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1.
Based on data from ground-based air quality stations, space–time variations of six principal atmospheric pollutants, such as particulate matter (PM2.5 and PM10) and gas pollutants (SO2, NO2, СО, and O3), obtained from January 1, 2014 to December 31, 2017 in the city of Lanzhou, have been studied. Average total concentrations of PM2.5 and PM10 were 53.2?±?26.91 and 124.54?±?82.33 µg/m3, respectively; however, the results showed that in 75.53% and 84.85% days, concentrations of these pollutants exceeded Chinese National Ambient Air Quality Standard and in 100% days exceeded World Health Organization guidelines standards. Daily mean values of aerosol optical depth and Ångström exponent based on data, received by satellite Moderate Resolution Imaging Spectroradiometer, show a broad range of values for aerosol optical depth (from 0.018 to 1.954) and Ångström exponent (from 0.003 to 1.8). Results of principal components analysis revealed three factor loadings. Thus, Factor 1 has the relevant loadings for PM2.5, PM10, CO, SO2, and NO2 (36%) and closely associated with transport emissions and industrial sources, which contribute to air pollution in Lanzhou. Factor 2 was heavily loaded with temperature and visibility (16.94%). Factor 3 consisted of relative humidity (14.11%). Cluster analysis revealed four subgroups: cluster 1 (PM2.5, NO2, SO2), cluster 2 (CO), cluster 3 (PM10) and cluster 4 (relative humidity, visibility, temperature, O3, wind speed), which were compliant with results, obtained from principal components analysis. Positive correlation was found among all pollutants, other than O3. According to processed backward trajectories obtained by Hybrid Single-Particle Lagrangian Integrated Trajectory model, it was found that movement of air masses occur from north, northwest, and west directions—the location of principal natural sources of aerosols.  相似文献   

2.
ISC-AERMOD dispersion model was used to predict air dispersion plumes from an diesel power plant complex. Emissions of NO2and SO2from stacks (5 numbers) and a waste oil incinerator were studied to evaluate the pollutant dispersion patterns and the risk of nearby population. Emission source strengths from the individual point sources were also evaluated to determine the sources of significant attribution. Results demonstrated the dispersions of pollutants were influenced by the dominant easterly wind direction with the cumulative maximum ground level concentrations of 589.86 μg/m3 (1 h TWA NO2) and 479.26 μg/m3 (1 h TWA SO2). Model performance evaluation by comparing the predicted concentrations with observed values at ten locations for the individual air pollutants using rigorous statistical procedures were found to be in good agreement. Among all the emission sources within the facility complex, SESB-Power (diesel power plant) had been singled out as a significant source of emission that contributed >85% of the total pollutants emitted.  相似文献   

3.
Atmospheric dust is considered to be the major cause of poor air quality due to its contribution to high particulate levels, but their interaction with the acidic gases helps in controlling the level of SO2 and NO2 through ambient neutralization reactions. In the present study, the interaction of acidic gases such as SO2 and NO2 with alkaline dust was investigated during October, 2013–July, 2014 at a site named as Babarpur located at the Trans-Yamuna region of Delhi. The concentration of SO2 ranged from 10 to 170 μg/m3 with an average of 36 μg/m3 while that of NO2 ranged from 15 to 54 μg/m3 with an average of 26?±?8 μg/m3. The results were observed to be well within the National Ambient Air Quality Standard (NAAQS) limits prescribed by the Central Pollution Control Board (CPCB). The average concentrations of SO2 during day and night time were recorded as 31?±?18 and 43?±?53 μg/m3 respectively while the mean concentrations of NO2 during day and night time were recorded as 26?±?7 and 27?±?12 μg/m3 respectively. A positive correlation between SO42? and NO3? was also observed indicating their secondary aerosol formation. In aerosol phase, average concentrations of SO42? during day and night time were 3.9?±?0.3 and 6.5?±?2.3 μg/m3 respectively while that of NO3? were 9.5?±?1.5 and 7.3?±?0.5 μg/m3 respectively. Molar ratios of Ca2+/SO42?, NH4+/SO42?, and NH4+/NO3? were observed as 8, 5, and 1.7 during daytime and 1.5, 0.4, and 0.8 during nighttime respectively. Such molar ratios confirmed high concentrations of sulphate (SO4)2? and low concentrations of nitrate (NO3?) during night time, thereby indicating different pathway of aerosol formation during day and night time. Surface morphology and elemental composition of aerosol samples showed various oval, globular, and platy shapes where the diameter varied from few nm to ~5 μm depending on their precursors. There were certain shapes like grossularite, irregular aggregate, grape-like, triangular, and flattened which indicate the crustal origin of aerosols and their possible role in SO2 and NO2 adsorption.  相似文献   

