共查询到20条相似文献,搜索用时 31 毫秒
1.
Precipitation is the best scavenger for the particulates and dissolved gaseous pollutants present in the atmosphere. The chemical composition of precipitation is dominated by a number of in-cloud and below-cloud scavenging processes. The present study is aimed at analyzing the chemical composition of rainwater in the relatively less industrialized part of Mumbai. The pH of rainwater in this region ranges from 4.8 to 6.4. The percentage contributions of ions were calculated and the major contributing ions were calcium (28%), chloride (23%), sodium (18%), sulfate (14%), magnesium (11%), ammonium (4%), potassium (1%), and nitrate (1%). The correlation coefficient is highest for Na and Cl ( r 2?=?0.99), giving a clear indication of contribution from sea salt. Sulfate and nitrate ions also show a very good correlation ( r 2?=?0.90), which may be due to their coemission from fossil fuel combustion. Acidification caused by these ions is neutralized by Ca, Mg, and NH 4 ions. The neutralization effect due to these ions is validated by calculating the neutralization factor (NF). The NF values are in the order Ca > Mg > NH 4. The major source contributors for the ions in precipitation are sea salt (Na, Cl, and K) and fossil fuel combustion (SO 4 and NO 3). These assumptions are supported by the values of wet-only ratio, enrichment factor, and percent sea salt fraction. 相似文献
2.
National data from the hydrological network for 38 rivers out of 25 watersheds were used to detect spatial and temporal trends in water quality and quantity characteristics between 1995 and 2002. Assessment of water quality and quantity included flow rate, water temperature, pH, electrical conductivity, sodium adsorption rate, Na, K, Ca+Mg, CO 3, HCO 3, Cl, SO 4, and boron. Among the major ions assessed on a watershed basis, Turkish river waters are relatively high in Ca+Mg, Na and HCO 3, and low in K and CO 3. The watersheds in Turkey experienced a general trend of 16% decrease in flow rates between 1995 and 2002 at a mean annual rate of about 4 m 3 s ?1, with a considerable spatial variation. Similarly, there appeared to be an increasing trend in river water temperature, at a mean annual rate of about 0.2°C. A substantial proportion of watersheds experienced an increase in pH, in particular, after 1997, with a maximum increase from 8.1 to 8.4 observed in Euphrates ( P?0.01). Kendall’s tau test revealed increasing trends of EC and SAR concentrations that exceeded existing standards, particularly, in the Meriç, K?z?l?rmak and Big Menderes watersheds where intensive agricultural activities take place. Such continued levels may threaten biotic integrity and both drinking and irrigation water quality of rivers. Best multiple linear regression (MLR) models constructed both annually and monthly differed in R 2 values in accounting for variations of pH and water temperature only. The findings of the study can provide a useful assessment of controls over water quality and quantity and assist in devising integrated and sustainable management practices for watersheds at the regional scale in Turkey. 相似文献
3.
Regime shifts of major salinity constituents (Ca, Mg, Na, K, SO4, Cl, HCO3, and NO3) in the lower Salinas River, an agricultural ecosystem, can have major impacts on ecosystem services central to continued agricultural production in the region. Regime shifts are large, persistent, and often abrupt changes in the structure and dynamics of social-ecological systems that occur when there is a reorganization of the dominant feedbacks in the system. Monitoring information on changes in the system state, controlling variables, and feedbacks is a crucial contributor to applying sustainability and ecosystem resilience at an operational level. To better understand the factors driving salinization of the lower Salinas River on the central coast of California, we examined a 27-year record of concentrations of major salinity constituents in the river. Although limited in providing an understanding of solute flux behavior during storm events, long-term “grab sampling” datasets with accompanying stream discharges can be used to estimate the actual history of concentrations and fluxes. We developed new concentration–discharge relationships to evaluate the dynamics of chemical weathering, hydrological processes, and agricultural practices in the watershed. Examinations of long-term records of surface water and groundwater salinity are required to provide both understanding and perspective towards managing salinity in arid and semi-arid regions while also enabling determination of the influence of external climatic variability and internal drivers in the system. We found that rock weathering is the main source of Ca, Mg, Na, HCO3, and SO4 in the river that further enables ion exchange between Ca, Mg, and Na. River concentrations of K, NO3, and Cl were associated with human activities while agricultural practices were the major source of K and NO3. A more direct anthropogenic positive trend in NO3 that has persisted since the mid-1990s is associated with the lag or memory effects of field cropping and use of flood irrigation. Event to inter-year scale patterns in the lower Salinas River salinity are further controlled by antecedent hydrologic conditions. This study underscores the importance of obtaining long-term monitoring records towards understanding watershed changes-of-state and time constants on the range of driving processes. 相似文献
4.
