scholarly journals Comparison of Microtox and Xenoassay Light as a Near Real Time River Monitoring Assay for Heavy Metals

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
M. I. E. Halmi ◽  
Hussain Jirangon ◽  
W. L. W. Johari ◽  
A. R. Abdul Rachman ◽  
M. Y. Shukor ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Sodium Chloride ◽  
Carbon Source ◽  
Molecular Phylogeny ◽  
Real Time ◽  
Copper Concentration ◽  
Optimum Conditions ◽  
River Monitoring ◽  
Microtox Assay ◽  
The Tropics

Luminescence-based assays for toxicants such as Microtox, ToxAlert, and Biotox have been used extensively worldwide. However, the use of these assays in near real time conditions is limited due to nonoptimal assay temperature for the tropical climate. An isolate that exhibits a high luminescence activity in a broad range of temperatures was successfully isolated from the mackerel,Rastrelliger kanagurta. This isolate was tentatively identified asPhotobacteriumsp. strain MIE, based on partial 16S rDNA molecular phylogeny. Optimum conditions that support high bioluminescence activity occurred between 24 and 30°C, with pH 5.5 to 7.5, 10 to 20 g/L of sodium chloride, 30 to 50 g/L of tryptone, and 4 g/L of glycerol as the carbon source. Assessment of near real time capability of this bacterial system, Xenoassay light to monitor heavy metals from a contaminated river running through the Juru River Basin shows near real time capability with assaying time of less than 30 minutes per samples. Samples returned to the lab were tested with a standard Microtox assay usingVibrio fishceri. Similar results were obtained to Xenoassay light that show temporal variation of copper concentration. Thus, this strain is suitable for near real time river monitoring of toxicants especially in the tropics.

Effect of co-existing copper and calcium on the removal of As(V) by reused aluminum oxides

2013 ◽  
Vol 67 (1) ◽  
pp. 187-192
Author(s):  
J. K. Yang ◽  
Y. J. Park ◽  
K. H. Kim ◽  
H. Y. Lee ◽  
K. C. Min ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Binary System ◽  
Aluminum Oxide ◽  
Aqueous Solutions ◽  
Copper Concentration ◽  
Calcium Concentration ◽  
Environmental Fate ◽  
Mine Drainage ◽  
Aluminum Oxides ◽  
Molar Ratios

Among the various heavy metals, arsenic is frequently found in abandoned mine drainage and the environmental fate of arsenic in real aqueous solutions can be highly dependent on the presence of co-existing ions. In this study, removal of arsenate through adsorption on the reused aluminum oxide or through precipitation was investigated in a single and in a binary system as a function of pH and concentration. Different removal behaviors of arsenate were observed in the presence of different cations as well as a variation of the molar ratios of arsenate to cations. Co-operative effects on arsenate removal by precipitation in solution occurred with an increase of copper concentration, while a decrease of arsenate removal resulted in increasing calcium concentration. It was observed that the arsenate removal in the presence of calcium would be highly dependent on the molar ratios of both elements.

Effect of Food Environment on Staphylococcal Enterotoxin Synthesis: A Review

1983 ◽  
Vol 46 (6) ◽  
pp. 545-555 ◽  
Author(s):  
J. L. SMITH ◽  
R. L. BUCHANAN ◽  
S. A. PALUMBO
Keyword(s):  
Staphylococcus Aureus ◽  
Sodium Chloride ◽  
Carbon Source ◽  
Environmental Factors ◽  
Food Environment ◽  
Inoculum Size ◽  
Model Systems ◽  
Sublethal Stress ◽  
Effect Of Food ◽  
Chloride Water

Effects of various nutritional and environmental factors on growth and enterotoxin synthesis by Staphylococcus aureus in model systems and foods are reviewed. Factors discussed include effects of inoculum size, competing microflora, gaseous atmosphere, carbon source, temperature, pH, sodium chloride, water activity, mineral ions and sublethal stress. Areas where additional research is needed are also discussed.

scholarly journals An overview of recent taxonomic studies on Euphorbiaceae s.l. in Brazil

Rodriguésia ◽  
2012 ◽  
Vol 63 (1) ◽  
pp. 227-242 ◽  
Author(s):  
Ricardo de S. Secco ◽  
Inês Cordeiro ◽  
Luci de Senna-Vale ◽  
Margareth F. de Sales ◽  
Letícia Ribes de Lima ◽  
...  
Keyword(s):  
New Species ◽  
Molecular Phylogeny ◽  
Sensu Stricto ◽  
Classification Systems ◽  
Taxonomic Position ◽  
Diverse Families ◽  
Taxonomic Studies ◽  
The Tropics

