Determination of some trace elements, Arsenic,Selenium, Chromium,and Zinc in several samples of fish of Bangladesh has been determined by neutron activation analysis. The results obtained are compared with those published elsewhere.
The document reports on a study that analyzed levels of arsenic, chromium, selenium, and zinc in several species of tropical marine fish from the Bay of Bengal in Bangladesh. Neutron activation analysis with radiochemical separation was used to determine concentrations of the elements in parts per million (μg/g) in dried fish samples. The results show concentrations of the elements were below permissible limits. Average concentrations were: arsenic - 3.234 μg/g, selenium - 4.385 μg/g, chromium - 1.007 μg/g, and zinc - 59 μg/g. Estimated daily intake of the elements from fish consumption was also below toxic levels. The study provides baseline data on metal contamination in these fish species commonly
Abstract— The water quality was studied for selected samples from groundwater and network water-supply. The values of NH3, NO3-, pH, TDS, alkalinity, hardness, Pb, Cd, Fe3+ and Mn2+ were estimated. Ammonia values ranged between 0.07-0.7 ppm. Nitrate values ranged between 2.4 and 0.35 ppm. The TDS was between 645 ppm and 480 ppm. For Fe3+ and Mn2+ the values are below the limits of WHO except for well 9; and manganese in wells 6-10. Several wells showed values of Cd above the Saudi STD. The network water-supply in Tabuk city was investigated. The TDS values for these samples were between 500-600 ppm. The hardness values exceed the Saudi STD limit. When ammonia was tested, only one sample showed high value. Chloride level was below 158 ppm, but sulfate values for most samples were 128-222 ppm. For iron only one sample (well no. 9) was above the permissible limit.
Characterization of mining tailings containing sulfides and carbonates applyi...Judson Arantes
Acid mine drainage (AMD) is the process resulting from the oxidation of sulfides exposed to the action of oxygen and water. The characterization of the minerals likely the formation and neutralization of AMD is important for the follow and evaluation of environmental impact. The analysis of X-ray diffraction (XRD) together with the Rietveld method is presented as a promising alternative to favor the identification and quantification of mineral phases. The results of the static test ANC achieved by accounting for carbonates consumed during the test, were correlated with the results obtained by the characterization techniques of X-ray diffraction (XRD) combined with the Rietveld method. The highest concentration of carbonate buffering found in AM2E, which may explain the static test results to be neutralizing for the sample. The major phases identified for both samples were aluminosilicates and quartz, with greater than 70% by weight levels.
Trace Metals in Tidal Creeks Sediments: The Effects of Anthropogenic Inputs ...Brian Burkhardt, PT, DPT
This study analyzed sediment samples from tidal creeks that flow into the Intracoastal Waterway in Wilmington, NC to determine concentrations of bioavailable trace metals. Sediment samples were extracted using 1M HCl and analyzed for concentrations of Ni, As, Cr, Co, Cu, Zn, Ag, Cd, and Pb. The study found relatively high concentrations of Zn and Cu in creek sediments that exceeded thresholds for potential toxicity to aquatic organisms. Depth analysis of sediment cores revealed increasing metal concentrations with depth in some creeks, possibly due to higher inorganic content, while other creeks showed decreasing metal concentrations with depth. The sources of elevated metals were attributed to inputs from anti-fouling boat paints
A GIS-based approach for detecting pollution sources and bioavailability of m...Pooria Ebrahimi
This document discusses a study analyzing metal pollution in sediments from Chabahar Bay, Iran. 19 sediment samples were collected and analyzed for concentrations of metals like copper, lead, zinc, cadmium, nickel, chromium, cobalt, vanadium, and iron. Sediment samples from 5 stations were subjected to sequential extraction analysis to determine the chemical forms and potential bioavailability of metals. Geographic information systems (GIS) and statistical analyses including contamination indices, cluster analysis, and correlation were used to identify pollution sources and spatial patterns of metal contamination in the bay. The results suggest the most contaminated sediments are located in the southeast of the bay, with contamination decreasing towards the northwest. Organic matter content is high likely due to discharges from
Carbonate removal from coastal sediments for the determination of organic c a...Mahbubul Hassan
The document compares two methods for removing inorganic carbon from samples to isolate organic carbon for analysis: the aqueous method using hydrochloric acid (HClaq) and the vaporous method using hydrochloric acid vapor (HClvap). It evaluates the methods based on their ability to have low blank levels, efficiently remove dolomite, yield accurate measurements of organic carbon percentage and isotopic signatures (δ13C and Δ14C). The vaporous method met all criteria if samples were not overexposed to acid. The aqueous method gave similar results but was less reliable and consistently underestimated organic carbon percentage. Optimal acid exposure times need to be determined for each sample type to obtain the most accurate isotopic measurements.
This document summarizes an investigation into the effects of palladium nanoparticles (PdNPs), pH, and temperature on the reduction of hexavalent chromium (CrVI) to its less toxic form CrIII. Key findings include:
1) The optimal conditions for the reduction reaction were pH 4 and 45°C temperature.
2) Reaction kinetics followed pseudo-first order behavior, indicating a linear decrease in CrVI over time.
3) PdNPs catalyzed the reaction, decreasing the activation energy by 20±10 kJ/mol and increasing the rate constant over an order of magnitude.
4) Under optimal conditions, a 26% reduction of CrVI was achieved.
This document contains 6 questions regarding water hardness, its treatment and analysis. It includes sub-questions about the constituents that cause hardness, calculating hardness from ion concentrations, the terms related to hardness, and methods for determining hardness including EDTA titrations and their principles. Methods for preventing scale formation and corrosion in boilers such as conditioning and Calgon treatment are also addressed.
The document reports on a study that analyzed levels of arsenic, chromium, selenium, and zinc in several species of tropical marine fish from the Bay of Bengal in Bangladesh. Neutron activation analysis with radiochemical separation was used to determine concentrations of the elements in parts per million (μg/g) in dried fish samples. The results show concentrations of the elements were below permissible limits. Average concentrations were: arsenic - 3.234 μg/g, selenium - 4.385 μg/g, chromium - 1.007 μg/g, and zinc - 59 μg/g. Estimated daily intake of the elements from fish consumption was also below toxic levels. The study provides baseline data on metal contamination in these fish species commonly
Abstract— The water quality was studied for selected samples from groundwater and network water-supply. The values of NH3, NO3-, pH, TDS, alkalinity, hardness, Pb, Cd, Fe3+ and Mn2+ were estimated. Ammonia values ranged between 0.07-0.7 ppm. Nitrate values ranged between 2.4 and 0.35 ppm. The TDS was between 645 ppm and 480 ppm. For Fe3+ and Mn2+ the values are below the limits of WHO except for well 9; and manganese in wells 6-10. Several wells showed values of Cd above the Saudi STD. The network water-supply in Tabuk city was investigated. The TDS values for these samples were between 500-600 ppm. The hardness values exceed the Saudi STD limit. When ammonia was tested, only one sample showed high value. Chloride level was below 158 ppm, but sulfate values for most samples were 128-222 ppm. For iron only one sample (well no. 9) was above the permissible limit.
