance. Our result also confirmed that higher soil moisture regime alleviates toxicity of NPs and opens new avenues of research to manage ecotoxicity and environmental hazard of NPs. 相似文献
8.
R. Ramesh P. Kavitha N. Kanipandian S. Arun R. Thirumurugan P. Subramanian 《Environmental monitoring and assessment》2013,185(7):5873-5881
The incorporation of nanoparticles in industrial and biomedical applications has increased significantly in recent years, yet their hazardous and toxic effects have not been studied extensively. While standard toxicological test methods are generally capable of detecting the toxic effects, the choice of relevant methods for nanomaterials is still discussed. Among the various oxide nanomaterials, silica nanoparticles are widely used in biological applications that include nano-medicine. But studies on adverse effects of silica nanoparticle exposure to fish remain unclear. Therefore, the present study was designed to investigate the oxidative toxic effects of silicon dioxide nanoparticles using fish model. The size of the SiO2 nanoparticles was between 68 and 100 nm which was confirmed by X-ray diffractometer, dynamic light scattering, scanning electron microscope and transmission electron microscope. The zebra fish were exposed to sub-lethal concentrations (5 and 2.5 mg/L) of characterized SiO2 nanoparticles for a period of 7 days. After 7 days, SiO2 nanoparticle-treated fishes were sacrificed, and tissues such as liver, muscle and gill were dissected out for the analysis of antioxidant enzymes and DNA fragmentation. The DNA profiles were analysed in the tissues of zebra fish that treated with SiO2 nanoparticles. Tissues of fish from clean water were used as control, and DNA profiles were analysed. It is found that DNA from control tissues was intact, whereas the tissues treated with SiO2 were all fragmented. SiO2 nanoparticle-mediated antioxidant enzymes activities, such as catalase, superoxide dismutase, glutathione (GSH)-S-transferase, glutathione reductase and GSH, in the tissues of zebra fish were measured. The results revealed that alteration of antioxidant enzymes due to SiO2 nanoparticle can be considered as a biomarker to SiO2-mediated oxidative stress in biological samples. 相似文献
9.
L. W. Kress J. M. Skelly K. H. Hinkelmann 《Environmental monitoring and assessment》1982,1(3):229-239
Seedlings of two full-sib families of loblolly pine expressing different degrees of sensitivity to O3 were exposed to 0.05 ppm O3, 0.10 ppm NO2, and/or 0.14 ppm SO2 for 6 hr/day for 28 consecutive days. The treatments were O3, NO2, SO2 (each used alone), O3+SO2, O3+NO2, and O3+NO2+SO2. Significant growth suppressions were noted with the relatively sensitive family in all but the the NO2 alone treatments. The O3+SO2 treatment had a more significant effect than O3 alone, but adding NO2 had an inconsistent effect. Significant growth suppressions were noted for the relatively non-sensitive family only in the O3+SO2 and O3+SO2+NO2 combination treatments. Adding NO2 to O3+SO2 had a slightly stimulatory effect. The relatively sensitive pine family suffered a 30% height growth suppression versus a 14% height growth suppression for the relatively insensitive family when exposed to the 3 pollutant combination. Symptoms were noted on less than 4% of the foliage in the most severe treatments. The pollutant concentrations used in this study were below the National Ambient Air Quality Standards (NAAQS) for each pollutant. 相似文献
10.
Nivedita Chaudhary Suruchi Singh S. B. Agrawal Madhoolika Agrawal 《Environmental monitoring and assessment》2013,185(9):7793-7807
Six Indian cultivars of Vigna radiata L. (HUM-1, HUM-2, HUM-6, HUM-23, HUM-24 and HUM-26) were exposed with ambient and elevated (ambient + 10 ppb ozone (O3) for 6 h?day?1) level of O3 in open top chambers. Ozone sensitivity was assessed by recording the magnitude of foliar visible injury and changes in various physiological parameters. All the six cultivars showed visible foliar symptoms due to O3, ranging 7.4 to 55.7 % injured leaf area. O3 significantly depressed total chlorophyll, photosynthetic rate (Ps), quantum yield (F v/F m) and total biomass although the extent of variation was cultivar specific. Cultivar HUM-1 showed maximum reduction in Ps and stomatal conductance. The fluorescence parameters also indicated maximum damage to PSII reaction centres of HUM-1. Injury percentage, chlorophyll loss, Ps, F v/F m and total biomass reduced least in HUM-23 depicting highest O3 resistance (R%). 相似文献
11.