The Euphorbiaceae sensu lato are distributed mainly in the tropics, in various types of vegetation and habitats, being one of the largest, most complex and diverse families of angiosperms. It has recently been divided into four families, according to classification systems based on molecular phylogeny: Euphorbiaceae sensu stricto, Phyllanthaceae, Putranjivaceae, and Picrodendraceae. There is a proposition to establish Peraceae still under discussion. There were also changes in the taxonomic position of genera widely distributed in the Brazilian territory, such as Amanoa, Drypetes, Pera, Phyllanthus, Podocalyx, Pogonophora, and Richeria, among others. In addition, new species have been proposed and the limits of taxa distribution are expanding in Brazil. Thus, the authors provide an overview of recent studies and advances in the taxonomy of Euphorbiaceae s.l. in the Northern, Northeastern, Southeastern and Southern regions of Brazil, concentrating on review works and regional floras, as well as the changes that resulted in setting a new taxonomic family.

scholarly journals Global ozone forecasting based on ERS-2 GOME observations

2002 ◽  
Vol 2 (4) ◽  
pp. 921-942 ◽  
Author(s):  
H. J. Eskes ◽  
P. F. J. van Velthoven, ◽  
H. M. Kelder
Keyword(s):  
Real Time ◽  
Present Model ◽  
Forecast Error ◽  
Model Driven ◽  
Medium Range ◽  
Forecasting System ◽  
Ozone Transport ◽  
Model Setup ◽  
The Tropics ◽  
Total Column

Abstract. The availability of near-real time ozone observations from satellite instruments has recently initiated the development of ozone data assimilation systems. In this paper we present the results of an ozone assimilation and forecasting system, in use since Autumn 2000. The forecasts are produced by an ozone transport and chemistry model, driven by the operational medium range forecasts of ECMWF. The forecasts are initialised with realistic ozone distributions, obtained by the assimilation of near-real time total column observations of the GOME spectrometer on ERS-2. The forecast error diagnostics demonstrate that the system produces meaningful total ozone forecasts for up to 6 days in the extratropics. In the tropics meaningful forecasts of the small anomalies are restricted to shorter periods of about two days with the present model setup. It is demonstrated that important events, such as the breakup of the South Pole ozone hole and mini-hole events above Europe can be successfully predicted 4--5 days in advance.

scholarly journals Effect of Modified Kiln Dust and a Cationic Surfactant on the Removal of Aromatic and Heavy Metal Compounds from Fuels

2019 ◽  
Vol 35 (5) ◽  
pp. 1508-1513
Author(s):  
Noura Yahya El Mehbad
Keyword(s):  
Heavy Metals ◽  
Cationic Surfactant ◽  
Oil Quality ◽  
Cement Kiln ◽  
Polar Molecules ◽  
Optimum Conditions ◽  
Metal Compounds ◽  
Before And After ◽  
The Stability ◽  
Kiln Dust

This paper aims to investigate removal of aromatic and heavy metals compounds from fuels using cement kiln dust, and a cationic surfactant. The effect of a cationic surfactant and the composition of kiln dust on the stability of fuel was studied. The optimum conditions of adsorption were investigated. The stability of fuels was improved after adsorption because of the absorption of heavy metals, which act as catalysts. The concentrations of kiln dust and additives are effective for the absorption of heteroatoms of polar and nonpolar molecules. The addition of different concentrations of the cationic surfactant to kiln dust enhances the removal of polar molecules in fuel. The relation between the efficiency of the cationic surfactant and the enhanced removal of polar molecules was established. This study suggests a new mechanism to remove polar molecules according to the structure of the additive. Several parameters that affect the performance of the removal process were investigated under all optimum conditions. A complete chemical analysis of the fuels before and after treatment was performed, and the stability of the fuel was evaluated at different conditions. The prepared additive could enhance the oil quality and is environmentally safe. The adsorption behaviour of kiln dust was investigated to find a new mechanism of its efficiency. The results confirm the role of the cationic surfactant in the purification of fuels and the effectiveness of kiln dust in improving the stability of fuels, which depend on the concentration of the cationic surfactant and the nature of the kiln dust.

scholarly journals Improvement of Ficin-Based Inhibitive Enzyme Assay for Mercury Using Response Surface Methodology and Its Application for Near Real-Time Monitoring of Mercury in Marine Waters

2020 ◽  
Author(s):  
Garba Uba ◽  
Motharasan Manogaran ◽  
Baskaran Gunasekaran ◽  
Mohd Izuan Effendi Halmi ◽  
Mohd Yunus Abd Shukor
Keyword(s):  
Heavy Metals ◽  
Response Surface Methodology ◽  
Response Surface ◽  
Real Time ◽  
Sampling Site ◽  
Real Time Monitoring ◽  
Preliminary Screening ◽  
Heavy Metals Pollution ◽  
Straits Of Malacca ◽  
Metal Assay

