This study compares the fat soluble components in the muscle and edible skin parts of farmed rain... more This study compares the fat soluble components in the muscle and edible skin parts of farmed rainbow trout (Oncorhynchus mykiss W.) fillets, sampled at two growth stages, from fish markets from Bulgaria. Insufficient information is available about the differential fat soluble pigments, cholesterol, vitamins and fatty acid compositions of rainbow trout fillets when eating them with or without the skin left on. Vitamins A, D3 and E, β-carotene and cholesterol were analyzed simultaneously using HPLC system with UV and FL detection (vitamins A and E). Total lipids were extracted according to Bligh and Dyer method. Analysis of fatty acid methyl esters (FAME) were perform by GC/MS. The average lipid content, the cholesterol and vitamin E amounts and the saturated fatty acids were significantly higher in the skin than in the muscle, whereas the proportion of vitamin A and D3, eicosapentaenoic acid (C20:5 ω-3) and docosahexaenoic acid (C22:6 ω-3) were higher in the muscle.
The environmental monitoring of chemical toxicants has been a widely studied topic in the last fe... more The environmental monitoring of chemical toxicants has been a widely studied topic in the last few decades. The main aim of the present study was to determine the total concentration of nine elements (Cd, Cr, Pb, Ni, Al, Cu, Fe, Mn, and Zn) in the fish species grey mullet (M. cephalus) and in the coastal marine waters collected from various sampling points along the Black Sea (Bulgaria) and the Ionian Sea (Italy). Further, those results were applied to predict the pollution degree in those coastal marine environments. The fish samples were subject to acid digestion followed by appropriate analytical determination. The metal concentrations in marine water samples collected from the Black Sea (Bulgaria) and the Ionian Sea (Italy) were also analyzed. Unpaired Student’s t-test and the one-way ANOVA were applied for the statistical analysis of the data. The statistical results revealed a significant variation (p < 0.0001) in the concentration of various fish tissues. The accumulation ...
In this study some heavy metals (Cd, Ni, Cr, As, Hg Cu, Fe, Mn, Pb and Zn) concentration in edibl... more In this study some heavy metals (Cd, Ni, Cr, As, Hg Cu, Fe, Mn, Pb and Zn) concentration in edible parts of five most consumed Bulgarian fish species -bluefish (Pomatomus saltatrix), gray mullet (Mugil cephalus), Mediterranean horse mackerel (Trachurus mediterraneus ponticus), shad (Alosa pontica) and sprat (Sprattus sprattus sulinus) collected from two stations across Bulgarian Black Sea coast were determined. The samples were digested with nitric acid followed by appropriate spectroscopic determination (Atomic Emission Spectroscopy with Inductively Coupled Plasma (AES-ICP), Flame Atomic Absorption Spectroscopy (FAAS) or Electrotermal Atomic Absorption Spectroscopy (ETAAS). The level of As in the edible part of gray mullet (Mugil cephalus) has shown a value higher than limits set from various health organizations (1.1 ± 0.1 mg/kg). On the contrary this fish species accumulates the other investigated heavy metals such as Hg, Zn, Fe and Pb to lower extend. The concentration of Zn and...
Human exposure to As, Cd, Cu, Cr, Mn, Fe, Ni, Zn and Pb through consumption of freshwater fishes ... more Human exposure to As, Cd, Cu, Cr, Mn, Fe, Ni, Zn and Pb through consumption of freshwater fishes (carassius, freshwater bream, common roach and European crap) was estimated by evaluation of target hazard quintet (THQ), target risk (TR), and hazard (HI) indexes. The elements were determined by ICP-OES. The results from this study show that the THQ for the studied toxic and essential microelements are less than one; signified that a daily exposure at this level is unlikely to cause any adverse effects during a person lifetime. Additionally hazard index of each microelement was also lower than one suggesting that these pollutants pose no hazard to local residents. The TR values were between 10 and 10 meaning that there is no important cancer risk associated with the consumption of the examined in the present study fish species.
