Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Red soil”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources
PubMed2002

Mechanisms of attenuation of metal availability in in situ remediation treatments.

One suite of in situ technologies for remediating metal contaminated soils involves the addition of reactive materials which lower metal availability. Until now it has been difficult to assess whether the amendment induced decrease in metal availability is due simply to increased sorption of the metal or whether it is the result of surface precipitation or other fixation mechanisms. This has made it difficult to predict the long-term stability of such remedial treatments. Using an isotopic dilution technique coupled with a stepwise acidification treatment, we examined changes in the labile pool of Cd and Zn in a polluted soil amended with either CaCO3, KH2PO4, red mud, or a kaolin byproduct. Fixation of both Cd and Zn was greatest in the KH2PO4 treated soil. The mode of fixation in this treatment was also found to be resistant to soil acidification. The results allowed a clear distinction between three classes of attenuation mechanisms which are hypothesized to increase in their resilience to environmental change as follows: reversible sorption < irreversible "fixation" at constant pH < irreversible "fixation" across a range of pH.

Adsorption↗
PubMed2005

[Decolorization of synthetic dyes with a new isolated yeast Candida krusei].

A new yeast isolate Y-G-1, identified as Candida krusei, capable of degrading Reactive Brilliant Red K-2BP, was obtained from soil by screening experiments. This strain gave a maximal decolorization (99%) for Reactive Brilliant Red K-2BP (200 mg/L) after incubation of 12 h. In order to get this decolorization effect, the optimal inoculation volume of Candida krusei was not less than 5%, the optimal pH of culture medium was within a range from 4 to 9, and the concentrations of (NH4)2SO4 and glucose were not lower than 0.1% and 0.5%, respectively. The research results on the mechanism of decolorization show that Candida krusei could biodegrade Reactive Brilliant Red K-2BP. In addition, Candida krusei could also decolorize 62% - 96% of another 9 dyes (50mg/ L). Specially for azo dyes, including Weak Acid Brilliant Red B, Reactive Black KN-B and Reactive Red M-3BE, their decolorization rates were over 90 %, and for triphenylmethane dye, Mordant Blue B, it was up to 93%. All these results indicate that this strain have potential application in dye wastewater treatment.

Azo Compounds↗
PubMed2003

Field measurements of root respiration indicate little to no seasonal temperature acclimation for sugar maple and red pine.

Increasing global temperatures could potentially cause large increases in root respiration and associated soil CO2 efflux. However, if root respiration acclimates to higher temperatures, increases in soil CO2 efflux from this source would be much less. Throughout the snow-free season, we measured fine root respiration in the field at ambient soil temperature in a sugar maple (Acer saccharum Marsh.) forest and a red pine (Pinus resinosa Ait.) plantation in Michigan. The objectives were to determine effects of soil temperature, soil water availability and experimental N additions on root respiration rates, and to test for temperature acclimation in response to seasonal changes in soil temperature. Soil temperature and soil water availability were important predictors of root respiration and together explained 76% of the variation in root respiration rates in the red pine plantation and 71% of the variation in the sugar maple forest. Root N concentration explained an additional 6% of the variation in the sugar maple trees. Experimental N additions did not affect root respiration rates at either site. From April to November, root respiration rates measured in the field increased exponentially with increasing soil temperature. For sugar maple, long-term Q10 values calculated from the field data were slightly, but not significantly, less than short-term Q10 values determined for instantaneous temperature series conducted in the laboratory (2.4 versus 2.62.7). For red pine, long-term and short-term Q10 values were similar (3.0 versus 3.0). Sugar maple root respiration rates at constant reference temperatures of 6, 18 and 24 degrees C were measured in the laboratory at various times during the year when field soil temperatures varied from 0.4 to 16.8 degrees C. No relationship existed between ambient soil temperature just before sampling and root respiration rates at 6 and 18 degrees C (P = 0.37 and 0.86, respectively), and only a very weak relationship was found between ambient soil temperature and root respiration at 24 degrees C (P = 0.08, slope = 0.09). We conclude that root respiration in these species undergoes little, if any, acclimation to seasonal changes in soil temperature.

Acclimatization↗
PubMed2003

Toxic potential of oleander derived compost and vegetables grown with oleander soil amendments.