One of the most important hydrogeologic problems in and adjacent areas of evaporitic formations is severe quality degradation
of groundwaters. These kinds of groundwaters contain high content of dissolved solids and generally have some limitations
for use. Tatlicay basin (north-central Turkey) is an example to effects of the evaporites on groundwater quality in the adjacent
alluvium aquifer. Gypsum and anhydrites in the two evaporite formations (Bayindir and Bozkir) effect of the groundwater quality
in the alluvium adversely, by dissolution of the evaporites by surface drainage and infiltration into the alluvium aquifer
(widespread effect) and by infiltration of low quality gypsum springs (local effect) into the aquifer. Evaporitic formations
significantly increased EC, TDS, Ca and SO 4 parameters in the alluvium aquifer in the central and downstream regions. EC has increased roughly from 500–800 to 1,700–2,000 μS/cm,
Ca has roughly increased from 3–4 to 10 meq/l, SO 4 has increased 0.5–1 to 11–12 meq/l. Consequently, three clusters were distinguished in the basin; (1) nonevaporitic waters
in low TDS, Na, Ca, Mg, Cl and SO 4, (2) diluted waters in high TDS and relatively high Cl, moderate-relatively high Na, Ca, Mg, SO 4, (3) gypsum springs in highest TDS, Ca, SO 4, but moderate Mg and low Na, Cl. 相似文献
5.
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: Ca 2+, Mg 2+ and K +. The estimated share of SO 4–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 SO 4–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 Ca 2+ and Mg 2+ 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
6.
A detailed study has been carried out on groundwater in rural communities in the Tema District of the Greater Accra region of Ghana to establish the hydrochemistry and identify the various sources of contaminants as well assess the physical and chemical quality of the groundwater to ascertain their wholesomeness and the health impacts of the groundwater on the communities. The groundwater was found to vary considerably in terms of chemical and physical properties. Generally, the water was mildly acidic (pH 4.3–7.4), brackish to fresh, and undersaturated with respect to gypsum and halite. The majority of groundwater clustered toward Ca–Mg–SO 4 and Na–Cl facies. About 70% of boreholes sampled have elevated levels of NO 3 ??–N, Cl ???, and SO 4 2? emanating from anthropogenic activities. 相似文献
7.
Chemical characteristics of 72 groundwater samples collected from Midyan Basin have been studied to evaluate major ion chemistry together with the geochemical and weathering processes controlling the water composition. Water chemistry of the study area is mainly dominated by Na, Ca, SO 4, and Cl. The molar ratios of (Ca?+?Mg)/total cations, (Na?+?K)/total cations, (Ca?+?Mg)/(Na?+?K), (Ca?+?Mg)/(HCO 3?+?SO 4), (Ca?+?Mg)/HCO 3, and Na/Cl reveal that water chemistry of the Midyan Basin is controlled by evaporite dissolution (gypsum and/or anhydrite, and halite), silicate weathering, and minor contribution of carbonate weathering. The studied groundwater samples are largely undersaturated with respect to dolomite, gypsum, and anhydrite. These waters are capable of dissolving more of these minerals under suitable physicochemical conditions. 相似文献
8.
