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1.
Estimates of soil erosion using cesium-137 tracer models 总被引:1,自引:0,他引:1
The soil erosion was studied by 137Cs technique in Yatagan basin in Western Turkey, where there exist intensive agricultural activities. This region is subject
to serious soil loss problems and yet there is not any erosion data towards soil management and control guidelines. During
the soil survey studies, the soil profiles were examined carefully to select the reference points. The soil samples were collected
from the slope facets in three different study areas (Kırtas, Peynirli and Kayısalan Hills). Three different models were applied
for erosion rate calculations in undisturbed and cultivated sites. The profile distribution model (PDM) was used for undisturbed
soils, while proportional model (PM) and simplified mass balance model (SMBM) were used for cultivated soils. The mean annual
erosion rates found using PDM in undisturbed soils were 15 t ha−1 year−1 at the Peynirli Hill and 27 t ha−1 year−1 at the Kırtas Hill. With the PM and SMBM in cultivated soils at Kayışalan, the mean annual erosion rates were obtained to
be 65 and 116 t ha−1 year−1, respectively. The results of 137Cs technique were compared with the results of the Universal Soil Loss Equation (USLE). 相似文献
2.
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
3.
The ungauged wet semi-arid watershed cluster, Seethagondi, lies in the Adilabad district of Telangana in India and is prone to severe erosion and water scarcity. The runoff and soil loss data at watershed, catchment, and field level are necessary for planning soil and water conservation interventions. In this study, an attempt was made to develop a spatial soil loss estimation model for Seethagondi cluster using RUSLE coupled with ARCGIS and was used to estimate the soil loss spatially and temporally. The daily rainfall data of Aphrodite for the period from 1951 to 2007 was used, and the annual rainfall varied from 508 to 1351 mm with a mean annual rainfall of 950 mm and a mean erosivity of 6789 MJ mm ha?1 h?1 year?1. Considerable variation in land use land cover especially in crop land and fallow land was observed during normal and drought years, and corresponding variation in the erosivity, C factor, and soil loss was also noted. The mean value of C factor derived from NDVI for crop land was 0.42 and 0.22 in normal year and drought years, respectively. The topography is undulating and major portion of the cluster has slope less than 10°, and 85.3 % of the cluster has soil loss below 20 t ha?1 year?1. The soil loss from crop land varied from 2.9 to 3.6 t ha?1 year?1 in low rainfall years to 31.8 to 34.7 t ha?1 year?1 in high rainfall years with a mean annual soil loss of 12.2 t ha?1 year?1. The soil loss from crop land was higher in the month of August with an annual soil loss of 13.1 and 2.9 t ha?1 year?1 in normal and drought year, respectively. Based on the soil loss in a normal year, the interventions recommended for 85.3 % of area of the watershed includes agronomic measures such as contour cultivation, graded bunds, strip cropping, mixed cropping, crop rotations, mulching, summer plowing, vegetative bunds, agri-horticultural system, and management practices such as broad bed furrow, raised sunken beds, and harvesting available water using farm ponds and percolation tanks. This methodology can be adopted for estimating the soil loss from similar ungauged watersheds with deficient data and for planning suitable soil and water conservation interventions for the sustainable management of the watersheds. 相似文献
4.
Singh SK Juwarkar AA Pandey RA Chakrabarti T 《Environmental monitoring and assessment》2008,141(1-3):201-212
The biologically treated distillery effluent (BTDE) contains intense colour, high total dissolved solids (TDS), chemical oxygen
demand (COD) and biochemical oxygen demand (BOD). These properties even after primary, secondary and tertiary treatments contain
high concentrations of TDS, COD and BOD. The paper highlights the safe disposal and treatment of BTDE on land through High
Rate Transpiration System (HRTS). HRTS is a zero discharge, low cost, high-tech method for improving the quality of BTDE for
potential reuse. The experiments conducted at bench and pilot scale showed that HRTS having coconut husk as a bedding material
could successfully treat the BTDE with a hydraulic load of 200 m3 ha−1 day−1 having BOD of 100 mg l−1 and 500 m3 ha−1 day−1 having BOD of 500 mg l−1 with average COD load of 0.686 and 2.88 ton ha−1 day−1 during the post and pre monsoon periods respectively. There was no significant increase in the organic carbon of the soil
irrigated with BTDE. The concentrations of various pollutants analyzed in the leachate were within the prescribed limit for
the drinking water sources. The colour removal was 99 to 100% and BOD and COD were possible to treat with optimum hydraulic
loading of BTDE through HRTS planted with Dendrocalamus strictus. 相似文献
5.
