scholarly journals The adsorption of cyanobacterial hepatoxins as a function of soil properties

2005 ◽  
Vol 3 (4) ◽  
pp. 339-347 ◽  
Author(s):  
Megge J. Miller ◽  
John Hutson ◽  
Howard J. Fallowfield
Keyword(s):  
Soil Properties ◽  
Low Cost ◽  
Sorption Isotherms ◽  
Developing Nations ◽  
Natural Process ◽  
Bank Filtration ◽  
Batch Studies ◽  
Toxin Removal ◽  
Positive Correlations ◽  
Different Soils

Cyanobacterial hepatotoxins present a risk to public health when present in drinking water supplies. Existing removal strategies, although efficient, are not economically viable or practical for remote Australian communities and developing nations. Bank filtration is a natural process and a potential low cost, toxin removal strategy. Batch studies were conducted in 12 texturally diverse soils to examine the soil properties influencing the adsorption of the cyanobacterial hepatotoxins, microcystin-LR and nodularin. Sorption isotherms were measured. Freundlich and linear isotherms were observed for both toxins with adsorption coefficients not exceeding 2.75 l kg−1 for nodularin and 3.8 l kg−1 for microcystin. Significant positive correlations were identified between hepatotoxin sorption and clay and silt contents of the soils. Desorption of toxins was also measured in three different soils. Pure nodularin and microcystin-LR readily desorbed from all soils.

Sorption of fenamiphos to different soils: The influence of soil properties

2008 ◽  
Vol 43 (7) ◽  
pp. 605-610 ◽  
Author(s):  
Tanya P. Cáceres ◽  
Mallavarapu Megharaj ◽  
Ravi Naidu
Keyword(s):  
Soil Properties ◽  
Different Soils

scholarly journals Regrowth and ornamental traits of bermudagrass fertilized with sewage sludge

2020 ◽  
Vol 26 (3) ◽  
pp. 390-398
Author(s):  
Philippe Solano Toledo Silva ◽  
Alessandro Reinaldo Zabotto ◽  
Patrick Luan Ferreira dos Santos ◽  
Matheus Vinícius Leal do Nascimento ◽  
Armando Reis Tavares ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Soil Solution ◽  
Digital Image Analysis ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Low Cost ◽  
Aesthetic Aspect ◽  
Positive Correlations ◽  
The Aesthetic ◽  
Ornamental Traits

Abstract The sewage sludge is a low-cost material and sustainable alternative to substitute chemical fertilizers on ornamental lawns and gardens. Thus, the objective was to evaluate the effects of the application of sewage sludge on the regrowth and ornamental traits of DiscoveryTM bermudagrass. The experiment was carried out during the fall/winter of 2019. The turf was removed and left the soil exposed for a new grass regrowth. The treatments applied were 0, 357, 714, 1,071 and 1,428 g m-2 sewage sludge spread evenly on the lawn in a single dose. The evaluations were carried out after 120 days and the soil solution (EC and NO3 -), Normalized difference vegetation index, root length, root + rhizome + stolon + leaves volume and digital image analysis were evaluated. The results showed that the increase of sewage sludge positively influenced the turfgrass development, both in the aesthetic aspect and on bermudagrass regrowth. The soil solution can show that the sludge increased the electrical conductivity and NO3- ions; however, it did not hinder the development of the lawn, even having positive correlations between these variables and the biometric evaluations of the plant. It is concluded that the dose of 1,428 g m-2 presented the best results for the evaluated characteristics, being the recommended one for use in the fertilization of bermudagrass DiscoveryTM.

scholarly journals Information and Communication Technology: Gender Issues in Developing Nations

10.28945/2521 ◽  
2002 ◽  
Author(s):  
Kimberly Betz Leahy ◽  
Ira Yermish
Keyword(s):  
Information And Communication Technology ◽  
Communication Technology ◽  
New Technologies ◽  
Low Cost ◽  
Gender Issues ◽  
Developing Nations ◽  
Great Abundance ◽  
Scarce Resources ◽  
Education Of Women ◽  
Information And Communication

As Developing Nations seek to leverage scarce resources toward the goal of achieving a developed status they must reevaluate past practices and explore available and affordable technologies. Where information and communication infrastructures are weak, use of low-cost, easily distributed technologies have proven effective. Still, many developing nations have failed to incorporate a resource in great abundance, their women, to use these new technologies to greatest advantage. This paper will address the implications of women’s lack of economic and educational parity, and offer examples of how the education of women through the use of information and communication technology can enhance a nation’s gross domestic product (GDP).

