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1.
Pore waters play an important role in phosphorus dynamics in aquatic ecosystems. Phosphorus concentrations in pore waters
are much higher than above the bottom. This is confirmed by the results of this study concerning the hypereutrophic lake.
Pore water was analyzed at 11 sampling stations in the upper layer of bottom sediments. This water was separated by centrifugation
and phosphorus level was measured spectrophotometrically with ascorbic acid as a reducer. Total phosphorus concentration in
pore waters ranged from 0.5 to 8.1 mgP l − 1 (mean 3.2 mgP l − 1). Mean phosphorus concentration in pore water samples of this lake was the highest in summer and the lowest in winter. High
concentrations were observed in samples from the pelagial and low from the macrophyte zone. 相似文献
2.
Modeling Phosphate Influence on Arsenate Reduction Kinetics by a Freshwater Cyanobacterium 总被引:1,自引:0,他引:1
Arsenic speciation in natural surface-water systems can be highly impacted through biological processes that result in non-thermodynamically
predicted species to dominate the system. In laboratory experiments, arsenate reduction by a freshwater cyanobacterium exhibited
saturation kinetics increasingly inhibited by elevating solution phosphate concentrations. Approximately 100% arsenate reduction
occurred by days 4, 7, and 10 in the low (0.35 μm), middle (3.5 μm), and high (35 μm) phosphate treatments, respectively,
with maximum arsenate reduction rates ranged from 0.013 μmol As g C−1 day−1 in the high-phosphate treatment to 0.398 μmol As g C−1 day−1 in the low-phosphate treatment. Saturation kinetic models were utilized to evaluate the impact of cell growth and arsenate-phosphate
uptake competition on arsenate reduction rates by the cyanobacterium. Results showed reduced arsenicals dominate arsenic speciation
once growth reached steady state, indicating reduced arsenicals may dominate natural systems, even when considering conservatively
high, abiotic arsenic reoxidation. 相似文献
3.
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
4.
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
5.
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
6.
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
7.
In a comprehensive program of environmental radioactivity survey in South Caspian region,137Cs inventories in soil has been measured at more than 50 sites in the Iranian northern province of Guilan. This has been the
first wide-range survey of soil radionuclide inventories in the narrow band sensitive ecosystem of south Caspian shore. Radioactivity
measurements were carried out using HPGe gamma-spectrometry system. The activity concentration of 137Cs in surface soil exhibits a mean value of 17.6 ± 9.4 Bq kg−1, with a range of 2.3–41.7 Bq kg−1. In many sites, split-level sampling method has been applied down to a depth of 20 cm. There were found generally two profiles.
Most profiles exhibit a negative exponential distribution, while others revealed a clear subsurface peak in 5–10-cm layer.
Cesium deposition in the study area has been estimated to be in the range of 0.38–2.9 kBq m−2 with a mean value of 1.7 kBq m−2. Distribution patterns of 137Cs concentration levels and deposition values have been estimated using Kriging interpolation method. Observed hotspots in
deposition pattern coincide with areas of higher precipitation. 相似文献
8.
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
9.
The aim of this study is to determine the possibility of using Rinodina sophodes (Ach.) Massal., a crustose lichen as polycyclic aromatic hydrocarbons (PAHs) bioaccumulator for evaluation of atmospheric
pollution in tropical areas of India, where few species of lichens are able to grow. PAHs were identified, quantified and
compared to evaluate the potential utility of R. sophodes. The limit of detection for different PAHs was found to be 0.008–0.050 μg g − 1. The total PAHs in different sites were ranged between 0.189 ± 0.029 and 0.494 ± 0.105 μg g − 1. The major sources of PAHs were combustion of organic materials, traffic and vehicular exhaust (diesel and gasoline engine).
Significantly higher concentration of acenaphthylene and phenanthrene indicates road traffic as major source of PAH pollution
in the city. Two-way ANOVA also confirms that all PAHs content showed significant differences between all sampling sites (P
1%). This study establishes the utility of R. sophodes in monitoring the PAHs accumulation potentiality for development of effective tool and explores the most potential traits
resistant to the hazardous environmental conditions in the tropical regions of north India, where no such other effective
way of biomonitoring is known so far. 相似文献
10.
In this study, we coupled a three-dimensional hydrodynamic model with an ecosystem model and applied it to the shallow complex floodplain wetland of Chini Lake in Malaysia. Our objective was to provide a better understanding of the lake’s ecosystem dynamics under different forcing mechanisms. Simulations and validation were performed over a dry month period. Wind speed ranged between 0 and 7.7 m s?1, whilst air temperature ranged between 22.0 and 35.6 °C. Advective transport driven by wind stress was the dominant physical force that shaped the water quality variations during the dry season. Convective circulation intermittently influenced the circulation during calm conditions. Nutrient concentration and stratification of dissolved oxygen (DO) varied between the lakes. Wind events saw patterns of the surface DO concentrations move spatially in the direction of the wind. The ecosystem model simulation suggested that the water quality in Chini Lake was influenced by macrophyte production, although the dissolved and particulate organic carbon accounted for the major fraction of organic matter content in the lake. 相似文献
11.
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
12.
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
13.
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
14.