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
6.
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
7.
Determination of imazosulfuron persistence in rice crop and soil 总被引:1,自引:0,他引:1
Sondhia S 《Environmental monitoring and assessment》2008,137(1-3):205-211
Imazosulfuron is a new post-emergence sulfonylurea herbicide. It is highly active at low application rates to control annual
and perennial broad-leaf weeds and sedges in rice. There is increasing concerned about the persistence of pesticide residues
in soils, crop produce and subsequent contamination of groundwater. Thus persistence of imazosulfuron residues under field
condition was evaluated. Imazosulfuron was applied at 30, 40, 50 and 60 a. i. g ha −1 rates, 4 days after transplanting of rice as post-emergence herbicide. Soil and plant samples treated with imazosulfuron
were collected at 60, 90 and 120 days after herbicide application and analyzed for residues. Rice grains and straw samples
were sampled at harvest (120 days). Residues of imazosulfuron in soil were not found after 90 and 120 DAS (days after spraying).
Rice grains contained 0.006, 0.009 μg g−1 residues at 50 and 60 g ha −1 application rates. 0.009 and 0.039 μg g−1 residues of imazosulfuron were detected at 50 and 60 g/ha rates respectively in rice straw. Residues of imazosulfuron were
not detected applied at 30 and 40 g ha−1 in rice grains and straw, respectively and can be safely applied to the transplanted rice. 相似文献
8.
Sileika AS Gaigalis K Kutra G Smitiene A 《Environmental monitoring and assessment》2005,102(1-3):359-374
Most of the important factors causing differences in nutrient losses and their interaction were analysed in three small catchments that are located in partially different geographic and climatic conditions in Lithuania. The investigation revealed that climatic factors change the amount and pattern of water discharge over year (larger water discharge during winter in the catchment located closer to the sea), but nutrient leaching is more dependent on land use. Agricultural factors, such as larger cultivated area and excessive fertilisation in one catchment cause larger nitrogen losses (15 kg N ha–1 year–1). Large area of non-intensively used grassland leads to very small nitrogen losses (5.7 kg N ha–1 year–1) in another catchment. However, larger water discharge combined with loamy sandy soils leads to comparatively high nitrogen losses (12 kg N ha–1 year–1). The highest P losses (0.318 kg P ha–1 year–1) occurred in the catchment with hilly relief and clay soil texture. In summary, extensive agriculture in the post-Soviet countries has reduced the importance of agricultural activity for the extent of nutrient losses and agricultural factors (cultivation, fertilisation and livestock density) are responsible for the losses only in the region of sufficient agricultural activity (N input – 71.5 kg N ha–1, livestock density – 0.87 LU ha–1). 相似文献
9.
Effect of land use land cover change on soil erosion potential in an agricultural watershed 总被引:6,自引:0,他引:6
Arabinda Sharma Kamlesh N. Tiwari P. B. S. Bhadoria 《Environmental monitoring and assessment》2011,173(1-4):789-801
Universal soil loss equation (USLE) was used in conjunction with a geographic information system to determine the influence of land use and land cover change (LUCC) on soil erosion potential of a reservoir catchment during the period 1989 to 2004. Results showed that the mean soil erosion potential of the watershed was increased slightly from 12.11 t ha???1 year???1 in the year 1989 to 13.21 t ha???1 year???1 in the year 2004. Spatial analysis revealed that the disappearance of forest patches from relatively flat areas, increased in wasteland in steep slope, and intensification of cultivation practice in relatively more erosion-prone soil were the main factors contributing toward the increased soil erosion potential of the watershed during the study period. Results indicated that transition of other land use land cover (LUC) categories to cropland was the most detrimental to watershed in terms of soil loss while forest acted as the most effective barrier to soil loss. A p value of 0.5503 obtained for two-tailed paired t test between the mean erosion potential of microwatersheds in 1989 and 2004 also indicated towards a moderate change in soil erosion potential of the watershed over the studied period. This study revealed that the spatial location of LUC parcels with respect to terrain and associated soil properties should be an important consideration in soil erosion assessment process. 相似文献
10.
