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1.
Heavy metal pollution of water resources can be apprehended in East Singhbhum region which is a highly mineralised zone with
extensive mining of copper, uranium and other minerals. Ten groundwater samples were collected from each site and the heavy
metal analysis was done by atomic absorption spectrophotometer. Analysis of the results of the study reveals that the concentration
of iron, manganese, zinc, lead, copper and nickel in groundwater of Bagjata mining area ranged 0.06–5.3 mg l − 1, 0.01–1.3 mg l − 1, 0.02–8.2 mg l − 1, 1.4–28.4 μg l − 1, 0.78–20.0 μg l − 1 and 1.05–20.1 μg l − 1, respectively. In case of Banduhurang mining area, the range was 0.04–2.93 mg l − 1, 0.02–1.1 mg l − 1, 0.01–4.68 mg l − 1, 1.04–33.21 μg l − 1, 1.24–18.7 μg l − 1 and 1.06–14.58 μg l − 1, respectively. The heavy metals were found to be below the drinking water standards (IS:10500 1993) except iron (0.3 mg l − 1) and manganese (0.1 mg l − 1). The hazard quotients of the heavy metals for drinking water were below 1 posing no threat due to intake of water to the
people for both the areas. 相似文献
2.
Disturbance by military maneuvers over short and long time scales may have differential effects on grassland communities.
We assessed small mammals as indicators of disturbance by military maneuvers in a mixed prairie in southern Oklahoma USA.
We examined sites on two soil series, Foard and Lawton, across a gradient of disturbance intensity. A MANOVA showed that abundance
of small mammals was associated (p = 0.03) with short-term (cover of vehicle tracks) disturbance but was not associated (p = 0.12) with long-term (loss of soil organic carbon, SOC) disturbance intensity. At the individual species level, Sigmodon hispidus (cotton rat) and Peromyscus maniculatus (deer mouse) occurred across all levels of disturbance and in both soil types. Only P. maniculatus abundance changed (p < 0.01) with short-term disturbance and increased by about one individual per 5% of additional track-cover. Abundance of
P. maniculatus also increased (p = 0.04) by about three individuals per 1% increase in soil carbon. Chaetodipus hispidus (hispid pocket mouse) and Reithrodontomys fulvescens (fulvous harvest mouse) only occurred in single soil types limiting their potential as more general indicators. Abundance
of P. maniculatus was positively related to shifts in plant species composition and likely reflected changes in vegetation structure (i.e.
litter depth) and forage availability resulting from disturbance. Peromyscus maniculatus may be a useful biological indicator of ecosystem change because it responded predictably to both long-term and short-term
disturbance and, when coupled with soil, plant, and disturbance history variables, can reveal land condition trends. 相似文献
3.
Chrastný V Vaněk A Teper L Cabala J Procházka J Pechar L Drahota P Penížek V Komárek M Novák M 《Environmental monitoring and assessment》2012,184(4):2517-2536
The soils adjacent to an area of historical mining, ore processing and smelting activities reflects the historical background
and a mixing of recent contamination sources. The main anthropogenic sources of metals can be connected with historical and
recent mine wastes, direct atmospheric deposition from mining and smelting processes and dust particles originating from open
tailings ponds. Contaminated agriculture and forest soil samples with mining and smelting related pollutants were collected
at different distances from the source of emission in the Pb–Zn–Ag mining area near Olkusz, Upper Silesia to (a) compare the
chemical speciation of metals in agriculture and forest soils situated at the same distance from the point source of pollution
(paired sampling design), (b) to evaluate the relationship between the distance from the polluter and the retention of the
metals in the soil, (c) to describe mineralogy transformation of anthropogenic soil particles in the soils, and (d) to assess
the effect of deposited fly ash vs. dumped mining/smelting waste on the mobility and bioavailability of metals in the soil.
