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1.
An experiment was conducted under laboratory conditions to investigate the effect of two systemic herbicides viz., pendimethalin
and quizalofop, at their recommended field rates (1.0 kg and 50 g active ingredient ha − 1, respectively) on the growth and activities of non-symbiotic N2-fixing bacteria in relation to mineralization and availability of nitrogen in a Typic Haplustept soil. Both the herbicides, either singly or in a combination, stimulated the growth and activities of N2-fixing bacteria resulting in higher mineralization and availability of nitrogen in soil. The single application of quizalofop
increased the proliferation of aerobic non-symbiotic N2-fixing bacteria to the highest extent while that of pendimethalin exerted maximum stimulation to their N2-fixing capacity in soil. Both the herbicides, either alone or in a combination, did not have any significant difference in
the stimulation of total nitrogen content and availability of exchangeable NH4
+ while the solubility of NO3
− was highly manifested when the herbicides were applied separately in soil. 相似文献
2.
A solid phase extraction method for the determination of gold(III) at trace levels by flame atomic absorption spectrometer
(FAAS) was developed. The method was based on retention of gold as chloro complexes through the Amberlite XAD-2000. The effect
of some analytical parameters including hydrochloric acid concentration, sample volume, sample and eluent flow rates, eluent
volume, eluent concentration and interfering ions on the recovery of gold(III) was investigated. The retention of gold(III)
from 1.5 mol l−1 HCl solution and the recovery of gold with 0.07 mol l−1 NH3 solution were quantitative (≥95%). The relative standard deviation (RSD) was calculated as 3.2% (n = 10). The detection limit for gold was 2 μg l−1. The accuracy was checked with the determination of gold spiked an artificial seawater and a pure copper samples. 相似文献
3.
Spatial variability of the shallow groundwater level and its chemistry characteristics in the low plain around the Bohai Sea,North China 总被引:2,自引:0,他引:2
Zaiming Zhou Guanghui Zhang Mingjiang Yan Jinzhe Wang 《Environmental monitoring and assessment》2012,184(6):3697-3710
To characterize the spatial distribution of groundwater level (GWL) and its chemistry characteristics in the low plain around
the Bohai Sea, shallow groundwater depth of 130 wells were determined. Water soluble ions composition, total dissolved solid
(TDS), electric conductivity (EC), total hardness (TH), total alkalinity (TA), and total salt content (TS) of 128 representative
groundwater samples were also measured. Classical statistics, geostatistical method combined with GIS technique were then
used to analyze the spatial variability and distribution of GWL and groundwater chemical properties. Results show that GWL,
TDS, EC, TH, TA, and TS all presented a lognormal distribution and could be fitted by different semivariogram models (spherical,
exponential, and Gaussian). Spatial structure of GWL, TDS, EC, TH, TA, and TS changed obviously. GWL decreased from west inland
plain to the east coastal plain, however, TDS, EC, and TS increased from west to east, TH and TA were higher in the middle
and coastal plain area. Groundwater chemical type in the coastal plain was SO42−·Cl−—Na+ while chemical types in the inland plain were SO42−·Cl−—Ca2+·Mg2+ and HCO3−—Ca2+·Mg2+. 相似文献
4.
Recent biological inventory data shows severe declines in freshwater mussel abundance and biodiversity in the Conasauga River
Basin in Northwest Georgia, USA. Based on assessments of habitat conditions, mussel populations should be sustainable. We
conducted a study of sediment and water quality to evaluate the impact of anthropogenic contamination on mussel populations.
Permeable membrane devices (PMD), polar organic chemical integrative samplers (POCIS™), conventional water and sediment quality
analyses, and stable nitrogen isotope ratio analyses (δ15N) of snails and sediments were used to assess sediment and water quality at target sites throughout the basin. Ambient concentrations
of organic contaminants in water were well below any aquatic life criteria; concentrations of some nutrients were detected
above aquatic life criteria levels. Most mussel species in the river are endangered or threatened; therefore, snails were
collected for δ15N analyses. Mean δ15N values for snails collected at forested upper watershed sites (national forest areas) were significantly lower than δ15N values from snails in agricultural areas. δ15N values for raw cow manure and manure-treated soil were similar to δ15N values for snails collected in agricultural areas. Dissolved nitrate from water samples had elevated δ15N values similar to the upper range of δ15N values for snails in agricultural areas. Data, particularly stable nitrogen isotope data, indicates that a land use change
from national forest land to agriculture alters nitrogen sources to the basin and snails. Implications of nutrient release
on freshwater molluscan reproduction, growth, and survival are discussed. 相似文献
5.