Richarde Marques da Silva Celso Augusto Guimarães Santos Valeriano Carneiro de Lima Silva Leonardo Pereira e Silva 《Environmental monitoring and assessment》2013,185(11):8977-8990
This study evaluates erosivity, surface runoff generation, and soil erosion rates for Mamuaba catchment, sub-catchment of Gramame River basin (Brazil) by using the ArcView Soil and Water Assessment Tool (AvSWAT) model. Calibration and validation of the model was performed on monthly basis, and it could simulate surface runoff and soil erosion to a good level of accuracy. Daily rainfall data between 1969 and 1989 from six rain gauges were used, and the monthly rainfall erosivity of each station was computed for all the studied years. In order to evaluate the calibration and validation of the model, monthly runoff data between January 1978 and April 1982 from one runoff gauge were used as well. The estimated soil loss rates were also realistic when compared to what can be observed in the field and to results from previous studies around of catchment. The long-term average soil loss was estimated at 9.4 t ha?1 year?1; most of the area of the catchment (60 %) was predicted to suffer from a low- to moderate-erosion risk (<6 t ha?1 year?1) and, in 20 % of the catchment, the soil erosion was estimated to exceed >?12 t ha?1 year?1. Expectedly, estimated soil loss was significantly correlated with measured rainfall and simulated surface runoff. Based on the estimated soil loss rates, the catchment was divided into four priority categories (low, moderate, high and very high) for conservation intervention. The study demonstrates that the AvSWAT model provides a useful tool for soil erosion assessment from catchments and facilitates the planning for a sustainable land management in northeastern Brazil. 相似文献
11.
Soil salinity in the Aral Sea Basin is one of the major limiting factors of sustainable crop production. Leaching of the salts
before planting season is usually a prerequisite for crop establishment and predetermined water amounts are applied uniformly
to fields often without discerning salinity levels. The use of predetermined water amounts for leaching perhaps partly emanate
from the inability of conventional soil salinity surveys (based on collection of soil samples, laboratory analyses) to generate
timely and high-resolution salinity maps. This paper has an objective to estimate the spatial distribution of soil salinity
based on readily or cheaply obtainable environmental parameters (terrain indices, remote sensing data, distance to drains,
and long-term groundwater observation data) using a neural network model. The farm-scale (∼15 km2) results were used to upscale soil salinity to a district area (∼300 km2). The use of environmental attributes and soil salinity relationships to upscale the spatial distribution of soil salinity
from farm to district scale resulted in the estimation of essentially similar average soil salinity values (estimated 0.94
vs. 1.04 dS m−1). Visual comparison of the maps suggests that the estimated map had soil salinity that was uniform in distribution. The upscaling
proved to be satisfactory; depending on critical salinity threshold values, around 70–90% of locations were correctly estimated. 相似文献
12.
土壤盐渍化已成为影响图木舒克地区农业生产与生态环境的重要因素。本文以0~150 cm深度范围内土壤和地下水为研究对象,利用实际野外调查与数据统计分析的方法,研究得出:①强盐渍化主要分布于距离河流与渠道较远的地下水浅埋深区域,在纵向上表层聚盐现象明显,盐渍土类型随着土壤层深度加大从亚氯-亚硫酸盐渍土变为亚硫酸盐渍土。②土壤易溶盐含量与地下水化学类型在平面分布上吻合程度较高、与潜水矿化度呈正的高度相关性、与潜水埋藏深度呈负的中度相关性、沿潜水径流方向各层土壤盐渍化减弱。③当地下水埋深较浅时,潜水通过毛细管将易溶盐带入土壤表层,形成表层土壤盐渍化;地下水埋藏较深时,易溶盐分会随着降水淋滤和灌溉冲洗不断降低,地表盐渍化减弱。中、轻度盐渍化区域应控制灌溉用水矿化度,重度盐渍化及盐土区域可在建立排水系统的基础上采用泡田洗盐法。 相似文献
13.