Forest soils are much more affected with smelting processes than agriculture soils. However, agriculture soils suffer from
the downward metal migration more than the forest soils. The maximum concentrations of Pb, Zn, and Cd were detected in a forest
soil profile near the smelter and reached about 25 g kg − 1, 20 g kg − 1 and 200 mg kg − 1 for Pb, Zn and Cd, respectively. The metal pollutants from smelting processes are less stable under slightly alkaline soil
pH then acidic due to the metal carbonates precipitation. Metal mobility ranges in the studied forest soils are as follows:
Pb > Zn ≈ Cd for relatively circum-neutral soil pH (near the smelter), Cd > Zn > Pb for acidic soils (further from the smelter).
Under relatively comparable pH conditions, the main soil properties influencing metal migration are total organic carbon and
cation exchange capacity. The mobilization of Pb, Zn and Cd in soils depends on the persistence of the metal-containing particles
in the atmosphere; the longer the time, the more abundant the stable forms. The dumped mining/smelting waste is less risk
of easily mobilizable metal forms, however, downward metal migration especially due to the periodical leaching of the waste
was observed. 相似文献
4.
Padmalal D Remya SI Jyothi SJ Baijulal B Babu KN Baiju RS 《Environmental monitoring and assessment》2012,184(3):1541-1557
The southwestern coast of India is drained by many small rivers with lengths less than 250 km and catchment areas less than
6,500 km2. These rivers are perennial and are also the major drinking water sources in the region. But, the fast pace of urbanization,
industrialization, fertilizer intensive agricultural activities and rise in pilgrim tourism in the past four to five decades
have imposed marked changes in water quality and solute fluxes of many of these rivers. The problems have aggravated further
due to leaching of ionic constituents from the organic-rich (peaty) impervious sub-surface layers that are exposed due to
channel incision resulting from indiscriminate instream mining for construction-grade sand and gravel. In this context, an
attempt has been made here to evaluate the water quality and the net nutrient flux of one of the important rivers in the southwestern
coast of India, the Manimala river which has a length of about 90 km and catchment area of 847 km2. The river exhibits seasonal variation in most of the water quality parameters (pH, electrical conductivity, dissolved oxygen,
total dissolved solids, Ca, Mg, Na, K, Fe, HCO3, NO2-N, NO3-N, P
\text-inorg_{\rm \text{-}inorg}, P
\text-tot_{\rm \text{-}tot}, chloride, SO4, and SiO2). Except for NO3-N and SiO2, all the other parameters are generally enriched in non-monsoon (December–May) samples than that of monsoon (June–November).
The flux estimation reveals that the Manimala river transports an amount of 2,308 t y − 1 of dissolved inorganic nitrogen, 87 t y − 1 dissolved inorganic phosphorus, and 9246 t y − 1 of SO4, and 1984 t y − 1 K into the receiving coastal waters. These together constitute about 23% of the total dissolved fluxes transported by the
Manimala river. Based on the study, a set of mitigation measures are also suggested to improve the overall water quality of
small catchment rivers of the densely populated tropics in general and the south western coast in particular. 相似文献
5.
von Bobrutzki K Ammon C Berg W Einert P Fiedler M Müller HJ Scherer D Strohbach B 《Environmental monitoring and assessment》2012,184(6):3775-3787
Agricultural NH3 emissions affect air quality and influence the nitrogen cycle. In the subject study, NH3 emissions from a broiler farm and the resulting atmospheric concentrations in the immediate vicinity during three growing
cycles have been quantified. Additionally, vegetation along a transect in an adjacent woodland was analysed. The emissions
were as high as 10 kg NH3 h−1 and the atmospheric concentrations ranged between 33 and 124 μg NH3 m−3 per week in the immediate vicinity. Measurements of the atmospheric concentrations over 7 weeks showed a substantial decline
of mean concentrations (based on a 3-week average) from ∼13 to <3 μg NH3 m−3, at 45- and 415-m distance from the farm. Vegetation surveys showed that nitrophilous species flourished when they grew closest
to the farm (their occurrence sank proportionately with distance). A clearly visible damage of pine trees was observed within
200 m of the farm; this illustrated the significant impact of NH3 emissions from agricultural sources on the sensitive ecosystem. 相似文献
6.
