Effects of electrolyte composition on chromium desorption in soils contaminated by tannery waste

Soil Research ◽  
2001 ◽  
Vol 39 (5) ◽  
pp. 1077 ◽  
Author(s):  
S. Avudainayagam ◽  
R. Naidu ◽  
R. S. Kookana ◽  
A. M. Alston ◽  
S. McClure ◽  
...  

We conducted batch studies to investigate the effect of phosphate and dominant cations present in tannery waste on desorption of chromium (Cr) from surface and subsurface soil horizons from a contaminated tannery waste site at Mount Barker, South Australia. The surface horizon (0–15 cm) of the soil profile was alkaline (pH 7.9) and the subsurface horizon (50–90 cm) was acidic (pH 3.9). Aqua-regia extractable Cr concentration ranged from 62 g/kg in the surface to 0.26 g/kg in the subsurface soils. X-ray diffraction and scanning electron microscopic studies revealed the predominance of carbonate and kaolin minerals in the surface soils, and highly weathered framboidal particles, with morphology similar to that of pyrites, in the subsurface soils. The amount of Cr desorbed from the contaminated soils varied considerably with both the electrolyte’s cationic charge and soil properties. The effect of cations, Ca 2+ and Na + (CaCl 2 , NaCl), and phosphate on desorption of Cr was investigated. While the ionic strength of the solutions was standardised at approximately 0.03 mol/L, the concentration of phosphate (as KH 2 PO 4) was varied from 0 to 3.2 mmol/L. On the basis of studies on solution to soil ratio and desorption kinetics we chose a 20: 1 solution to soil ratio and 2 h equilibration time. In the surface alkaline soil, the amount of Cr released decreased in the order Na + (286 μg/L) ≥ water (256 μg/L) > Ca 2+ (156 μg/L). In contrast subsurface acidic soil showed a reverse trend, i.e. Ca 2+ (52 μg/L) > Na + (29 μg/L) > water (20 μg/ L). Speciation of Cr in the extracts showed predominantly Cr(VI) in the alkaline surface soil and Cr(III) in the subsurface acidic soil. A strong effect of phosphate on the cumulative amount of chromate desorbed was observed. The study shows that the presence of high concentrations of Na + (0.03 mol/L) and phosphate (3.2 mmol/L) in soil solution enhances Cr(VI) mobility. In contrast, Ca 2+ may induce retention of Cr(VI) in Cr-contaminated alkaline soils.

2002 ◽  
Vol 53 (9) ◽  
pp. 1019 ◽  
Author(s):  
M. D. Denton ◽  
D. R. Coventry ◽  
P. J. Murphy ◽  
J. G. Howieson ◽  
W. D. Bellotti

Inoculant rhizobia typically need to compete with naturalised soil populations of rhizobia to form legume nodules. We have used the polymerase chain reaction to test the ability of seed-inoculated rhizobia to compete with naturalised populations of rhizobia and form nodules on clover (Trifolium alexandrinum, T.�purpureum, and T. resupinatum) in alkaline soil. Clover rhizobia, Rhizobium leguminosarum bv. trifolii, were identified at the strain level using either a nif-specific RP01 primer or ERIC primers. Analysis of rhizobia isolated from nodules indicated that strain TA1 competed poorly for nodule occupancy at 2 field sites (Roseworthy and Mallala, South Australia), with the exception that it nodulated T. alexandrinum at a level of 39% at the Roseworthy site in the first year of the trial. Strains CC2483g and WSM409 successfully colonised nodules when inoculated onto a particular clover species (T. resupinatum and T. purpureum, respectively) in the first year of inoculation and persisted in the soil to form nodules in the following year. Nodules frequently contained naturalised strains of rhizobia, distinct from introduced commercial strains. Dominant isolates were specific to a field site and nodulated all 3 clover species in both years of the field trial, with each isolate occupying up to 19% of the total nodules at a field site. It was hypothesised that field isolates had a better alkaline soil tolerance conferring a greater ability to nodulate clovers under these edaphic conditions. The results indicate that soil populations of rhizobia may provide a significant constraint to the introduction of current Australian commercial clover rhizobia into alkaline soils, and a more profitable strategy may be to seek rhizobial inoculants that are adapted to these soils.