4.
People living in the urban area and the surrounding suburban area have disparities in exposure and health risks due to different levels of ambient air pollutants. The main objective of this study is to investigate the concentrations, seasonal variations, and related health risks of ambient air pollutants (PM10, NO2, and SO2) in urban and suburban areas of Ningbo, China. The results showed that the average PM10, NO2, and SO2 concentrations in the urban area were 85.2, 49.3, and 37.4 μg/m3, which were 1.13, 1.25, and 1.41 times the values of the suburban area during the period of March 2009 to February 2010. For the potential health risk analysis, the residents have been divided into four age categories namely, infants, children (1 year), children (8–10 years), and adults. The analysis took into account age-specific breathing rates, body weights for different age categories. The results showed that the potential health risks to respiratory disease for all age categories living in urban area were higher than those in suburban area.  相似文献   

5.
The increasing emission of primary and gaseous precursors of secondarily formed atmospheric particulate matter due to continuing industrial development and urbanization are leading to an increased public awareness of environmental issues and human health risks in China. As part of a pilot study, 12-h integrated fine fraction particulate matter (PM2.5) filter samples were collected to chemically characterize and investigate the sources of ambient particulate matter in Guiyang City, Guizhou Province, southwestern China. Results showed that the 12-h integrated PM2.5 concentrations exhibited a daytime average of 51 ± 22 µg m?3 (mean ± standard deviation) with a range of 17–128 µg m?3 and a nighttime average of 55 ± 32 µg m?3 with a range of 4–186 µg m?3. The 24-h integrated PM2.5 concentrations varied from 15 to 157 µg m?3, with a mean value of 53 ± 25 µg m?3, which exceeded the 24-h PM2.5 standard of 35 µg m?3 set by USEPA, but was below the standard of 75 µg m?3, set by China Ministry of Environmental Protection. Energy-dispersive X-ray fluorescence spectrometry (XRF) was applied to determine PM2.5 chemical element concentrations. The order of concentrations of heavy metals in PM2.5 were iron (Fe) > zinc (Zn) > manganese (Mn) > lead (Pb) > arsenic (As) > chromium (Cr). The total concentration of 18 chemical elements was 13 ± 2 µg m?3, accounting for 25% in PM2.5, which is comparable to other major cities in China, but much higher than cities outside of China.  相似文献   

6.
Size distribution of PM10 mass aerosols and its ionic characteristics were studied for 2 years from January 2006 to December 2007 at central Delhi by employing an 8-stage Andersen Cascade Impactor sampler. The mass of fine (PM2.5) and coarse (PM10?2.5) mode particles were integrated from particle mass determined in different stages. Average concentrations of mass PM10 and PM2.5 were observed to be 306 ± 182 and 136 ± 84 μg m?3, respectively, which are far in excess of annual averages stipulated by the Indian National Ambient Air Quality Standards (PM10: 60 μg m?3 and PM2.5: 40 μg m?3). The highest concentrations of PM10?2.5 (coarse) and PM2.5 (fine) were observed 505 ± 44 and 368 ± 61 μg m?3, respectively, during summer (June 2006) period, whereas the lower concentrations of PM10?2.5 (35 ± 9 μg m?3) and PM2.5 (29 ± 13 μg m?3) were observed during monsoon (September 2007). In summer, because of frequent dust storms, coarse particles are more dominant than fine particles during study period. However, during winter, the PM2.5 contribution became more pronounced as compared to summer probably due to enhanced emissions from anthropogenic activities, burning of biofuels/biomass and other human activities. A high ratio (0.58) of PM2.5/PM10 was observed during winter and low (0.24) during monsoon. A strong correlation between PM10 and PM2.5 (r 2 = 0.93) was observed, indicating that variation in PM10 mass is governed by the variation in PM2.5. Major cations (NH4 +, Na+, K+, Ca2+ and Mg2+) and anions (F?, Cl?, SO4 2? and NO3 ?) were analyzed along with pH. Average concentrations of SO4 2? and NO3 ? were observed to be 12.93 ± 0.98 and 10.33 ± 1.10 μg m?3, respectively. Significant correlation between SO4 2? and NO3 ? in PM1.0 was observed indicating the major sources of secondary aerosol which may be from thermal power plants located in the southeast and incomplete combustion by vehicular exhaust. A good correlation among secondary species (NH+, NO3 ? and SO4 2?) suggests that most of NH4 + is in the form of ammonium sulfate and ammonium nitrate in the atmosphere. During winter, the concentration of Ca2+ was also higher; it may be due to entrainment of roadside dust particles, traffic activities and low temperature. The molar ratio (1.39) between Cl? and Na+ was observed to be close to that of seawater (1.16). The presence of higher Cl? during winter is due to western disturbances and probably local emission of Cl? due to fabric bleaching activity in a number of export garment factories in the proximity of the sampling site.  相似文献   

