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1.
Starr M Ukonmaanaho L Sibley PK Hazlett PW Gordon AM 《Environmental monitoring and assessment》2007,125(1-3):123-136
Open precipitation and throughfall was collected at a Norway spruce stand in Finland using funnel-type collectors and at a
black spruce stand in Canada using trough-type collectors. The presence or absence of a rim on the funnel, funnel diameter
(9, 14 and 20 cm) and length of sampling period (1, 2 and 4 weeks) on monthly values were evaluated at the Norway spruce stand,
and the number of collectors required for defined levels of accuracy and precision of throughfall loads to be reached and
the influence of the spatial arrangement of collectors on solute concentrations was studied at both stands. The presence of
a rim had no significant effect on open precipitation and throughfall amounts, but did on throughfall DOC, Ca2+, Mg2+, K+, Na+ and Cl− ion loads. Deposition loads increased with decreasing funnel diameter; for open precipitation, this was due to increased
catch efficiency while for throughfall the increase was attributed to canopy interaction and leaching of litter trapped in
the collectors. Calculated monthly H+ loads decreased and those for all other constituents increased with collection period length. Using 15 collectors at the
Norway spruce stand would allow throughfall loads to be determined to within 20% of the true mean weekly value with a confidence
level of 95% for most solute, but not for NH4
+–N, NO3
−–N, Mg2+ and SO4
2−-S. Using 15 trough collectors, the same confidence level at the more heterogeneous black spruce stand would only be achieved
for H+, Cl−, DOC and SO4
2−-S loads. In both stands, using either random or systematic placements of throughfall collectors gave similar results. 相似文献
2.
Fölster J Göransson E Johansson K Wilander A 《Environmental monitoring and assessment》2005,102(1-3):389-403
Variation in water chemistry was studied in 80 lakes in southern Sweden. The lakes had forest dominated catchments. The length of the time series was 14 years. Synchrony was calculated as Pearsons product moment correlation coefficients for all combinations of lakes, i.e. 3160 lake-pairs. The chemical variables studied were non-marine sulphate (SO4
*), non-marine calcium (Ca*), absorbance and acid neutralising capacity (ANC). Statistically significant synchrony occurred in 93% of all lake-pairs for SO4
*, and between 58 and 67% for absorbance, Ca* and ANC. In 70% of all lake-pairs, the synchrony was \s>0.71 for SO4
*, which means that more than half of the variation in one lake could be explained by the variation in the other lake. For absorbance, Ca* and ANC, about 25% of the lake-pairs had a synchrony \s>0.71. The relatively high synchrony for SO4
* occurred during an overall downward trend in SO4
* concentration.The degree of synchrony in our study was at a level comparable to other studies in northern America and England. However, our study included lakes in a much larger area, with distances of up to 500 km between the lakes, while earlier studies were made on small lake districts with lakes located within approximately 50 km. In contrast to these earlier studies, there was no correlation between synchrony and distance, lake characteristics or catchment characteristics. However, when a small subset of 15 lakes in the southeast of Sweden was selected, such relations were found. 相似文献
3.
Impact of Coal Power Plant Emission on the Foliar Elemental Concentrations in Plants in a Low Rainfall Tropical Region 总被引:1,自引:0,他引:1
A field study was conducted around two thermal power plants of India to quantify the changes in foliar elemental concentrations due to emission in a low rainfall tropical area. Sulphur dioxide and particulates were at high levels which may cause serious ecological effects. Emission from the power plants has altered the elemental concentrations in the leaves of evergreen and deciduous plants. The foliar total-S and SO4
2–-S levels were significantly higher in all the plants growing at polluted sites. However, the organic-S content was more or less unaltered. In evergreen plants, the SO4
2–-S content increased gradually from summer through winter, whereas in the deciduous plants there was a higher magnitude of increase after onset of new leaves during summer. With the increasing pollution load, foliar Ca2+ and K+ contents increased, whereas N content decreased. The reduction in N content was greater during summer in evergreen plants and during winter in deciduous plants. The plants growing closer to the power plants accumulated more trace elements (Mn, Fe, Cd, Pb and Ni) as compared to those growing at distant sites. In deciduous plants the leaf fall during winter lowered down the trace element 相似文献
4.