Wigand C McKinney RA Cole ML Thursby GB Cummings J 《Environmental monitoring and assessment》2007,131(1-3):71-81
The stable nitrogen isotope ratios of some biota have been used as indicators of sources of anthropogenic nitrogen. In this
study the relationships of the stable nitrogen isotope ratios of marsh plants, Iva frutescens (L.), Phragmites australis (Cav.) Trin ex Steud, Spartina patens (Ait.) Muhl, Spartina alterniflora Loisel, Ulva lactuca (L.), and Enteromorpha intestinalis (L.) with wastewater nitrogen and land development in New England are described. Five of the six plant species (all but U. lactuca) showed significant relationships of increasing δ
15N values with increasing wastewater nitrogen. There was a significant (P < 0.0001) downward shift in the δ
15N of S. patens (6.0 ± 0.48‰) which is mycorrhizal compared with S. alterniflora (8.5 ± 0.41‰). The downward shift in δ
15N may be caused by the assimilation of fixed nitrogen in the roots of S. patens. P. australis within sites had wide ranges of δ
15N values, evidently influenced by the type of shoreline development or buffer at the upland border. In residential areas,
the presence of a vegetated buffer (n = 24 locations) significantly (P < 0.001) reduced the δ
15N (mean = 7.4 ± 0.43‰) of the P. australis compared to stands where there was no buffer (mean = 10.9 ± 1.0‰; n = 15). Among the plant species, I. frutescens located near the upland border showed the most significant (R
2 = 0.64; P = 0.006) inverse relationship with the percent agricultural land in the watershed. The δ
15N of P. australis and I. frustescens is apparently an indicator of local inputs near the upland border, while the δ
15N of Spartina relates with the integrated, watershed-sea nitrogen inputs. 相似文献
6.
Eutrophication and Sedimentation Patterns in Complete Exploitation of Water Resources Scenarios: An Example from Northwestern Semi-arid Mexico 总被引:1,自引:0,他引:1
Sánchez-Carrillo S Alatorre LC Sánchez-Andrés R Garatuza-Payán J 《Environmental monitoring and assessment》2007,132(1-3):377-393
Water requirements to supply human needs lead water stakeholders to store more water during surplus periods to fulfil the
demand during – not only – scarcity periods. At the reservoirs, mostly those in semi-arid regions, water level then fluctuates
extremely between rises and downward during one single year. Besides of water management implications, changes on physical,
chemical and biological dynamics of these drawdown and refilling are little known yet. This paper shows the results, throughout
a year, on solids, nutrients (N and P), chlorophyll-a, and sedimentation changes on the dynamics, when the former policy was applied in a reservoir from the semi-arid Northwestern
Mexico. Water level sinusoidal trend impinged changes on thermal stratification and mixing, modifying nutrient cycling and
primary producer responses. According to nitrogen and phosphorus concentration as well as chlorophyll-a, reservoir was mesotrophic, becoming hypertrophic during drawdown. Nutrient concentrations were high (1.22 ± 0.70 and 0.14 ± 0.12 mg
P l−1), increasing phosphorus and lowering N:P significantly throughout the study period, although no intensive agricultural, no
urban development, neither industrial activities take place in the watershed. This suggests nutrient recycling complex mechanisms,
including nutrient release from the sediment–water interface as the main nutrient pathway when shallowness, at the same time
as mineralization, increases. Outflows controlled nitrogen and phosphorus availability on the ecosystem while organic matter
depended on river inflows. As on other subtropical aquatic ecosystems, nitrogen limited primary productivity (Spearman correlation
R = 0.75) but chlorophyll-a seasonal pattern showed an irregular trend, prompting other no-nutrient related limitants. Shallowness induced a homogeneous
temporal pattern on water quality. This observed temporal variability was mainly explained statistically by changes on solids
(mineral and organic), chlorophyll-a and flows (62.3%). Annual sedimentation rates of total solids ranged from 11.73 to 16.29 kg m−2 year−1 with organic matter comprising around 30%. N:P ratio on sedimentation rates were as high as could be expected in a resuspension
dominated ecosystem, and spatially inverse related with N:P ratio on bottom sediments. Distance from river inlet into the
reservoir reveals a marked spatial heterogeneity on solid and nitrogen sedimentation, showing the system dependence on river
inflows and supporting resuspension as the main phosphorus pathway. Accretion rates (2.19 ± 0.40 cm year−1) were not related to hydrological variability but decreased with the distance to the river input. Total sediment accumulation
(9,895 tons km−2 year−1) denotes siltation as other serious environmental problem in reservoirs but possibly not related with operational procedures. 相似文献
7.