Walt W. McNab Jr 《Environmental monitoring and assessment》1999,59(3):257-274
Biotransformation processes play an active role in reducing the environmental impact of fuel hydrocarbon releases to groundwater. Because monitoring data at release locations are typically sparse, spatial variations in geochemical indicator parameters are often called upon as indirect evidence of biotransformation. These parameters include concentrations of electron acceptors (O2, NO3
-, SO>
4
2-
, reduced redox reaction by-products (Fe2+, Mn2+, CH4), as well as bicarbonate alkalinity, pH and Eh. However, background variability in a number of these parameters complicates the task of data interpretation, particularly in the case of small data sets. In this study, correlation analyses are applied to geochemical indicator data at six hydrocarbon groundwater contamination sites in California to identify which parameters are the most reliable indicators. The results of the analyses suggest that the most direct indicators of the local redox environment – Fe2+, Mn2+, CH4, Eh – yield the most consistent evidence of hydrocarbon biotransformation. Indicators which rely largely on mass balance – O2, NO
3
-
, SO
4
2-
, alkalinity – appear to be less reliable. These findings may provide guidance in both the collection and interpretation of groundwater monitoring data at hydrocarbon contamination sites. 相似文献
12.
Phosphorus (P) leaching from a sandy soil was investigated in the presence of modified and unmodified clay minerals and nanoparticles (NPs). Compared with control soil, amended soil with NPs had the highest percentage of P retention than amended soil with clay minerals. Among the adsorbents used, the highest percentage of P retention was produced by Al2O3-chitosan while the lowest percentage of P retention was by zeolite. Data measured for P leaching after using adsorbents were used to predict P leaching using transport model. PHREEQC model was able to model P leaching from control and amended soil. After leaching, P values in control and amended soil were fractionated by a sequential extraction procedure. Concentration of P in Ca-bound fraction (HCl–P) after application of modified and unmodified clay minerals and NPs (except TiO2 and Al2O3) increased and decreased, respectively. Saturation indices (SIs) and P speciation were assessed using the Visual MINTEQ version 2.3 program. According to the SIs, leaching P from control and amended soil with different adsorbent was controlled by dissolution of hydroxyapatite. The results indicated that used adsorbents can reduce P leaching from the sandy soil. Thus, retention of P by amended soil reduced a risk in terms of groundwater contamination with P. 相似文献
13.
Shams Ali Baig Zimo Lou Muzaffar Ali Baig Muhammad Qasim Dilawar Farhan Shams Qaisar Mahmood Xinhua Xu 《Environmental monitoring and assessment》2017,189(4):194
Corrosion deposits formed within drinking water distribution systems deteriorate drinking water quality and resultantly cause public health consequences. In the present study, an attempt was made to investigate the concurrent conditions of corrosion scales and the drinking water quality in selected water supply schemes (WSS) in districts Chitral, Peshawar, and Abbottabad, northern Pakistan. Characterization analyses of the corrosion by-products revealed the presence of α-FeOOH, γ-FeOOH, Fe3O4, and SiO2 as major constituents with different proportions. The constituents of all the representative XRD peaks of Peshawar WSS were found insignificant as compared to other WSS, and the reason could be the variation of source water quality. Well-crystallized particles in SEM images indicated the formation of dense oxide layer on corrosion by-products. A wider asymmetric vibration peak of SiO2 appeared only in Chitral and Abbottabad WSS, which demonstrated higher siltation in the water source. One-way ANOVA analysis showed significant variations in pH, turbidity, TDS, K, Mg, PO4, Cl, and SO4 values, which revealed that these parameters differently contributed to the source water quality. Findings from this study suggested the implementation of proper corrosion prevention measures and the establishment of international collaboration for best corrosion practices, expertise, and developing standards. 相似文献
14.
Saadia R. Tariq N. Shaheen A. Khalique Munir H. Shah 《Environmental monitoring and assessment》2010,163(1-4):303-312
The short-term responses of H2O2-depletion-related parameters in moss Hypnum plumaeforme to the combined stress induced by Pb and Ni were investigated. The results showed that the Pb and Ni stress induced dose-dependent accumulation of hydrogen peroxide (H2O2). The increase of peroxidase (POD) activity and decrease of ascorbate peroxidase (APX) activity were observed under the combined heavy metal application. The antioxidants, ascorbate (AsA) and proline content, increased significantly when the metals were applied together. The study indicated that the cell damage caused by Pb stress was higher than that caused by Ni stress, Pb and Ni had synergistic effect in inducing the oxidative stress in moss H. plumaeforme, especially under the combination of high concentration of Ni (0.1 and 1.0 mM) and Pb. Content of proline, H2O2 and the activity of POD, all showed a dose-dependent increase under Pb and Ni stress, suggesting their practical value as biomarkers in moss biomonitoring, especially in the case of light pollution caused by heavy metals without the changes in the appearance of mosses. 相似文献
15.