D. S. Jeffries D. C. L. Lam I. Wong R. M. Bloxam 《Environmental monitoring and assessment》1992,23(1-3):99-113
Changes in SO
inf4
sup2-
deposition predicted to occur in response to implementation of announced SO2 emission control programs in Canada and the U.S.A. have been used as input to water chemistry models thereby giving an estimate of the changes in lake acid neutralizing capacity (ANC) and pH that can be expected from these programs. Eastern Canada has been divided into 22 subregions for the purpose of this analysis. Relative to the current level (1982–86) of SO
inf4
sup2-
deposition (Scenario 1), the effect of the Canadian SO2 emission control program alone (Scenario 2) is compared to that obtained when controls are implemented throughout North America (Scenarios 3 and 4). SO2 emission reduction will effect a shrinkage of the high wet SO
inf4
sup2-
deposition field in NE North America such that under Scenario 4 conditions, almost no area will remain in Canada that receives >20 kg ha-1 yr-1. The greatest decrease in deposition and resulting change in lake chemistry occurs in southern Ontario and southwestern Quebec. ANC distributions shift to higher concentrations and the percentage of lakes having pH<6 decreases in these areas. The Atlantic Provinces will obtain only a minor benefit from the control programs, i.e. experiencing only a small decrease in deposition and improvement in water quality. High sensitivity of the terrain in many parts of Atlantic Canada means that large numbers of lakes will remain acidic (i.e. ANC<0) and/or have pH<6 (an important biological threshold) even after full implementation of the current plans for SO2 control in Canada and the U.S. 相似文献
5.
Sulphate, Nitrogen and Base Cation Budgets at 21 Forested Catchments in Canada, the United States and Europe 总被引:1,自引:0,他引:1
Watmough SA Aherne J Alewell C Arp P Bailey S Clair T Dillon P Duchesne L Eimers C Fernandez I Foster N Larssen T Miller E Mitchell M Page S 《Environmental monitoring and assessment》2005,109(1-3):1-36
To assess the concern over declining base cation levels in forest soils caused by acid deposition, input-output budgets (1990s
average) for sulphate (SO4), inorganic nitrogen (NO3-N; NH4-N), calcium (Ca), magnesium (Mg) and potassium (K) were synthesised for 21 forested catchments from 17 regions in Canada,
the United States and Europe. Trend analysis was conducted on monthly ion concentrations in deposition and runoff when more
than 9 years of data were available (14 regions, 17 sites). Annual average SO4 deposition during the 1990s ranged between 7.3 and 28.4 kg ha−1 per year, and inorganic nitrogen (N) deposition was between 2.8 and 13.8 kg ha−1 per year, of which 41–67% was nitrate (NO3-N). Over the period of record, SO4 concentration in deposition decreased in 13/14 (13 out of 14 total) regions and SO4 in runoff decreased at 14/17 catchments. In contrast, NO3-N concentrations in deposition decreased in only 1/14 regions, while NH4-N concentration patterns varied; increasing at 3/14 regions and decreasing at 2/14 regions. Nitrate concentrations in runoff
decreased at 4/17 catchments and increased at only 1 site, whereas runoff levels of NH4-N increased at 5/17 catchments. Decreasing trends in deposition were also recorded for Ca, Mg, and K at many of the catchments
and on an equivalent basis, accounted for up to 131% (median 22%) of the decrease in acid anion deposition. Base cation concentrations
in streams generally declined over time, with significant decreases in Ca, Mg and K occurring at 8, 9 and 7 of 17 sites respectively,
which accounted for up to 133% (median 48%) of the decrease in acid anion concentration. Sulphate export exceeded input at
18/21 catchments, likely due to dry deposition and/or internal sources. The majority of N in deposition (31–100%; median 94%)
was retained in the catchments, although there was a tendency for greater NO3-N leaching at sites receiving higher (<7 kg ha-1 per year) bulk inorganic N deposition. Mass balance calculations show that export of Ca and Mg in runoff exceeds input at
all 21 catchments, but K export only exceeds input at 16/21 sites. Estimates of base cation weathering were available for
18 sites. When included in the mass balance calculation, Ca, Mg and K exports exceeded inputs at 14, 10 and 2 sites respectively.