Montes AM González-Farias FA Botello AV 《Environmental monitoring and assessment》2012,184(3):1359-1369
The lagoon system of Navachiste-Macapule is located in northern Mexico, in the state of Sinaloa, with an area of 24,000 ha.
The main economic activity in the area is agriculture, and the lagoon lies next to the irrigation district ID-063 which covers
116,615 ha. The purpose of this study is to evaluate the levels of pollution generated by organochlorine pesticides (OC) in
the surface sediments of the lagoon and in the agricultural drains of the ID-063 that are supposedly transported into the
system as a result of agricultural activities and runoff from adjacent land. For this, between 2006 and 2007, 45 surface sediment
samples were collected (warm dry, rainy and cold dry) from 15 sampling sites, during the three climatic seasons. Of these,
eight were located inside the lagoon in marine conditions (salinity >31 PSU) and seven in the agricultural drains of the ID-063
in freshwater conditions (salinity <5 PSU). The average concentration of the OC in the sediments was 44.75 ng g − 1, among which the group of the alicyclic compounds presented the greatest concentrations. The average value of the total organic
carbon (TOC) in the sediments of the system was 0.90%. The sediments collected inside the lagoon had an average OC concentration
of 18.97 ng g − 1, and the predominant type of sediment was fine to very fine sand. The average OC concentration in the sediments collected
in the agricultural drains was 75.69 ng g − 1, where fine sediments (silt) were predominant. The presence of methoxychlor, endrin and heptachlor suggested that these compounds
were continuously used in the system, even though their use is forbidden in Mexico. 相似文献
7.
Remeteiová D Rusnák R Kucanová E Fióová B Ružičková S Fekete I Horváth M Dirner V 《Environmental monitoring and assessment》2012,184(2):1121-1130
In this work are presented results of the complex study of two significant solid environmental samples: gravitation dust sediments
(industrial pollutants, potential source of risk elements input to soils) and soils (component of the environment, potential
source of risk elements input to food web). The first phase of this study was focused on the study of the significant chemical
properties (phase composition, content of organic and inorganic carbon) of the dust and soil samples. In the second phase,
the fractionation analysis was used on the evaluation of the mobility of chosen risk elements (Cu, Ni, Pb, Zn) in the studied
samples. The single-step extractions were applied in the order of the isolation of the element forms (fractions), with different
mobilities during defined ecological conditions by utilization of the following reagents: 1 mol dm − 3 NH4NO3 for isolation of the “mobile” fraction, 0.05 mol dm − 3 ethylenediaminetetraacetic acid and 0.43 mol dm − 3 CH3COOH for isolation of the “mobilizable” fraction, and 2 mol dm − 3 HNO3 for isolation of all releasable forms. On the basis of the results obtained in this study, it is possible to state that different
origins and positions of solid environmental samples in the environment reflect in different chemical properties of their
matrix. The different properties of the sample matrix result in different mobilities of risk elements in these kinds of samples.
The fractionation analysis with single-step extraction for isolation element fractions is the method most suitable for easy
checking of environmental pollution and for evaluation of risk elements cycle in the environment. 相似文献
8.