Vanadium oxide-zirconia catalysts were prepared by impregnation of ZrO2 powder with an aqueous so... more Vanadium oxide-zirconia catalysts were prepared by impregnation of ZrO2 powder with an aqueous solution of NH4VO3. The thermal stability, activity and selectivity of a series of V2O5-ZrO2 catalyst samples towards o-xylene oxidation to phthalic anhydride have been investigated. It has been established that the phthalic anhydride content reaches about 55 mol% in samples containing 7 and 10 wt% V2O5. The physicochemical characterisation of the catalysts prepared was performed using IR spectroscopy, XPS analysis, X-ray spectroscopy, derivatograph analysis, EPR spectroscopy and temperature - programmed reduction.
Spent vanadium oxide catalysts, which are not yet completely exhausted can be utilized as regener... more Spent vanadium oxide catalysts, which are not yet completely exhausted can be utilized as regenerated catalysts. The present paper shows that the acid-extracted V 2 O 5 from partially deactivated vanadium oxide catalysts for o-xylene oxidation is suitable for the synthesis of fresh catalysis samples. The catalytic activity and selectivity have been tested in a laboratory flow apparatus and found to be very close to those of the industrial catalyst.
The thermal stability, activity and selectivity of a series of V2O5-ZrO2 catalyst samples towards... more The thermal stability, activity and selectivity of a series of V2O5-ZrO2 catalyst samples towards o-xylene oxidation to phthalic anhydride have been investigated. It has been established that the phthalic anhydride content yield reaches about 55 mol.% in samples containing 7 and 10 wt.% V2O5. The selectivity of the catalyst with 7 wt.% V2O5-ZrO2 has been compared to that of commercially available V2O5-TiO2 (anatase). The investigations have been performed within two temperature ranges. At low temperatures (below 410°C) the V2O5-TiO2 (anatase) catalyst shows a better selectivity to phthalic anhydride than the V2O5-ZrO2 catalyst does. At high temperatures, the V2O5-ZrO2 catalyst is more selective with respect to the main product of partial oxidation due to the positive effect of the ZrO2 support. Even when the temperature rises up to 550°C and the time of exploitation becomes 50 h, the selectivity of V2O5-ZrO2 decreases slightly and remains above 50 mol.%, whereas with the V2O5-TiO2 (...
The total content of fat soluble vitamins and their percentages in the recommended daily intake f... more The total content of fat soluble vitamins and their percentages in the recommended daily intake for humans per 100 g portion, fatty acids composition, the atherogenic (IA) and thrombogenicity (IT) indices in two freshwater fish species – Common carp (Cyprinus carpio) and European catfish (Sillurus glanis) were investigated. Retinol contents in fresh edible tissues of the Common carp and European catfish were found to be 30.8 ± 3.4 mg/100 g wet weight (ww) for the Common carp 30.8 ± 3.4 µg/100 g ww and 1.9 ± 0.1 µg/100 g ww for the European catfish, cholecalciferol contents 14.8 ± 1.0 and 3.1 ± 0.1 µg/100 g ww, and α-tocopherol contents 2764.5 ± 44.0 and 2182.5 ± 31.5 µg/100 g ww, respectively. The sum of monounsaturated FA accounted for 50.02% (catfish) and 23.15% (carp). Polyunsaturated FA (PUFA) showed a higher level in the carp (36.75%) and a lower one in the catfish (21.64%). Both fishes are good sources of cholecalciferol in terms of the recommended daily intake of vitamins est...
Abstract The changes in industrial vanadium oxide catalysts for the oxidation of sulphur dioxide,... more Abstract The changes in industrial vanadium oxide catalysts for the oxidation of sulphur dioxide, leading to their deactivation have been studied by various chemical and physicochemical methods (chemical and X-ray analysis, IR and Moessbauer spectroscopy etc.). Chemical changes in the active phase and support and the accumulation of catalytic poisons and iron compounds are considered to be more important factors than changes in the catalyst physical properties.