Fourteen domestic and seven imported bottled water brands were analysed in Saudi Arabia for various physico-chemical water quality parameters. The results of the analysis were compared with the drinking water standards set by Saudi Arabia and World Health Organization. The levels of different physico-chemical parameters like TDS, Ca, Mg, Na, K, NO 3, Cl and SO 4 of all local and imported bottled water brands met the different drinking water standards. Fluoride was found below the Saudi Arabian Standard Organization recommended limits in two of the local brands whereas fluoride levels in all of the imported brands were below the recommended values. In one imported brand, pH was found not conforming to the recommended standards. The concentrations of trace metals in all brands were within the drinking water standards. Comparison of the study results with the reported label values indicated good agreement with stated pH values but considerable variation for Ca, Mg, and Na in the local brands and comparatively low variation in the imported brands. Low F and SO 4 variations were found in the local brands and comparatively high SO 4 variation in the imported brands. 相似文献
9.
The present study investigated the chemical composition of wet atmospheric precipitation over Dhanbad, coal city of India.
The precipitation samples were collected on event basis for three years (July 2003 to October 2005) at Central Mining Research
Institute. The precipitation samples were analyzed for pH, conductivity, major anions (F, Cl, NO 3, SO 4) and cations (Ca, Mg, Na, K, NH 4). The pH value varied from 4.01 to 6.92 (avg. 5.37) indicating acidic to alkaline nature of rainwater. The pH of the rainwater
was found well above the reference pH (5.6), showing alkalinity during the non-monsoon and early phase of monsoon, but during
the late phase of monsoon, pH tendency was towards acidity (<5.6~pH) indicating the non-availability of proper neutralizer
for acidic ions. The observed acidic events at this site were 91, ( n = 162) accounting 56% for the entire monitoring months. The (NO 3 + Cl)/SO 4 ratio in majority of samples was found below 1.0, indicating that the acidity is greatly influenced by SO 4. The calculated ratio of (Ca + NH 4)/(NO 3 + SO 4) ranges between 0.42–5.13 (average 1.14), however in most of the samples, the ratio is greater than unity (>1.0) indicating
that Ca and NH 4 play an important role in neutralization of acidic ions in rainwater. Ca and SO 4 dominate the bulk ionic deposition and these two ions along with NH 4 accounts 63% of the annual ionic deposition. 相似文献
10.
Seventeen fog events were sampled in Baton Rouge, Louisiana during 2002–2004 as part of characterizing wet deposition by fogwater
in the heavily industrialized corridor along the Louisiana Gulf Coast in the United States. These samples were analyzed for
chemical characteristics such as pH, conductivity, total organic and inorganic carbon, total metals and the principal ion
concentrations. The dominant ionic species in all samples were NH 4+, NO 3−, Cl − and SO 42−. The pH of the fogwater sampled had a mean value of 6.7 with two cases of acidic pH of 4.7. Rainwater and fogwater pH were
similar in this region. The acidity of fogwater was a result of NO 3− but partly offset by high NH 4+. The measured gaseous SO 2 accounted for a small percentage of the observed sulfate concentration, indicating additional gas-to-particle conversion
of SO 2 to sulfate in fogwater. The gaseous NO x accounted for most of the dissolved nitrate and nitrite concentration in fogwater. The high chloride concentration was attributable
to the degradation of chlorinated organics in the atmosphere. The metal composition was traced directly to soil-derived aerosol
precursors in the air. The major metals observed in fogwater were Na, K, Ca, Fe, Al, Mg and Zn. Of these Na, K, Ca and Mg
were predominant with mean concentrations > 100 μM. Al, Fe and Zn were present in the samples, at mean concentrations < 100
μM. Small concentrations of Mn (7.8 μM), Cu (2 μM), Pb (0.07 μM) and As (0.32 μM) were also observed in the fogwaters, and
these were shown to result from particulates (PM 2.5) in the atmosphere. The contribution to both ions and metals from the marine sources in the Louisiana Gulf Coast was minimal.
The concentrations of all principal ionic species and metals in fogwater were 1–2 orders of magnitude larger than in rainwater.
Several linear alkane organic compounds were observed in the fogwater, representing the contributions from petroleum products
at concentrations far exceeding their aqueous solubility. A pesticide (atrazine) was also observed in fogwater, representing
the contribution from the agricultural activities nearby. 相似文献
11.