The results of an innovative study on a new and highly efficient stationary phase based on the SnO2 nanorods coating on fused silica have been reported in this paper. SnO2 nanorods have been grown on fused silica fibers using a hydrothermal process. The extraction properties of the fiber were investigated using headspace solid-phase microextraction (HS-SPME) mode coupled with gas chromatography–mass spectrometry detection for 1,4-dichloro-2-nitrobenzene, biphenyl, and acenaphthene. The effect of different variables on extraction efficiency was studied simultaneously using Box–Behnken method as experimental design. The variables of interest in the HS-SPME were salt effect, adsorption temperature, extraction, and desorption time. Under optimal conditions, the calibration curves were linear up to 102–105 ng?L?1 (R 2?>?0.998) with detection limits of 10?3, 10?1, and 10 ng?L?1 for acenaphthene, biphenyl, and 1,4-dichloro-2-nitrobenzene, respectively. The relative standard deviations for single fiber and fiber to fiber were less than 9.8 and 12.5 %, respectively. The high stability of the SnO2 nanostructure coating is proved at relatively high temperatures (up to 300 °C) with a high extraction capacity and long lifespan (more than 100 times). By applying the proposed technique, promising recoveries (93–98 %) were obtained in the analysis of environmental water samples. 相似文献
16.
Satyavan Singh Arti Bhatia Ritu Tomer Vinod Kumar B. Singh S. D. Singh 《Environmental monitoring and assessment》2013,185(8):6517-6529
Field experiments were conducted in open top chamber during rabi seasons of 2009–10 and 2010–11 at the research farm of the Indian Agricultural Research Institute, New Delhi to study the effect of tropospheric ozone (O3) and carbon dioxide (CO2) interaction on yield and nutritional quality of Indian mustard (Brassica juncea (L.) Czern.). Mustard plants were grown from emergence to maturity under different treatments: charcoal-filtered air (CF, 80–85 % less O3 than ambient O3 and ambient CO2), nonfiltered air (NF, 5–10 % less O3 than ambient O3 and ambient CO2 ), nonfiltered air with elevated carbon dioxide (NF?+?CO2, NF air and 550?±?50 ppm CO2), elevated ozone (EO, NF air and 25–35 ppb elevated O3), elevated ozone along with elevated carbon dioxide (EO?+?CO2, NF air, 25–35 ppb O3 and 550?±?50 ppm CO2), and ambient chamber less control (AC, ambient O3 and CO2). Elevated O3 exposure led to reduced photosynthesis and leaf area index resulting in decreased seed yield of mustard. Elevated ozone significantly decreased the oil and micronutrient content in mustard. Thirteen to 17 ppm hour O3 exposure (accumulated over threshold of 40 ppm, AOT 40) reduced the oil content by 18–20 %. Elevated CO2 (500?±?50 ppm) along with EO was able to counter the decline in oil content in the seed, and it increased by 11 to 13 % over EO alone. Elevated CO2, however, decreased protein, calcium, zinc, iron, magnesium, and sulfur content in seed as compared to the nonfiltered control, whereas removal of O3 from air in the charcoal-filtered treatment resulted in a significant increase in the same. 相似文献
17.
A loamy soil contaminated with 137CsCl 40 years ago was investigated by a sequential extraction technique to determine the effect of ageing on chemical availability
of 137Cs. The soil samples were sequentially extracted with H2O, NH4Ac, NH2OH·HCl, H2O2, and HNO3. Extractability of 137Cs decreased in the order: HNO3 > Residual > H2O2 > NH4Ac > NH2OH·HCl > H2O. Only 0.94% in labile fractions (H2O and NH4Ac), while more than 96% was found in the strongly bound fraction (HNO3 and residual). However, the activity percentage in labile fractions was increased to 1.34% after autoclaving treatment, while
those in the other fractions did not significantly differ. This indicates that the microbial activity played a role in the
137Cs retention. In the subsequent pot experiments with ryegrass and leek, specific activities in both plants were significantly
higher in autoclaved soil than in non-autoclaved soil, and uptake of 137Cs in the five cuts by ryegrass was 25% of the labile 137Cs in the soil. In addition, a positive correlation was found between the amount of 137Cs in labile fractions and that by plant uptake. 相似文献
18.