Annual Ca and Mg losses represent appreciable proportions of the current exchangeable soil Ca and Mg pools, although losses
at some of the sites likely occur from weathering reactions beneath the rooting zone and there is considerable uncertainty
associated with mineral weathering estimates. Critical loads for sulphur (S) and N, using a critical base cation to aluminium
ratio of 10 in soil solution, are currently exceeded at 7 of the 18 sites with base cation weathering estimates. Despite reductions
in SO4 and H+ deposition, mass balance estimates indicate that acid deposition continues to acidify soils in many regions with losses of
Ca and Mg of primary concern.
The U.S. Government's right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged.
The Canadian Crown reserves the right to retain a non-exclusive, royalty free licence in and to any copyright. 相似文献
6.
Sisr L Mihaljevic M Ettler V Strnad L Sebek O 《Environmental monitoring and assessment》2007,135(1-3):465-473
The mobility of arsenic in Cambisol under the influence of added barnyard manure and application of a phosphate solution to
the soil was described on the basis of column experiments. A soil sample containing 126 mg/kg total As and 3.72 mg/kg specifically-sorbed
As was extracted using demineralized water (DIW) or a 28 μmol/l phosphate solution in a column containing untreated soil and
in a column with added barnyard fertilizer. The pH, Eh, alkalinity, main components, including DOC, and selected trace elements
(Al, Mn, Pb, Cu, Zn, Cd, Cr, Co, Ni, Ba and As) were determined in the extracts. Hydrodynamic tests of the flow and transport
of the substances in the columns were carried out. The addition of barnyard manure was manifested in elevated concentrations
of the main inorganic components, DOC and Al and a decrease in the Eh value and Mn concentration. Application of a phosphate
solution was manifested in a decrease in the NO3 and SO4 concentrations, probably as a result of the effect of increased biological fixation. The As concentration in extracts varied
from 8.8 to 15.5 μg/l and was not dependent on the composition of the extracting solution or the addition of barnyard fertilizer. 相似文献
7.
Chung-Yih Kuo Yan-Ruei Lin Shih-Yu Chang Chuan-Yao Lin Chun-Hung Chou 《Environmental monitoring and assessment》2013,185(12):9777-9787
Daily and hourly average data from nine air-quality monitoring stations distributed across central Taiwan, which include ten items (i.e., PM10, PM2.5, wind direction, wind speed, temperature, relative humidity, SO2, NO2, NO, and CO), were collected from 2005 to 2009. Four episode types: long-range transport with dust storms (DS), long-range transport with frontal pollution (FP), river dust (RD), and stagnant weather (SW), and one mixed type of episode were identified. Of these four episode types, the SW was the dominant type, averaging about 70 %. The mean ratio of PM2.5/PM10 was the lowest during the RD episodes (0.42), while the mean ratio of PM2.5/PM10 was the highest during the SW episodes (0.64). Fine aerosol (PM2.5) and coarse aerosol (PM10–2.5) samples were collected by high-volume samplers for chemical composition analysis, from only three stations (Douliou, Lunbei, and Siansi) during the days of SW, RD, DS, and FP. The concentrations of PM2.5 and three ionic species (NH4 +, NO3 ?, and SO4 2?) all showed significant differences among the four episode types. The highest levels of NO3 ? (12.1 μg/m3) and SO4 2? (20.5 μg/m3) were found during the SW and FP episodes, respectively. A comparison on the spatial similarity of aerosol compositions among the episodes and/or non-episodes (control) was characterized by the coefficient of divergence (CD). The results showed higher CD values in PM10–2.5 than in PM2.5, and the CD values between RD episodes and the other three episodes were higher than those between two types of episode for the other three episodes. The ratios of SOR (sulfur oxidation ratio), SO4 2?/EC (elemental carbon), NOR (nitrogen oxidation ratio), and NO3 ?/EC showed that sulfate formation was most rapid during the FP, while nitrate formation was most rapid during the SW. 相似文献
8.
Throughfall and open field bulk precipitation were measured at three coniferous sites during 1995–2002 in the framework of
ICP Integrated Monitoring and at five coniferous sites during 1996–2002 in the framework of ICP Forests (Level II). The coniferous
canopies acted as a sink for nitrate and ammonium and as a source for base cations: Ca2+, Mg2+ and K+. The estimated share of SO4–S dry deposition from total deposition was 1.5–4 times higher for dormant period compared to growing period. During the study
period average annual throughfall and bulk deposition of SO4–S decreased significantly, 2.8 and 2.3 times, respectively.