California recycles 50% of previously disposed trash. Increased use of yardwastes and composts has raised concern about toxic materials in these products. Oleander is a toxic shrub common to CA landscapes and is frequently clipped and disposed of in greenwaste containers, resulting in concerns about the toxicity of oleander-contaminated yardwastes and composts from these wastes. Information about breakdown of oleandrin (one of the glycoside toxicants of oleander) during composting or the ability of plants to absorb this molecule has not been reported. In separate experiments, we documented the apparent first-order disappearance of oleandrin from composts of pure oleander, with a disappearance half-life of 15 d. Within 50 d, 90% of the oleandrin was removed during aerobic composting in a turned pile. In an amendment study with fresh uncomposted oleander, no oleandrin was detected in tomato and zuchinni fruit, snap beans, carrot tubers, or green lettuce. Oleandrin was found in red leaf lettuce growing in soils mulched with oleander, but oleandrin concentrations were near the detection limit of the assay. Soil from oleander mulched and amended plots contained low levels of oleandrin at the time of harvest.

California↗
PubMed2006

Effect of coal mine soil contamination on the elemental uptake and distribution in two edible Amaranthus species, A. dubius and A. hybridus.

The impact of coal mine dump contaminated soil on the elemental uptake by two edible plants, namely, Amaranthus dubius (red herbs) and Amaranthus hybridus (green herbs), was studied by investigating their response and ability to tolerate and accumulate varying levels of elements in their roots and shoots. The vegetation was grown on varying amounts of contaminated soil, viz. 0%, 5%, 15%, 25% w/w using coal mine dump soil. The soil was analyzed for soil pH, cation exchange capacity (CEC), soil organic matter (SOM), moisture content, and selected heavy metals. The distribution of six metals, namely, Pb, Cd, Hg, Ni, Mn, and Fe, in roots, stem, and leaves of the plants was determined in two stages of growth after 5 weeks and 10 weeks. All soil and plant samples were microwave digested and subjected to heavy metal analysis using the ICP-OES, GFAAS, and CVAAS. The pH of the coal mine dump contaminated soil decreased with an increase in contamination. Both the SOM and CEC values decreased, which increases the availability of elements, by providing more binding sites in the soil. Relatively, the red herbs had higher elemental concentrations than the green herbs. Both plants recorded high manganese accumulation. No mercury was detected in the soils or plants.

Amaranthus↗
PubMed2002

In situ fixation of metals in soils using bauxite residue: chemical assessment.

Contamination of soils with heavy metals and metalloids is a widespread problem all over the world. Low cost, non-invasive, in situ technologies are required for remediation processes. We investigated the efficiency of a bauxite residue (red mud) to fix heavy metals in two soils, one contaminated by industrial activities (French soil), and one by sewage sludge applications (UK soil). This Fe-oxide rich material was compared with lime, or beringite, a modified aluminosilicate that has been used for in situ fixation processes. Four different crop species were successively grown in pots. Metal concentrations in the soil pore waters were analyzed during the growing cycles. At the end of the experiment fluxes of heavy metals were measured using a diffusive gradient in thin film technique (DGT). Furthermore, a sequential extraction procedure (SEP) and an acidification test were performed to investigate the mechanisms of metal fixation by different soil amendments. In both soils, the concentrations of metals in the soil pore water and metal fluxes were greatly decreased by the amendments. An application of 2% red mud performed as well as beringite applied at 5%. Increasing soil pH was a common mechanism of action for all the amendments. However, the red mud amendment shifted metals from the exchangeable to the Fe-oxide fraction, and decreased acid extractability of metals. The results suggest that specific chemisorption, and possibly metal diffusion into oxide particles could also be the mechanisms responsible for the fixation of metals by red mud.

Aluminum Oxide↗
PubMed1997

Relevance and applicability of a simple earthworm biomarker of copper exposure. I. Links to ecological effects in a laboratory study with Eisenia andrei.

A simple earthworm biomarker, neutral-red retention by coelomocyte lysosomes, was measured concurrently with ecological parameters in order to link effects at different levels of biological organization in a laboratory study. Exposure of the earthworm Eisenia andrei to an increasing range of soil copper concentrations in the laboratory indicated a threshold range for the neutral-red assay at soil copper concentrations between 40 and 80 mg Cu kg-1. This threshold coincided with the soil to worm copper bioconcentration factor decreasing from 1 to 0.3 and thus an apparent onset of a copper regulatory mechanism. Effects at the individual and population levels only occurred at soil copper concentrations beyond that of the biomarker threshold. Thus, it was possible to differentiate between exposure and toxicity. It was therefore possible to conclude that the neutral-red assay has great potential and relevance in earthworm ecotoxicity studies. The assay provides an early warning that can be linked directly to important physiological changes that were observed to precede adverse effects on individuals or populations in this laboratory study.