The purpose of this study was to predict quantitative changes in evaporation from bare soils in the Mediterranean climate
region of Turkey in response to the projections of a regional climate model developed in Japan (hereafter RCM). Daily RCM
data for the estimation of reference evapotranspiration (ET
r) and soil evaporation were obtained for the periods of 1994–2003 and 2070–2079. Potential evaporation (E
p) from bare soils was calculated using the Penman–Monteith equation with a surface resistance of zero. Simulation of actual
soil evaporation (E
a) was carried out using Aydin model (Aydin et al., Ecological Modelling 182:91–105, 2005) combined with Aydin and Uygur (2006,
A model for estimating soil water potential of bare fields. In Proceedings of the 18th International Soil Meeting (ISM) on Soils Sustaining Life on Earth, Managing Soil and Technology,
Sanliurfa, 477–480pp.) model of predicting soil water potential at the top surface layer of a bare soil, after performances of Aydin
model (R
2 = 94.0%) and Aydin and Uygur model (R
2 = 97.6) were tested. The latter model is based on the relations among potential soil evaporation, hydraulic diffusivity,
and soil wetness, with some simplified assumptions. Input parameters of the model are simple and easily obtainable such as
climatic parameters used to compute the potential soil evaporation, average diffusivity for the drying soil, and volumetric
water content at field capacity. The combination of Aydin and Aydin and Uygur models appeared to be useful in estimating water
potential of soils and E
a from bare soils, with only a few parameters. Unlike ET
r and E
p projected to increase by 92 and 69 mm (equivalent to 8.0 and 7.3% increases) due to the elevated evaporative demand of the
atmosphere, respectively, E
a from bare soils is projected to reduce by 50 mm (equivalent to a 16.5% decrease) in response to a decrease in rainfall by
46% in the Mediterranean region of Turkey by the 2070s predicted by RCM, and consequently, to decreased soil wetness in the
future. 相似文献
8.
S. A. Norton I. J. Fernandez J. S. Kahl L. E. Rustad Tomás Navrátil H. Almquist 《Environmental monitoring and assessment》2010,171(1-4):3-21
The Bear Brook Watershed in Maine (BBWM), USA is a paired watershed study with chemical manipulation of one watershed (West Bear = WB) while the other watershed (East Bear = EB) serves as a reference. Characterization of hydrology and chemical fluxes occurred in 1987–1989 and demonstrated the similarity of the ca. 10 ha adjacent forested watersheds. From 1989–2010, we have added 1,800 eq (NH4)2SO4 ha???1 y???1 to WB. EB runoff has slowly acidified even as atmospheric deposition of SO $_{4}^{2-}$ has declined. EB acidification included decreasing pH, base cation concentrations, and alkalinity, and increasing inorganic Al concentration, as SO $_{4}^{2-}$ declined. Organic Al increased. WB has acidified more rapidly, including a 6-year period of increasing leaching of base cations, followed by a long-term decline of base cations, although still elevated over pretreatment values, as base saturation declined in the soils. Sulfate in WB has not increased to a new steady state because of increased anion adsorption accompanying soil acidification. Dissolved Al has increased dramatically in WB; increased export of particulate Al and P has accompanied the acidification in both watersheds, WB more than EB. Nitrogen retention in EB increased after 3 years of study, as did many watersheds in the northeastern USA. Nitrogen retention in WB still remains at over 80%, in spite of 20+ years of N addition. The 20-year chemical treatment with continuous measurements of critical variables in both watersheds has enabled the identification of decadal-scale processes, including ecosystem response to declining SO $_{4}^{-2}$ in ambient precipitation in EB and evolving mechanisms of treatment response in WB. The study has demonstrated soil mechanisms buffering pH, declines in soil base saturation, altered P biogeochemistry, unexpected mechanisms of storage of S, and continuous high retention of treatment N. 相似文献
9.