7.
In this study, the concentrations of ambient total suspended particulates (TSP) and their dry deposition were measured using a PS-1 sampler with dry deposition plates at a wetland sampling site in central Taiwan during a sampling period from October 2016 to December 2016. The PS-1 sampler was fixed at set distances (1.5 and 2 m) from a dry deposition plate, and sampled particulate pollutants were sampled to determine their concentrations and dry deposition rates simultaneously. A dry deposition plate 3 m from the PS-1 sampler was also used to collect dry deposition particulate. This plate was also used to compare dry depositions from ambient air, collected from new device. The results thus obtained indicated that the average dry deposition rates on the dry deposition plates that were 1.5 and 2 m from the sampler were 103.15 and 103.94 µg/m2 min, respectively, in October, 83.36 and 100.18 µg/m2 min in November, and 171.2 and 157.5 µg/m2 min in December. These dry deposition rates were compared with that 3 m away from the PS-1 sampler. The statistical t test revealed no significant differences between the dry depositions on dry deposition plates at 1.5 and 2 m from the sampler. The dry deposition rates at 1.5 and 2 m from the sampler did not differ significantly from that at 3 m from the PS-1 sampler. This study proves that a PS-1 sampler can be combined with a dry deposition plate to measure TSP concentrations and dry depositions simultaneously using a single device.  相似文献   

8.
The 19th Common Wealth Games was organized at Delhi, India, during October 3 to 14, 2010, where more than 8,000 athletes from 71 Commonwealth Nations have participated. In order to give them better environment information for proper preparedness, mass concentrations of particulate matters below 10 microns (PM10) and 2.5 microns (PM2.5), black carbon (BC) particles and gaseous pollutants such as carbon monoxide (CO) and nitrogen oxide (NO) were monitored and displayed online for ten different locations around Delhi, including inside and outside the stadiums. This extensive information system for air quality has been set up for the period from September 24 to October 21, 2010, and data have been archived at 5-min interval for further research. During the study period, average concentration of PM10 and PM2.5 was observed to be 229.7 ± 85.5 and 112.1 ± 56.0 μg m?3, respectively, which is far in excess of the corresponding annual averages, stipulated by the national ambient air quality standards. Significant large and positive correlation (r = 0.93) between PM10 and PM2.5 implies that variations in PM10 mass are governed by the variations in PM2.5 mass. The mass concentrations of PM2.5 inside the stadium were found to be ~18 % lower than those outside; however, no large variations were observed in PM10. Mean concentrations of BC, CO and NO for the observation period were 10.9 μg m?3 (Min, 02 μg m?3; Max, 31 μg m?3), 1.83 ± 0.89 ppm (Min, 0.48 ppm; Max, 4.55 ppm) and 37.82 ppb (Min, 2.4 ppb; Max, 206.05 ppb), respectively. BC showed positive correlation (r = 0.73) with CO suggests unified source for both of them, mainly from combustion emissions. All the measured parameters, however, show a significant diurnal variation with enhanced peaks in the morning and late night hours and lower values during daytime.  相似文献   