Hui Xue Xiaoyi Ren Shiyu Li Xu Wu Hao Cheng Bin Xu Baojing Gu Guofu Yang Changhui Peng Ying Ge Jie Chang 《Environmental monitoring and assessment》2013,185(10):8501-8516
Tea plantations are rapidly expanding in China and other countries in the tropical and subtropical zones, driven by relatively high private economic benefit. However, the impact of tea plantations on the regional environment, including ecosystem services and disservices are unclear. In this study, we developed an assessment framework for determining the private economic benefits and environmental externalities (the algebraic sum of the regulating services and disservices) of tea plantations in China. Our results showed that tea plantations provided private economic benefits of 5,652 yuan ha?1 year?1 (7.6 yuan?=?1 USD in 2007) for tea farmers, plus positive environmental externalities of 6,054 yuan ha?1 year?1 for the society. The environmental externalities were calculated as the sum of the value of four regulating services, including carbon sequestration (392 yuan ha?1 year?1); soil retention (72 yuan ha?1 year?1); soil fertility protection (3,189 yuan ha?1 year?1) and water conservation (2,685 yuan ha?1 year?1), and three disservices, including CO2 emission (?39 yuan ha?1 year?1), N2O emission (?137 yuan ha?1 year?1) and nonpoint source pollution (?108 yuan ha?1 year?1). Before the private optimal level, the positive environmental externalities can be maintained by private economic benefits; if a social optimal level is required, subsidies from government are necessary. 相似文献
14.
Soil erosion and sediment fluxes analysis: a watershed study of the Ni Reservoir,Spotsylvania County,VA, USA 总被引:1,自引:0,他引:1
Anthropogenic forces that alter the physical landscape are known to cause significant soil erosion, which has negative impact on surface water bodies, such as rivers, lakes/reservoirs, and coastal zones, and thus sediment control has become one of the central aspects of catchment management planning. The revised universal soil loss equation empirical model, erosion pins, and isotopic sediment core analyses were used to evaluate watershed erosion, stream bank erosion, and reservoir sediment accumulation rates for Ni Reservoir, in central Virginia. Land-use and land cover seems to be dominant control in watershed soil erosion, with barren land and human-disturbed areas contributing the most sediment, and forest and herbaceous areas contributing the least. Results show a 7 % increase in human development from 2001 (14 %) to 2009 (21.6 %), corresponding to an increase in soil loss of 0.82 Mg ha-1 year-1 in the same time period. 210Pb-based sediment accumulation rates at three locations in Ni Reservoir were 1.020, 0.364, and 0.543 g cm-2 year-1 respectively, indicating that sediment accumulation and distribution in the reservoir is influenced by reservoir configuration and significant contributions from bedload. All three locations indicate an increase in modern sediment accumulation rates. Erosion pin results show variability in stream bank erosion with values ranging from 4.7 to 11.3 cm year-1. These results indicate that urban growth and the decline in vegetative cover has increased sediment fluxes from the watershed and poses a significant threat to the long-term sustainability of the Ni Reservoir as urbanization continues to increase. 相似文献
15.
Lacerda LD Molisani MM Sena D Maia LP 《Environmental monitoring and assessment》2008,141(1-3):149-164
The Northeastern semi-arid Brazilian region is experiencing rapid social and economic development based on improving water
management and even in areas of low human occupation, anthropogenic emissions of N and P surpass natural emissions in at least
one order of magnitude and these additional loads can alter the water quality of the receiving estuaries. This study estimates,
using an emission factor approach, the annual emissions of N and P from natural processes and anthropogenic sources for estuaries
along the Ceará State, NE Brazil. Emission factors from natural sources are one to two orders of magnitude lower than those
for anthropogenic sources. Among the anthropogenic activities, the aquaculture is responsible for most N emission (0.52 t
km−2 year−1) followed by waste water and husbandry. For P, the largest average emission factors are from husbandry (0.30 t km−2 year−1), waste water and agriculture. 相似文献
16.