Large-scale exposure of acid sulfate soils during a hydrological drought in the Lower Lakes of South Australia resulted in acidification of surface water in several locations. Our aim was to describe the techniques used to monitor, assess and manage these acidification events using a field and laboratory dataset ( n?=?1,208) of acidic to circum-neutral pH water samples. The median pH of the acidified (pH?<?6.5) samples was 3.8. Significant ( p?<?0.05) increases in soluble metals (Al, Co, Mn, Ni and Zn above guidelines for ecosystem protection), SO 4 (from pyrite oxidation), Si (from aluminosilicate dissolution) and Ca (from carbonate dissolution and limestone addition), were observed under the acidic conditions. The log of the soluble metal concentrations, acidity and SO 4/Cl ratio increased linearly with pH. The pH, alkalinity and acidity measurements were used to inform aerial limestone dosing events to neutralise acidic water. Field measurements correlated strongly with laboratory measurements for pH, alkalinity and conductivity ( r 2?≥?0.97) but only moderately with acidity ( r 2?=?0.54), which could be due to difficulties in determining the indicator-based field titration endpoint. Laboratory measured acidity correlated well with calculated acidity ( r 2?=?0.87, acidity present as Al III?>>?H +?≈?Mn II?>?Fe II/III) but was about 20 % higher on average. Geochemical speciation calculations and XRD measurements indicated that solid phase minerals (schwertmannite and jarosite for Fe and jurbanite for Al) were likely controlling dissolved metal concentrations and influencing measured acidity between pH 2 and 5. 相似文献
12.
At the Bear Brook Watershed in Maine (BBWM), the forest tree composition was characterized and the effects of the chronic ammonium sulfate ((NH 4) 2SO 4) treatment on basal area growth, foliar chemistry, and gas exchange were investigated on forest species. The BBWM is a paired watershed forest ecosystem study with one watershed, West Bear (WB), treated since 1989 with 26.6 kg N ha ???1 year ???1 and 30 kg S ha ???1 year ???1applied bimonthly as (NH 4) 2SO 4, while the other watershed, East Bear (EB), serves as a reference. Tree species richness, density, and mortality were found to be similar between watersheds. Basal area increment was estimated from red spruce and sugar maple, showing that, for the first 7 years of treatment, it was significantly higher for sugar maple growing in WB compared to EB, but no differences were observed for red spruce between watersheds. However, the initial higher sugar maple basal area growth in WB subsequently decreased after 8 years of treatment. Foliar chemical analysis performed in trees, saplings, and ground flora showed higher N concentrations in the treated WB compared to the reference EB. But, foliar cation concentrations, especially Ca and Mg, were significantly lower for most of the species growing in WB compared with those growing in EB. For sugar maple, foliar N was higher on WB, but there were no differences in foliar Ca and Mg concentrations between treated and reference watersheds. In addition, only sugar maple trees in the treated WB showed significantly higher photosynthetic rates compared to reference EB trees. 相似文献
13.
Biochemical constituents and master elements (Pb, Cr, Cd, Fe, Cu, Zn, Hg, B, Al, SO 4 2?, Na, K, Li, Ca, Mg, and F) were investigated in six different seaweed species from Abu Qir Bay in the Egyptian Mediterranean Sea coast. The moisture level ranged from 30.26% in Corallina mediterranea to 77.57% in Padina boryana. On dry weight basis, the ash contents varied from 25.53% in Jania rubens to 88.84% in Sargassum wightii. The protein contents fluctuated from 8.26% in S. wightii to 28.01% in J. rubens. Enteromorpha linza showed the highest lipids (4.66%) and carbohydrate contents (78.95%), whereas C. mediterranea had the lowest lipid (0.5%), and carbohydrate contents (38.12%). Chlorophylls and carotenoid contents varied among the species. Total antioxidant capacity of the tested green seaweeds had the highest activities followed by brown and red seaweeds which had a similar trend of phenol and tannins contents. High reducing power was observed in all tested seaweeds extract except Ulva lactuca. Brown species had the highest amount of elements followed by red and green seaweeds. Notably, SO 4 2? recorded the highest level in the tested green species (108.05 mg/g dry weight (DW)). The Ca/Mg and K/Na ratios reflected highly significant difference between seaweed species. This study keeps an eye on 29 parameters and by applying stepwise multiple regression analysis, prospective equations have been set to describe the interactions between these parameters inside seaweeds. Accordingly, the tested seaweeds can be recommended as a source of healthy food with suitable ion quotient and estimated daily intake values. 相似文献
14.