Throughfall enrichment with base cations increased in the order Mg < Na < Ca < K. Using Na as a tracer ion, average dry deposition
and canopy leaching were calculated. Leaching was the dominant process for TF enrichment by potassium. Leaching of base cations
occurred during growing as well as dormant period.
The calculated internal flux of Ca2+ and Mg2+ varied in the range of 0.6–2.0 and 0.6–1.2 kg ha−1 per year in spruce and pine stands, respectively. The internal circulation of K+ was significantly higher (8.9–10.9 kg ha−1 per year) in spruce stands than in pine stands (2.7–4.4 kg ha−1 per year). 相似文献
9.
An atmospheric pollution survey was carried out at 13 sites in Karachi, Pakistan, simultaneously from 0600 h to 2100 h for 15 consecutive days in May 1990 which also included meteorological measurements. The monitoring sites were included along the prevailing wind patterns in Karachi. Carbon monoxide levels in the ambient air were found to reach 9–10 ppm along the busy urban streets whereas CO2 level exceeded 370 ppm in these areas. Our survey indicates that NO2 levels were exceeding U.S. ambient air quality standards. Maxmum NO2 concentrations were observed (0.3–0.5 ppm) during the daytime from 0600 h to 2100 h. The surface ozone maximum around noon at the inland sites reached the levels of 40 ppb and 50 ppb respectively compared to upwind coastal Sites 1 level of 25 ppb. The Pb concentrations were approximately 3- to 7-fold higher than average, which corresponded well to urban air. Fossil fuel SO4 (excess) and NO3 were apportionally based on the assumption that these two anions were present as (NH4)2SO4, and NH4NO3 in the aerosols. In the eastern part of the city atmospheric sulphate (SO4) shows the combustion of coal as its source from the vicinity and downwind of a steel manufacturing plant. 相似文献
10.
Using non-parametric techniques, we studied water chemistry changes from 1983 to 1992 in 18 rivers located at the extreme northeastern portion of North America. This period was marked by a decrease in sulfate (SO
4
–
) production in eastern Canada from 1982 to 1986, followed by a levelling off from 1986 to 1992. Nitrate (NO
3
–
) production and deposition generally increased over this whole period. We used two time windows, 1983 to 1989 and 1983 to 1992, to determine if changes in river acidification variables occurred over the ten year period. We found significant trends of increasing pH and acid neutralization capacity (ANC) concentrations at eight sites using both time windows, while SO
4
–2
increased at five and seven sites during the same two time periods. Nitrate concentrations showed few consistent trends, while base cations showed increases in the earlier part of the data set and total organic carbon (TOC) showed long-term decreases. There were few significant trends in hydrogen (H+), and a slight decrease in SO
4
–2
exports as opposed to increased concentrations over the same period. We attribute the discrepancy between SO
4
–2
concentration and export trends to be due to evapotranspiration in the basins, causing a concentration of ions in water. Nitrate and calcium exports showed no trends, while TOC decreased at four or five sites, depending on the time window used. Longer data sets tended to produce more detectable trends. Overall, water chemistry in the region is showing the effects of reduced SO
4
–
loads and is not yet being affected by the increases in NO
3
–
deposition. 相似文献
11.
利用简单、方便、不用电源的被动采样技术分别对川南地区6市区域范围内空气中SO2和NO2在雨季和旱季的空间分布特征进行研究。按16 km×16 km的均匀网格布设点位162个,并在雨季于6市各选1个空气自动站布设城区点位采集空气中SO2和NO2。获得的样品经0.3%的双氧水浸提后采用离子色谱法进行分析,经换算后获得空气中SO2和NO2的浓度,了解了其含量水平,绘制了SO2和NO2的空间分布图,掌握了其空间分布特征,并对可能的来源进行了浅析。将被动采样监测结果与自动站监测结果进行相关分析,两者高度线性相关,NO2和SO2线性相关系数分别为0.901 3和0.874 5,均大于r0.05(4)=0.811 4。 相似文献
12.