Characterization of mining tailings containing sulfides and carbonates applyi...Judson Arantes
Acid mine drainage (AMD) is the process resulting from the oxidation of sulfides exposed to the action of oxygen and water. The characterization of the minerals likely the formation and neutralization of AMD is important for the follow and evaluation of environmental impact. The analysis of X-ray diffraction (XRD) together with the Rietveld method is presented as a promising alternative to favor the identification and quantification of mineral phases. The results of the static test ANC achieved by accounting for carbonates consumed during the test, were correlated with the results obtained by the characterization techniques of X-ray diffraction (XRD) combined with the Rietveld method. The highest concentration of carbonate buffering found in AM2E, which may explain the static test results to be neutralizing for the sample. The major phases identified for both samples were aluminosilicates and quartz, with greater than 70% by weight levels.
Trace Metals in Tidal Creeks Sediments: The Effects of Anthropogenic Inputs ...Brian Burkhardt, PT, DPT
This study analyzed sediment samples from tidal creeks that flow into the Intracoastal Waterway in Wilmington, NC to determine concentrations of bioavailable trace metals. Sediment samples were extracted using 1M HCl and analyzed for concentrations of Ni, As, Cr, Co, Cu, Zn, Ag, Cd, and Pb. The study found relatively high concentrations of Zn and Cu in creek sediments that exceeded thresholds for potential toxicity to aquatic organisms. Depth analysis of sediment cores revealed increasing metal concentrations with depth in some creeks, possibly due to higher inorganic content, while other creeks showed decreasing metal concentrations with depth. The sources of elevated metals were attributed to inputs from anti-fouling boat paints
A GIS-based approach for detecting pollution sources and bioavailability of m...Pooria Ebrahimi
This document discusses a study analyzing metal pollution in sediments from Chabahar Bay, Iran. 19 sediment samples were collected and analyzed for concentrations of metals like copper, lead, zinc, cadmium, nickel, chromium, cobalt, vanadium, and iron. Sediment samples from 5 stations were subjected to sequential extraction analysis to determine the chemical forms and potential bioavailability of metals. Geographic information systems (GIS) and statistical analyses including contamination indices, cluster analysis, and correlation were used to identify pollution sources and spatial patterns of metal contamination in the bay. The results suggest the most contaminated sediments are located in the southeast of the bay, with contamination decreasing towards the northwest. Organic matter content is high likely due to discharges from
Carbonate removal from coastal sediments for the determination of organic c a...Mahbubul Hassan
The document compares two methods for removing inorganic carbon from samples to isolate organic carbon for analysis: the aqueous method using hydrochloric acid (HClaq) and the vaporous method using hydrochloric acid vapor (HClvap). It evaluates the methods based on their ability to have low blank levels, efficiently remove dolomite, yield accurate measurements of organic carbon percentage and isotopic signatures (δ13C and Δ14C). The vaporous method met all criteria if samples were not overexposed to acid. The aqueous method gave similar results but was less reliable and consistently underestimated organic carbon percentage. Optimal acid exposure times need to be determined for each sample type to obtain the most accurate isotopic measurements.
This document summarizes an investigation into the effects of palladium nanoparticles (PdNPs), pH, and temperature on the reduction of hexavalent chromium (CrVI) to its less toxic form CrIII. Key findings include:
1) The optimal conditions for the reduction reaction were pH 4 and 45°C temperature.
2) Reaction kinetics followed pseudo-first order behavior, indicating a linear decrease in CrVI over time.
3) PdNPs catalyzed the reaction, decreasing the activation energy by 20±10 kJ/mol and increasing the rate constant over an order of magnitude.
4) Under optimal conditions, a 26% reduction of CrVI was achieved.
This document contains 6 questions regarding water hardness, its treatment and analysis. It includes sub-questions about the constituents that cause hardness, calculating hardness from ion concentrations, the terms related to hardness, and methods for determining hardness including EDTA titrations and their principles. Methods for preventing scale formation and corrosion in boilers such as conditioning and Calgon treatment are also addressed.
This document presents a project proposal for analyzing the biological components of groundwater in selected industrial and residential areas in Chinhoyi, Zimbabwe. It introduces the significance of groundwater and issues of contamination from human and other activities. Key water quality parameters that will be analyzed include microbiological (total coliform, E. coli), chemical (COD, BOD), and physical properties. Methodologies for sample collection, handling, and analyzing COD, BOD and total coliform are described, including calculations. Health risks of coliform contamination are also discussed. The analysis will assess water quality and identify sources of pollution to inform water management.
Application of emulsion liquid membranes for removal of Cd ,Co,Ni and Pb from...IOSR Journals
The paper points to the presence of heavy elements such as cobalt, nickel, lead and cadmium ratios of small but very harmful to the environment as well as health harmful if used by people for agricultural purposes, etc. This is the heavy elements harmful if it exceeds the limit as it is then used as components of the value after the extract has found these elements mentioned sources such as Ismailia Canal - Manzala Lake and the Red Sea, has been used as comparison tap water ELM for the separation of these elements has been selected cobalt (III) dicarbolide Span surfactant 80/85 and the use of acid silicon tungestic stage stripping effect concentrations of the carrier and the amendment, has been selected Co(III) dicarbolide because metal organic compound with a larger surface area and the distinction between the structure of certain net structure.
- Aquatic humic substances (AHS) are macromolecular organic acids found in natural waters like streams and lakes that are derived from decaying plant matter. They represent around 50% of dissolved organic carbon in water.
- An extraction column was developed to isolate AHS from water samples using a solid sorbent. A permanganate titration method was also developed to quantify dissolved organic carbon (DOC) in water samples, which showed a precision of 10% but a systematic error of 33% compared to a reference material.
- The goals were to construct the extraction column, develop the DOC analysis method, and use these to characterize AHS and measure DOC concentrations in various water bodies in the Potomac River waters
Reduction of cu o and cu2o with h2 h embedding and kinetics effects in the ...Luciana Pirone
This document summarizes a study that used time-resolved X-ray diffraction, X-ray absorption fine structure spectroscopy, and density functional theory calculations to investigate the reduction of CuO and Cu2O with hydrogen gas. The main findings were:
1) CuO reduces directly to metallic copper without forming intermediate copper suboxides like Cu4O3 or Cu2O under normal hydrogen flow rates.
2) The reduction of CuO is easier than the reduction of Cu2O, with apparent activation energies of 14.5 kcal/mol and 27.4 kcal/mol, respectively.
3) During CuO reduction, the system can reach metastable states and react with hydrogen instead of
This document discusses various methods for analyzing water quality parameters. It describes how to collect water samples, including using sampling devices like the Kemmerer and Van Dorn samplers. Common constituents found in natural river water are listed, such as ions from inorganic salts and dissolved or colloidal compounds from decomposing plant material. Methods are provided for measuring parameters like pH, dissolved oxygen, and ions, including using a pH meter, Winkler titration for dissolved oxygen, and collecting samples in appropriate bottles for different analyses.
This document summarizes the work of Sayan Sarkar on isolating and characterizing arsenic-tolerant bacteria from soil and water samples. Three bacterial strains, CRS2, CRS4, and CMW3, were isolated that could grow in media containing high concentrations of arsenic. Initial tests showed the strains were Gram negative, and CRS4 and CMW3 tested positive for catalase. A soil-water study found the strains could mobilize arsenic from soil into water. Further sequencing and analysis of the strains' arsenic transformation abilities is planned to understand their potential for bioremediating arsenic-contaminated environments.
Nanoscale perspective on the effect of acid washing carbon catalyst supportsPhilip R. Davies
The document summarizes research on the effect of acid washing carbon catalyst supports. Acid washing with HCl and HNO3 is commonly used to prepare carbon supports for metal catalysts. Using high-resolution techniques, the study found that low concentrations of HCl produced surface features covering 20% of the highly ordered pyrolytic graphite (HOPG) surface. Increasing the HCl concentration led to greater surface coverage. HNO3 had a similar effect but was less effective than HCl at lower concentrations. Models are needed to account for the nanoscale features produced by acid washing.