Analysis of Variance↗
PubMed2000

A battery of toxicity tests as indicators of decontamination in composting oily waste.

Heterogeneous oily waste from an old dumping site was composted in three windrows constructed from different proportions of waste, sewage sludge, and bark. The objectives of this pilot study were to examine the usefulness of composting as a treatment method for this particular waste and to study decontamination in the composting process by using a battery of toxicity tests. Five samples from the windrow having intermediate oil concentrations were tested with toxicity tests based on microbes (Pseudomonas putida growth inhibition test, ToxiChromotest, MetPLATE, and three different modifications of a luminescent bacterial test), enzyme inhibition (reverse electron transport), plants (duckweed growth inhibition and red clover seed germination), and soil animals (Folsomia candida, Enchytraeus albidus, and Enchytraeus sp.). The luminescent bacterial tests were used as prescreening tests. Chemical analyses of samples were carried out simultaneously. Both toxicity and oil concentration, including those of polyaromatic hydrocarbons (PAHs), were reduced during composting and soil quality improved significantly. The total oil hydrocarbon concentration decreased from 90,000 to 19,000 mg/kg, measured with the IR method, in 4 months, and from 86,000 to 1400 mg/kg, measured with GC method. The concentration of PAHs decreased from 135 to 23.5 mg/kg. During the fourth month of composting (stabilization stage), the proportion of the heaviest oil fractions (asphaltenes) became dominant. Toxicity varied between different samples and between different bioassays; however, the first sample was significantly more toxic than the others, and most of the tests revealed a decrease in toxicity during the composting process.

Animals↗
PubMed2004

Liquid chromatographic determination of novel aminithiazolecarboxamide fungicide residues in soil and crops using online solid-phase extraction.

A simple and convenient liquid chromatographic method has been developed and applied to the analysis of the novel aminothiazolecarboxamide fungicide, ethaboxam, in soil and crops. After the isolation and concentration of analyte from soil and crops, clean-up and separation of sample solutions are performed by high-performance liquid chromatography with online solid-phase extraction. Good linearity (r2 > 0.9995), recovery [for soil, 95.3-98.4%, and crops (grape, red pepper), 92.9-95.9%], and repeatability are achieved in the calibration range of 0.1-10.3 microg/mL. The limit of detection is the 2.5 parts per billion (ppb) (40 g of soil) and the 20 ppb (25 g of crops), respectively. This assay method shows the suitability for the residual analysis of ethaboxam in soil and crops.

Calibration↗
PubMed1995

A new solid medium for enumerating cellulose-utilizing bacteria in soil.

A solid medium containing ashed, acid-washed cellulose and a dye, Congo red, has been developed for enumeration of cellulose-utilizing bacteria in soil. Bacteria able to use the cellulose in this medium produced distinct zones of clearing around their colonies. A vivid contrast between the uniform red color of the medium and these halos made this method of differentiation of these organisms superior to other methods.

Journal Article↗
PubMed2002

Soil persistence of 4-HPPD-inhibitors in different soil types.

In field experiments carried out during the 1997-2001 period on four different soil types (sand, sandy loam, heavy sandy loam and clay) in Flanders (Belgium), the persistence of the three 4-HPPD inhibiting maize herbicides mesotrione (100 and 150 g ha-1), sulcotrione (300 and 450 g ha-1) and isoxaflutole (75 and 125 g ha-1) was studied. Therefore, soil samples were taken at regular intervals from application in spring and frozen. When all samples had been taken, greenhouse bioassays were set up to detect herbicide residues in the different soil types. Therefore, two extremely sensitive test plants, sugarbeet (Beta vulgaris L. spp. altissima Doell. var. saccharifera Deck.-Dill) and red clover (Trifolium pratense L.) were sown in the soil samples. Test plants were harvested after 2 (sugarbeet) and 3 (red clover) weeks and foliage fresh weight per plant was determined. This parameter was expressed relatively to the average fresh weight per plant of the plants sown in the control soil samples taken at each sampling date. The bioassays revealed several factors that influence the persistence of the herbicide tested. First, there is a remarkable influence of the experimental year due to variation in weather conditions (especially rainfall and temperature during the first weeks after spraying). Secondly, a different soil texture results in a highly different persistence: the shortest biological persistence was noticed each year in clay, followed by heavy sandy loam; the longest persistence was recorded in sandy and sandy loam soil types. Thirdly, there are important differences between the three herbicides tested: isoxaflutole (a member of the isoxazole chemical family) was shown to be less persistent than sulcotrione and mesotrione (both members of the triketone family). Remarkably, this was not the case in clay, where a longer persistence could be seen for isoxaflutole compared to sulcotrione and mesotrione. This study also revealed that applying a low rate results in a shorter persistence period compared to the higher rate. All these factors work together in a complex way which determines the persistence of the three herbicides tested.