Sharma KK Rao CS Dubey JK Patyal SK Parihar NS Battu RS Sharma V Gupta P Kumar A Kalpana Jaya M Singh B Sharma ID Nath A Gour TB 《Environmental monitoring and assessment》2007,132(1-3):25-31
In a field study carried out at three different locations, the dissipation of spiromesifen on cotton and chili was studied
and its DT50, and DT99 were estimated at each location. Spiromesifen was sprayed on chili at 96 and 192 g a.i. ha−1 and cotton at 120 and 240 g a.i. ha−1. Samples of chili fruits were drawn at 0, 1, 3, 5, 7, 10, 15, 21, 30 days after treatment and that of cotton seed and lint
at first picking and harvest. Soil samples were drawn 30 days after treatment from 0 to 15 and 15 to 30 cm layer. Quantification
of residues was done on GC–MS in Selected Ion Monitoring (SIM) mode in mass range 271–274 m/z. The LOQ of this method was
found 0.033 μg g−1, LOD being 0.01 μg g−1. The DT50 of spiromesifen when applied at recommended doses in chili fruits was found to be 2.18–2.40 days. Ninety-nine percent degradation
was found to occur within 14.5–16.3 days after application. Residues of spiromesifen were not detected in cotton seed and
lint samples at the first picking. In soil, no residues of spiromesifen were detectable 15 days after treatment. 相似文献
17.
Factors controlling the salinity in groundwater in parts of Guntur district, Andhra Pradesh, India 总被引:1,自引:0,他引:1
Subba Rao N 《Environmental monitoring and assessment》2008,138(1-3):327-341
Groundwater chemistry has been studied to examine the associated hydrogeochemical processes operating for the development
of salinity in the groundwater in parts of Guntur district, Andhra Pradesh, India. The study area is underlain by charnockites
and granitic gneisses associated with schists of the Precambrian Eastern Ghats. Groundwater is the main resource for irrigation
besides drinking. Chemical parameters, pH, EC, TDS, Ca2+, Mg2+, Na+, K+, , , Cl−, , , F− and SiO2, are taken into account. Groundwater is of brackish type. Na+−Cl− facies dominates the groundwater. Examination of compositional relations and mineral saturation states shows that the ion
exchange of Ca2+ for adsorbed Na+, evapotranspiration, dissolution of soil salts, dissolution of NaCl and CaSO4, and precipitation of CaCO3 are the dominant hydrogeochemical processes associated with the groundwater composition in the area. Evapotranspiration causes
accumulation of salts in the soil/weathered zone. These salts reach the water table by leaching through infiltrating recharge
water. A positive relation between depth to water table and TDS with season supports this inference. The effects of human
activities, such as intensive and long-term irrigation, irrigation-return-flow, application of unlimited agricultural fertilizers
and recycling of saline groundwater, act to further increase the salinity in the groundwater. Therefore, the groundwater quality
increases towards the flow path, while the post-monsoon groundwater shows higher concentrations of TDS, Na+, Mg2+, Cl−, , , F− and SiO2 ions. The study could help to understand the hydrogeochemical characteristics of the aquifer system for taking effective
management measures to mitigate the inferior groundwater quality for sustainable development. 相似文献
18.