Water quality assessment: surface water sources used for drinking and irrigation in Zaria,Nigeria are a public health hazard 总被引:1,自引:0,他引:1
Chigor VN Umoh VJ Okuofu CA Ameh JB Igbinosa EO Okoh AI 《Environmental monitoring and assessment》2012,184(5):3389-3400
We assessed the quality and pollution status of source surface waters in Zaria, Nigeria by monitoring the nature, cause and
extent of pollution in Samaru stream, Kubanni River and Kubanni dam over a period of 10 months, between March and December
2002. A total of 228 water samples was collected from 12 sites and analysed for a total of ten physicochemical and one bacteriological
quality indicators, using standard methods. Aesthetic water quality impairment parameters were also observed. The mean values
of most water quality parameters were significantly higher (P < 0.05) in both the stream and river than in the dam. There was no significant correlation between faecal coliform counts
(FCC) and water temperature (in the range 15–33°C); pH (5.77–7.32); and turbidity (1.4–567 NTU). The high FCC ranged from
2.0 × 101 to 1.6 × 106 MPN/100 ml and exceeded the WHO standards for drinking water and water used for fresh-produce irrigation, and correlated
positively (P < 0.05) with conductivity (in the range 68–1,029 μS/cm); TDS (10.0–70.0 mg/l); TSS (10.0–70.0 mg/l); Cl (7.5–181 mg/l); PO4−P (0.01–0.41 mg/l); NO3−N (0.6–3.8 mg/l) and BOD5 (0.1–14.9 mg/l). The main pollution sources were municipal wastewater, stormwater runoffs, the ABU sewage treatment plant,
abattoir effluents and irrigation farms treated with chemical fertilisers. We conclude that these water bodies are potentially
hazardous to public health and that proper sewage treatment and river quality monitoring are needed to warn against hazards
to public health. 相似文献
9.
The chemical forms and ecological risk of As were characterized in the sediment of the Daliao River System (DRS), which has
been affected by long-term intensive industrial, urban, and agricultural activities. Twenty-seven samples of surface sediment
were collected and analyzed for total As content and that of its chemical forms. The results indicated that the average total
As content in the sediment was 9.83 mg kg − 1 but that the levels ranged from 1.57 to 83.09 mg kg − 1. At the sites near cities, mining sites, and the estuary of the DRS, it is likely that adverse effects on aquatic organisms
occur, due to As levels in the sediment that are often higher than the threshold effect level and occasionally higher than
the probable effect level. A selectively sequential extraction indicated that the majority of As in the sediment was bound
to Fe oxides (62.1%), with moderate proportions of residual As (19.8%), specifically adsorbed As (17.9%), and a low proportion
of non-specifically adsorbed As (1.1%). In addition, the content of Fe in the sediment was positively and significantly correlated
with the contents of amorphous and crystalline Fe oxide-bound As, confirming the crucial role of Fe oxides in immobilizing
high amounts of As in superficial environments. The average molar ratio of As to Fe was 1.18 × 10 − 4 in the surface sediment of the DRS, similar to that of natural Fe oxides, but much lower than that of synthesized Schwertmannite.
Therefore, the release of As under reduced and low pH conditions can cause serious problems for water resources and for living
organisms. 相似文献
10.
Al-Tayar NG Nagaraja P Vasantha RA Shresta AK 《Environmental monitoring and assessment》2012,184(1):181-191
A simple, rapid, and sensitive method involving the interaction of 2,4-dinitrophenylhydrazine with imipramine hydrochloride
in presence of vanadium (V) in sulfuric acid medium has been proposed for the determination of vanadium. The purple-colored
product developed showed an absorption maximum at 560 nm and was stable for 24 h. The working curve was linear over the concentration
range of 0.1–2.8 μg ml − 1, with sensitivity of detection of 0.0124 μg ml − 1. Molar absorptivity and Sandell’s sensitivity were found to be 2.6 × 104 l/mol cm and 0.0039 μg cm − 1, respectively. The accuracy of the proposed method was assessed by Student’s t test and variance ratio F test, and the results were on par with the reported method. The method was successfully used in the determination of V in
water, human urine, soil, and plant samples, and it was free from interference by various concomitant ions. 相似文献
11.
Accumulation and tolerance characteristics of cadmium in Chlorophytum comosum: a popular ornamental plant and potential Cd hyperaccumulator 总被引:3,自引:0,他引:3
The effects on the growth, physiological indexes and the cadmium (Cd) accumulation in Chlorophytum comosum under Cd stress were examined by pot-planting. The results showed that the tolerance index (TI) of C. comosum were all above 100 in soil Cd concentration of 100 mg kg − 1. The O2·-_{2^{\bullet}}^{-} production rate and electrical conductivity of C. comosum were significantly positively correlated to Cd adding-concentration while the MDA content increased and had significant differences
with the control. The activities of SOD, CAT, and POD all rose significantly in lower Cd concentration and the Cd threshold
of them were around 10, 50 and 20 mg kg − 1, respectively. The Cd in C. comosum root and aboveground part reached 1,522 and 865·5 mg kg − 1, respectively, in Cd concentration of soil up to 200 mg kg − 1. For the advantages of high tolerance, high accumulation, and high ornamental value, C. comosum may have tremendous application value in the treatment of Cd-contaminated soils. 相似文献
12.
