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91.
Borhan Mansouri Afshin Maleki Seyed Ali Johari Behzad Shahmoradi Ebrahim Mohammadi 《Chemistry and Ecology》2017,33(4):295-308
In current research, the combined effects of copper oxide nanoparticles (CuO NPs) and titanium dioxide nanoparticles (TiO2 NPs) on the histopathological anomalies of gill and intestine tissues in common carp (Cyprinus carpio) were studied. Common carp were exposed to TiO2 NPs (10.0?mg L?1), CuO NPs (2.5 and 5.0?mg L?1), and mixture of TiO2 NPs (10.0?mg L?1)?+?CuO NPs (2.5 and 5.0 mg?L?1) for two periods of exposure (10 and 20 days) and recovery (30 and 40 days). The most common histopathological anomalies in the gill of common carp such as hyperplasia, oedema, curvature, fusion, aneurism, and necrosis were observed. The synergistic effect of co-existing TiO2 NPs and CuO NPs reduced the length of secondary lamella and increased the diameters of the gill filaments and secondary lamellae. Moreover, the presence of TiO2 NPs increased the CuO NPs effects on the histopathological anomalies of intestine tissue and the synergistic effect of TiO2 NPs and CuO mixture leads to an increase in the severity of histopathological lesions such as degeneration, swelling of goblet cells, and necrosis - erosion in the intestine tissue. In conclusion, the presence of TiO2 NPs increased the toxicity of CuO NPs. 相似文献
92.
Groundwater and water resources management plays a key role in conserving the sustainable conditions in arid and semi-arid
regions. Applying management tools which can reveal the critical and hot conditions seems necessary due to some limitations
such as labor and funding. In this study, spatial and temporal analysis of monthly groundwater level fluctuations of 39 piezometric
wells monitored during 12 years was carried out. Geostatistics which has been introduced as a management and decision tool
by many researchers has been applied to reveal the spatial and temporal structure of groundwater level fluctuation. Results
showed that a strong spatial and temporal structure existed for groundwater level fluctuations due to very low nugget effects.
Spatial analysis showed a strong structure of groundwater level drop across the study area and temporal analysis showed that
groundwater level fluctuations have temporal structure. On average, the range of variograms for spatial and temporal analysis
was about 9.7 km and 7.2 months, respectively. Ordinary and universal kriging methods with cross-validation were applied to
assess the accuracy of the chosen variograms in estimation of the groundwater level drop and groundwater level fluctuations
for spatial and temporal scales, respectively. Results of ordinary and universal krigings revealed that groundwater level
drop and groundwater level fluctuations were underestimated by 3% and 6% for spatial and temporal analysis, respectively,
which are very low and acceptable errors and support the unbiasedness hypothesis of kriging. Although, our results demonstrated
that spatial structure was a little bit stronger than temporal structure, however, estimation of groundwater level drop and
groundwater level fluctuations could be performed with low uncertainty in both space and time scales. Moreover, the results
showed that kriging is a beneficial and capable tool for detecting those critical regions where need more attentions for sustainable
use of groundwater. Regions in which were detected as critical areas need to be much more managed for using the current water
resources efficiently. Conducting water harvesting systems especially in critical and hot areas in order to recharge the groundwater,
and altering the current cropping pattern to another one that need less water requirement and applying modern irrigation techniques
are highly recommended; otherwise, it is most likely that in a few years no more crop would be cultivated. 相似文献
93.
Ali Salavati-Zadeh Ahmad Javaheri Seyed Vahid Ghavami Vahid Esfahanian Masoud Masih Tehrani Hossein Akbari 《International Journal of Green Energy》2016,13(10):1042-1049
This study investigates the effects of hydrogen enrichment on formation of pollutants and greenhouse gases in gas-fueled spark ignition engines. To this end, a previously validated detailed mechanism is embedded with a comprehensive one-dimensional engine model and the results are verified with experimental observations at different compression ratios and engine loads. The simulations are then performed for different mixtures of hydrogen and natural gas. The results indicate that adding hydrogen increases the cylinder peak pressure at different loads and compression ratios, despite the fact that reduces the amount of carbon monoxide, carbon dioxide, and methane in all the conditions. 相似文献
94.