This document summarizes a study that examined the impact of water chemistry on the dissolution of lead carbonate in drinking water distribution systems. Specifically, it investigated the effects of pH (7.0-9.5), temperature (5°C vs 20°C), and alkalinity (moderate vs low) on the dissolution of hydrocerussite and cerussite in batch experiments. The results showed that pH did not significantly impact dissolution from 7.0-9.5. Cold temperature (5°C) and moderate alkalinity decreased the solubility of lead species, which was unexpected. The purpose was to better understand how water chemistry affects the stability of lead corrosion scales and the release of lead into drinking water.
This Presentation Clarifying about potable Water analysis and their methods which i gave training on operation and maintenance team for Oman Al Ghubrah Independence Water Project (SWRO Desalination 42 MIGD)
This document discusses a project report submitted by Saurav K. Rawat for their Master's degree. The report analyzes metals in alcoholic beverages using flame atomic absorption spectrophotometry. It provides an introduction to the sources of metals in alcoholic beverages, their effects, regulatory limits, removal methods, and analytical determination techniques. The report will analyze metals such as calcium, chromium, copper, iron, lead, nickel, and sodium in six common alcoholic beverages to study their concentrations and effects.
This study analyzed heavy metal concentrations in fish species from the Perak River in Malaysia. Iron showed the highest concentration in most fish species, while cadmium showed the lowest. Concentrations decreased in the order of Fe > Zn > Pb > Cu > Cd for most species. Bioaccumulation factors for iron and zinc exceeded thresholds in several fish. Estimated daily intake of cadmium, iron, and lead exceeded safety limits for all species. However, target hazard quotients and cancer risks were below EPA limits, indicating fish from the river pose minimal health risks for local consumption.
Ghoorah et al_2014_Selection of acid for weak acid processing of wollastonite...Reydick D Balucan
This document evaluates three weak organic acids (formic, acetic, and DL-lactic acid) for extracting calcium from wollastonite at temperatures between 22°C and 80°C. Experiments found that formic acid achieved the highest calcium extraction rate of 26(±7) × 10−5 mol m−2 s−1 at 80°C, followed by acetic acid and DL-lactic acid. Activation energies indicated the initial dissolution in formic acid was diffusion controlled, while kinetic limitations controlled dissolution in acetic and DL-lactic acids. Formic acid showed the best performance for calcium extraction and potential for mineral carbonation.
Quality assessment of some groundwater samples in ogbomosoAlexander Decker
The document summarizes a study that assessed the physico-chemical and microbiological quality of groundwater samples from 10 boreholes in Ogbomoso, Nigeria over a 5 month period. Key findings include:
- Several water quality parameters like total alkalinity, total hardness, BOD and COD exceeded permissible levels in some samples.
- Microbial analysis found all samples contaminated with heterotrophic bacteria and coliforms. Some also contained Salmonella-Shigella, staphylococci and molds/yeasts.
- Isolated bacteria exhibited multiple drug resistance.
- The study provides baseline data on underground water quality in Ogbomoso and suggests regular borehole cleaning
Water supply and sewerage engineering laboratoryTaufique Hasan
The document discusses water quality testing performed on samples from the First Ladies Hall of Shahjalal University of Science and Technology, Sylhet. Water samples were tested for various parameters under water supply engineering (drinking water) and sewerage engineering (sewage). For drinking water, tests found the pH, carbon dioxide, turbidity, alkalinity, iron, and manganese levels were all within acceptable limits for drinking water. For sewage, tests were conducted to determine total solids, biochemical oxygen demand, chemical oxygen demand, and chloride. The hardness of the water sample was also found to be within acceptable limits.
Application of Rapid Bioassay Method for Assessing Its Water Purification by ...IJERA Editor
Appreciated integral toxicity of four water samples taken from various sources, urban and rural environment,
and explored some of the properties of the reagent chemical purification of water - potassium ferrate K2FeO4.
These data allow suggesting for practical use test system based on bacterial luminescence for express evaluation
of the toxicity of chemical reagents used for water purification, selection of their effective concentrations and
optimal processing time of water samples.
The document provides information about the Post Graduate Common Entrance Test (PGCET) to be held on July 1, 2017 for various engineering courses. It specifies the exam duration as 150 minutes, with 120 minutes allotted for answering. Candidates are instructed to fill in personal details like PGCET number, course and version code on the answer sheet. They are advised to follow instructions regarding signing the sheet, handling question booklets and timing. The test contains 75 questions worth 100 marks, with 50 one-mark questions in Part 1 and 25 two-mark questions in Part 2.
This document describes a method for determining the concentration of vanadium(V) in sediment samples. The method involves leaching vanadium(V) compounds from sediment samples using sodium carbonate solution, followed by analysis using electrothermal atomic absorption spectrometry (ET-AAS). The method was validated on certified reference materials PACS-2 and MESS-3, which are marine sediments with known total vanadium content. Approximately 19% of the total vanadium in PACS-2 and 5% in MESS-3 was found to be in the vanadium(V) form. Validation experiments showed quantitative recovery of vanadium(V) spikes added to the samples. The method provides an accurate means of determining vanadium(V)
The document analyzes trace metal levels in various alcoholic beverages commonly consumed in Agra, India using flame atomic absorption spectrophotometry. Metal concentrations were found to vary between beverage types. The highest copper and iron levels were detected in brandy and whisky, likely due to the use of copper stills in production. All metal levels measured were below regulatory limits. The study aims to provide data on essential mineral intake from alcoholic beverages and ensure metal levels do not pose health risks.
Levels of lead and cadmium in 17 species of fresh water fish of bangladeshown
This study analyzed levels of lead and cadmium in 17 species of commonly consumed freshwater fish in Bangladesh. Atomic absorption spectrometry was used to determine metal concentrations in fish samples collected from markets. The highest lead level was 10.05 μg/g in Sicamugil cascasia and the lowest was 0.29 μg/g in Mystus vittatus. The highest cadmium level was 0.16 μg/g in Ompok pabda and the lowest was 0.03 μg/g in Mastacembelus armatus. Metal intake from average fish consumption in Bangladesh was below tolerable limits set by WHO. The study provides baseline data on metal contamination in important fish species for monitoring environmental
74.three digestion methods to determine concentrations of cu, zn, cd, ni, pb,...Alexandra Vasile
This document compares the effectiveness of three digestion methods - aqua-regia heating, block digestion, and microwave digestion - for determining concentrations of heavy metals like copper, zinc, cadmium, nickel, lead, chromium, manganese, and iron in sediments from three mangrove sites in Hong Kong. Microwave digestion extracted slightly more zinc and nickel than the other methods. Aqua-regia was better for chromium extraction. The methods showed good correlation and recoveries compared to certified reference materials. Metal concentrations varied significantly between sites depending on factors like proximity to industry and organic content.
This document summarizes a study that determined the concentrations of lead, cadmium, and chromium in spice samples from eastern Ethiopia using atomic absorption spectroscopy. Spice samples of fenugreek, black cumin, garlic, and ginger were collected and digested using microwave digestion with nitric acid and hydrogen peroxide. Lead, cadmium, and chromium concentrations were then measured. The study found detectable levels of all three metals in the samples tested, with the highest lead level found in ginger and the only detectable cadmium found in fenugreek. Microwave digestion was determined to be the optimal sample preparation method compared to dry and wet digestion based on shorter time and smaller deviations in results.
