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101.
Odor and odorant emission rates from freshly dewatered biosolids in a dewatering building of a Water Reclamation Plant (WRP) are measured using the EPA flux chamber and wind tunnel methods. Experimental results are compared statistically to test whether the two methods result in similar emission rates when experiments are performed under field conditions. To the best of our knowledge the literature is void of studies comparing the two methods indoors. In this paper the two methods are compared indoors where the wind velocity and air exchange rate are pertinent field conditions and can be measured. The difference between emission rates of odor and hydrogen sulfide measured with the two methods is not statistically significant (P values: 0.505 for odor, 0.130 for H(2)S). It is concluded that both methods can be used to estimate source emissions but selection of the most effective or efficient method depends on prevailing environmental conditions. The wind tunnel is appropriate for outdoor environments where wind effects on source emissions are more pronounced than indoors. The EPA flux chamber depends on the air exchange rate of the chamber, which simulates corresponding conditions of the indoor environment under investigation and is recommended for estimation of indoor pollution sources.  相似文献   
102.
Activities of 210Po and 210Pb in various tissues of four species of decapod crabs and two species of cephalopod mollusks (cuttlefishes) of Kudankulam coast were studied. A non-uniform distribution of these radionuclides was observed between the organs. Of all the tissues, 210Po and 210Pb were found accumulated more in the hepatopancreas and intestine of crabs and in the digestive gland, shell gland, and intestine of cephalopods. Among crabs, Charybdis lucifera registered a little higher 210Po and 210Pb activities. The cephalopod species Loligo duvauceli displayed higher 210Po and 210Pb in some organs when compared to Sepia pharaonis. The muscle of all the species registered lower activity. In cephalopods, the activity ratio of 210Po/210Pb fell within the range of 1?C2 for most of the organs, and in crab tissues, it varied from 1.7 to 31.4. The biological concentration factor for organs of cephalopods ranged from 1.2 ×103 to 4.3 ×105 for 210Po and 4.8 ×102 to 8.4 ×104 for 210Pb and for organs of crabs it varied between 2.0 ×104 and 1.9 ×106 for 210Po and 9.2 ×102 and 2.4 ×104 for 210Pb. The study revealed that the organs associated with digestion and metabolism displayed a higher activity concentration than the other tissues. A significant variation in the accumulation of 210Po and 210Pb was noted between species (P?<?0.05). The activity levels recorded are in agreement with values recorded in related organisms in other parts of the world. The data generated will act as a reference database for these organisms of this coast in which a nuclear power station is under construction.  相似文献   
103.
This work describes the results of assessment of the heavy metals, Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn in urban soil of Guwahati City, India from 31 sites of five different land use types covering residential, commercial, industrial, public utilities, and roadside. Sequential extraction procedure was used to evaluate the relative distribution of the eight metals in exchangeable, carbonate, reducible (Fe?CMn oxide), organic and sulfide, and residual fractions. Of the eight metals, Cd and Co occur in lower concentrations (Cd <?< Co) in all types of land, and concentration variation from one type of land use to another is not much significant for both the metals. Ni presence is more than Co, and the concentrations show some variation depending on land use status. Average Cr and Cu concentrations are ??100?mg/kg, but Cr has a significantly higher presence in industrial land use. The results are similar in case of Pb. The two metals, Mn and Zn have domination over the other metals, and the values are ??300?mg/kg. Industrial and roadside soil contains much more Mn, while commercial soil is most enriched with Zn. Of the metals, Ni has the largest proportion (~42%) bound to the exchangeable fraction and Co, Cr, and Pb also have appreciable proportion bound to the same fraction. A significant amount of Co is associated with carbonates. The reducible fraction has bound considerable quantity of Mn and Zn, while most of Cu is associated with the organic and sulfide fraction. Both Cd and Pb are dominantly associated with the residual fraction. Computation of the mobility factor of the metals indicates Mn to be the most mobile metal present in the soil samples.  相似文献   
104.
p-Aminodiphenylamine (p-ADPA) has got a binding capacity with tissue proteins. Aspartic and glutamic acids are presumably the responsible units in the protein chain involved in this binding with p-ADPA. p-ADPA is changed into a quinone structure after atmospheric oxidation in Krebs-Ringer-Bicarbonate buffer, pH 7.4 in the presence of trace metal ions. This oxidised form of p-ADPA binds with aspartic acid at pH 7.4 and temperature 40° in 2 hrs. The derivative thus formed absorbs at 450 nm instead of 430 nm.  相似文献   
105.
High polymer blends of Polymethyl methacrylate (PMMA) with cellulose acetate (CA) and Cellulose acetate phthalate (CAP) of varying blend compositions have been prepared to study their biodegradation behavior and blend miscibility. Films of PMMA–CA, and PMMA–CAP blends have been prepared by solution casting using Acetone and Dimethyl formamide(DMF) as solvents respectively. Biodegradability of these blends has been studied by four different methods namely, soil burial test, enzymatic degradation, and degradation in phosphate buffer and activated sludge degradation followed by water absorption tests to support the degradation studies. Degradation analysis was done by weight loss method. The results of all the tests showed sufficient biodegradability of these blends. Degradability increased with the increase in CA and CAP content in the blend compositions. The miscibility of PMMA–CA and PMMA–CAP blends have been studied by solution viscometric and ultrasonic methods. The results obtained reveal that PMMA forms miscible blends with either CA or CAP in the entire composition range. Miscibility of the blends may be due to the formation of hydrogen bond between the carbonyl group of PMMA and the free hydroxyl group of CA and CAP.  相似文献   
106.