M. E. Gonzalez Gomez R. Howard-Hildige J. J. Leahy T. O'Reilly B. Supple M. Malone 《Environmental monitoring and assessment》2000,65(1-2):13-20
Exhaust emission and performance characteristics were evaluated in a Toyota van, powered by a 21 indirect injection (IDI) naturally aspirated diesel engine, operating on vegetable based waste cooking oil methyl ester (WCOME).Tests were performed on a chassis dynamometer and the data were compared with previous results conducted on the same vehicle using mineral diesel fuel. The data obtained includes smoke opacity, carbon monoxide (CO), carbon dioxide (CO2), oxygen (O2), nitrogen dioxide (NO2), nitric oxide (NO), sulfur dioxide (SO2) and brake power. Engine lubricating oil samples were also taken. Results from this study indicated a difference of approximately 9% in brake power between the two fuels. WCOME developed a significant lower smoke opacity level and reduced CO, CO2, SO2 emissions. However, O2, NO2 and NO levels were higher with the vegetable oil based fuel. Power values were comparable for both fuels. Lubricating oil analysis gave little change of viscosity and wear metal concentrations after 2887km were: Silicon 35ppm, Chromium 3.3ppm, Iron 33.8ppm, Copper 14.1ppm and lead 78.6ppm. 相似文献
19.
Magdolenova Z Bilaničová D Pojana G Fjellsbø LM Hudecova A Hasplova K Marcomini A Dusinska M 《Journal of environmental monitoring : JEM》2012,14(2):455-464
The published results on nanoparticles cytotoxicity and genotoxicity such as titanium dioxide nanoparticles (TiO(2) NPs) are inconsistent, and often conflicting and insufficient. Since different parameters may have impact on the toxicity results, there is need to lay stress on detailed characterization of NPs and the use of different testing conditions for assessment of NPs toxicity. In order to investigate whether dispersion procedures influence NP cytotoxicity and genotoxicity, we compared two protocols giving TiO(2) NP dispersions with different stability and agglomeration states. Detailed primary and secondary characteristics of both TiO(2) NP dispersions in culture media were carried out before toxicological testing; TK6 human lymphoblast cells, EUE human embryonic epithelial cells and Cos-1 monkey kidney fibroblasts were used to assess cytotoxicity (by trypan blue exclusion, proliferation activity and plating efficiency assays) and genotoxicity (by the comet assay). DNA strand breaks were detected by the alkaline comet assay. DNA oxidation lesions (especially 8-oxo-7,8-dihydroguanine, 8-oxoG) were measured with a modified comet assay including incubation with specific repair enzyme formamidopyrimidine DNA glycosylase (FPG). The TiO(2) NPs dispersion with large agglomerates (3 min sonication and no serum in stock solution) induced DNA damage in all three cell lines, while the TiO(2) NPs dispersed with agglomerates less than 200 nm (foetal serum in stock solution and sonication 15 min) had no effect on genotoxicity. An increased level of DNA oxidation lesions detected in Cos-1 and TK6 cells indicates that the leading mechanism by which TiO(2) NPs trigger genotoxicity is most likely oxidative stress. Our results show that the dispersion method used can influence the results of toxicity studies. Therefore at least two different dispersion procedures should be incorporated into assessment of cyto- and genotoxic effects of NPs. It is important, when assessing the hazard associated with NPs, to establish standard testing procedures and thorough strategies to consider the diverse conditions relevant to possible exposures. 相似文献
20.
Reich S Magallanes J Dawidowski L Gómez D Groselj N Zupan J 《Environmental monitoring and assessment》2006,119(1-3):441-457
Air pollutant concentrations from a monitoring campaign in Buenos Aires City, Argentina, are used to investigate the relationships between ambient levels of ozone (O3), nitric oxide (NO) and nitrogen dioxide (NO2) as a function of NO
x
(=NO + NO2). This campaign undertaken by the electricity sector was aimed at elucidating the apportionment of thermal power plants to air quality deterioration. Concentrations of carbon monoxide (CO) and sulphur dioxide (SO2) were also registered. Photo stationary state (PSS) of the NO, NO2, O3 and peroxy radicals species has been analysed. The ‘oxidant’ level concept has been introduced, OX (=O3 + NO2), which varies with the level of NO
x
. It is shown that this level is made up of NO
x
-independent and NO
x
-dependent contributions. The former is a regional contribution that equates the background O3 level, whereas the latter is a local contribution that correlates with the level of primary pollution. Furthermore, the anticorrelation between NO2 and O3 levels, which is a characteristic of the atmospheric photo stationary cycle has been verified.The analysis of the concentration of the primary pollutants CO and NO strongly suggests that the vehicle traffic is the principal source of them. Levels of continuous measurements of SO2 for Buenos Aires City are reported in this work as a complement of previously published results. 相似文献