This document presents a project proposal for analyzing the biological components of groundwater in selected industrial and residential areas in Chinhoyi, Zimbabwe. It introduces the significance of groundwater and issues of contamination from human and other activities. Key water quality parameters that will be analyzed include microbiological (total coliform, E. coli), chemical (COD, BOD), and physical properties. Methodologies for sample collection, handling, and analyzing COD, BOD and total coliform are described, including calculations. Health risks of coliform contamination are also discussed. The analysis will assess water quality and identify sources of pollution to inform water management.
Application of emulsion liquid membranes for removal of Cd ,Co,Ni and Pb from...IOSR Journals
The paper points to the presence of heavy elements such as cobalt, nickel, lead and cadmium ratios of small but very harmful to the environment as well as health harmful if used by people for agricultural purposes, etc. This is the heavy elements harmful if it exceeds the limit as it is then used as components of the value after the extract has found these elements mentioned sources such as Ismailia Canal - Manzala Lake and the Red Sea, has been used as comparison tap water ELM for the separation of these elements has been selected cobalt (III) dicarbolide Span surfactant 80/85 and the use of acid silicon tungestic stage stripping effect concentrations of the carrier and the amendment, has been selected Co(III) dicarbolide because metal organic compound with a larger surface area and the distinction between the structure of certain net structure.
- Aquatic humic substances (AHS) are macromolecular organic acids found in natural waters like streams and lakes that are derived from decaying plant matter. They represent around 50% of dissolved organic carbon in water.
- An extraction column was developed to isolate AHS from water samples using a solid sorbent. A permanganate titration method was also developed to quantify dissolved organic carbon (DOC) in water samples, which showed a precision of 10% but a systematic error of 33% compared to a reference material.
- The goals were to construct the extraction column, develop the DOC analysis method, and use these to characterize AHS and measure DOC concentrations in various water bodies in the Potomac River waters
Reduction of cu o and cu2o with h2 h embedding and kinetics effects in the ...Luciana Pirone
This document summarizes a study that used time-resolved X-ray diffraction, X-ray absorption fine structure spectroscopy, and density functional theory calculations to investigate the reduction of CuO and Cu2O with hydrogen gas. The main findings were:
1) CuO reduces directly to metallic copper without forming intermediate copper suboxides like Cu4O3 or Cu2O under normal hydrogen flow rates.
2) The reduction of CuO is easier than the reduction of Cu2O, with apparent activation energies of 14.5 kcal/mol and 27.4 kcal/mol, respectively.
3) During CuO reduction, the system can reach metastable states and react with hydrogen instead of
This document discusses various methods for analyzing water quality parameters. It describes how to collect water samples, including using sampling devices like the Kemmerer and Van Dorn samplers. Common constituents found in natural river water are listed, such as ions from inorganic salts and dissolved or colloidal compounds from decomposing plant material. Methods are provided for measuring parameters like pH, dissolved oxygen, and ions, including using a pH meter, Winkler titration for dissolved oxygen, and collecting samples in appropriate bottles for different analyses.
This document summarizes the work of Sayan Sarkar on isolating and characterizing arsenic-tolerant bacteria from soil and water samples. Three bacterial strains, CRS2, CRS4, and CMW3, were isolated that could grow in media containing high concentrations of arsenic. Initial tests showed the strains were Gram negative, and CRS4 and CMW3 tested positive for catalase. A soil-water study found the strains could mobilize arsenic from soil into water. Further sequencing and analysis of the strains' arsenic transformation abilities is planned to understand their potential for bioremediating arsenic-contaminated environments.
Nanoscale perspective on the effect of acid washing carbon catalyst supportsPhilip R. Davies
The document summarizes research on the effect of acid washing carbon catalyst supports. Acid washing with HCl and HNO3 is commonly used to prepare carbon supports for metal catalysts. Using high-resolution techniques, the study found that low concentrations of HCl produced surface features covering 20% of the highly ordered pyrolytic graphite (HOPG) surface. Increasing the HCl concentration led to greater surface coverage. HNO3 had a similar effect but was less effective than HCl at lower concentrations. Models are needed to account for the nanoscale features produced by acid washing.
This document summarizes a study that examined the impact of water chemistry on the dissolution of lead carbonate in drinking water distribution systems. Specifically, it investigated the effects of pH (7.0-9.5), temperature (5°C vs 20°C), and alkalinity (moderate vs low) on the dissolution of hydrocerussite and cerussite in batch experiments. The results showed that pH did not significantly impact dissolution from 7.0-9.5. Cold temperature (5°C) and moderate alkalinity decreased the solubility of lead species, which was unexpected. The purpose was to better understand how water chemistry affects the stability of lead corrosion scales and the release of lead into drinking water.
This Presentation Clarifying about potable Water analysis and their methods which i gave training on operation and maintenance team for Oman Al Ghubrah Independence Water Project (SWRO Desalination 42 MIGD)
This document discusses a project report submitted by Saurav K. Rawat for their Master's degree. The report analyzes metals in alcoholic beverages using flame atomic absorption spectrophotometry. It provides an introduction to the sources of metals in alcoholic beverages, their effects, regulatory limits, removal methods, and analytical determination techniques. The report will analyze metals such as calcium, chromium, copper, iron, lead, nickel, and sodium in six common alcoholic beverages to study their concentrations and effects.
This study analyzed heavy metal concentrations in fish species from the Perak River in Malaysia. Iron showed the highest concentration in most fish species, while cadmium showed the lowest. Concentrations decreased in the order of Fe > Zn > Pb > Cu > Cd for most species. Bioaccumulation factors for iron and zinc exceeded thresholds in several fish. Estimated daily intake of cadmium, iron, and lead exceeded safety limits for all species. However, target hazard quotients and cancer risks were below EPA limits, indicating fish from the river pose minimal health risks for local consumption.
Ghoorah et al_2014_Selection of acid for weak acid processing of wollastonite...Reydick D Balucan
This document evaluates three weak organic acids (formic, acetic, and DL-lactic acid) for extracting calcium from wollastonite at temperatures between 22°C and 80°C. Experiments found that formic acid achieved the highest calcium extraction rate of 26(±7) × 10−5 mol m−2 s−1 at 80°C, followed by acetic acid and DL-lactic acid. Activation energies indicated the initial dissolution in formic acid was diffusion controlled, while kinetic limitations controlled dissolution in acetic and DL-lactic acids. Formic acid showed the best performance for calcium extraction and potential for mineral carbonation.
Quality assessment of some groundwater samples in ogbomosoAlexander Decker
The document summarizes a study that assessed the physico-chemical and microbiological quality of groundwater samples from 10 boreholes in Ogbomoso, Nigeria over a 5 month period. Key findings include:
- Several water quality parameters like total alkalinity, total hardness, BOD and COD exceeded permissible levels in some samples.
- Microbial analysis found all samples contaminated with heterotrophic bacteria and coliforms. Some also contained Salmonella-Shigella, staphylococci and molds/yeasts.
- Isolated bacteria exhibited multiple drug resistance.
