Composition Analysis of Remaining Metal Particles on Ferrochrome Kitchen Knife / 法医学杂志

OBJECTIVE@#To establish a feasible evaluation index and method to identify composition of remaining metal particles on ferrochrome kitchen knife.@*METHODS@#The small samples of remaining metal particles were rubbed from the knives using filter paper. The composition of remaining metal particles was detected by scanning electron microscopy and energy dispersive X-ray spectrometer (SEM-EDX) and GSR particle analysis function, using mathematical methods to calculate the ratio (relative amount) of Fe and Cr in remaining metal particles.@*RESULTS@#The ratio (relative amount) of Fe and Cr of remaining metal particles had significant differences among most ferrochrome kitchen knives (P < 0.05).@*CONCLUSION@#Using GSR particle analysis function to quantitatively detect the ratio (relative amount) of Fe and Cr of remaining metal particles on ferrochrome kitchen knife, which can establish the feasible evaluation method to estimate such injury tool.

[Reduction of hexavalent chromium from aqueous solution using modified zeolite cationic surfactant]

Hexavalent Chromium is an important contaminant in surface and ground waters and removal from contaminated water and waste water has received interest in recent years. Modified Zeolite with cationic surfactant can remove Cr[VI] from contaminant water. The aim of this research is investigation of Cr [VI] removal from aqueous solutions and its effective parameters by using Modified Zeolite with cationic surfactant. In this research the efficiency of Cr[VI] removal and impact of the important parameters including adsorbent dose, pH and contact time in the batch system was studied. The results of this research showed that SMZ can remove more than 90% Cr[VI] in the concentration 0.1-1.25 mg/l with optimum dose 0.3 gr and pH=6, 120 minute in contact time. Modified natural zeolite have significant potential in Cr[VI] removal from contaminated water. Maximum percent removal of Cr[VI] was in the pH=6 and 120 minute contact time. Adsorption data in the equilibrium was fitted with Langmuir isotherm. Separation factor was between 0 and 1 that indicates the favorable condition for Cr[VI] adsorption on the SMZ

Chromium (VI) tolerance in two halotolerant strains of Nostoc.

The present study reports on chromium (VI) tolerance of two cyanobacterial strains Nostoc linckia and Nostoc spongiaeforme isolated from salt affected soils using uni-algal and bi-algal systems. Besides distinct halophilism, the two strains exhibited remarkable tolerance to chromium (VI) and revealed 1.2 to 2.8 times more chlorophyll in the presence of the metal. While phycobilins and carotenoids also increased in Nostoc linckia with total dissolved salts (TDS) as well as metal, a decline was observed in Nostoc spongiaeforme in the presence of Cr (VI). Relative algal biomass (as % of control) showed significantly higher values (123-239) in Nostoc linckia in the presence of salt, metal and combination of the two. In Nostoc spongiaeforme it declined in the presence of metal (72-81) but increased in the presence of salts (143-249) and also in the binary systems (121-440). The bi-algal consortium showed relatively less tolerance to salt and metal stress. Nostoc linckia (20 day culture) showed upto 40% chromium removal whereas Nostoc spongiaeforme showed up to 12% removal, indicating greater suitability of the former for use in bioremediation studies.

Cr (VI) and Fe (III) removal using Cajanus cajan husk.

Husk of tur dal (Cajanus cajan) was investigated as a new biosorbent for the removal of Fe (III) and Cr (VI) ions from aqueous solutions. Parameters like agitation time, adsorbent dosage and pH were studied at different initial Fe (III) and Cr (VI) concentrations. The biosorptive capacity of the Tur dal husk was dependent on the pH of the chromium and iron solution, with pH 2 and 2.5 respectively being optimal. The adsorption data fit well with Langmuir and Freundlich isotherm models. The practical limiting adsorption capacity (qmax) calculated from the Langmuir isotherm was 96.05 mg of Cr(VI)/ g of the biosorbent at an initial pH of 2.0 and 66.65 mg/g at pH 2.5. The infrared spectra of the biomass revealed that hydroxyl, carboxyl and amide bonds are involved in the uptake of Cr (VI) and Fe (III) ions. Characterisation of tur dal husk has revealed that it is an excellent material for treating wastewaters containing low concentration of metal ions.

Removal of trace chromium (VI) from contaminated water: bio-sorption by Ipomea aquatica.