Degradation of cyanobacterial hepatotoxins in batch experiments

2001 ◽  
Vol 43 (12) ◽  
pp. 229-232 ◽  
Author(s):  
M. J. Miller ◽  
H. J. Fallowfield
Keyword(s):  
Textural Properties ◽  
Clay Content ◽  
Cost Effective ◽  
Complete Removal ◽  
Degradation Process ◽  
Organic Carbon Content ◽  
Bank Filtration ◽  
Batch Experiments ◽  
Water Matrix ◽  
Toxin Removal

Bank filtration offers a cost effective and low maintenance technique for the removal of cyanobacterial hepatotoxins from drinking water. For bank filtration to be effective, the toxins must be degraded. The broad aim of this research was to determine whether the hepatotoxins, nodularin and microcystin-LR, could be completely removed from the soil/water matrix of three soils by microbial degradation. The results indicated that complete toxin removal was possible within 10-16 d in 2/3 soils that were incubated in the dark at 20°C. The soils with the highest organic carbon content (2.9%) and the highest clay content (16.1%) were the most effective at removing the toxins in batch experiments. However, the sandy soil (98.5% sand) was incapable of degrading either toxin. The half-lives of toxin losses due to adsorption, desorption and degradation were calculated and for all soils. The degradation process had the highest half-life for both toxins. This suggested that degradation was likely to be the rate-limiting step of complete toxin removal. It was concluded that when a bank filtration site was being chosen, the degradation potential and the textural properties of the riverbank soil would be important when considering complete removal of cyanobacterial hepatotoxins.

scholarly journals Multiple linear regression and random forest to predict and map soil properties using data from portable X-ray fluorescence spectrometer (pXRF)

2017 ◽  
Vol 41 (6) ◽  
pp. 648-664 ◽  
Author(s):  
Sérgio Henrique Godinho Silva ◽  
Anita Fernanda dos Santos Teixeira ◽  
Michele Duarte de Menezes ◽  
Luiz Roberto Guimarães Guilherme ◽  
Fatima Maria de Souza Moreira ◽  
...  
Keyword(s):  
Random Forest ◽  
Linear Regression ◽  
Soil Properties ◽  
Multiple Linear Regression ◽  
Low Cost ◽  
High Accuracy ◽  
Important Variable ◽  
X Ray ◽  
Element Contents ◽  
Fluorescence Spectrometer

ABSTRACT Determination of soil properties helps in the correct management of soil fertility. The portable X-ray fluorescence spectrometer (pXRF) has been recently adopted to determine total chemical element contents in soils, allowing soil property inferences. However, these studies are still scarce in Brazil and other countries. The objectives of this work were to predict soil properties using pXRF data, comparing stepwise multiple linear regression (SMLR) and random forest (RF) methods, as well as mapping and validating soil properties. 120 soil samples were collected at three depths and submitted to laboratory analyses. pXRF was used in the samples and total element contents were determined. From pXRF data, SMLR and RF were used to predict soil laboratory results, reflecting soil properties, and the models were validated. The best method was used to spatialize soil properties. Using SMLR, models had high values of R² (≥0.8), however the highest accuracy was obtained in RF modeling. Exchangeable Ca, Al, Mg, potential and effective cation exchange capacity, soil organic matter, pH, and base saturation had adequate adjustment and accurate predictions with RF. Eight out of the 10 soil properties predicted by RF using pXRF data had CaO as the most important variable helping predictions, followed by P2O5, Zn and Cr. Maps generated using RF from pXRF data had high accuracy for six soil properties, reaching R2 up to 0.83. pXRF in association with RF can be used to predict soil properties with high accuracy at low cost and time, besides providing variables aiding digital soil mapping.

Studies of Central Australian Semidesert Rangelands. II. Range Condition and the Nutrient Dynamics of the Herbage Layer, Litter and Soil.