9.
Using a portable emissions measurement system, 16 gasoline passenger cars were tested on a fixed route consisting of different types of roads in Macao and the data were normalized with the vehicle-specific power bin method. The normalized HC, CO and NO X emission levels of the seven passenger car samples with model year older than 2000 were 3.19 ± 5.04, 14.59 ± 22.88, 2.57 ± 2.12 g/km, respectively. The HC, CO and NO X emission levels of other newer samples were 0.02 ± 0.02, 0.23 ± 0.29 and 0.10 ± 0.13 g/km, respectively. The scrappage of old passenger cars in Macao should be a high priority to control the total emissions of motor vehicles. Based on relative emission levels, a clear and similar pattern for gaseous pollutants and fuel consumption with driving conditions was identified. The emissions of HC, CO and NO X are best fitted to average speed with inverse functions. Fuel consumption is best fitted to average speed with a power function. Compared to the average driving conditions, the emission factors of HC, CO and NO X and fuel consumption of gasoline passenger cars during the rush hours on the Macau Peninsula will be increased by 61, 55, 45 and 90 %, respectively. This situation will deteriorate by 2015 if no further transportation management strategies are implemented in Macao. To save energy and mitigate the air pollutant emissions in the urban area, improved traffic planning and travel demand management are also necessary.  相似文献   

10.
Tidal marshes act as a buffer system for nutrients in the pore water and play important roles in controlling the budget of nutrients and pollutants that reach the sea. Spatial and seasonal dynamics of pore water nutrients were surveyed in three tidal marshes (Chongming Island, Hengsha Island, and Fengxian tidal flat) near the Yangtze Estuary and Hangzhou Bay from August 2007 to May 2008. Nutrient variations in pore water closely followed seawater quality in the estuaries, while the average concentration of NH4 +–N, the main form of inorganic nitrogen in pore water, was over two orders of magnitude higher than that in seawater which was dominated by nitrate. NH4 +–N export (13.81 μmol m?2 h?1) was lower than the import of (NO3 ?+NO2 ?)–N (?24.17 μmol m?2 h?1) into sediment over the 1-year period, hence reducing N-eutrophication in coastal waters. The export of SiO3 2?–Si and PO4 3?–P from tidal marshes regulated nutrient level and composition and lifted the ratio beyond potentidal element limitation in the coastal system. Moreover, macrophyte plants (Spartina alterniflora and Phragmites australis) played significant roles in controlling nutrient concentration in pore water and its exchange between marshes and estuaries. Fengxian marsh was characterized by higher nutrient concentrations and fluxes than other marshes in response to the more serious eutrophication in Hangzhou Bay than in the Yangtze Estuary.  相似文献   

11.
Due to its negative impact on the living environment of human beings, ambient air pollution has become a global challenge to human health. In this study, surface observations of six criteria air pollutants, including PM2.5, PM10, SO2, NO2, CO and O3, were collected to investigate the spatial and temporal variation in the Beijing–Tianjin–Hebei (BTH) region during 2013–2016 and to explore the relationships between atmospheric pollutants and meteorological variables using quantile regression model (QRM) and multiple linear regression model (MLRM). The results show that BTH region has experienced significant air pollution, and the southern part generally has more severe conditions. The annual average indicates clear decreasing trends of the particulate matters, SO2 and CO concentrations over the last 4 years and slight increasing trends of NO2 and O3 in several cities. The seasonal and monthly characteristics indicate that the concentrations of five species reach their maxima in the winter and their minima in the summer, whereas O3 has the opposite behaviour. Finally, the pseudo R2 values show that the QRMs have the best performance in the winter, followed by spring, fall, and summer. Specifically, all the meteorological factors have significant impacts on air pollution but change with pollutants and seasons. The MLRM results are generally consistent with the QRM results in all seasons, and the inconsistencies are more common in the fall and winter. The results of this research provide foundational knowledge for predicting the response of air quality to climate change in the BTH region.  相似文献   