This paper reports the utilization of 4-(2-pyridylazo) resorcinol (PAR) as a chelating reagent for in-column derivatization
and the determination of trace Co, Fe, and Ni ions by reversed-phase high-performance liquid chromatography with photodiode
array detector. A good separation of Co, Fe, and Ni chelates were achieved by using an Inertsil ODS-3 column and a mobile
phase, consisted of methanol–THF–water mixture (50:5:45) containing ammonium acetate buffer (pH 5.0) and PAR. After full optimization,
good repeatability of retention times (relative standard deviation (RSD) < 0.05%) and peak areas (RSD < 1.7%) was achieved
as well as a good linearity (r
2 > 0.9991). The detection limits (S/N = 3), expressed as micrograms per liter, were 0.50 (Co), 9.07 (Fe), and 2.00 (Ni). The applicability and the accuracy of
the developed method were estimated by the analysis of spiked water samples and certified reference material BCR 715 wastewater-SRM. 相似文献
13.
Díaz A Arnedo R Céspedes-Sánchez R Devesa R Martin-Alonso J 《Environmental monitoring and assessment》2012,184(1):539-548
A performance study of diffusive gradients in thin films (DGT) and inductively coupled plasma optical emission spectrometry
(ICP-OES) was applied for the monitoring of the labile fraction of metals Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn, in Sant
Joan Despí Drinking Water Treatment Plant located in the South of Barcelona’s Metropolitan Area (Spain). The DWTP monitoring
protocol was optimized by working for 1 day of deployment (24 h) with the DGT device in contact with both treated and river
water matrixes. Additionally, it was demonstrated that an increase in the deployment time of 1 week did not decrease the evaluated
concentrations of the studied metals. The quality parameters of the DGT device and ICP-OES determination, such as limit of
quantification, accuracy expressed as relative error (%) and reproducibility expressed as relative standard deviation, were
evaluated. Good results were obtained for all the metals in ultrapure water; limits of quantification ranged from 1.5 μg L − 1 for cadmium to 28 μg L − 1 for zinc when deployment time of 24 h was used and from 0.2 μg L − 1 for cadmium to 4 μg L − 1 for zinc when this time was increased by 1 week. Accuracy and precisions lower than or equal to 10% were obtained at a parametric
concentration value of the metals regulated in the European Drinking Water Guidelines (98/83/EC). DGT deployment was tested
in river and treated water, and good results were obtained for Cd, Ni, Co and Zn, whereas for the other metals, a continuous
control of their metallic labile fractions was monitored. Therefore, DGT device allows the continuous monitoring of the labile
metal species in a drinking water treatment plant. 相似文献
14.