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Quality Assurance and Safety of Crops & Foods, 2013
Persistent organochlorine pollutants like polychlorinated biphenyls (PCBs) and dichloro diphenyl ... more Persistent organochlorine pollutants like polychlorinated biphenyls (PCBs) and dichloro diphenyl trichloroethane residues (DDTs) can still be a problem for the aquatic environment and human health. The levels of DDTs and PCB congeners were determined in fish from the Bulgarian Black Sea coast. Four fish species with different feeding behaviour, goby (Neogobius cephalargoides), sprat (Sprattus sprattus sulinus), horse mackerel (Trachurus Mediterraneus ponticus) and shad (Alosa pontica pontica) were sampled from the Bulgarian Black Sea coast during 2007-2010. The DDT and PCB residues were measured in clean fish extracts by gas chromatography with mass detection. The main metabolite p,p'-dichloro diphenyl dichloroethylene was the most frequently detected compound in all fish species and was present in much higher concentrations than the other DDTs (ranging from 119.32 to 1,324.44 ng/g fat). PCBs were found in all fish species at concentrations ranging between 135.1 ng/g fat in horse mackerel and 990.8 ng/g f...
The wide application of V in the steel-producing industry is based on the strong effect of traces... more The wide application of V in the steel-producing industry is based on the strong effect of traces of V on the properties of Fe alloys. The introduction of 0.15-0.20% V strongly increases the strength, plasticity and wear resistance of the alloys. The aims of the present study were to obtain ferrovanadium from HC1 solutions after precipitation of V followed by
ABSTRACT In spite of a worldwide reduction in the utilization of organochlorine pesticides (OCPs)... more ABSTRACT In spite of a worldwide reduction in the utilization of organochlorine pesticides (OCPs), they are still a problem for the aquatic environment and human health. The Black Sea is still being polluted with persistent chemicals, including OCPs. Aquatic organisms (sprat, scad, bluefish, shad, belted bonito, goby, and black mussel) with different feeding behaviours were sampled on a seasonal basis from the Bulgarian region of the Black Sea, and the concentrations of 13 OCP residues were determined. Although many of the OCPs were not detected in the samples, in all samples 1,1,1-trichloro-2,2-bis(4- chlorophenyl) ethane (DDT) was present mainly in the form of its metabolites 1,1-dichloro-2,2-bis(4-chlorophenyl) ethane (DDD) and 1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene (DDE). Only about 12% of the total DDT was present as the parent compound pp-DDT, which suggests that it was not being used recently in the region. The total DDT concentrations were generally below 150 μgkg−1 fresh weight, but higher levels — up to 354 μgkg−1 fresh weight — were also measured for fish species with a high fat content. Between-species differences were observed, even when the concentrations were presented on a fat-level basis. DDT concentrations did not show any significant changes over the 2-yr sampling period. Fish sampled in the northern areas of the Bulgarian Black Sea coast seemed to contain higher DDT levels than those from the southern areas, suggesting a major (historical) influence of the Danube River. For permanent monitoring purposes, the utility of Black Sea gobies and scad should be considered.
... 2009 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria. V2O5-ZrO2 catalyst for sel... more ... 2009 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria. V2O5-ZrO2 catalyst for selective oxidation of o-xylene to phthalic anhydride: *II. ... Medical University, 55 Marin Drinov St., 9002 Varna, Bulgaria. Received May 15, 2008; Revised January 15, 2009. ...
This study compares the fat soluble components in the muscle and edible skin parts of farmed rain... more This study compares the fat soluble components in the muscle and edible skin parts of farmed rainbow trout (Oncorhynchus mykiss W.) fillets, sampled at two growth stages, from fish markets from Bulgaria. Insufficient information is available about the differential fat soluble pigments, cholesterol, vitamins and fatty acid compositions of rainbow trout fillets when eating them with or without the skin left on. Vitamins A, D3 and E, β-carotene and cholesterol were analyzed simultaneously using HPLC system with UV and FL detection (vitamins A and E). Total lipids were extracted according to Bligh and Dyer method. Analysis of fatty acid methyl esters (FAME) were perform by GC/MS. The average lipid content, the cholesterol and vitamin E amounts and the saturated fatty acids were significantly higher in the skin than in the muscle, whereas the proportion of vitamin A and D3, eicosapentaenoic acid (C20:5 ω-3) and docosahexaenoic acid (C22:6 ω-3) were higher in the muscle.