12.
El Shalal-Kema area is located east of Aswan town and Nile River. The Quaternary sediments (unconsolidated material of sands, gravels, and clays intercalation) represent the main aquifer in the studied area. Its water is under unconfined condition, and the water table is shallow (vary from 7.5 to 16.3 m). The concerned aquifer is recharged mainly from Aswan Dam Lake, from the excess irrigation water and from septic tanks, where the area is not served by sewage system. The direction of the groundwater movement is generally from south to north. The transmissivity values of the Quaternary aquifer (from three pumping tests) are relatively high (vary from 1,996 to 3,029 m2/day). The exploitation of groundwater is carried out where there is continuous withdrawal for industrial and domestic uses with a total average quantity of groundwater of 71,304 m3 per day (25.67 million m3 per year). The hydrochemical characteristics of the Quaternary aquifer is studied based on the chemical analysis of 29 groundwater and four surface water samples collected from different sites. The chemical composition of the groundwater is dominated by calcium Ca2+ from the cations and bicarbonate (HCO 3 ? ) from the anions, and the order of cation abundance is Ca2+ > Na+ > Mg2+ > K+ and HCO 3 ? > SO 4 2? > Cl? among the anions. The groundwater types are normal chloride water, normal sulfate water, and normal carbonate water. The hypothetical salt combination revealed the presence of different salts arranged in terms of their predominant as Ca(HCO3)2, Mg(HCO3)2, NaCl, Na2SO4, MgSO4, KCL, NaHCO3, MgCl2, CaSO4, and K2SO4. The analytical measurements to the NO2 and NH3 reveal that their values decrease in summer and increase in winter due to the stoppage of pumping which leads to the increase of the wastewater quantities that reach the groundwater. The chemical and microbiological analyses show that the aquifer in this area is contaminated with fecal and disease-causing bacteria. The main cause of this contamination is the outflow from the septic tanks; therefore, the construction of sewage network is a vital solution. Chlorination is important to disinfect the groundwater at the tanks before its distribution to the houses.  相似文献   

13.
Reverse dispersion modelling was employed to quantify sulphur dioxide (SO2) and nitrogen dioxide (NO2) emissions from brick firing clamp kilns and spontaneous combustion from a coal discard dump. Reverse dispersion modelling technique integrates ambient monitoring and dispersion simulation to calculate actual emission rates from an assumed rate of 1 g per second (g/s). Emission rates and emission factors were successfully quantified for SO2, but not for NO2, due to the influence of external sources and the complexity regarding the varying proportion of nitrogen oxides released from the kiln. Quantified emission factor for clamp kiln firing ranged from 1.91–3.24 g of SO2 per brick fired and 0.67–1.14 g of SO2 per kilogram of bricks fired. The variation in SO2 emission factors was linked to high variability in energy input. The source configuration input to the dispersion model, assumed to represent the kiln, was changed from a volume source to a more effective “bi-point” source situated at the top of the kiln, with buoyancy calculated from the carbon combustion rate. In addition, SO2 emission rate for spontaneous combustion from the discard dump was quantified as 0.35 g/s. 274 tons of discard material was estimated to burn annually, assuming that the emission rate is consistent over a year. Consequently, the reverse dispersion modelling and the elevated “bi-point” source technique may be considered a novel approach for quantifying emissions from combustion of materials or mixture of materials where knowledge of source parameters is limited.  相似文献   

14.
The thermal stability of sideronatrite, ideally Na2Fe3+(SO4)2(OH)·3(H2O), and its decomposition products were investigated by combining thermogravimetric and differential thermal analysis, in situ high-temperature X-ray powder diffraction (HT-XRPD) and Fourier transform infrared spectroscopy (HT-FTIR). The data show that for increasing temperature there are four main dehydration/transformation steps in sideronatrite: (a) between 30 and 40 °C sideronatrite transforms into metasideronatrite after the loss of two water molecules; both XRD and FTIR suggest that this transformation occurs via minor adjustments in the building block. (b) between 120 and 300 °C metasideronatrite transforms into metasideronatrite II, a still poorly characterized phase with possible orthorhombic symmetry, consequently to the loss of an additional water molecule; X-ray diffraction data suggest that metasideronatrite disappears from the assemblage above 175 °C. (c) between 315 and 415 °C metasideronatrite II transforms into the anhydrous Na3Fe(SO4)3 compound. This step occurs via the loss of hydroxyl groups that involves the breakdown of the [Fe3+(SO4)2(OH)] ∞ 2? chains and the formation of an intermediate transient amorphous phase precursor of Na3Fe(SO4)3. (d) for T > 500 °C, the Na3Fe(SO4)3 compound is replaced by the Na-sulfate thenardite, Na2SO4, plus Fe-oxides, according to the Na3Fe3+(SO4)3 → 3/2 Na2(SO4) + 1/2 Fe2O3 + SOx reaction products. The Na–Fe sulfate disappears around 540 °C. For higher temperatures, the Na-sulfates decomposes and only hematite survives in the final product. The understanding of the thermal behavior of minerals such as sideronatrite and related sulfates is important both from an environmental point of view, due to the presence of these phases in evaporitic deposits, soils and sediments including extraterrestrial occurrences, and from the technological point of view, due to the use of these materials in many industrial applications.  相似文献   

15.