Licata P Naccari F Dugo G Fotia V Lo Turco V Potorti AG Di Bella G 《Environmental monitoring and assessment》2012,184(5):2881-2892
In the present study, we investigated the concentrations and distribution of organochlorine pesticides (OCs) and polychlorinated
biphenyls (PCBs) in intestine, liver, and muscle samples of 11 common buzzards (Buteo buteo) from Sicily used as bioindicator for monitoring pollution in environment. All samples of common buzzards were collected
at the “Recovery Center of Wild Fauna” of Palermo, through the Zooprophilactic Institute. Quantitative determination of OCs
and PCBs in the samples examined has been carried out using HRGC-ECD and GC-MS. The results obtained show the presence of
concentrations of ∑DDT and ∑PCB in almost all samples. Regarding ∑DDT (4,4′-DDE, 2,4′-DDD, 4,4′-DDD, 2,4′-DDT, and 4,4′-DDT), the highest concentrations were found in intestine (0.411 ± 0.050 μg/g) followed by muscle (0.130 ± 0.017 μg/g) and
liver samples (0.109 ± 0.014 μg/g). As regards the ∑PCB congeners (PCB-28, PCB-52, PCB-95, PCB-99, PCB-101, PCB-110, PCB-138,
PCB-146, PCB-149, PCB-151, PCB-153, PCB-170, PCB-177, PCB-180, PCB-183, and PCB-187), the highest concentrations were found
in intestine (1.686 ± 0.144 μg/g) followed by liver (1.064 ± 0.162 μg/g) and muscle samples (0.797 ± 0.078 μg/g). Our data
deserve particular attention not only for their significance but especially because they were recorded in Sicily, a region
with a very low risk of environmental pollution due to the shortage of industries. 相似文献
15.
A sensitive spectrophotometric method has been developed for determination of ametryn in agricultural samples. The proposed
method was based on reaction with pyridine and further coupling with sulfanilic acid to form a colored product. The absorbance
was measured at 400 nm with a molar absorptivity of 2.1 × 105 L mol−1 cm−1. The method shows a linear range from 0.2–20 μg mL−1 with limit of detection and limit of quantification 0.16 and 0.54 μg mL−1, respectively. The method has been successfully applied to the determination of ametryn in sugarcane juice and commercial
formulations after separation of ametryn from triazine herbicides based on solvent extraction. Recovery values were found
to be in the range of 96.0 ± 0.2% to 98.4 ± 0.1%. 相似文献
16.
The contribution of fugitive dust from traffic to air pollution can no longer be ignored in China. In order to obtain the
road dust loadings and to understand the chemical characteristics of PM10 and PM2.5 from typical road dust, different paved roads in eight districts of Beijing were selected for dust collection during the
four seasons of 2005. Ninety-eight samples from 28 roads were obtained. The samples were resuspended using equipment assembled
to simulate the rising process of road dust caused by the wind or wheels in order to obtain the PM10 and PM2.5 filter samples. The average road dust loading was 3.82 g m − 2, with the highest of 24.22 g m − 2 being in Hutongs in the rural–urban continuum during winter. The road dust loadings on higher-grade roads were lower than
those on lower-grade roads. Attention should be paid to the pollution in the rural–urban continuum areas. The sums of element
abundances measured were 16.17% and 18.50% for PM10 and PM2.5 in road dust. The average abundances of OC and EC in PM10 and PM2.5 in road dust were 11.52%, 2.01% and 12.50%, 2.06%, respectively. The abundance of elements, water-soluble ions, and OC, EC
in PM10 and PM2.5 resuspended from road dust did not change greatly with seasons and road types. The soil dust, construction dust, dust emitted
from burning coal, vehicle exhaust, and deposition of particles in the air were the main sources of road dust in Beijing.
Affected by the application of snow-melting agents in Beijing during winter, the amount of Cl − and Na + was much higher during that time than in the other seasons. This will have a certain influence on roads, bridges, vegetations,
and groundwater. 相似文献
17.
The total petroleum hydrocarbons (TPH) pollution in regional agricultural soils was investigated. Seventy soil samples collected
from surface layers (0–20 cm) and horizons of five selected pedons in the vicinity of a petrochemical complex in Guangzhou,
China were analyzed, and the vertical variation and spatial variability of TPH were evaluated. The TPH concentration in top
soils around the petrochemical complex ranged from 1,179.3 to 6,354.9 mg kg − 1, with the average of 2,676.6 mg kg − 1. Furthermore, significant differences between land-use types showed that the TPH concentration in top soils was strongly
influenced by accidental spills. Both the TPH trends in pedons and the identified hot-spot areas also showed that the accidental
explosions or burning accidents were mainly responsible for the pollution. The results reported here suggest that the regular
monitoring and inspection shall be conducted for safety and to avoid or minimize the accidents, and the effective measures
should be taken to remediate the contaminated areas and to assure that the important industrialization of Guangzhou area would
not mean human health risks near the petrochemical complex. 相似文献
18.