Heavy metals pollution in the Straits of Malacca warrants the development of rapid, simple and sensitive assays. Enzyme-based assays are excellent preliminary screening tool with near real-time potential. The heavy-metal assay based on the protease ficin was optimized for mercury detection using Response Surface Methodology. The inhibitive assay is based on ficin action on the substrate casein and residual casein is determined using the Coomassie dye-binding assay. Heavy metals strongly inhibit the hydrolysis. A Central Composite Design (CCD) was utilized to optimize detection. The results show a marked improvement for the concentration causing 50% inhibition (IC50) for mercury, silver and copper. Compared to One-factor-at-a-time (OFAT) optimization, RSM gave an improvement of IC50 from 0.060 (95% CI, 0.0300.080) to 0.017 (95% CI, 0.0160.019), from 0.098 (95% CI, 0.0770.127) to 0.028 (95% CI, 0.0220.037) and from 0.040 (95% CI, 0.035.045) to 0.023 (95% CI, 0.0200.027), for mercury, silver and copper, respectively. A near real-time monitoring of mercury concentration in the Straits of Malacca at one location in Port Klang was carried out over a 4-h interval for a total of 24 h and validated by instrumental analysis with the result revealing an absence of mercury pollution in the sampling site.

Utilization of Powdered Cassava Stem as an Alternative Bioadsorbent for Lead (Pb2+) Removal from Aqueous Solution

2021 ◽  
Vol 1033 ◽  
pp. 82-86
Author(s):  
Tintin Mutiara ◽  
Andira Budi Trimartina ◽  
Rafika Erniza Putri ◽  
Achmad Chafidz
Keyword(s):  
Heavy Metals ◽  
Industrial Waste ◽  
Contact Time ◽  
Metal Ion ◽  
Adsorption Process ◽  
Cellulose Content ◽  
Optimum Conditions ◽  
Adsorption Method ◽  
Cassava Stem ◽  
Mesh Sieve

Industrial waste containing heavy metals can pollute the aquatic environment. One method that can be done to manage heavy waste is the adsorption method that uses adsorbent from cassava stem powder. This research was conducted to utilize cassava stem powder waste for the adsorption of Pb2 + metal ions. Cassava stem powder was mashed until it passed 100 mesh sieve. Cassava stems have a cellulose content of 70-80%, lignin 15-20%, ADF 15-20% and cellulose can be used as an absorber of heavy metals. The adsorption process is carried out with variations in pH, time and concentration under optimum conditions. In this adsorption involves the functional groups contained therein so that the interaction between the adsorbent with the metal ion Pb2 +. Based on the research, the optimum conditions were obtained at pH 6, 180 minutes contact time and 50 ppm concentration. This test is carried out using Atomic Absorption Spectroscopy (AAS).

Earthworm Processing of Livestock Manure and Accumulation of Heavy Metals

2012 ◽  
Vol 573-574 ◽  
pp. 1129-1133 ◽  
Author(s):  
Ji Cai Qiu
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Organic Waste ◽  
Cow Dung ◽  
Optimum Conditions ◽  
Metal Enrichment ◽  
Heavy Metal Elements ◽  
Enrichment Techniques ◽  
Animal Feces ◽  
Strong Ability

The earthworm is an omnivorous animal low saprophytic, has a strong ability to decompose organic waste. The earthworm can directly grows on dung, consume a large amount of organic waste, numerous research reports, earthworm on heavy metal elements have very strong enrichment. Therefore, the use of earthworms as a bioreactor for animal feces, excessive heavy metals to biological concentration, reduce the content of heavy metals in animal feces, is a task that is worth to discuss. Taking the rural animal feces in the largest number, the most widely distributed of cow dung as study objects, to carry out the earthworm absorption in cow dung, Zn Pb Cu, the study of the optimum conditions for the further study of Earthworm on cattle manure, heavy metal enrichment techniques provide a basis.

Recovery of Silver from Zinc Leach Residue by Flotation

2012 ◽  
Vol 524-527 ◽  
pp. 1041-1046
Author(s):  
Jian Liu ◽  
Shu Ming Wen ◽  
Dan Dan Wu
Keyword(s):  
Sodium Chloride ◽  
Detrimental Effect ◽  
Leach Residue ◽  
Optimum Conditions ◽  
Diethyl Dithiocarbamate ◽  
Flotation Method ◽  
Flotation Performance ◽  
Concentrate Grade

The study aims to recovery of silver minerals from zinc leach residue by flotation method with mixed collectors, namely, ammonium dibutyl dithiophosphate (ADD) and diethyl dithiocarbamate (DD). The effect of key parameters, i.e., grinding fineness, dosage of collectors and dosage of sodium chloride on the flotation performance was investigated. The results indicate that dosages of ADD and DD have both significant effects on the flotation performance, and sodium chloride plays an important role in the increase of the grade of silver, by eliminating the detrimental effect of Zn2+ in the pulp. The optimum conditions for flotation of silver from the material were identified as grinding fineness of 90%, dosage of ADD at 400 g/t, dosage of DD at 75 g/t and dosage of NaCl at 60 g/t; under such a condition, a sliver recovery of 76.92% with a concentrate grade of 2012.30 g/t was achieved, and the tailing from the flotation has a lower sliver grade of 17.30g/t, with only 15.04% of silver lost in the tailing.

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