基于AGNES算法优化BP神经网络和GIS系统的大气污染物浓度预测 总被引:1,自引:0,他引:1
建立了大气污染物浓度与影响因子之间的BP神经网络,对城市中各监测点位的次日大气污染物浓度进行预测,采用GIS的插值分析进行污染物空间分布预测,其中BP神经网络的输入向量采用AGNES算法进行处理。以太原市区SO2、PM10浓度预测为例,选择气温、湿度、降水量、大气压强、风速和前5天的污染物浓度等10个参数训练BP神经网络,结果表明,BP神经网络的训练效果较好,预测结果与实际浓度显著相关,R2分别为0.988、0.976;结合太原市8个监测点位的污染物浓度预测值,运用GIS空间差值法绘出SO2、PM10的浓度分布预测图,该图与实际情况大体符合,并且与国控大气污染企业的分布显著相关,Pearson相关系数分别为0.969、0.949。 相似文献
13.
James A. Entry 《Environmental monitoring and assessment》2013,185(2):1985-2000
The Loxahatchee National Wildlife Refuge (Refuge) is affected by inflows containing elevated contaminant concentrations originating from agricultural and urban areas. Water quality was determined using three networks: the Northern Refuge (NRN), the Southern Refuge (SRN), and the Consent Decree (CDN) monitoring networks. Within these networks, the Refuge was divided into four zones: (1) the canal zone surrounding the marsh, (2) the perimeter zone (0 to 2.5 km into the marsh), (3) the transition zone (2.5 to 4.5 km into the marsh), and (4) the interior zone (>4.5 km into the marsh). In the NRN, alkalinity (ALK) and conductivity (SpC) and dissolved organic carbon, total organic carbon, total dissolved solids (TDS), Ca, Cl, Si, and SO4 concentrations were greater in the perimeter zone than in the transition or interior zone. ALK, SpC, and SO4 concentrations were greater in the transition than in the interior zone. ALK, SpC, and TDS values, Ca, SO4, and Cl had negative curvilinear relationships with distance from the canal toward the Refuge interior (r 2?=?0.78, 0.67, 0.61, 0.77, 0.62, and 0.57, respectively). ALK, TB and SpC, and Ca and SO4 concentrations decreased in the canal and perimeter zones from 2005 to 2009. Important water quality assessments using the SRN and CDN cannot be made due to the sparseness and location of sampling sites in these networks. The number and placement monitoring sites in the Refuge requires optimization based on flow pattern, distance from contaminant source, and water volume to determine the effect of canal water intrusion on water quality. 相似文献
14.
D. P. Singh Ranu Gadi T. K. Mandal C. K. Dixit Khem Singh T. Saud Nahar Singh Prabhat K. Gupta 《Environmental monitoring and assessment》2010,163(1-4):1-13
The variation in air quality was assessed from the ambient concentrations of various air pollutants [total suspended particle (TSP), particulate matter ≤10 μm (PM10), SO2, and NO2] for pre-Diwali, Diwali festival, post-Diwali, and foggy day (October, November, and December), Delhi (India), from 2002 to 2007. The extensive use of fireworks was found to be related to short-term variation in air quality. During the festival, TSP is almost of the same order as compared to the concentration at an industrial site in Delhi in all the years. However, the concentrations of PM10, SO2, and NO2 increased two to six times during the Diwali period when compared to the data reported for an industrial site. Similar trend was observed when the concentrations of pollutants were compared with values obtained for a typical foggy day each year in December. The levels of these pollutants observed during Diwali were found to be higher due to adverse meteorological conditions, i.e., decrease in 24 h average mixing height, temperature, and wind speed. The trend analysis shows that TSP, PM10, NO2, and SO2 concentration increased just before Diwali and reached to a maximum concentration on the day of the festival. The values gradually decreased after the festival. On Diwali day, 24-h values for TSP and PM10 in all the years from 2002 to 2007 and for NO2 in 2004 and 2007 were found to be higher than prescribed limits of National Ambient Air Quality Standards and exceptionally high (3.6 times) for PM10 in 2007. These results indicate that fireworks during the Diwali festival affected the ambient air quality adversely due to emission and accumulation of TSP, PM10, SO2, and NO2. 相似文献
15.