Kumar KS Suvardhan K Rekha D Kiran K Rao GC Jayaraj B Janardhanam K Chiranjeevi P 《Environmental monitoring and assessment》2007,129(1-3):271-276
Facile, selective and sensitive spectrophotometric method has been developed for the determination of carbosulfan in insecticidal
formulations, fortified water, food grains, agriculture wastewater and soil samples with newly synthesized reagents. The method
was based on acid and alkaline hydrolysis of the carbosulfan pesticide, and the resultant hydrolysis product of carbosulfan
was coupled with 2,6-dibromo-4-methylaniline to give a yellow color product with λ
max of 464 nm or interaction with 2,6-dibromo-4-nitroaniline to produce yellow colored product with λ
max of 408 nm or coupling with 2,4,6-tribromoaniline to form red colored product has a λ
max of 471 nm. Under optimal conditions, Beer’s law range for 2,6-dibromo-4-methylaniline (DBMA) was found to be 0.2–12.0 μg
ml−1, 0.6–16.0 μg ml−1 for 2,6-dibromo-4-nitroaniline (DBNA) and 0.4–15.0 μg ml−1 for 2,4,6-tribromoaniline (TBA). The molar absorptivity of the color systems were found to be 3.112 × 104 l mol−1 cm−1 for DBMA, 3.214 × 104 l mol−1 cm−1 for DBNA and 3.881 × 104 l mol−1 cm−1 for TBA. Sandell’s of the color reactions are 0.013 μg cm−2 (DBMA), 0.012 μg cm−2 (DBNA) and 0.011 μg cm−2 (TBA) respectively. The effect of the non-target species on the determination of carbosulfan was studied to enhance the selectivity
of the proposed methods. The formation of colored derivatives with the coupling agents is instantaneous and stable for 28,
30, and 26 h. Performance of the proposed methods were compared statistically in terms Student’s F and t-tests with the reported methods.
An erratum to this article can be found at 相似文献
10.
Citation of cyanobacterial cultures from the shores of south west coast of Gujarat, India and their relationship with sea water quality, influenced by extensive pollutant runoff is reported in this study. Intensity of pollution was evaluated by physico-chemical analysis of water. Higher load of suspended solids (60–1000 mg l−1) and nutrients (PO4
−P: 1.3–4 μmole l−1 and NO3
−N: 12.5–17.8 μmole l−1) were persistent throughout the analysis. Community structure is seen to be influenced by such persistent pollution. Twenty nine cyanobacterial species were isolated belonging to 9 genera of 4 families, with an elevated occurrence of Oscillatoria and Lyngbya species. No heterocystous cyanobacteria were isolated throughout the study. 相似文献
11.
Lakhani A Parmar RS Satsangi GS Prakash S 《Environmental monitoring and assessment》2007,133(1-3):435-445
Fog water samples were collected in the months of December and January during 1998–2000 at Agra, India. The samples were analyzed
for pH, major anions (F−, Cl−, SO4
2−, NO3
−, HCOO− and CH3COO−), major cations (Ca2+, Mg2+, Na+ and K+) and NH4
+ using ion chromatography, ICP-AES and spectrophotometer methods, respectively. pH of fog water samples ranged between 7.0
and 7.6 with a volume weighted mean of 7.2, indicating its alkaline characteristic. NH4
+ contributed 40%, SO4
2− and NO3
− accounted for 28%, while Ca2+, Mg2+, Na+ and K+ accounted for 16% of the total ionic concentration. The ratios of Mg2+/Ca2+ and Na+/Ca2+ in fog water indicates that 50–75% of fog water samples correspond to the respective ratios in local soil. Significant correlation
between Ca2+, Mg2+, Na+ and K+ suggests their soil origin. The order of neutralization, NH4
+ (1.4) > Ca2+ (0.28) > Mg2+ (0.12), indicates that NH4
+ is the major neutralizing species. Fog water and atmospheric alkalinity were also computed and were found to be 873 and 903 neqm−3, respectively. Both of these values are higher than values reported from temperate sites and thus indicate that at the present
level of pollutants, there is no risk of acid fog problem. The study also shows that the alkaline nature of fog water is due
to dissolution of ammonia gas and partly due to interaction of fog water with soil derived aerosols. 相似文献
12.