Coal mining has serious impacts on local environment, including damage to the land and soil by subsidence, damage to ground-water systems through the fracturing and subsiding of overlying rocks, contamination of surface waters with acid mine drainage, and pollution of the atmosphere by release of toxic gases. The damage to ground water and its consequent impacts on the regional environment is the core of research of the coal mining from the perspective of environment protection. The present paper focuses on the changes of surface vegetation coverage, the pollutants released from pit coal power plants, and the damages to the ground aquifers induced by mining activities in arid Eastern Junggar coalfield of China. At first, the authors investigated the changes of surface vegetation coverage, since mining began in the 2000s using Landsat data. Results show that the low surface vegetation coverage (grade 1 plus grade 2) in the southern part of the region decreased from 11.62?×?108 m2 in 2003 to 9.57?×?108 m2 in 2017 (?17.6%), while it increased from 11.58?×?108 m2 in 2003 to 12.70?×?108 m2 in 2017 (+?9.7%) in the eastern part. The high surface vegetation coverage (grade 3 plus grade 4) in the southern part increased from 1.94?×?108 m2 in 2003 to 4.00?×?108 m2 in 2017 (+?106.2%), while it decreased from 4.39?×?108 m2 in 2003 to 3.26?×?108 m2 in 2017 (?25.74%) in the eastern part. The data of annual precipitation during the same period in this area show that the changes of surface vegetation coverage have less relationship with the annual precipitation, which indicates that the mining activities is probably the major factor for that. Second, a statistic of air pollutants generated from pit coal power plants was made based on data of references. Results show that the estimated gaseous pollutant emissions increased as 865.23 tons of smoke particles, 5940.73 tons of SO2, and 7584.48 tons of NO2 in 2013, which increased rapidly with 9.73 times the smoke particle, 21.69 times the SO2, and 9.24 times the NO2 than that of 2007. And then, the physical and numerical simulation of the damage of mining activities to aquifers was made to show the permeability of the reference points of overlying aquifers varies associated with mining activities. Results show that the porous rock matrix permeability has a negative relationship with fluctuation during mining, while the fracture permeability shows a positive one. Finally, a case investigation in southern area surrounding this coalfield was illustrated. Result shows that the local ground-water level decreased by 16 m difference from the altitude level of?+?774 m in 2003 to?+?758 m in 2013. Data and results from this study presented the already and the potential pollutions and damages to local environment induced by the mining activities in this region.

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16.
Al hydroxide was prepared by hydrolysis of Al(NO3)3, and oc-B-Al hydroxide was prepared by hydrolysis of Al(NO3)3 in the presence of boric acid solution. Curve-fitted B1s XPS spectrum of oc-B-Al hydroxide demonstrated that the boron atom was probably incorporated with Al hydroxide to some extent. The IR band of Al–OH at 1,074 cm?1 of oc-B-Al hydroxide was weaker than that of Al hydroxide. This indicated some surface hydroxyl groups of Al–OH of oc-B-Al hydroxide had disappeared. These peaks at 1,320 and 1,458 cm?1 bands found in the oc-B-Al hydroxide were closer together than the salts containing boron, which are attributed to an interaction of aluminum hydroxide with boron. Analysis of XRD patterns indicated that Al hydroxide was very poorly crystalline boehmite, and oc-B-Al hydroxide appeared to have crystallite dimensions slightly smaller than those present in Al hydroxide. TEM showed that the presence of boron significantly decreased the size of Al hydroxide particles. The specific surface area of oc-B-Al hydroxide (556.0 m2 g?1) using BET method was larger than that of Al hydroxide (421.6 m2 g?1). This indicated the likelihood of Mn2+ adsorption ability of oc-B-Al hydroxide than the Al hydroxide. Boron-doped Al hydroxide always adsorbed more Mn2+, stabilized the sample solution pH to a higher value and slowed soil acidification than the Al hydroxide. It is suggested that boron in soils not only serves as a plant nutrient, but can also decrease the Mn2+ toxicity and slows soil acidification by formation of oc-B-Al hydroxide.  相似文献   