Mohammad Miri Elham Akbari Abdeltif Amrane Seyed Javad Jafari Hadi Eslami Edris Hoseinzadeh Mansur Zarrabi Javad Salimi Mohsen Sayyad-Arbabi Mahmoud Taghavi 《Environmental monitoring and assessment》2017,189(11):583
The heavy metal (Pb, Cd, Cr, and Ni) content of a fish species consumed by the Sistan population and its associated health risk factors were investigated. The mean concentrations of Pb, Cd, and Cr were slightly higher than the standard levels. The Ni content of fish was below the maximum guideline proposed by the US Food and Drug Administration (USFDA). The average estimated weekly intake was significantly below the provisional tolerable intake based on the FAO and WHO standards for all studied metals. The target hazard quotients (THQ) of all metals were below 1, showing an absence of health hazard for the population of Sistan. The combined target hazard quotient for the considered metals was 26.94 × 10?3. The cancer risk factor for Pb (1.57 × 10?7) was below the acceptable lifetime carcinogenic risk (10?5). The results of this study reveal an almost safe level of Pb, Cd, Cr, and Ni contents in the fish consumed by the Sistan population. 相似文献
95.
Characterization of ionic composition of TSP and PM10 during the Middle Eastern Dust (MED) storms in Ahvaz, Iran 总被引:1,自引:0,他引:1
Shahsavani A Naddafi K Jaafarzadeh Haghighifard N Mesdaghinia A Yunesian M Nabizadeh R Arhami M Yarahmadi M Sowlat MH Ghani M Jonidi Jafari A Alimohamadi M Motevalian SA Soleimani Z 《Environmental monitoring and assessment》2012,184(11):6683-6692
Because of the recent frequent observations of major dust storms in southwestern cities in Iran such as Ahvaz, and the importance of the ionic composition of particulate matters regarding their health effects, source apportionment, etc., the present work was conducted aiming at characterizing the ionic composition of total suspended particles (TSP) and particles on the order of ~10?μm or less (PM(10)) during dust storms in Ahvaz in April-September 2010. TSP and PM(10) samples were collected and their ionic compositions were determined using an ion chromatography. Mean concentrations of TSP and PM(10) were 1,481.5 and 1,072.9?μg/m(3), respectively. Particle concentrations during the Middle Eastern Dust (MED) days were up to four times higher than those in normal days. Ionic components contributed to only 9.5% and 11.3% of the total mass of TSP and PM(10), respectively. Crustal ions were most abundant during dust days, while secondary ions were dominant during non-dust days. Ca(2+)/Na(+) and Cl(-)/Na(+) ratios can be considered as the indicators for identification of the MED occurrence. It was found that possible chemical forms of NaCl, (NH(4))(2)SO(4), KCl, K(2)SO(4), CaCl(2), Ca(NO(3))(2), and CaSO(4) may exist in TSP. Correlation between the anionic and cationic components suggests slight anion and cation deficiencies in TSP and PM(10) samples, though the deficiencies were negligible. 相似文献
96.
Y Kooch SM Hosseini C Zaccone H Jalilvand SM Hojjati 《Journal of environmental monitoring : JEM》2012,14(9):2438-2446
Following the ratification of the Kyoto Protocol, afforestation of formerly arable lands and/or degraded areas has been acknowledged as a land-use change contributing to the mitigation of increasing atmospheric CO(2) concentration in the atmosphere. In the present work, we study the soil organic carbon sequestration (SOCS) in 21 year old stands of maple (Acer velutinum Bioss.), oak (Quercus castaneifolia C.A. Mey.), and red pine (Pinus brutia Ten.) in the Darab Kola region, north of Iran. Soil samples were collected at four different depths (0-10, 10-20, 20-30, and 30-40 cm), and characterized with respect to bulk density, water content, electrical conductivity, pH, texture, lime content, total organic C, total N, and earthworm density and biomass. Data showed that afforested stands significantly affected soil characteristics, also raising SOCS phenomena, with values of 163.3, 120.6, and 102.1 Mg C ha(-1) for red pine, oak and maple stands, respectively, vs. 83.0 Mg C ha(-1) for the control region. Even if the dynamics of organic matter (OM) in soil is very complex and affected by several pedo-climatic factors, a stepwise regression method indicates that SOCS values in the studied area could be predicted using the following parameters, i.e., sand, clay, lime, and total N contents, and C/N ratio. In particular, although the chemical and physical stabilization capacity of organic C by soil is believed to be mainly governed by clay content, regression analysis showed a positive correlation between SOCS and sand (R = 0.86(**)), whereas a negative correlation with clay (R = -0.77(**)) was observed, thus suggesting that most of this organic C occurs as particulate OM instead of mineral-associated OM. Although the proposed models do not take into account possible changes due to natural and anthropogenic processes, they represent a simple way that could be used to evaluate and/or monitor the potential of each forest plantation in immobilizing organic C in soil (thus reducing atmospheric C concentration), as well as to select more appropriate species during forestation plan management at least in the north of Iran. 相似文献
97.