2014 ◽  
Vol 60 (No. 11) ◽  
pp. 489-495 ◽  
Author(s):  
M. Hejcman ◽  
V. Müllerová ◽  
S. Vondráčková ◽  
J. Száková ◽  
P. Tlustoš

Using a pot experiment with slightly acidic and alkaline soils anthropogenically contaminated by As, Cd, Pb, and Zn, we assessed how the establishment of Bryum argenteum and concentrations of elements (P, Ca, Mg, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in its biomass are affected by the pH of the substrate, mobility of trace elements, and by quick lime (CaO) and superphosphate (P) additives. Over one vegetation season, in pots naturally colonised by B. argenteum, a substantially higher cover of B. argenteum was recorded on acidic soil that was heavily contaminated with Cd, Pb, and Zn than on alkaline soil with higher As but lower Cd, Pb, and Zn mobility. In acidic soil, the establishment of B. argenteum was substantially improved by CaO additive, which reduced the mobility of Zn and Cd, and by P additive, which improved the P nutritional status and reduced the extremely high concentrations of many elements (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in its biomass. Although B. argenteum can be used for the monitoring of soil contamination, concentrations of trace elements in its biomass must be evaluated with caution as they can be affected by total and mobile concentrations of elements in the substrate, and by other soil chemical properties.


2009 ◽  
Vol 71-73 ◽  
pp. 533-540 ◽  
Author(s):  
Stoyan N. Groudev ◽  
Irena Spasova ◽  
Marina Nicolova ◽  
Plamen S. Georgiev

Experimental plots consisting of acidic and alkaline soils heavily contaminated with radionuclides (mainly U and Ra) and non-ferrous metals (mainly Cu, Zn, Cd, Pb) were treated in situ under real field conditions using the activity of the indigenous soil microflora. This activity was enhanced by suitable changes of some essential environmental factors such as pH and water, oxygen and nutrient contents of the soil. The treatment was connected with solubilization and removal of contaminants from the top soil layers (horizon A) due to the joint action of the soil microorganisms and leach solutions used to irrigate the soils (mainly acidophilic chemolothotrophic bacteria and diluted sulphuric acid in the acidic soil, and various heterotrophs and bicarbonate and soluble organics in the alkaline soil). The dissolved contaminants were removed from the soil profile through the drainage soil effluents or were transferred to the deeply located soil subhorizon B2 where they were precipitated as the relevant insoluble forms (uranium as uraninite, and the non-ferrous metals as the relevant sulphides) as a result of the activity of the sulphate-reducing bacteria inhabiting this soil subhorizon.


Author(s):  
Jan Zarzycki ◽  
Joseph Szroeder

The mammary gland ultrastructure in various functional states is the object of our investigations. The material prepared for electron microscopic examination by the conventional chemical methods has several limitations, the most important are the protein denaturation processes and the loss of large amounts of chemical constituents from the cells. In relevance to this,one can't be sure about a degree the observed images are adequate to the realy ultrastructure of a living cell. To avoid the disadvantages of the chemical preparation methods,some autors worked out alternative physical methods based on tissue freezing / freeze-drying, freeze-substitution, freeze-eatching techniqs/; actually the technique of cryoultraraicrotomy,i,e.cutting ultrathin sections from deep frozen specimens is assented as a complete alternative method. According to the limitations of the routine plastic embbeding methods we were interested to analize the mammary gland ultrastructure during lactation by the cryoultramicrotomy method.


Author(s):  
F. G. Zaki ◽  
E. Detzi ◽  
C. H. Keysser

This study represents the first in a series of investigations carried out to elucidate the mechanism(s) of early hepatocellular damage induced by drugs and other related compounds. During screening tests of CNS-active compounds in rats, it has been found that daily oral administration of one of these compounds at a dose level of 40 mg. per kg. of body weight induced diffuse massive hepatic necrosis within 7 weeks in Charles River Sprague Dawley rats of both sexes. Partial hepatectomy enhanced the development of this peculiar type of necrosis (3 weeks instead of 7) while treatment with phenobarbital prior to the administration of the drug delayed the appearance of necrosis but did not reduce its severity.Electron microscopic studies revealed that early development of this liver injury (2 days after the administration of the drug) appeared in the form of small dark osmiophilic vesicles located around the bile canaliculi of all hepatocytes (Fig. 1). These structures differed from the regular microbodies or the pericanalicular multivesicular bodies. They first appeared regularly rounded with electron dense matrix bound with a single membrane. After one week on the drug, these vesicles appeared vacuolated and resembled autophagosomes which soon developed whorls of concentric lamellae or cisterns characteristic of lysosomes (Fig. 2). These lysosomes were found, later on, scattered all over the hepatocytes.