When agricultural lands are no longer used for agriculture and allowed to recover its natural vegetation, soil organic carbon
can accumulate in the soil. Measurements of soil organic carbon and aggregate stability changes under various forms of land
use are needed for the development of sustainable systems. Therefore, comparison of soil samples taken from both agricultural
and nearby area close to land-mined fields where no agricultural practices have been done since 1956 can be a good approach
to evaluate the effects of tillage and agriculture on soil quality. The objective of this study was to compare tillage, cropping
and no tillage effects on some soil-quality parameters. Four different locations along the Turkey–Syria border were selected
to determine effects of tillage and cropping on soil quality. Each location was evaluated separately because of different
soil type and treatments. Comparisons were made between non-tilled and non-cropped fallow since 1956 and adjacent restricted
lands that were tilled about every 2 years but not planted (T) or adjacent lands tilled and planted with wheat and lentil
(P). Three samples were taken from the depths of 0–20 and 20–40 cm each site. Soil organic carbon (SOC), pH ,electrical conductivity,
water soluble Ca++, Mg++, CO3-2{\rm CO}_{3}^{-2} and HCO3-{\rm HCO}_{3}^{-}, extractable potassium (K+) and sodium (Na+), soil texture, ammonium (NH4+{\rm NH}_{4}^{+}–N) and nitrate (NO3–N), extractable phosphorous and soil aggregate stability were determined. While the SOC contents of continuous tillage without
cropping and continuous tillage and cropping were 2.2 and 11.6 g kg−1, respectively, it was 30 g kg−1 in non-tilled and non-planted site. Tillage of soil without the input of any plant material resulted in loss of carbon from
the soil in all sites. Soil extractable NO3−N contents of non-tilled and non-cropped sites were greatest among all treatments. Agricultural practices increased phosphorus
and potassium contents in the soil profile. P2O5 contents of planted soils were approximately 20 to 39 times greater than those of non-tilled and non-cropped soils at different
sites. FTIR spectra showed that never tilled sites had greater phenol, carboxylic acid, amide, aromatic compounds, polysaccharide
and carbohydrates than other treatments. 相似文献
13.
Evrendilek F Berberoglu S Taskinsu-Meydan S Yilmaz E 《Environmental monitoring and assessment》2006,119(1-3):527-543
Abstact Aboveground biomass, aboveground litterfall, and leaf litter decomposition of five indigenous tree stands (pure stands ofPinus brutia,Pinus nigra,Cedrus libani,Juniperus excelsa, and a mixed stand ofAbies cilicica,P. nigra, andC. libani) were measured in an eastern Mediterranean evergreen needleleaf forest of Turkey. Measurements were converted to regional scale estimates of carbon (C) stocks and fluxes of forest ecosystems, based on general non-site-specific allometric relationships. Mean C stock of the conifer forests was estimated as 97.8± 79 Mg C ha−1consisting of 83.0 ± 67 Mg C ha−1in the aboveground and 14.8 ± 12 Mg C ha−1in the belowground biomass. The forest stands had mean soil organic carbon (SOC) and nitrogen (SON) stocks of 172.0 ± 25.7 Mg C ha−1and 9.2 ± 1.2 Mg N ha−1, respectively. Mean total monthly litterfall was 376.2± 191.3 kg C ha−1, ranging from 641 ± 385 kg C ha−1forPinus brutiato 286 ± 82 kg C ha−1forCedrus libani. Decomposition rate constants (k) for pine needles were 0.0016 forCedrus libani, 0.0009 forPinus nigra, 0.0006 for the mixed stand, and 0.0005 day−1forPinus brutiaand
Juniperus excelsa. Estimation of components of the C budgets revealed that the forest ecosystems were net C sinks, with a mean sequestration rate of 2.0 ± 1.1 Mg C ha−1 yr−1ranging from 3.2 ± 2 Mg C ha−1forPinus brutiato 1.6 ± 0.6 Mg C ha−1forCedrus libani. Mean net ecosystem productivity (NEP) resulted in sequestration of 98.4 ± 54.1 Gg CO2 yr−1from the atmosphere when extrapolated for the entire study area of 134.2 km2(Gg = 109 g). The quantitative C data from the study revealed the significance of the conifer Mediterranean forests as C sinks 相似文献
14.