- The study provides baseline data on underground water quality in Ogbomoso and suggests regular borehole cleaning
Water supply and sewerage engineering laboratoryTaufique Hasan
The document discusses water quality testing performed on samples from the First Ladies Hall of Shahjalal University of Science and Technology, Sylhet. Water samples were tested for various parameters under water supply engineering (drinking water) and sewerage engineering (sewage). For drinking water, tests found the pH, carbon dioxide, turbidity, alkalinity, iron, and manganese levels were all within acceptable limits for drinking water. For sewage, tests were conducted to determine total solids, biochemical oxygen demand, chemical oxygen demand, and chloride. The hardness of the water sample was also found to be within acceptable limits.
Application of Rapid Bioassay Method for Assessing Its Water Purification by ...IJERA Editor
Appreciated integral toxicity of four water samples taken from various sources, urban and rural environment,
and explored some of the properties of the reagent chemical purification of water - potassium ferrate K2FeO4.
These data allow suggesting for practical use test system based on bacterial luminescence for express evaluation
of the toxicity of chemical reagents used for water purification, selection of their effective concentrations and
optimal processing time of water samples.
The document provides information about the Post Graduate Common Entrance Test (PGCET) to be held on July 1, 2017 for various engineering courses. It specifies the exam duration as 150 minutes, with 120 minutes allotted for answering. Candidates are instructed to fill in personal details like PGCET number, course and version code on the answer sheet. They are advised to follow instructions regarding signing the sheet, handling question booklets and timing. The test contains 75 questions worth 100 marks, with 50 one-mark questions in Part 1 and 25 two-mark questions in Part 2.
This document describes a method for determining the concentration of vanadium(V) in sediment samples. The method involves leaching vanadium(V) compounds from sediment samples using sodium carbonate solution, followed by analysis using electrothermal atomic absorption spectrometry (ET-AAS). The method was validated on certified reference materials PACS-2 and MESS-3, which are marine sediments with known total vanadium content. Approximately 19% of the total vanadium in PACS-2 and 5% in MESS-3 was found to be in the vanadium(V) form. Validation experiments showed quantitative recovery of vanadium(V) spikes added to the samples. The method provides an accurate means of determining vanadium(V)
The document analyzes trace metal levels in various alcoholic beverages commonly consumed in Agra, India using flame atomic absorption spectrophotometry. Metal concentrations were found to vary between beverage types. The highest copper and iron levels were detected in brandy and whisky, likely due to the use of copper stills in production. All metal levels measured were below regulatory limits. The study aims to provide data on essential mineral intake from alcoholic beverages and ensure metal levels do not pose health risks.
Levels of lead and cadmium in 17 species of fresh water fish of bangladeshown
This study analyzed levels of lead and cadmium in 17 species of commonly consumed freshwater fish in Bangladesh. Atomic absorption spectrometry was used to determine metal concentrations in fish samples collected from markets. The highest lead level was 10.05 μg/g in Sicamugil cascasia and the lowest was 0.29 μg/g in Mystus vittatus. The highest cadmium level was 0.16 μg/g in Ompok pabda and the lowest was 0.03 μg/g in Mastacembelus armatus. Metal intake from average fish consumption in Bangladesh was below tolerable limits set by WHO. The study provides baseline data on metal contamination in important fish species for monitoring environmental
74.three digestion methods to determine concentrations of cu, zn, cd, ni, pb,...Alexandra Vasile
This document compares the effectiveness of three digestion methods - aqua-regia heating, block digestion, and microwave digestion - for determining concentrations of heavy metals like copper, zinc, cadmium, nickel, lead, chromium, manganese, and iron in sediments from three mangrove sites in Hong Kong. Microwave digestion extracted slightly more zinc and nickel than the other methods. Aqua-regia was better for chromium extraction. The methods showed good correlation and recoveries compared to certified reference materials. Metal concentrations varied significantly between sites depending on factors like proximity to industry and organic content.
This document summarizes a study that determined the concentrations of lead, cadmium, and chromium in spice samples from eastern Ethiopia using atomic absorption spectroscopy. Spice samples of fenugreek, black cumin, garlic, and ginger were collected and digested using microwave digestion with nitric acid and hydrogen peroxide. Lead, cadmium, and chromium concentrations were then measured. The study found detectable levels of all three metals in the samples tested, with the highest lead level found in ginger and the only detectable cadmium found in fenugreek. Microwave digestion was determined to be the optimal sample preparation method compared to dry and wet digestion based on shorter time and smaller deviations in results.
This document analyzes heavy metal concentrations in sediments and fish from the Korle Lagoon estuary in Accra, Ghana. It finds that heavy metal levels in sediments were generally below guidelines, but ranked in the order of Pb>Zn>Cu>Cd. Heavy metal levels in the flesh of two fish species, Seriola dumerili and Pteroscion peli, were low for copper and zinc but higher for lead and cadmium compared to WHO standards. Both fish species accumulated higher levels of lead and cadmium regardless of size. The study concludes that consuming fish from the lagoon should be prohibited due to high levels of lead and cadmium that could be detrimental to human health.
This document summarizes a study that investigated the adsorption isotherm of Hg(II), Pb(II), and Cd(II) ions onto unmodified and ester-modified Senilia senilus and Thais coronata biomass. Adsorption capacity was tested using Langmuir, Freundlich, and Temkin isotherm models. The study found that unmodified biomass was a better adsorbent for removing heavy metals. Adsorption increased with increasing initial metal ion concentration. Among the isotherm models, Freundlich isotherm best fit the equilibrium data with r2 values ranging from 0.9887 to 1.000. The biomass and adsorption method proved
An Assignment On Biotechnological Methods In Pollution AbatementDaphne Smith
This document discusses biotechnological methods for pollution abatement. It summarizes research using biological markers like fish to monitor metal pollution in various bodies of water. It also describes the mechanisms and factors involved in enhanced biological phosphorus removal (EBPR) wastewater treatment processes. EBPR relies on selecting microbes that uptake phosphates beyond their needs. It uses alternating anaerobic and aerobic zones to encourage phosphorus-accumulating organisms that store phosphates for removal. Key factors for EBPR include sludge age, volatile fatty acids as an energy source, and maintaining sufficient BOD or COD levels relative to phosphorus.
Determination of vanadium, nickel, copper and iron as complexes of bis acetyl...Alexander Decker
This document describes a study that used high performance liquid chromatography (HPLC) to determine the concentrations of vanadium, nickel, copper, and iron in Nigerian crude oil samples. The researchers analyzed samples from 5 oil wells, both onshore and offshore. They found that nickel generally had the highest concentration, while copper had the lowest. Concentration levels ranged from 210-1620 ppb for nickel, 975-1125 ppb for iron, 225-1060 ppb for vanadium, and 54-138 ppb for copper. The results were consistent with previous studies on metals in Nigerian crude oils. The study provides data on heavy metal concentrations that can help assess the environmental and economic impacts of Nigerian crude
A pilot study on effect of copper and cadmium toxicity in Tilapia Mossambicusresearchanimalsciences
Cu and Cd is trace element for most organisms including fish, but above certain limit Cu and Cd will be toxic. The present study was conducted to evaluate the toxic effect of Cu and Cd on Tilapia mossambicus via estimating the acute 96h median lethal concentration (LC50) value. A total 120 number of Tilapia mossambicus fingerlings were subjected to 12 numbers 20-L aquaria. Fish were exposed to 0.0, 2.0, 4.0, 6.0, 8.0 and 10.0mg Cu and Cd/L for 4 days. Each dose was represented by two aquaria. Fish was daily observed and dead fish were removed immediately. The data obtained were evaluated using Behrens-Karber’s Method. The 96 h LC50 value of Cu for Tilapia mossambicus was calculated to be 6.0mg Cu/L with Behrens-Karber’s Method. The 96 h LC50 value of Cd for Tilapia mossambicus was calculated to be 4.8mg Cd/L with Behrens-Karber’s Method. The behavioral changes of Tilapia mossambicus were primarily observed. It could be concluded that Tilapia mossambicus species slightly sensitive to Cu and Cd when compare both metal cadmium is more toxic than copper for the fish species.