Agroforestry is recognized as a strategy for soil carbon sequestration (SCS) under the afforestation/reforestation activities, but our understanding of soil carbon (C) dynamics under agroforestry systems (AFS) is not adequate. Although some SCS estimates are available, many of them lack scientific rigor. Several interrelated and site-specific factors ranging from agroecological conditions to system management practices influence the rate and extent of SCS under AFS, so that generalizations tend to become unrealistic. Furthermore, widely and easily adoptable methodologies are not available for estimating the SCS potential under different conditions. In spite of these, there is an increasing demand for developing “best-bet estimates” based on the current level of knowledge and experience. This document presents an attempt in that direction. The appraisal validates the conjecture that AFS can contribute to SCS, and presents indicative ranges of SCS under different AFS in the major agroecological regions of the tropics. The suggested values range from 5 to 10 kg C ha?1 in about 25 years in extensive tree-intercropping systems of arid and semiarid lands to 100–250 kg C ha?1 in about 10 years in species-intensive multistrata shaded perennial systems and homegardens of humid tropics.  相似文献   
107.

Bioleaching is considered an eco-friendly technique for leaching metals from spent hydroprocessing catalysts; however, the low bioleaching yield of some valuable metals (Mo and V) is a severe bottleneck to its successful implementation. The present study reported the potential of an integrated bioleaching-chemical oxidation process in improved leaching of valuable metals (Mo and V) from refinery spent hydroprocessing catalysts. The first stage bioleaching of a spent catalyst (coked/decoked) was conducted using sulfur-oxidizing microbes. The results suggested that after 72 h of bioleaching, 85.7% Ni, 86.9% V, and 72.1% Mo were leached out from the coked spent catalyst. Bioleaching yield in decoked spent catalyst was relatively lower (86.8% Ni, 79.8% V, and 59.8% Mo). The low bioleaching yield in the decoked spent catalyst was attributed to metals’ presence in stable fractions (residual + oxidizable). After first stage bioleaching, the integration of a second stage chemical oxidation process (1 M H2O2) drastically improved the leaching of Ni, Mo, and V (94.2–100%) from the coked spent catalyst. The improvement was attributed to the high redox potential (1.77 V) of the H2O2, which led to the transformation of low-valence metal sulfides into high-valence metallic ions more conducive to acidic bioleaching. In the decoked spent catalyst, the increment in the leaching yield after second stage chemical oxidation was marginal (<5%). The results suggested that the integrated bioleaching-chemical oxidation process is an effective method for the complete leaching of valuable metals from the coked spent catalyst.

  相似文献   
108.
In this study, nerve conduction, organochlorine (OC) pesticide residues in blood and cholinesterase activity levels of pesticide sprayers employed in mango plantations at Lucknow, North India, were determined. Fifty-two sprayers from mango plantations who regularly spray mixture of pesticides like organophosphates (OP), OCs, and carbamates were considered as exposed group. Eighteen subjects with similar socio-economic status of exposed group, who do not handle pesticides, were selected as controls. Questionnaire-based interviews related to personal and occupational histories of the study subjects were carried out. Sprayers did not use any personal protective equipment during pesticide handling. The blood-pesticide analyses of sprayers show higher mean values of hexachlorohexane (HCH), γ-HCH, δ-HCH, total HCH, op-DDT compared with the controls. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activites were significantly reduced among sprayers. Risk of motor nerve conduction deficits was observed in sprayers with low AChE activity. Negative correlation of motor and sensory nerve conduction deficits was observed with the duration of exposure and age among sprayers. The study demonstrated that the prolonged exposure to mixture of pesticides, ergonomic factors, decline in cholinesterase activity may lead to nerve conduction dysfunction. The findings suggest the need for controlled use of pesticides in the plantation and indicated the need for training and implementation of hygiene practices like proper usage of personal protective equipments.  相似文献   
109.
Free radical production and oxidative stress are known to increase in liver during diabetes and may contribute to oxidative damage. In this study, the effect of oral feeding of Trigonella foenum-graecum seed powder (TSP) has been studied on blood glucose, membrane-linked ATPases, antioxidant enzymes, lipid peroxidation, lipofuscin content and membrane fluidity in livers of a diabetic rat. Diabetes was induced by administration of alloxan monohydrate. Hyperglycemia during diabetes has been shown to entail free radical generation, with a concomitant increase in lipid peroxidation and lipofuscin content, inhibition of membrane-linked ATPases, increased antioxidant enzyme activities and decreased membrane fluidity. TSP treatment reverses the changes to near normal levels thereby ameliorating the management of diabetic complications.  相似文献   
110.
New oxovanadium(IV) mixed-ligand complexes of the general composition [VO(L)(A)], where KHL?=?potassium salt of salicylideneglycine, A1?=?bis(benzylidene)ethylenediamine, A2?=?bis (acetophenone)ethylenediamine, A3?=?di(2-pyridyl)amine, A4?=?bis(benzylidene)-1,8-diaminonaphthalene, A5?=?thiophene-o-carboxaldene-aniline, A6?=?thiophene-o-carboxaldene-p-anisidine, have been synthesized by the interaction of these ligands with vanadyl sulphate. The mixed-ligand complexes have been characterized on the basis of elemental analysis, magnetic measurements, electronic and infrared spectra. An octahedral structure has tentatively been assigned to all of the mixed-ligand complexes. The mixed-ligand complexes show higher toxic activity against the Salmonella typhi, Escherichia coli and Serratia mercescen as compared to the ligands, vanadyl sulphate and control (dimethyl sulphoxide). The mixed-ligand complexes were also tested against a standard drug (tetracycline).  相似文献   
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