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
15.
Al-Momani IF Momani KA Jaradat QM Massadeh AM Yousef YA Alomary AA 《Environmental monitoring and assessment》2008,136(1-3):209-218
Wet and dry deposition samples were collected in the capital of Jordan, Amman. Concentrations of Al, Ba, Bi, Cd, Co, Cr, Cu,
Mn, Mo, Ni, Pb, Sb, V, Zn, Fe, Sr, Mg2+, Ca2+, Na+, K+, Cl−, NO3
− and SO4
2−, along with pH were determined in collected samples. Mean trace metal concentrations were similar or less than those reported
for other urban regions worldwide, while concentrations of Ca2+ and SO4
2− were among the highest. High Ca2+ concentrations were attributed to the calcareous nature of the local soil and to the influence of the Saharan dust. However,
high SO4
2− concentrations were attributed to the influence of both anthropogenic and natural sources. Except for Cl−, NO3
−, SO4
2− and Cu, monthly dry deposition fluxes of all measured species were higher than wet deposition fluxes. The annual wet deposition
fluxes of trace metals were much lower than those reported for other urban areas worldwide. 相似文献
16.
Total selenium (Se) and water-soluble Se in soil, and Se in a shallow groundwater were hydrogeochemically researched in an
alluvial fan area in Tsukui, Central Japan. The water-soluble Se was estimated at average level of 2.6 ± 1.2μg Se kg−1 dry soil (± SD, n = 25), showing less than 1% of the total Se (349–508μg Se kg−1 dry soil) in soil. The monthly Se concentration in groundwater was average 2.2μg,L−1, ranging 1.6–2.4μg,L−1 during 2001–2003. The Se in groundwater significantly decreased with increasing groundwater level after rainfall. This result
indicated that Se-bearing water percolated with relatively low Se concentration through the soil layer. According to our prediction
model of linear regression curve on the observation data, Se concentration in the groundwater was estimated to be increasing
with the very low rate of 4.35 × 10−3μg Se L−1,yr−1. The hydrogeochemical research and the result of the prediction model showed that any explosive increase of Se will hardly
occur in this groundwater without an anthropogenic Se contamination. 相似文献
17.
Raja S Ravikrishna R Kommalapati RR Valsaraj KT 《Environmental monitoring and assessment》2005,110(1-3):99-120
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 NH4+, NO3−, Cl− and SO42−. 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 NO3− but partly offset by high NH4+. The measured gaseous SO2 accounted for a small percentage of the observed sulfate concentration, indicating additional gas-to-particle conversion
of SO2 to sulfate in fogwater. The gaseous NOx 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 (PM2.5) 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
18.
This study monitored atmospheric pollutants during high wind speed (> 7 m s−1) at two sampling sites: Taichung Harbor (TH) and Wuci traffic (WT) during March 2004 to January 2005 in central Taiwan. The
correlation coefficient (R
2) between TSP, PM2.5, PM2.5−10 particle concentration vs. wind speed at the TH and WT sampling site during high wind speed (< 7 m s−1) were also displayed in this study. In addition, the correlation coefficients between TSP, PM2.5 and PM2.5−10 of ionic species vs. high wind speed were also observed. The results indicated that the correlation coefficient order was
TSP > PM2.5−10 > PM2.5 for particle at both sampling sites near Taiwan strait. In addition, the concentration of Cl−, NO3
−, SO4
2−, NH4
+, Mg2+, Ca2+ and Na+ were also analyzed in this study. 相似文献
19.