Article Citation:
Anushia C, Sampath kumar P and Selva Prabhu A.
A Pilot Study on Effect of Copper and Cadmium Toxicity in Tilapia Mossambicus.
Journal of Research in Animal Sciences (2012) 1(1): 020-027.
Full Text:
http://janimalsciences.com/documents/AS0008.pdf
A Pilot Study on Effect of Copper and Cadmium Toxicity in Tilapia Mossambicus researchanimalsciences
Cu and Cd is trace element for most organisms including fish, but above certain limit Cu and Cd will be toxic. The present study was conducted to evaluate the
toxic effect of Cu and Cd on Tilapia mossambicus
via estimating the acute 96h median lethal concentration (LC 50 ) value. A total 120 number of
Tilapia mossambicus fingerlings were subjected to 12 numbers 20 L aquaria. Fish were exposed to 0.0, 2.0,
4.0, 6.0, 8.0 and 10.0mg Cu and Cd/L for 4 days. Each dose was represented by two aquaria. Fish was daily observed and dead fish were removed immediately. The data obtained were evaluated using Behrens - Karber’s Method. The 96 h LC 50 value of Cu for Tilapia mossambicus was calculated to be 6.0mg Cu/L with Behrens - Karber’s Method. The 96 h LC
50 value of Cd for Tilapia mossambicus was calculated to be 4.8mg Cd/L with Behrens - Karber’s Method. The behavioral changs of Tilapia mossambicus
were primarily observed. It could be concluded that Tilapia mossambicus species slightly sensitive to Cu and Cd when compare both metal
cadmium is more toxic than copper for the fish species.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
This document summarizes the synthesis and characterization of lanthanide complexes with the drug cloxacillin. Cloxacillin is an antibiotic drug that is commonly used to treat bacterial infections. Seven lanthanide complexes of the form [Ln(Clox)2(H2O)2]Cl where Ln = La(III), Pr(III), Nd(III), Sm(III), Dy(III), Ho(III) and Er(III) were synthesized. The complexes were characterized using elemental analysis, infrared spectroscopy, electronic spectroscopy, magnetic susceptibility measurements, and thermal analysis. Elemental analysis showed a 1:2 metal to ligand ratio in the complexes. Infrared spectroscopy indicated that cloxacillin binds in
11.assessment of human health risk for arsenic, copper, nickel, mercury and z...Alexander Decker
This study analyzed levels of arsenic, copper, mercury, nickel, and zinc in muscle tissues of fish from wetlands in Kolkata, India. The levels of heavy metals in fish tissues were below international limits. The researchers calculated tolerable intake levels and estimated human health risks from consuming the contaminated fish. The target hazard quotients for individual metals were below thresholds, but the hazard index for arsenic, copper, mercury, nickel and zinc in one fish species was marginally high. The estimated target cancer risks of arsenic and nickel from some fish species were above acceptable levels. More research is needed to fully understand health risks from toxic metals in fish consumed in the region.
Assessment of human health risk for arsenic, copper, nickel, mercury and zinc...Alexander Decker
This study analyzed levels of arsenic, copper, mercury, nickel, and zinc in fish muscle tissues collected from wetlands in India. The levels of heavy metals were below international limits. The researchers calculated tolerable intake levels and estimated human health risks from fish consumption. The target hazard quotients for individual metals were below thresholds, but the hazard index for a mixture was marginally high for one fish species. The estimated cancer risks of arsenic and nickel from some fish were also above acceptable levels. More research is needed to better understand health risks from toxic metals in fish.
Determination of volatile organic compounds in surface water and sediment usi...IOSR Journals
This research presents the development of a methodology for analysing volatile organic compounds in selected zones of Asa River, Kwara State. The liquid-liquid extraction procedure of two organic solvent (Hexane : Dichloromethane) (1:1 v/v) was employed to remove volatile organic compounds from river and sediment samples, for further identification and quantification showed very good recovery and repeatability. The mean recovery percentage range was between 96.7±1.5 - 104.0±1.0 for river samples while 97.3±2.2 - 104.0±1.0 for sediment samples at a fortification level of 0.01 μg/l. In addition, volatile organic compounds were determined by Gas chromatography – mass spectrometry. The limit of quantification was 0.05 μg/l which was below the maximum level allowed by the European council directives for volatile organic compounds (0.5 μg/l).
1. The study analyzed levels of minerals and trace elements in seeds, pulp, and skin of pumpkins from three regions in Guyana. Atomic absorption spectrophotometry was used to determine the concentration of elements in the samples.
2. Higher quantities of important minerals like iron, copper, zinc, and phosphorus were found in the seeds compared to the pulp and skin. The seed samples provided over 20% of the daily value for some of these minerals.
3. Concentrations of elements varied between the different pumpkin parts and growing regions, likely due to differences in soil composition and environmental conditions. However, the seeds were consistently shown to be a good source of several essential nutrients.
Mercury concentrations in 14 commonly consumed fresh water fish of bangladeshown
This study analyzed mercury concentrations in 14 commonly consumed freshwater fish species in Bangladesh. Samples were collected from markets and irradiation and radiochemical separation methods were used to determine mercury levels. Results ranged from 0.20-0.91 μg/g dry weight. Six species had 0.20-0.32 μg/g, seven had 0.30-0.50 μg/g, and one had 0.80-0.91 μg/g. The total average was 0.377 μg/g. Mercury levels were found to be within international safety limits and did not pose health risks to Bangladeshi consumers based on estimated dietary intake. The highest levels were found in the catfish Clarias gariepinus
SYNTHESIS AND CHARACTERIZATION OF KAOLINITE COATED WITH CU-OXIDE AND ITS EFFE...Premier Publishers
This document summarizes a study that synthesized copper oxide coated kaolinite to remove mercury ions from aqueous solution. Kaolinite was characterized and then coated with copper oxide via precipitation and thermal treatment. The coated material was then tested for removing mercury ions from water. Key findings include:
1) The copper oxide coated kaolinite was characterized through various analyses which confirmed the coating and composition.
2) Reactivity experiments determined the proton coefficient was 0.89, indicating decreased proton consumption compared to uncoated kaolinite.
3) Kinetic studies found maximum 85% mercury adsorption after 12 hours, with mass transfer rates lower than for uncoated kaolinite, possibly due to blocked reaction sites on the
1) The document evaluates the performance of a locally developed paddle wheel aerator on catfish effluent quality in Lagos, Nigeria.
2) Two basins containing diluted catfish effluent were used - one with a paddle wheel aerator and one without (the control).
3) Water quality parameters like suspended solids, nitrogen, phosphorus, ammonia, nitrite and biochemical oxygen demand were measured over time in both basins.
4) The results showed that the paddle wheel aerator significantly reduced levels of all water quality parameters measured compared to the control basin without aeration.