98.
Human milk is usually the only source of food for infants during the first 4 to 5 months of their life. Maternal environmental
mercury exposure is directly related to fish consumption or amalgam filling. In this research, 38 human milk samples were
collected from mothers of Lenjan area who were not occupationally exposed with mercury. Mercury concentration in human milk
was determined by AMA254 Mercury Analyzer. A level of mercury was examined in relation to somatometric, demographic and dental
amalgam parameters. Obtained results showed that only dental amalgam significantly increased the mercury level in human milk
(p < 0.001). The mean mercury concentrations in milk of mothers without teeth fillings (n = 13), with one to three teeth fillings (n = 10), and four to eight teeth fillings (n = 15) were 2.87, 5.47, and 13.33 μg/l, respectively. The result of this study also showed a positive correlation of mercury
milk levels with the number of teeth fillings of the mother (p < 0.05, r = 0.755). The estimated weekly intake of mercury of a breastfed infant in this study was, in some cases, higher than provisional
tolerance weekly intake recommended by FAO/WHO, which pose a threat to their health. 相似文献
99.
A novel pollution index based on the bioavailability of elements: a study on Anzali wetland bed sediments 总被引:2,自引:0,他引:2
Fariba Zamani Hargalani Abdolreza Karbassi Seyed Masoud Monavari Parviz Abroomand Azar 《Environmental monitoring and assessment》2014,186(4):2329-2348
In this research, we study on the distribution of several elements in bed sediments of Anzali wetland. Anzali, one of the most important international wetlands, is located on the southern coast of the Caspian Sea in Iran. This wetland receives discharges of domestic, agricultural, and industrial wastewater, which affect the distribution of elements. Our contribution in this study is threefold. First, we measured the total concentration of metals as well as their chemical partitioning and bioavailability in the sediments. Second, we calculated anthropogenic portions of metals in the sediment of this area. The results reveal anthropogenic portion of metals as Mo > Mn > Cd > As > Zn > Hg > Co > Sn > Cu > V > Ag > Ni > Pb > Fe > Cr > Al, respectively. We evaluated the intensity of pollution by using an enrichment factor, the geo-accumulation index and the pollution index. All these indices do not take into consideration the bioavailability of the elements. As our third and most important contribution, we introduced a new formula that takes into account the bioavailability of different elements. In comparison with aforementioned pollution indices, our newly introduced pollution index has a higher Pearson correlation with anthropogenic portion of metals. This high-correlation coefficient shows that our proposed pollution index is an effective indicator for determining the level of pollution, while other indices preserve their own merits. 相似文献
100.
Mahla Hosseini Vardei Abdolrasoul Salmanmahiny Seyed Masoud Monavari Mir Masoud Kheirkhah Zarkesh 《Environmental monitoring and assessment》2014,186(11):7335-7347
Population growth, during the twentieth century, has increased demand for new farmlands. Accordingly, road networks have rapidly been developed to facilitate and accelerate human access to the essential resources resulted in extensive land use changes. The present study aims at assessing cumulative effects of developed road network on tree cover of Golestan Province in northern Iran. In order to detect changes over the study period of 1987–2002, the LULC map of the study area was initially prepared from the satellite images of Landsat TM (1987) and ETM+ (2002) using maximum likelihood supervised classification method. Afterwards, a total number of seven landscape matrices were selected to detect cumulative effects of the developed road network on woodland cover. The obtained results indicated that the fragile patches are mainly located at a distance of 171–342 m from the roadside. Furthermore, the majority of the patches affected by cumulative effects of development activities are situated at a distance of 342–684 m from the roadside, over an approximate area of 55 ha. The analysis of landscape metrics revealed that the developed road network has increased the landscape metrics of “the number of patches” and “patches perimeter-area ratio”. It has also followed by a decrease in metrics such as “patches area”, “Euclidean nearest neighbor distance”, “patches proximity”, “shape index”, “contiguity”, and “mean patches fractal dimension”. The road network has also increased the “number of patches” and decreased the “mean patches area” representing further fragmentation of the landscape. With identification of highly affected wooldland cover patches, it would be possible to apply adaptive environmental management strategies to preserve and rehabilitate high-priority patches. 相似文献