4-Hydroxyphenylpyruvate Dioxygenase↗
PubMed2000

Sorption and desorption of radiocesium on red earth and its solid components: relative contribution and hysteresis.

The relative contributions of organic matter and iron oxides to the Cs+ sorption on red earth were investigated by using the batch technique and selective extraction methods. The sorption and desorption isotherms and the distribution coefficients of Cs+ on the untreated red earth and the three treated soils to remove organic matter, iron oxides and organic matter plus iron oxides were determined at 20 degrees C, pH 6.3+/-0.2, in the presence of 0.01 mol/l CaCl2. It was found that all the isotherms are linear in the Cs+ concentration range used here, that the sorption desorption hysteresis on the red earth actually occurs, and besides the clay minerals, the organic matter present in the red earth is a significant trap of Cs+ and is responsible for the hysteresis instead of the iron oxides.

Adsorption↗
PubMed2002

Toxicity of bauxite manufacturing by-products in sea urchin embryos.

By-products from a bauxite manufacturing plant located in Seydişehir, Turkey, were investigated for their composition and any toxicity to sea urchin embryogenesis. Samples from three other bauxite plants located in France, Greece, and Italy were simultaneously tested for toxicity in sea urchin embryos. Samples included sludge and solid residues in the plant and sediment and water columns from two holding ponds (red sludge or cryolite residues). Samples were analyzed for their inorganic content by inductively coupled plasma optical emission spectroscopy (ICP-OES). Analyses were carried out either following strong acid extraction or after release of soluble components from seawater-suspended pellets. Toxicity was tested by sea urchin bioassays, to evaluate the following endpoints: (a) acute and/or developmental toxicity, (b) changes in fertilization success, and (c) transmissible damage from sperm to offspring. The results revealed the following: (1) inorganic analysis, following strong acid extraction, showed a prevalence of Al and Fe; (2) seawater release of soluble contaminants was confined to Fe and Mn, whereas Al levels were not changed by suspending increasing sample amounts in seawater; (3) the most severe toxicity to sea urchin embryos was exerted by a 2% water column from the red sludge holding pond and by soil and sludge collected near the plant reactor; (4) sludge supernatant was the most toxic sample to sperm and offspring. The data showed a prevailing association of free Fe (and possibly Mn) levels with Seydişehir sample toxicity. The water column of the red sludge holding pond showed both excess levels of free Al and high pH, thus suggesting a combined effect. The differences in sample toxicity in the Seydişehir plant compared with other bauxite manufacturing plants suggest a possible variable toxicity as related to bauxite ore composition and/or manufacturing processes.

Aluminum Oxide↗
PubMedDate not supplied

Assessment of the use of industrial by-products to remediate a copper- and arsenic-contaminated soil.

Two water treatment sludges (WTS-A, WTS-B), two red muds (RM), and red gypsum (RG), all rich in iron oxy-hydroxides, were added to a soil highly polluted with As and Cu at 2% (w/w) to reduce metal bioavailability. Because the amendments increased soil pH to approximately 6, a lime treatment to the same pH and an unamended treatment were included for comparison. All the amendments had significant positive effects on the soil microbial biomass and growth of ryegrass (Lolium multiflorum Lam. cv. Avance), but only WTS-A improved lettuce (Lactuca sativa L. cv. Tom Thumb) growth. The mineralization of added ammonium nitrogen was not significantly affected by the treatments, while a physiologically based extraction test (PBET) showed that bioaccessibility of As was low (< 5%) and decreased only in the WTS-A treatment. Concentrations of As in soil pore water and extractable As only decreased in the WTS and RG treatments. In contrast, Cu concentrations in soil pore water and extractable Cu decreased in all treatments, by more than 84% in the WTS, RM, and RG treatments. Non-isotopically exchangeable As and Cu were present in colloids in the soil pore water. Untreated soil had < 4% isotopically exchangeable As and this decreased by approximately 50%, with WTS, RM, and RG. The labile Cu pool represented a large proportion (34%) of the total Cu pool, and the isotopically exchangeable and soluble Cu were strongly correlated with soil pH. Acidification of the treated soils showed that the labile As and Cu both increased in the treated soils compared with untreated soils. The significance of the treatment effects on soil fertility and potential off-site transport of As and Cu to ground water are discussed.