The fertigation effect of distillery effluents concentrations such as 5%, 10%, 25%, 50%, 75% and 100% were studied on Trigonella foenu-graecu (Pusa early bunching) along with control (bore well water). On irrigation of soil with different effluents up to 90 days
of harvesting, it was observed that there was a significant effect on moisture content (P < 0.001), EC, pH, Cl − , total organic carbon (TOC), HCO3-_{3}^{-}, CO3-2_{3}^{-2}, Na + , K + , Ca2 + , Mg2 + , Fe2 + , TKN, NO32-_{3}^{2-}, PO43-_{4}^{3-}, and SO42-_{4}^{2-} (P < 0.0001) and insignificant effect on WHC and bulk density (P > 0.05).There was no significant change in the soil texture
of the soil. Among various concentrations of effluent irrigation, the irrigation with 100% effluent concentration decreased
pH (16.66%) and increased moisture content (30.82%), EC(84.13%), Cl − (292.37%), TOC (4311.61%), HCO3-_{3}^{-} (27.76%), CO3-2_{3}^{-2} (32.63%), Na + (273%), K + (31.59%), Ca2 + (729.76%), Mg2 + (740.47%), TKN (1723.32%), NO32-_{3}^{2-} (98.02%), PO43-_{4}^{3-} (337.79%), and SO42-_{4}^{2-} (77.78%), Fe2 + (359.91%), Zn (980.48%), Cu (451.51%), Cd (3033.33%), Pb (2350.00%), and Cr (2375.00%) in the soil. The agronomical parameters
such as shoot length, root length, number of leaves, flowers, pods, dry weight, chlorophyll content, LAI, crop yield, and
HI of T. foenum-graecum were recorded to be in increasing order at low concentration of the effluent, i.e., from 5% to 50% and in decreasing order
at higher effluent concentration, i.e., from 75% to 100% as compared to control. The enrichment factor of various heavy metals
was ordered for soil Cd>Cr> Pb>Zn>Cu>Fe and for T. foenum-graecum plants Pb>Cr>Cd>Cu>Zn>Fe after irrigation with distillery effluent. 相似文献
20.
Kumar KS Suvardhan K Rekha D Kiran K Jayaraj B Janardhanam K Chiranjeevi P 《Environmental monitoring and assessment》2007,127(1-3):67-72
Facile, selective and sensitive spectrophotometric method has been developed for the determination of bendiocarb in its insecticidal
formulations, fortified water, food grains, agriculture wastewater and agriculture soil samples with prepared reagents. The
method was based on alkaline hydrolysis of the bendiocarb pesticide, and the resultant hydrolysis product of bendiocarb was
coupled with 2,6-dibromo-4-methylaniline to give a yellow color product with λmaxof457 nmorcouplingwith2, 6−dibromo−4−nitroanilinetoproducearedcoloredproductwithλmax
of474~nmorcouplingwith2, 4, 6−tribromoanilinetoformorangeredcoloredproducthasaλmax
of465 nm.Underoptimalconditions, Beer'slawrangefor2, 6−dibromo−4−methylaniline(DBMA)wasfoundtobe0.6−−14.0~μgmL
-1, 0.8−−10.0 μgmL
-1
for2, 6−dibromo−4−nitroaniline(DBNA)and0.4−−10.0 μgmL
-1
for2, 4, 6−tribromoaniline(TBA).Themolarabsorptivityofthecolorsystemswerefoundtobe4.126~×~104
lmol
-1 cm
-1
forDBMA, 3.254×104
l~mol
-1 cm
-1
forDBNAand2.812×104
lmol
-1 cm
-1
forTBA.Sandell'softhecolorreactionsare0.018 μgcm
-2(DBMA), 0.052 μgcm
-2(DBNA)and0.065 μgcm
-2$ (TBA) respectively. The effect of the non-target species on the determination of bendiocarb was studied. The formation of
colored derivatives with the coupling agents is instantaneous and stable for 18 h, 30 h, and 12 h. Performance of the proposed
methods were compared statistically in terms Student's F and t-tests with the reported methods. 相似文献