Dere S Dalkiran N Karacaoğlu D Elmaci A Dülger B Sentürk E 《Environmental monitoring and assessment》2006,115(1-3):1-22
The implications of metal contamination of agricultural soils due to long term irrigation with treated industrial wastewater and their subsequent accumulation in the vegetables/crops growing on such soils has been assessed in an area of industrial complex, Jajmau, Kanpur (India). Physico-chemical properties of the soil were also studied. The soil and vegetables/crops were sampled from an area of 2100 acre agricultural land and analyzed for physico-chemical properties and metal accumulation in different parts of the plants. The comparison of the data of physico-chemical properties of control and contaminated soil showed that salinity, electrical conductivity, available phosphorous, sodium and potassium content (both water soluble and exchangeable) were found high in contaminated soil. The analysis of plant available metal content in the soil showed the highest level of Fe, which ranged from 529.02 to 2615 μg g−1 dw and lowest level of Ni (3.12 to 10.51 μg g−1 dw). The analysis of the results revealed that accumulation of toxic metal Cr in leafy vegetables was found more than fruit bearing vegetables/crops. Thus, it is recommended that the leafy vegetables are unsuitable to grow in such contaminated sites. It is important to note that toxic metal, Ni was not detected in all the plants. The edible part of the vegetables (under ground) such as, garlic (19.27 μg g−1 dw), potato (11.81 μg g−1 dw) and turmeric (20.86 μg g−1 dw) has accumulated lowest level of toxic metal, Cr than leafy and fruit bearing vegetables. In some fruit part of vegetables such as, bitter gourd, egg plant, jack tree, maize and okra, the accumulation of Cr was not detected and may be grown in this area. 相似文献
19.
Wetherbee GA Gay DA Brunette RC Sweet CW 《Environmental monitoring and assessment》2007,131(1-3):49-69
The National Atmospheric Deposition Program/Mercury Deposition Network (MDN) provides long-term, quality-assured records of
mercury in wet deposition in the USA and Canada. Interpretation of spatial and temporal trends in the MDN data requires quantification
of the variability of the MDN measurements. Variability is quantified for MDN data from collocated samplers at MDN sites in
two states, one in Illinois and one in Washington. Median absolute differences in the collocated sampler data for total mercury
concentration are approximately 11% of the median mercury concentration for all valid 1999–2004 MDN data. Median absolute
differences are between 3.0% and 14% of the median MDN value for collector catch (sample volume) and between 6.0% and 15%
of the median MDN value for mercury wet deposition. The overall measurement errors are sufficiently low to resolve between
NADP/MDN measurements by ±2 ng·l−1 and ±2 μg·m−2·year−1, which are the contour intervals used to display the data on NADP isopleths maps for concentration and deposition, respectively. 相似文献
20.
A five-stage sequential extraction procedure was used to fractionate heavy metals (Cd, Cu, Pb, Cr, Zn, Fe, Mn, Ni, Co, As,
V and Ba) in a biosludge from the biological wastewater treatment plant of Stora Enso Oyj Veitsiluoto Mills at Kemi, Northern
Finland, into the following fractions: (1) water-soluble fraction, (2) exchangeable fraction, (3) easily reduced fraction,
(4) oxidizable fraction, and (5) residual fraction. The biosludge investigated in this study is a combination of sludge from
the primary and secondary clarifiers at the biological wastewater treatment plant. Extraction stages (2)–(4) follow the protocol
proposed by the Measurements and Testing Program (formerly BCR Programme) of the European Commission, which is based on acetic
acid extraction (stage 2), hydroxylamine hydrochloride extraction (stage 3), and hydrogen peroxide digestion following the
ammonium acetate extraction (stage 4). The residual fraction (stage 5) was based on digestion of the residue from stage 4
in a mixture of HF + HNO3 + HCl. Although metals were extractable in all fractions, the highest concentrations of most of the metals occurred in the
residual fraction. From the environmental point of view, it was notable that the total heavy metal concentrations in the biosludge
did not exceed the maximal allowable heavy metal concentrations for sewage sludge used in agriculture, set on the basis of
environmental protection of soil by European Union Directive 86/278/EEC, and by the Finnish legislation. The Ca (98.6 g kg−1; dry weight) and Mg (2.2 g kg−1; dry weight) concentrations in the biosludge were 62 and 11 times higher than the typical values of 1.6 and of 0.2 g kg−1 (dry weight), respectively, in arable land in Central Finland. The biosludge had a slightly alkaline pH (∼8.30), a high loss-on-ignition
value (∼78%) and a liming effect of 10.3% expressed as Ca equivalents (dry weight). This indicates its potential as a soil
conditioner and improvement agent, as well as a pH buffer. 相似文献