Arsenic↗
PubMed1998

Distribution of cesium-137 in Japanese forest soils: correlation with the contents of organic carbon.

The spatial and vertical distributions of 137Cs in surface soils were surveyed and analyzed then correlated with the contents of organic carbon in the hinoki (Chamaecyparis obtusa Sieb. et Zucc.) plantation forest and secondary forest dominated by red pine (Pinus densiflora Sieb. et Zucc.) in Japan. The spatial variation of 137Cs activity was observed in the surface soil around the red pine. The average activity of 16 samples around the tree is 42.4 Bq/kg and the standard deviation is 25.9 Bq/kg. This finding indicates the importance in the selection of a sampling site and the number of samples from the surface soils especially around a tree. For the vertical distribution of 137Cs activity, it was found that the concentration in the surface soil is highest, 149 Bq/kg in the hinoki stand and 101 Bq/kg in the red pine stand, and decreases with depth. The relationship between 137Cs activity and carbon content in the forest soil was investigated in two undisturbed forest stands. The relations were more precisely expressed using an exponential equation than by a linear equation. From the same forest, similar regression equations were obtained. This indicates that the distribution of 137Cs could be characterized by the organic carbon content in an undisturbed forest. It is also suggested that the coefficient values in the regression equation help to define the movement of 137Cs accompanying the decomposition of organic matter.

Carbon↗
PubMed2000

[Relationship of NO3(-)-N, NO2(-)-N accumulation in some crop seeds with N fertilizers application].

From 1996 to 1997, the effect of applying organic and chemical fertilizers on NO3- and NO2- accumulation in crop seeds was studied in four green food bases of kidney beans (Yunan Province), red small beans (Hebei Province), soybeans (Heilongjiang Province), and peanuts (Shandong Province). For kidney beans and red small beans, the highest grey correlation was existed between available N in soil and NO2- in seeds, no matter whether organic fertilizer or urea was applied. In organic fertilizer trials, the highest grey correlation appeared in soil pool (between total N and available N) or seed pool (between NO3- and NO2-), while in chemical N fertilizer trials, it existed between total N in soil and NO3- in seeds. For kidney beans and red small beans, the dynamics of NO3-/NO2- in seeds was different with the kind of fertilizers applied. Extremely significant negative linear correlation and positive linear regression were existed between the content of NO3- and NO2- in all four crop seeds.

Fabaceae↗
PubMed2003

Aroma content of fresh basil (Ocimum basilicum L.) leaves is affected by light reflected from colored mulches.

Sweet basil (Ocimum basilicum L.) is an herb that is used to add a distinct aroma and flavor to food. Volatile compounds emitted from fully expanded fresh leaves grown in drip-irrigated plots that were covered with six colors of mulch were compared. The colors reflected a range of photosynthetic photon flux, far-red, red, and blue light from the soil surface to developing leaves. Our objective was to determine whether reflection from the different colors could influence concentrations of volatile compounds emitted from the fresh leaves. Volatile compounds were isolated by headspace sampling and quantified by gas chromatography. Twenty-six compounds were identified, of which the terpenoids linalool and 1,8-cineole comprised more than 50% of the total yield. Concentrations of volatile compounds from leaves that developed over green, blue, yellow, white, and red mulches followed the same patterns as they did for air-dried leaves of the same cultivar. However, the concentration of volatile compounds from fresh leaves was about 50-fold higher than those found in the previous study of air-dried leaves.

Acyclic Monoterpenes↗
PubMed1995

Practical applications of neuronal tissue culture in in vitro toxicology.

1. Primary chick embryo forebrain neurones are relatively easy to culture and are quite resilient to treatment manipulation. These characteristics have allowed application in a surprisingly diverse number of areas. 2. These cultures have been used to investigate the anticholinesterase potencies of many organophosphate (OP) nerve agents and insecticides. 3. These cultures have been used to quantitate levels of OP in 'spiked' unknowns and in OP-contaminated soil samples. 4. These cells have also been used to test a variety of compounds using the MTT and neutral red cytotoxicity assays.

Animals↗