Removal of heavy metals (Cr, Cd, Ni and Pb) using fresh water algae (Utricula...Innspub Net
A study was conducted to check the efficiency of different fresh water algae for removing heavy metals (Cr, Cd, Ni and Pb) from contaminated water. The three most abundant indigenous algal species namely Ulothrix tenuissima, Oscillatoria tenuis and Zygogonium ericetorum were collected from fresh water channels of Parachinar, Pakistan and brought to the laboratory of Soil and Environmental Sciences Department at the University of Agriculture, Peshawar Pakistan for proper identification. To check the efficiency for removing heavy metals artificial contaminated water was prepared and was inoculated with mix culture of above mentioned algae and incubated for 10 days. After incubation algal species were removed from water through centrifugation and was dried, digested and analyzed for heavy metals. The results showed that the concentration of all heavy metals was substantially reduced in the algal inoculated contaminated water. The analysis of algal biomass showed that considerable amount of metals and other elements were recovered in algae. Among the tested algal species, Zygogonium ericetorum showed maximum removal Ni(99.40ug) and Cr(66.84ug) from contaminated water followed by Oscillatoria tenuis with 84ug(Ni) and 64.83ug(Cr) respectively. However Oscillatoria tenuis showed maximum removal of Cd(41.00ug) than the other algal species. Similarly Zygogonium ericetorum showed maximum removal of Pb (451ug) followed by Ulothrix tenuissima where 441ug was recorded. Highest amount Cd, and Ni were recovered in Zygogonium ericetorum biomass while highest amount of Cr and Pb were recorded in the biomass of Oscillatoria tenuis. Finally it could be concluded that algae have efficiently removed heavy metals from contaminated water. Further research is needed to test other algal species for removal of heavy metal and other elements from the contaminated water.
This document summarizes a study on the phytochemical-mediated synthesis of gold nanoparticles using the aqueous extract of the seaweed Sargassum ilicifolium. Key findings include:
1) The seaweed extract reduced gold ions (Au+) to gold nanoparticles (Au0) in solution, indicated by a color change to ruby red and characterized using UV-Vis spectroscopy and XRD.
2) FTIR analysis showed that carboxyl and hydroxyl groups in the seaweed mediated reduction and stabilization of the gold nanoparticles.
3) TEM images showed the produced gold nanoparticles were monodisperse and spherical, ranging in size from 2 to 30 nm.
2. J.Nat.O.A.M.Institute, Vol.22, No.2,1-8,2005
Some of the investigators [7-12] have reported significantly high levels of cadmium and
arsenic in some species of fish. However, the investigation of DE GOEIJ [13] and
GUINN [14] have shown that there is no significant difference of these levels of certain
trace elements, like arsenic, cadmium than those in unpolluted areas.
Whether or not fish will be contaminated will depend on the chemical form of the
element and its concentration in the surrounding medium, microbiological activity in the
marine environment, texture of the sediment, type and age of the fish, etc. However, there
are still insufficient data available in Bangladesh for toxic metals like arsenic, cadmium,
etc. It is strongly believed that this study will consequently be a great help for
Bangladesh’s economy in view of quality assurance for trade as well as the health, safety
and benefit of her people. This paper presents information on the concentration of
arsenic, chromium, selenium and zinc in some varieties of fish and also describes briefly
the chemical procedure followed.
The instrumental neutron activation analysis (INAA) of such elements as As, Cr, Cd, Zn
and Cu in animal organs and fish tissues is difficult because of the 24
Na and 86
Br
activities developed on irradiation. This is because the photopeaks of radioactive products
of these elements are masked, particularly by the Compton continuum of the high 24
Na
matrix activity, thus posing problem not only in handling but also in the computation of
the peak areas from the γ-ray spectra. This problem has necessitated post-irradiation
chemical separation of isotopes of interest. This paper describes such a scheme for
determination of seven trace elements (As, Cr, Se and Zn) in biological materials.
EXPERIMENTAL
Samples collection and irradiation. Eight varieties of common marine fish, selected in
accordance with their public flavor for Bangladeshi (near coastal belt) in both taste and
cost, namely, Coilia neglecta, Cirrhinna reba,Johnius argantus, Harpondon nehereus,
Setipinna phasa and Lepturacanthus savala were collected from the coastal belt of the
Bay of Bengal and sun-dried after removal of their internal organs, head, skin, and tails.
The dried samples were then chopped into pieces with the aid of a stainless steel knife
(steam cleaned). Only the edible muscle tissue samples were used for analysis. The
sample pieces were dried at 105o
-110o
C in an oven until a constant weight was obtained
(dry weight).
The dried samples were ground, sieved and thoroughly mixed in a stainless steel rotating
drum for 100 hours to produce a homogeneous powder. The sample powder was finally
preserved in clean and dry polyethylene bottles. Portions of the samples (200-300 mg
each) were heat-sealed in polyethylene bags and irradiated along with a known amount of
MA-A-2 ™, the fish flesh homogenate standard of IAEA in the CIRUS reactor at Bhabha
Atomic Research Center, Trombay, Bombay, India, at a flux of about
(0.5 to 1) .1012
n. cm-2
. s-1
for 20 hours.
2
3. J.Nat.O.A.M. Institute,Vol.22(2),1-8,2005
Chemical reagents. (1) NH3, HCl, HNO3, HClO4 and acetic acid; (2) Na2SO3 solution:
4 mg/cm3
; (3) NaOH pellets; (4) thioacetamide; (5) H2O2; (6) BaCl2 (=0.2M solution in
water; (7) NH4H2PO4= 1M solution; (8) hydroxylamine hydrochloride (NH2OH.HCl).
Dissolution. Each of the irradiated samples was allowed to “cool” for 4-5 days to enable
the decay of short-lived isotopes and also to reduce the 82
Br and 24
Na activities. About 10
mg carrier for each of the element was added to a 100 ml round-bottomed flask and the
irradiated sample was carefully opened and emptied into it. Then, the sample was
digested in Bethge’s apparatus with a mixture of 6 cm3
concentrated nitric acid and 2 cm3
of concentrated perchloric acid till a liquid remained in the flask.
Chemical separation and determination of metal
After the digestion was completed, the distillates were, evaporated to dryness on a sand
bath to remove nitric acid, and leached with conc. HCl (10 cm3
) and preserved to be
combined with the filtrates from chromium and selenium precipitation.
(1) Determination of chromium: 4 cm3
HClO4 was added to the residue in the flask
and drops of conc. HCl added to the hot solution to distil of CrO2Cl2 . The
distillate was collected in 10 ml sodium hydroxide solution (1N) . To this was 1.5
cm3
BaCl2 solution followed by addition of 2-3 drops of H2O2. The pH was set at
6. BaCrO4 was digested in a water bath and was filtered, dried and counted for
51
Cr. The filtrate was combined with the distillate from decomposition step.
Cr is oxidized to Cr(VI) by HClO4
H2Cr2O7 + 4 HCl → 2CrO2Cl2 + 2H2O(reddish vapor)
CrO2Cl2 + 2NaOH →Na2CrO4 +2HCl (yellow distillate)
Na2CrO4 + BaCl2 → BaCrO4 + 2 NaCl
(2) Determination of selenium: To the residue remaining in the flask 20 ml of conc.
HCl was added and the volume kept at 50 ml. To the warm solution 4-5 cm3
Na2SO3 solution was added and digested in a water bath for 1 hour. The
precipitated Se metal was filtered, dried and counted for 75
Se. This filtrate also
was combined with the distillate from the decomposition step.