Author(s):  
T. Mullin ◽  
G. Yee ◽  
M. Aheam ◽  
J. Trujillo

There have been numerous reports in the current literature suggesting that hematopoietic precursor cells in some human chronic myelocytic leukemias (CML) undergo lymphoblastic transformation at the time of the acute blast crisis (BC) stage. The primary evidence offered in support of this transformation theory--lymphoblastic appearing morphology, increased terminal deoxynucleotidyl transferase (TdT) activity, and chemotherapeutic sensitivity to vincristine and prednisone--has been indirect, however, since these features may occur in nonlymphoid cells. More direct support for the Pre-B lineage of these cells has recently been provided by immunofluorescent light microscopic studies demonstrating the presence of intracytoplasmic immunoglobulin M (IgM) in these CML-BC cells.


Author(s):  
F. G. Zaki ◽  
J. A. Greenlee ◽  
C. H. Keysser

Nuclear inclusion bodies seen in human liver cells may appear in light microscopy as deposits of fat or glycogen resulting from various diseases such as diabetes, hepatitis, cholestasis or glycogen storage disease. These deposits have been also encountered in experimental liver injury and in our animals subjected to nutritional deficiencies, drug intoxication and hepatocarcinogens. Sometimes these deposits fail to demonstrate the presence of fat or glycogen and show PAS negative reaction. Such deposits are considered as viral products.Electron microscopic studies of these nuclei revealed that such inclusion bodies were not products of the nucleus per se but were mere segments of endoplasmic reticulum trapped inside invaginating nuclei (Fig. 1-3).


Author(s):  
P. Frayssinet ◽  
J. Hanker ◽  
D. Hardy ◽  
B. Giammara

Prostheses implanted in hard tissues cannot be processed for electron microscopic examination or microanalysis in the same way as those in other tissues. For these reasons, we have developed methods allowing light and electron microscopic studies as well as microanalysis of the interface between bone and a metal biomaterial coated by plasma-sprayed hydroxylapatite(HA) ceramic.An HA-coated titanium hip prosthesis (Corail, Landos, France), which had been implanted for two years, was removed after death (unrelated to the orthopaedic problem). After fixation it was dehydrated in solutions of increasing ethanol concentration prior to embedment in polymethylmethacrylate(PMMA). Transverse femur sections were obtained with a diamond saw and the sections then carefully ground to a thickness of 200 microns. Plastic-embedded sections were stained for calcium with a silver methenamine modification of the von Kossa method for calcium staining and coated by carbon. They have been examined by back-scatter SEM on an ISI-SS60 operated at 25 KV. EDAX has been done on cellular inclusions and extracellular bone matrix.


Author(s):  
G. Rowden ◽  
M. G. Lewis ◽  
T. M. Phillips

Langerhans cells of mammalian stratified squamous epithelial have proven to be an enigma since their discovery in 1868. These dendritic suprabasal cells have been considered as related to melanocytes either as effete cells, or as post divisional products. Although grafting experiments seemed to demonstrate the independence of the cell types, much confusion still exists. The presence in the epidermis of a cell type with morphological features seemingly shared by melanocytes and Langerhans cells has been especially troublesome. This so called "indeterminate", or " -dendritic cell" lacks both Langerhans cells granules and melanosomes, yet it is clearly not a keratinocyte. Suggestions have been made that it is related to either Langerhans cells or melanocyte. Recent studies have unequivocally demonstrated that Langerhans cells are independent cells with immune function. They display Fc and C3 receptors on their surface as well as la (immune region associated) antigens.


Author(s):  
T. G. Merrill ◽  
B. J. Payne ◽  
A. J. Tousimis

Rats given SK&F 14336-D (9-[3-Dimethylamino propyl]-2-chloroacridane), a tranquilizing drug, developed an increased number of vacuolated lymphocytes as observed by light microscopy. Vacuoles in peripheral blood of rats and humans apparently are rare and are not usually reported in differential counts. Transforming agents such as phytohemagglutinin and pokeweed mitogen induce similar vacuoles in in vitro cultures of lymphocytes. These vacuoles have also been reported in some of the lipid-storage diseases of humans such as amaurotic familial idiocy, familial neurovisceral lipidosis, lipomucopolysaccharidosis and sphingomyelinosis. Electron microscopic studies of Tay-Sachs' disease and of chloroquine treated swine have demonstrated large numbers of “membranous cytoplasmic granules” in the cytoplasm of neurons, in addition to lymphocytes. The present study was undertaken with the purpose of characterizing the membranous inclusions and developing an experimental animal model which may be used for the study of lipid storage diseases.


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