Vladimira Vadjić Mirjana Gentilizza Janko Hršak Ivan Eškinja 《Environmental monitoring and assessment》1991,18(3):163-171
The effect of metals and ammonia on the relationship between mass concentrations of sulphur dioxide and sulphate in the air was studied near an aluminium plant over a 1-year period. Sulphur dioxide, sulphates and ammonia in the air as well as metals (Pb, Fe, Mn, Zn, Cu, Cd and Al) in the deposit were measured at four measuring sites.The levels of mass concentrations of SO2 were low at all measuring sites while the levels of mass concentrations of sulphates in the air and concentrations of metals in the deposit were high. The levels of ammonia were found to decrease in relationship to the distance from the source of pollution.The relationship between the mass concentrations of sulphate and SO2 can be described by the equation y=ax
b
;where y is the percentage of sulphate sulphur in the total sulphur (sulphate and SO2) and x is the mass concentration of the total sulphur in the air. The values of the coefficients a and b are characteristic of individual areas.As the results show the coefficients a and b obtained at a measuring site close to the plant and outside the urban area are characteristic of an industrial area. At control sites in the urban area the coefficients are characteristic of an urban area. At the measuring site close to the industrial zone and the centre of the urban area the interaction of the effects occurs. Therefore, the coefficient a is characteristic of an urban area and b of an industrial one. 相似文献
16.
Yelda Ulu Gülen H. Güllü Semra G. Tuncel Cevdet Köse Muzaffer Yazar Gürdal Tuncel 《Environmental monitoring and assessment》1994,33(3):215-235
Data from continuous measurements of SO2 NO
x
, suspended particulate matter (SPM) and meteorological parameters at seven sites around a highly industrialized region in the Aegean coast of Turkey, between July 15, 1991 to July 31, 1992 were used to evaluate spatial and temporal variations of air quality parameters. Low annual averages and insignificant differences between day and night concentrations were observed at stations far from sources. At stations close to sources, annual average concentrations were high and diurnal patterns were significant. Annual average SO2 and SPM concentrations in all stations used the Krigging technique to assess the impact of industries on air quality in the surrounding airshed. Results have demonstrated that Turkish air quality standards for SO2 were exceeded in a circle with a radius of 4 km and which was centered on the petrochemical complex and refinery. Similarly, standards for SPM were exceeded in a circle with a radius of 1.2 km and which was centered on the ironwork plants. Both SO2 and SPM showed well defined diurnal variations, particularly in stations close to sources. The SO2 concentrations showed a maximum during day-time, while SPM concentrations peaked after midnight. Although annual average SO2 and SPM concentrations were highly variable depending on distances between stations and sources, background concentrations of the same pollutants, calculated by stripping episodes from data, did not change significantly from one station to another. Long range transport and resuspension of local soil were suggested as sources of background SO2 and SPM, respectively. The difference between observed and background concentrations of SO2 and SPM in each station was related to the impact of industries on air quality at that particular site. 相似文献
17.
Pannatier EG Thimonier A Schmitt M Walthert L Waldner P 《Environmental monitoring and assessment》2011,174(1-4):3-30
Trends in atmospheric acid deposition and in soil solution acidity from 1995 or later until 2007 were investigated at several forest sites throughout Switzerland to assess the effects of air pollution abatements on deposition and the response of the soil solution chemistry. Deposition of the major elements was estimated from throughfall and bulk deposition measurements at nine sites of the Swiss Long-Term Forest Ecosystem Research network (LWF) since 1995 or later. Soil solution was measured at seven plots at four soil depths since 1998 or later. Trends in the molar ratio of base cations to aluminum (BC/Al) in soil solutions and in concentrations and fluxes of inorganic N (NO(3)-N + NH(4)-N), sulfate (SO(4)-S), and base cations (BC) were used to detect changes in soil solution chemistry. Acid deposition significantly decreased at three out of the nine study sites due to a decrease in total N deposition. Total SO(4)-S deposition decreased at the nine sites, but due to the relatively low amount of SO(4)-S load compared to N deposition, it did not contribute to decrease acid deposition significantly. No trend in total BC deposition was detected. In the soil solution, no trend in concentrations and fluxes of BC, SO(4)-S, and inorganic N were found at most soil depths at five out of the seven sites. This suggests that the soil solution reacted very little to the changes in atmospheric deposition. A stronger reduction in base cations compared to aluminum was detected at two sites, which might indicate that acidification of the soil solution was proceeding faster at these sites. 相似文献
18.