Metal fractionation provides information on mobility and stability of various metal species which can be used to evaluate
the movement of such metals in soils. The effect of wastewater irrigation on the fractions, spatial distribution, and mobility
of cadmium (Cd) and zinc (Zn) was investigated in five urban gardens in Kano, Nigeria. Concentration of total Zn in the surface
soils (0–20 cm) ranged from 121 to 207 mg kg − 1 while Cd concentration was 0.3–2.0 mg kg − 1. Speciation of both heavy metals into seven operationally defined fractions indicated that the most reactive forms extracted
with ammonium nitrate and ammonium acetate, also considered as the bioavailable fractions, accounted for 29–42% of total Cd
and 22–54% of total Zn, respectively. The weakly bound fractions of Cd and Zn reached up to 50% of the total Cd and Zn concentrations
in the soils. Such high proportions of labile Cd and Zn fractions are indicative of anthropogenic origins, arising from the
application of wastewater for irrigation and municipal biosolids for soil fertility improvement. Thus, given the predominance
of sandy soil textures, high concentrations of labile Cd and Zn in these garden soils represent a potential hazard for the
redistribution and translocation of these metals into the food chain and aquifer. 相似文献
19.
Bhatia A Pathak H Jain N Singh PK Tomer R 《Environmental monitoring and assessment》2012,184(5):3095-3107
Conventional blanket application of nitrogen (N) fertilizer results in more loss of N from soil system and emission of nitrous
oxide, a greenhouse gas (GHG). The leaf color chart (LCC) can be used for real-time N management and synchronizing N application
with crop demand to reduce GHG emission. A 1-year study was carried out to evaluate the impact of conventional and LCC-based
urea application on emission of nitrous oxide, methane, and carbon dioxide in a rice–wheat system of the Indo-Gangetic Plains
of India. Treatments consisted of LCC scores of ≤4 and 5 for rice and wheat and were compared with conventional fixed-time
N splitting schedule. The LCC-based urea application reduced nitrous oxide emission in rice and wheat. Application of 120 kg
N per hectare at LCC ≤ 4 decreased nitrous oxide emission by 16% and methane by 11% over the conventional split application
of urea in rice. However, application of N at LCC ≤ 5 increased nitrous oxide emission by 11% over the LCC ≤ 4 treatment in
rice. Wheat reduction of nitrous oxide at LCC ≤ 4 was 18% as compared to the conventional method. Application of LCC-based
N did not affect carbon dioxide emission from soil in rice and wheat. The global warming potential (GWP) were 12,395 and 13,692 kg CO2 ha−1 in LCC ≤ 4 and conventional urea application, respectively. Total carbon fixed in conventional urea application in rice–wheat
system was 4.89 Mg C ha−1 and it increased to 5.54 Mg C ha−1 in LCC-based urea application (LCC ≤ 4). The study showed that LCC-based urea application can reduce GWP of a rice–wheat
system by 10.5%. 相似文献
20.
Bondareva L 《Environmental monitoring and assessment》2012,184(6):3831-3847
Discharges from the Mining-and-Chemical Combine (MCC) of Rosatom, downstream from Krasnoyarsk, resulted in radioactive contamination
of sediments of the River Yenisei. The concentration of artificial gamma-emitting radionuclides (137Cs, 60Co, 152Eu, and 241Am) was determined with the objective to analyze the migration processes leading to the transport of these radionuclides.
The content of artificial radionuclides in the surface layers of the study area varied in wide ranges: 137Cs—318–1,800 Bq/kg, 60Co—87–720 Bq/kg, 152Eu—12–287 Bq/kg and 241Am—6–76 Bq/kg. There was a sequence of migration of radionuclides investigated in the surface layer of sediments that were
collected in the near zone of influence of the MCC: 241Am ≈ 152Eu > 60Co > 137Cs. Radionuclide species have been found to be directly related to sediment structure and composition. 相似文献