Removal of hexavalent chromium from contaminated ground water using zero-valent iron nanoparticles 总被引:1,自引:0,他引:1
Ritu Singh Virendra Misra Rana Pratap Singh 《Environmental monitoring and assessment》2012,184(6):3643-3651
Batch experiments were conducted on ground water samples collected from a site contaminated with Cr(VI) to evaluate the redox
potential of zero-valent iron (Fe0) nanoparticles for remediation of Cr(VI)-contaminated ground water. For this, various samples of contaminated ground water
were allowed to react with various loadings of Fe0 nanoparticles for a reaction period of 60 min. Data showed 100% reduction of Cr(VI) in all the contaminated ground water
samples after treatment with 0.20 gL−1 of Fe0 nanoparticles. An increase in the reduction of Cr(VI) from 45% to 100% was noticed with the increase in the loading of Fe0 nanoparticles from 0.05 to 0.20 gL−1. Reaction kinetics of Cr(VI) reduction showed pseudo first-order kinetics with rate constant in the range of 1.1 × 10−3 to 3.9 × 10−3 min−1. This work demonstrates the potential utility of Fe0 nanoparticles in treatment and remediation of Cr(VI)-contaminated water source. 相似文献
15.
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
16.
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
17.
Reddy KJ Kumar JR Ramachandraiah C Reddy SA Reddy AV 《Environmental monitoring and assessment》2008,136(1-3):337-346
N-Ethyl-3-cabazolecarboxaldehydethiosemicarbazone (ECCT) is proposed as a new, sensitive and selective complexing reagent
for the separation and extractive spectrophotometric determination of palladium(II) at pH: 4.0 to form a yellowish orange
colored 1:1 chelate complex, which is very well extracted in to n-butanol. The absorbance was measured at a maximum wavelength,
410 nm. This method obeys Beer’s law in the concentration range 0.0–6.6 μg mL−1 and the correlation coefficient of Pd(II)-ECCT complex is 0.998, which indicates an excellent linearity between the two variables
with good molar absorptivity and Sandell’s sensitivity, 1.647 × 104 l mol−1cm−1, 6.49 × 10−3 μg cm−2, respectively. The instability constant of complex calculated from Edmond’s method, 2.724 × 10−5 was in good agreement with the value calculated from Asmus’ method 2.624 × 10−5, at room temperature. The precision and accuracy of the method is checked with calculation of relative standard deviation
(n = 5), 0.839. Edmond’s method was observed to be a more selective method in the presence of EDTA, oxalate and phosphate ions.
The method was successfully applied for the determination of Pd(II) in water samples, synthetic mixtures and hydrogenation
catalysts, employing an atomic absorption spectrometer for comparing these results. 相似文献
18.
Health risk assessment of heavy metals for edible parts of vegetables grown in sewage-irrigated soils in suburbs of Baoding City,China 总被引:1,自引:0,他引:1
Zhan-Jun Xue Shu-Qing Liu Yan-Ling Liu Yong-Lu Yan 《Environmental monitoring and assessment》2012,184(6):3503-3513
With the long-term application of wastewater to vegetable production fields, there is concern about potential health risks
of heavy metals contaminating the edible parts of vegetables grown in contaminated soils in the suburban areas of Baoding
City, China. The average concentration of elemental Zn in sewage-irrigated soil was the highest (153.77 mg kg−1), followed by Pb (38.35 mg kg−1), Cu (35.06 mg kg−1), Ni (29.81 mg kg−1), and Cd (0.22 mg kg−1) which were significantly higher (P < 0.05) than those in the reference soil. The results showed that long-term sewage irrigation had led to a growing accumulation
of heavy metals in the soils, especially for Cd, Zn, and Pb. Furthermore, the concentrations of elemental Cd, Zn, and Ni in
vegetables (e.g., Beassica pekinensis L., Allium fistulosum L., Spinacia oleracea L.) collected from the wastewater-irrigated soils exceeded the maximum permissible limits, and this also increased the daily
intake of metals by food. However, compared with the health risk index of <1 for heavy metals, the ingestion of vegetables
from the soils irrigated with sewage effluent posed a low health risk. Nevertheless, heavy metal concentrations should be
periodically monitored in vegetables grown in these soils together with the implementation effective remediation technologies
to minimize possible impacts on human health. 相似文献
19.
Pasture selection by livestock is an essential topic for rangeland management, especially in trace element-contaminated soils.
We have studied the composition (nutrients and trace elements) of a grass-based diet from soils affected by a mine spill at
different growth stages (October 2008 to May 2009). A diet based on other plants (mainly Compositae species) was also studied (May 2009) for comparison. Faeces and mane hair of horses feeding on these pastures were also analysed.
Micronutrient (Cu, Fe, Mn and Zn) and potentially toxic trace element (As, Cd, Pb, Tl) concentrations were below the maximum
tolerable levels (MTL) for horses, except for Fe (at early growth of pastures) and Cd (in the diet based on ‘other’ plants).
Values of potential ingestion of Fe by horses were higher than 10 mg kg body weight − 1 day − 1. Cadmium concentrations in some pasture samples (those composed of Compositae species) were higher than 3 mg kg − 1. Potential toxicity of such Cd levels in pastures is uncertain, since a high disparity of criteria about MTL by cattle exists
(between 0.5 and 10 mg kg − 1 diet). Nutrient concentrations were adequate for horses, which could counteract possible harmful effects derived from trace
element ingestion. The analyses of excreta and mane hair point to the low risk of toxicity derived from the consumption of
these contaminated pastures. However, the ingestion of regenerating pastures (autumnal samples) should be avoided due to the
greater risk of ingestion of contaminated soil attached to the plant material. Management of these pastures by grazing requires
periodic monitoring. Special attention should be given to Fe and particularly Cd (non-essential element) which accumulates
in animal organs, where it could provoke uncertain long-term effects. 相似文献
20.
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