To determine the possible contributions of point and non-point sources to carbon and nutrient loading in the Ganga River, we analyzed N, P, and organic carbon (OC) in the atmospheric deposits, surface runoff, and in the river along a 37-km stretch from 2013 to 2015. We also assessed the trophic status of the river as influenced by such sources of nutrient input. Although the river N, P, and productivity showed a declining trend with increasing discharge, runoff DOC and dissolved reactive phosphorus (DRP) increased by 88.05 and 122.7% between the Adpr and Rjht sites, indicating contributions from atmospheric deposition (AD) coupled with land use where agriculture appeared to be the major contributor. Point source input led to increased river concentrations of NO3 ?, NH4 +, DRP, and DOC by 10.5, 115.9, 115.2, and 67.3%, respectively. Increases in N, P, and productivity along the gradient were significantly negatively correlated with river discharge (p < 0.001), while river DOC and dissolved silica showed positive relationships. The results revealed large differences in point and non-point sources of carbon and nutrient input into the Ganga River, although these variations were strongly influenced by the seasonality in surface runoff and river discharge. Despite these variations, N and P concentrations were sufficient to enhance phytoplankton growth along the study stretch. Allochthonous input together with enhanced autotrophy would accelerate heterotrophic growth, degrading the river more rapidly in the near future. This study suggests the need for large-scale inter-regional time series data on the point and non-point source partitioning and associated food web dynamics of this major river system. 相似文献
19.
为研究大同市大气颗粒物质量浓度与水溶性离子组成特征,于2013年2、7、9、12月,分别对大同市及其对照点庞泉沟国家大气背景点进行了PM2.5及PM10的采样,通过超声萃取-IC法测定了样品中的9种水溶性离子,结果表明,大同市大气颗粒物污染1、4季度重于2、3季度,PM2.5季度均值全年均未超标,PM10仅第1季度超标1.4倍,污染状况总体良好,PM2.5与PM10相关系数R为0.75,说明大同市颗粒物污染有较为相近的来源,且不同季节均以粗颗粒物为主;大同市PM2.5中水溶性离子浓度分布为SO2-4、NO-3、NH+4Cl-、Ca2+K+、Na+F-、Mg2+,PM10中Ca2+浓度仅次于SO2-4、NO-3,控制扬尘将有效降低PM10的浓度;PM2.5及PM10中的9种水溶性离子在不同季度的浓度与颗粒物浓度分布规律类似,1、4季度较高,2、3季度较低;由阴阳离子平衡计算结果可知,相关性方程的斜率K为1.045,表明大同市大气颗粒物中阳离子相对亏损,大气细粒子组分偏酸性。NO-3与SO2-4浓度比值均小于1,大同市以硫酸型污染为主,大气中的SO2-4主要来源于人类活动排放。 相似文献
20.
Water quality indices (WQIs) have been developed to assess the suitability of water for a variety of uses. These indices reflect the status of water quality in lakes, streams, rivers, and reservoirs. The concept of WQIs is based on a comparison of the concentration of contaminants with the respective environmental standards. The number, frequency, and magnitude by which the environmental standards for specific variables are not met in a given time period are reflected in WQIs. Further, the water quality trend analysis predicts the behavior of the water quality parameters and overall water quality in the time domain. In this paper, the concept of WQI was applied to three selected watersheds of Atlantic region: the Mersey River, the Point Wolfe River, and the Dunk River sites. To have robust study, two different water quality indices are used: Canadian Water Quality Index (CWQI), and British Columbia Water Quality Index (BWQI). The complete study was conducted in two steps. The first step was to organize and process the data into a format compatible with WQI analysis. After processing the input data, the WQI was calculated. The second step outlined in the paper discusses detailed trend analysis using linear and quadratic models for all the three sites. As per the 25 years trend analysis, overall water quality for agriculture use observed an improving trend at all the three sites studied. Water quality for raw water used for drinking (prior to treatment) and aquatic uses has shown improving trend at Point Wolfe River. It is further observed that pH, SO4, and NO3 concentrations are improving at Dunk River, Mersey River, and Point Wolfe River sites. To ascertain the reliability and significance of the trend analysis, a detailed error analysis and parametric significance tests were also conducted It was observed that for most of the sites and water uses quadratic trend models were a better fit than the linear models. 相似文献