The present study has been carried out to assess groundwater quality in parts of Hindon–Yamuna interfluve region of western
Uttar Pradesh. Fifty-five groundwater samples were collected from hand pumps in post-monsoon 2005 and pre-monsoon 2006 period,
respectively, covering an area of about 1,345 km 2. Physical and chemical parameters of groundwater such as electrical conductivity, pH, total dissolved solid, Na, K, Ca, Mg,
HCO 3, Cl, and SO 4 were determined. Concentration of the chemical constituents in groundwater of the study area varies spatially and temporarily.
Interpretation of analytical data of major ion chemistry helps to identify three chemical types of groundwater i.e. ‘mixed’,
‘mixed bicarbonate’ and ‘alkali bicarbonate’ types. The species likely to occur in groundwater of the study area are Ca-HCO 3, Mg-HCO 3, Ca-SO 4, Na-Cl, Na-SO 4, Na-HCO 3, K-Cl, and some other possible species of K, depending on its abundance. The groundwater of the study area comes under the
category of moderately hard to very hard, mildly acidic to slightly alkaline in nature. There is anomalously high concentration
of major ions, particularly, Na, K, SO 4, and Cl. High SO 4 and K values may be related to anthropogenic influences, rather than through some natural process. Sodium along with Cl may
be added to the system through sewage pollution and leachate percolation. 相似文献
15.
2021年对济南市大气PM 2.5中17种2,3,7,8氯取代二(口恶)英(PCDD/Fs)污染现状进行监测。对其异构体分布、指示性单体、季节变化规律等特征及其与常规污染物相关性进行了分析。结果表明:大气PM 2.5中PCDD/Fs浓度范围和年平均值分别为0.157~1.595 pg/m 3和0.785 pg/m 3,而毒性当量(以I-TEQ计)范围和年平均值分别为0.009~0.116 pg TEQ/m 3和0.052 pg TEQ/m 3。PCDD/Fs浓度与毒性当量季节变化特征显著,均呈现出冬季>春季>秋季>夏季的情况,可能由季节性排放源和气象条件不同导致。不同季节PCDD/Fs异构体分布模式一致,主要由高氯代(1,2,3,4,6,7,8-HpCDF、OCDD、OCDF和1,2,3,4,6,7,8-HpCDD)单体组成;而对毒性当量贡献最大的单体是2,3,4,7,8-PeCDF,其与总毒性当量具有较好的相关性。同时,PCDD/Fs浓度与SO 2、NO 2、PM 2.5等大气常规污染物呈显著正相关。这表明,大气PM 2.5中PCDD/Fs与常规污染物的生成和排放密切相关。 相似文献
16.
The Euphrates and Tigris watersheds originating from Turkey and passing through Syria and Iraq are one of the most important transboundary watersheds in the Middle East. Long-term data (1971 to 2002) from 14 stations over the Euphrates river and seven stations over the Tigris river were analyzed and compared using the nonparametric Kruskal–Wallis and Mann–Kendall trend tests, and box-and-whisker plots. The upper Euphrates river had significantly lower values of flow rate (FR), water temperature (WT), electrical conductivity (EC), Cl, and SO 4 than did the lower Euphrates river. The middle Euphrates river had significantly higher Na, K, HCO 3, Cl, sodium adsorption ratio (SAR), and boron (B) and lower EC and SO 4 than the lower Euphrates river. The upper west Tigris river had higher EC, Ca + Mg, and SO 4 and lower FR, Na, and SAR than the lower Tigris river. The upper east Tigris river had higher HCO 3 and B and lower FR and WT than the lower Tigris river. 相似文献
17.