1981 ◽  
Vol 29 (2) ◽  
pp. 233 ◽  
Author(s):  
MH Friedel
Keyword(s):  
Plant Communities ◽  
Arid Regions ◽  
Nutrient Dynamics ◽  
Plant Parts ◽  
Range Condition ◽  
Positive Correlations ◽  
Nitrogen Phosphorus ◽  
Herbage Layer ◽  
Phosphorus Levels ◽  
Different Soils

The levels and turnover of nitrogen, phosphorus and sulfur in the herbage layer: litter and soil of three central Australian plant communities were investigated, following several years of above-average rainfall, and the possibility of a relationship between nutrient levels and range condition assessment was examined. There were only a few positive correlations between range condition and phosphorus levels, and they were not associated with the susceptibility of different soils to erosional losses. There were no positive correlations between range condition and the levels of either nitrogen or sulfur. The herbage and litter layers together, of the three plant communities, contained 30-72 kg ha-1 of total nitrogen, 4 kg ha-1 of total phosphorus and 4-7 kg ha-1 of total sulfur. These quantities were comparable to those of arid regions in other parts of the world, but the levels of nitrogen, phosphorus and sulfur in soils, estimated by incubation or extraction to be available to plants, were comparatively low. Incubated nitrogen in the 0-10 cm depth of soils was 9-14 ppm and extractable phosphorus was 3-1 1 ppm. The 0-4 cm depth of soil contained 0.5-3 ppm extractable sulfur, and concentrations decreased with depth. Total soil nitrogen was lower than that in other arid regions whereas the amount of organic carbon in soil was comparable, so that C:N was relatively high. Substantial withdrawal of nutrients from senescing plant parts and rapid cycling of nutrients through litter appeared to be responsible for maintaining the level of nutrients in the herbage layer.

scholarly journals New carbon from low cost vegetal precursors: acorn and cypress cone

2013 ◽  
Vol 11 (12) ◽  
pp. 2012-2021
Author(s):  
Giovanni Toscano ◽  
Giuseppe Cimino
Keyword(s):  
Methylene Blue ◽  
Low Cost ◽  
Chemical Properties ◽  
Sorption Isotherms ◽  
Surface Chemical ◽  
Sodium Dodecylbenzenesulfonate ◽  
Sorption Data ◽  
Treatment Changes ◽  
Mass Titration ◽  
Minor Extent

AbstractThermal-treated carbons from acorn and cypress cone were prepared and characterized. The uptakes of heavy metal ions (Ag+, Cd2+ and Cr+3) and organics (phenol, methylene blue and sodium dodecylbenzenesulfonate) from aqueous solution have been studied. Effects of activation by HCl and HNO3 acids on the sorption properties of these carbons were investigated by mass titration, sorption isotherms, IRS, SEM and XRS. The models of Langmuir and Freundlich do not represent our sorption data very well. An earlier proposed empirical correlation is applied successfully to carry out a parameter of comparison between the studied carbons. The acidic treatment changes the surface chemical properties of the two thermal-treated carbons lowering their sorption performances. The carbons show good capacities to uptake metals, phenol and methylene blue, but sodium dodecylbenzenesulfonate is removed from its solutions to minor extent. The up-taking properties are found similar to those of two worldwide used commercial grade carbons.

Refuting objections to a Global Rural Network (GRNet) for developing nations (originally published in August 2004)

First Monday ◽  
2007 ◽  
Author(s):  
Larry Press
Keyword(s):  
Rural Areas ◽  
High Speed ◽  
Low Cost ◽  
Developing Nations ◽  
Appropriate Technology ◽  
Grand Challenge ◽  
Sustainable Business ◽  
Internet Service ◽  
Developing Nation ◽  
Internet Connectivity

In a previous article, we suggested that it is now time to undertake a Grand Challenge project: providing Internet connectivity for every village in every developing nation. Doing so would require perhaps a decade and billions of dollars for design and planning, procurement, installation and operation. Critics object that such a project would not be worth the effort and investment. This article considers nine objections to such an undertaking. 1. Internet connectivity would be nice, but it is not a high priority. 2. Internet service has been offered in rural areas of developing nations, and there is little demand for it. 3. There are no applications of interest or value to illiterate rural people who do not speak English. 4. There is no sustainable business model. 5. Developing nations lack the people and resources to do research. 6. Even if the world community can justify sponsoring the research leading to a concrete backbone plan, developing nations cannot afford to implement it. 7. Villagers cannot afford to use the network even if the backbone transport and connection are free. 8. Developing nations cannot afford high–speed connectivity — low–cost store–and–forward technology is more appropriate technology for a poor, developing nation. 9. We should focus on cities where there is already demand, not rural areas. We discuss each of these, and conclude with a brief outline of next steps.

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