Ipomea aquatica is a wetland plant, which floats in water bodies and is being used as a vegetable. This plant has ability to remove Cr(VI) from the contaminated water by transforming Cr (VI) to Cr (III). This adsorption of Cr(VI) basically takes place in roots of this plant. The contact time required to bring down Cr(VI) concentration below the permissible level (0.05 mg/1) is 30 to 40 days for this plant, and that varies with varying initial concentration. The lower level of contamination requires greater contact time than the higher one to bring down Cr(VI) below the permissible level. Recovery (94 +/- 1%) of chromium from the treated plant has been reported in this paper, and at the same time disposal problem also dose not arise. The study revealed that the plant Ipomea aquatica adsorbs Cr(VI) from the contaminated water very slowly compared to the other reported plants.

Comparative study of removal of Cr(VI) with PAC, GAC and adsorbent prepared from tobacco roots.

Tobacco roots activated carbon (TRAC) has been prepared from tobacco roots impregnated with 20% of ZnCl2 and carbonized at 6000 degrees C. Its adsorption capacity has been tested for the treatment of wastewater containing hexavalent chromium. The experiments were carried out in a batch process to study the different system variables such as concentration, adsorbent dosage and contact time. Removal of chromium in the process has been found to increase with increase in adsorbent dosage and contact time. The adsorption isotherm data fitted the Langmuir adsorption isotherm model.

Removal of chromium by two aquatic pteridophytes.

In the recent years, the use of phytoremediation for ameliorating metal pollution has been gaining ground. This study explores the. possibility of utilising two common aquatic ferns, Salvinia molesta Mitchell and Azolla rubra R.Br. for scavenging chromium from solutions. Chromium removal from spiked solutions ranged from 40-99% during the seven day exposure. Results reveal their bioremoval capabilities and potentialfor use in wastewater decontaminant

Chromium uptake by Saccharomyces cerevisiae and isolation of glucose tolerance factor from yeast biomass.

Fermentations with yeast Saccharomyces cerevisiae in semiaerobic and in static conditions with the addition of chromic chloride into the used molasses medium were analysed. It was proved that the addition of optimal amounts of CrCl3 into the basal medium enhanced the kinetics of alcohol fermentations. The addition of 200 mg/l CrCl3 into the medium stimulated both the yeast growth and the ethanol production in all experimental conditions. On the other hand, the results showed that Cr3+ ions were incorporated into yeast cells during fermentation. Under these conditions the accumulation of Cr3+ ions was performed by yeast cells during the exponential growth phase, and with enriched amounts of 30-45 microg/g(d.m) of cells. Yeast biomass enriched with chromium ions was extracted with 0.1 mol/l NH4OH assuming that the extracts had the glucose tolerance factor (GTF). Then the extracts were passed through a gel-filtration column in order to isolate and purify the GTF. The presence of GTF in the purified fractions was determined by measuring the absorbance at 260 nm. It is evident from the obtained results that the added purified fractions enhanced the rates of CO2 production as well as the glucose utilization during alcoholic fermentation. As expected, the enhancement of both rates depended on the amounts of extracts added to the fermentation substrate. Thus, it is evident that purified extracts contained the GTF compound, and that Cr3+ ions were bonded to the protein molecule.

Evaluación toxicológica de cromo, hierro, manganeso y sulfato de las aguas de mr y especies marinas de la Bahia de San Nicolas del Distrito de Marcona / Toxicology evaluation of chromium, iron, manganese and sulfate of sea water and seafood of Bahia San Nicolas, Marcona

Se evalua el riesgo de contaminación por cromo, hierro, manganeso y sulfatos en especies marinas de consumo habitual, procedentes de la Bahía de San Nicolas de Marcona, resultado de la actividad minera que se realiza en la zona. El cromo, hierro y manganeso se determinó por espectrofotometría de absorción atómica, los sulfatos por medición de la turbides en un espectrofotómetro. Los resultados obtenidos para las especies marinas se evalúan en relación con la ingesta promedio por día en una dieta normal (según OMS). Los resultados se comparan con los obtenidos en muestras de la zona de Chorillos en Lima considerada de baja contaminación por estos minerales. Los valoresmás significativos en las especies marinas se encuentran en choros y machas tanto para hierro como para sulfatos. Dichos valores se encuentran por debajo de las cantidades consideradas tóxicas por tanto no representan mayor riesgo para la salud de la población.