To assess the concern over declining base cation levels in forest soils caused by acid deposition, input-output budgets (1990s
average) for sulphate (SO 4), inorganic nitrogen (NO 3-N; NH 4-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 SO 4 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 (NO 3-N). Over the period of record, SO 4 concentration in deposition decreased in 13/14 (13 out of 14 total) regions and SO 4 in runoff decreased at 14/17 catchments. In contrast, NO 3-N concentrations in deposition decreased in only 1/14 regions, while NH 4-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 NH 4-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 NO 3-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 SO 4 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
18.
In this study, we investigated the relationships between stream water chemistry and watershed characteristics (topography—mean altitude and slope; climate—mean annual temperature and precipitation; geology—geochemical reactivity; land cover; inhabitation—population density, road density and number of municipalities). We analyzed the concentrations of the major anions (Cl, F, NO 3, SO 4, SiO 2), cations (Ca, Mg, Na, K, Mn, Fe, Al), trace elements (Li, Sr, Cu), ABS 245, TDP (total dissolved phosphorus), pH, and conductivity at 3,220 diverse watersheds covering a wide variety of watershed characteristics in the Czech Republic. We used marginal and partial multivariate analyses to reveal the most important variables. The partial analysis showed that only 14 % of the variance could be assigned to a specific factor and that 41 % of the variance is shared among the factors, which indicated complex interactions between the watershed characteristics. 相似文献
19.
Ion-exchange resins (IER) offer alternative approaches to measuring ionic movement in soils that may have advantages over
traditional approaches in some settings, but more information is needed to understand how IER compare with traditional methods
of measurement in forested ecosystems. At the Bear Brook Watershed in Maine (BBWM), one of two paired, forested watersheds
is treated bi-monthly with S and N (28.8 and 25.2kgha −1yr −1 of S and N, respectively). Both IER and ceramic cup tension lysimeters were used to study soil solution responses after ∼11
years of treatment. Results from both methods showed treatments resulted in the mobilization of base cations and Al, and higher
SO 4—S and inorganic N in the treated watershed. Both methods indicated similar differences in results associated with forest
type (hardwoods versus softwoods), a result of differences in litter quality and atmospheric aerosol interception capacity.
The correlation between lysimeter and IER data for individual analytes varied greatly. Significant correlations were evident
for Na ( r=0.75), Al ( r=0.65), Mn ( r=0.61), Fe ( r=0.57), Ca ( r=0.49), K ( r=0.41) and NO 3—N ( r=0.59). No correlation was evident between IER and soil solution data for NH 4—N and Pb. Both IER and soil solution techniques suggested similar interpretations of biogeochemical behavior in the watershed. 相似文献
20.
于2017年对浦东城区和郊区大气PM2.5中的重金属特征和来源进行了分析。结果表明,K、Fe、Na、Ca、Mg、Al等矿物元素为浦东新区PM2.5中含量最高的金属元素,其中K的年均值为297.3 ng/m^3。浦东城区的不同元素在季节变化上呈现较为不同的变化规律,郊区的金属元素值大部分呈现春季先逐月下降,在夏、秋季有起伏波动,在10月之后逐渐上升;沙尘+道路源+建筑扬尘、煤燃烧、工业排放、金属冶炼、船舶排放、海盐+垃圾焚烧+生物质燃烧为浦东城区PM2.5中重金属元素的6大类主要来源。其中沙尘+道路源+建筑扬尘对Ca的贡献率为82.7%,煤燃烧对As的贡献率为86.6%,工业排放对SO4^2-的贡献率达到65.9%,金属冶炼对Cr的贡献率为75.7%,船舶排放对V的贡献率为97.5%、海盐+垃圾焚烧+生物质燃烧对Cl^-的贡献率为93.0%。煤燃烧和金属冶炼主要来自于西部方向。船舶排放分布在长江口及其延伸带。浦东新区PM2.5中重金属元素的质量浓度与本地源排放强度、外界传输和大气扩散条件均有密切关系。 相似文献
|