17.
The objective of the study is to investigate spatio-temporal variations of PM10, PM2.5, and PM1 concentrations at seven residential sites, located in the vicinity of opencast coal projects, Basundhara Garjanbahal Area (BGA), India. Meteorological parameters such as wind speed, wind direction, relative humidity, and temperature were collected simultaneously with PM concentrations. Mean concentrations of PM10 in the range 215 ± 169–526 ± 412 μg m?3, PM2.5 in the range of 91 ± 79–297 ± 107 μg m?3, PM1 in the range of 68 ± 60–247 ± 84 μg m?3 were obtained. Coarse fractions (PM2.5–10) varied from 27 to 58% whereas fine fractions (PM1–2.5 and PM1) varied in the range of 51–73%. PM2.5 concentration was 41–74% of PM10 concentration, PM1 concentration was 31–62% of PM10 concentration, and PM1 concentration was 73–83% of PM2.5 concentration. Role of meteorology on PM concentrations was assessed using correlation analysis. Linear relationships were established among PM concentrations using least square regression analysis. With the aid of principal component analysis, two components were drawn out of eight variables, which represent more than 75% of variance. The results indicated that major sources of air pollutants (PM10, PM2.5, PM1, CO, CO2) at the residential sites are road dust raised by vehicular movement, spillage of coal generated during transportation, spontaneous combustion of coal, and biomass burning in village area.  相似文献   

18.
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19.
It is important to have qualitative as well as quantitative understanding of the hydraulic exchange between lake and groundwater for effective water resource management. Dal, a famous urban fresh water lake, plays a fundamental role in social, cultural and economic dynamics of the Kashmir Valley. In this paper geochemical, isotopic and hydrological mass balance approaches are used to constrain the lake water–groundwater interaction of Dal Lake and to identify the sources of lake water. Water samples of precipitation (n = 27), lake water (n = 18) and groundwater (n = 32) were collected across the lake and its catchment for the analysis of δ18O and δ2H. A total of 444 lake water samples and 440 groundwater samples (springs, tube wells and dug wells) were collected for the analysis of Ca2+, Mg2+, HCO3 ?, SO4 2?, Cl?, NO3 ?, Na+ and K+. Water table and lake water level were monitored at 40 observation locations in the catchment. Water table map including pH and EC values corroborate and verify the gaining nature of the Dal Lake. Stable isotopes of lake water in Boddal and Gagribal basins showed more deviation from the global meteoric water line than Hazratbal and Nigeen basins, indicating the evaporation of lake water. The isotopic and geochemical mass balance suggested that groundwater contributes a significant proportion (23–40%) to Dal Lake. The estimated average groundwater contribution to Dal Lake ranged from 31.2 × 103 to 674 × 103 m3 day?1 with an average of 276 × 103 m3 day?1. The study will be useful to delineate the possible sources of nutrients and pollutants entering the lake and for the management of lake water resources for sustainable development.  相似文献   

20.
Over the past decades, the Gujarat state of India experienced intensive agricultural and industrial activities, fertilizer consumption and abstraction of groundwater, which in turn has degraded the ground water quality. Protection of aquifers from nitrate pollution is a matter of prime concern for the planners and decision-makers. The present study assessed the spatial and temporal variation of groundwater nitrate levels in areas with different land use/land cover activities for both pre- and post-monsoon period. The pre-monsoon nitrate level (1.6–630.7 mg/L) in groundwater was observed to be higher as compared to the post-monsoon level (2.7–131.7 mg/L), possibly due to insufficient recharge and evaporation induced enrichment of agrichemical salts in groundwater. High HCO3 ? (200–1,000 mg/L) as well as SO4 2?/Cl? (0.111–0.992) in post-monsoon period provides a favourable environment for denitrification, and lower the NO3 levels during the post-monsoon period. The K vs NO3 scatter plot suggests a common source of these ions when the concentration is <5 mg/L, the relationships between different pollutants and nitrate also suggest that fertilizers and other sources, such as, animal waste, crop residue, septic tanks and effluents from different food processing units present in the area can be attributed to higher nitrate levels in the groundwater. Appropriate agronomic practices such as application of fertilizers based on calibrated soil tests and proper irrigation with respect to crop can minimize the requirement for inorganic fertilizers, which can bring down the cost of cultivation considerably, and also protect groundwater from further degradation.  相似文献   

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