MCl2 + SO2 +2H2O → M (metal) + 2HCl + H2SO4
(3) Determination of arsenic: The acidity of the first distillate, with the filtrates from
chromium precipitation and selenium precipitation mixed together, was adjusted
to 1M HCl and 1 ml of a 1% solution of thioacetamide was added to the boiling
solution. This was digested in a water bath. Precipitates of sulfides of As were
filtered off, washed, dried and counted 76
As.
CH3CSNH2 + H2O → CH3CONH4 + H2S
CH3CONH2 + H2O→ CH3COONH4
H2S + M+++
→ MS + 2H+
[M = As]
3
4. J.Nat.O.A.M.Institute,Vol.22,No.2,1-8,2005
(4) Determination of zinc. The filtrate from (3) was evaporated to dryness in a boiling
water bath followed by addition of drops of conc.HNO3 until the ammonium salts
were completely destroyed. To this was added 1 cm3
1M NH4H4PO4 solution. The
pH of the solution was then adjusted to 6 and it was heated for a few minutes. The
mixture was then kept in a water bath for 1 hour. The precipitates obtained were
filtered off, washed, dried and counted for 65
Zn.
ZnCl2 + NH4H2PO4 → ZnNH4PO4 + 2HCl [M= Zn]
Counting
The samples and the standards were counted on a 45 cm3
HPGe detector connected to
a 4096 channel pulse-height analyzer (Ortec PCA-MCA card). The energies (in keV)
chosen for the evaluation of the peak areas were: 76
As(26.4 h), Eγ=657 keV (since,
the photopeaks of 122
Sb (561keV) interfered with photopeak 76
As at 559 keV, the 657
keV photopeak was chosen to measure 76
As photopeak area) ; 51
Cr(27.7 d),
Eγ=320.08keV; 75
Se (119.77 d), Eγ = 264.66 keV; 65
Zn (243.9 d), Eγ= 1115.5 keV.
Accuracy and precision
Experiments were initially carried out using radioactive tracers and the corresponding
carriers to evaluate the recoveries. The yields were in the range of 93% to 98%. The
accuracy of the method was evaluated by analyzing homogenate fish flesh (IAEA)
Standard Reference Material, MA-A-2™. Our results (values in μg/g) are in good
agreement with the IAEA certified values.
RESULTS AND DISCUSSION
The As, Se, Cr and Zn concentrations determined in the fish species are presented in
Table 1. The values are expressed in μg.g-1
dry weight. The range of concentrations
found in the fish samples are As (2.843-3.920), Se (2.961-6.274), Cr (0.498-1.8430),
and Zn (37.59-101.19). These variations are likely to be due to the migratory nature
and feeding habits of the different species of fish.
Normally, the levels of As (3 ng/ml), Se (0.09 ng/ml) and Zn (0.01 ng/ml) have been
found to be quite low in sea-water [15], but the levels of these metals as found in fish
samples under investigation are higher. This is due to the tendency of various species
of fish to concentrate certain elements in the tissue more than surrounding medium.
The mean concentrations of arsenic, selenium, chromium and zinc in fish are 3.234
μg/g, 4.385 μg/g, 1.007 μg/g and 59 μg/g, respectively.
Using neutron activation, HAMILTON AND MINSKI [16] reported the mean values
for As in fish as 2.0±0.08 μg fresh weight. Up to 174 ppm has been found in prawns
from the coastal waters of Britain [17] and 42 ppm in shrimp from the southeastern
4
5. J.Nat.O.A.M.Institute,Vol.22,No.2,1-8,2005
coastal waters of the United States [18]. Fish flour for human consumption has been
reported [19] to contain 1.8 ppm Se and tuna meal median levels as high as 5.1 and
6.2 ppm (dry basis)[20]. High natural Se levels in tuna [21] and marine mammals [22]
have been reported. Open ocean water contains as little as 10 μg/l of Zn at the surface
[23] although coastal seawater usually contains 0.5-2 μg/l of Zn as a result of river
inputs and sewage outfalls [24-26].
Table 1
Arsenic, selenium, chromium and zinc in different varieties of fish
(μg. g-1
dry weight basis)
Types of
fish
Weight
Analyzed,
g
Arsenic Selenium Chromium Zinc
Organic
Matter,
%
Colia
neglectic
0.36220 3.025 4.751 1.843 80.48 79.75
Cirrhina
reba
0.31093 3.076 2.961 1.287 49.55 84.85
Johnius
argantus
0.32212 3.920 3.856 0.550 37.59 83.45
Harpodon
nehereus
0.27691 3.070 6.274 0.871 101.19 81.82
Setipinna
phasa
0.31377 3.469 3.839 0.995 50.73 82.68
Leturacan-
Thus
salala
0.36220 2.843 4.627 0.498 38.02 81.73
Stromateus
sinensis
- 2.52 - - 51.0 -
Rita rita - 3.78 3.15 - - -
Mean - 3.234 4.385 1.007 59.59 82.36
Range - 2.843-
3.920
2.961-
6.274
0.498-
1.843
37.59-
101.19
79.75-
84.85
Taking 6 g of fish as the maximum consumption [27] per person per day for
Chittagong and coastal areas of Bangladesh, it is estimated that the average intake of
arsenic, selenium, chromium and zinc through fish is 3.881 μg, 5.262 μg 1.208 μg and
71.51 μg, respectively. The daily intake of arsenic is quite low[28]. Table 2. gives the
comparison of the levels of arsenic, selenium, chromium and zinc in fish by various
researchers in different countries.
5
6. J.Nat.O.A.M.Institute, Vol.22,No.2,1-8,2005
CONCLUSIONS
The present study indicates that the radiochemical separation scheme should be used
for the isolation nuclides with mutually interfering γ-rays (e.g., 75
Se, with 203
Hg at
265 keV ) . In the case of 76
As, due to the interference of 122
Sb, at 559 keV, we have
chosen the less sensitive 657 keV peak for computation of arsenic.
Eight tropical marine fish species collected from the Bay of Bengal were analyzed in
order to assess the level of trace toxic elements in this food item consumed by the
Table 2
Trace element concentrations (mg. Kg-1
wet weight ) in muscle tissue of various
species of fish from different areas of the world
Source Area Cr As Se Zn Species
Bebbington
Et al (1977)
[29]
Australia,
N.S.W
- 0.2-
2.2
- 4.24-
6.60
Commercial
Species
including
flathead,mullet
Roth and
Harnung
(1977) [30]
Israel 2.8-4.9 - - 14.9-
25.5
J.H.Powell
et al.
[31]
Papua
New
Guinea
- 0.4-3.5 - 3.0-4.5 8 species
including
sharks,travelly
Khan et.al
(1987)
[32]
Dhaka,
Bangladesh
- 2.52-
5.53
3.15 26.0-
93.8
6 species
including prawn,
rita,gar
fish
Anand.S.J.S.
(1978)
[33]
Bombay,
India
- 0.069-
0.931
- - 6 species
(pampus
argentius,
harpodon
neherer etc.)
*Present
study (on
dry weight
basis)
Bay of
Bengal,
Bangladesh
(1998)
0.50-
1.84
2.84-
3.92
2.96-
6.27
37.59-
101.19
6 species (coilia
neglecta,cirrhina
reba, johnius
argentus,
harpodon
nehereus,setipina
fhasa and
lepturacanthus
savala)
*The present data were calculated on dry weight basis
6
7. J.Nat.O.A.M.Institute,Vol.22,No.2,1-8,2005
population of Bangladesh. The results indicate that the concentrations of these
elements are much below the toxic levels.
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