The environmental monitoring of chemical toxicants has been a widely studied topic in the last fe... more The environmental monitoring of chemical toxicants has been a widely studied topic in the last few decades. The main aim of the present study was to determine the total concentration of nine elements (Cd, Cr, Pb, Ni, Al, Cu, Fe, Mn, and Zn) in the fish species grey mullet (M. cephalus) and in the coastal marine waters collected from various sampling points along the Black Sea (Bulgaria) and the Ionian Sea (Italy). Further, those results were applied to predict the pollution degree in those coastal marine environments. The fish samples were subject to acid digestion followed by appropriate analytical determination. The metal concentrations in marine water samples collected from the Black Sea (Bulgaria) and the Ionian Sea (Italy) were also analyzed. Unpaired Student’s t-test and the one-way ANOVA were applied for the statistical analysis of the data. The statistical results revealed a significant variation (p < 0.0001) in the concentration of various fish tissues. The accumulation ...
In this study some heavy metals (Cd, Ni, Cr, As, Hg Cu, Fe, Mn, Pb and Zn) concentration in edibl... more In this study some heavy metals (Cd, Ni, Cr, As, Hg Cu, Fe, Mn, Pb and Zn) concentration in edible parts of five most consumed Bulgarian fish species -bluefish (Pomatomus saltatrix), gray mullet (Mugil cephalus), Mediterranean horse mackerel (Trachurus mediterraneus ponticus), shad (Alosa pontica) and sprat (Sprattus sprattus sulinus) collected from two stations across Bulgarian Black Sea coast were determined. The samples were digested with nitric acid followed by appropriate spectroscopic determination (Atomic Emission Spectroscopy with Inductively Coupled Plasma (AES-ICP), Flame Atomic Absorption Spectroscopy (FAAS) or Electrotermal Atomic Absorption Spectroscopy (ETAAS). The level of As in the edible part of gray mullet (Mugil cephalus) has shown a value higher than limits set from various health organizations (1.1 ± 0.1 mg/kg). On the contrary this fish species accumulates the other investigated heavy metals such as Hg, Zn, Fe and Pb to lower extend. The concentration of Zn and...
Human exposure to As, Cd, Cu, Cr, Mn, Fe, Ni, Zn and Pb through consumption of freshwater fishes ... more Human exposure to As, Cd, Cu, Cr, Mn, Fe, Ni, Zn and Pb through consumption of freshwater fishes (carassius, freshwater bream, common roach and European crap) was estimated by evaluation of target hazard quintet (THQ), target risk (TR), and hazard (HI) indexes. The elements were determined by ICP-OES. The results from this study show that the THQ for the studied toxic and essential microelements are less than one; signified that a daily exposure at this level is unlikely to cause any adverse effects during a person lifetime. Additionally hazard index of each microelement was also lower than one suggesting that these pollutants pose no hazard to local residents. The TR values were between 10 and 10 meaning that there is no important cancer risk associated with the consumption of the examined in the present study fish species.
Vanadium oxide-zirconia catalysts were prepared by impregnation of ZrO2 powder with an aqueous so... more Vanadium oxide-zirconia catalysts were prepared by impregnation of ZrO2 powder with an aqueous solution of NH4VO3. The thermal stability, activity and selectivity of a series of V2O5-ZrO2 catalyst samples towards o-xylene oxidation to phthalic anhydride have been investigated. It has been established that the phthalic anhydride content reaches about 55 mol% in samples containing 7 and 10 wt% V2O5. The physicochemical characterisation of the catalysts prepared was performed using IR spectroscopy, XPS analysis, X-ray spectroscopy, derivatograph analysis, EPR spectroscopy and temperature - programmed reduction.
Spent vanadium oxide catalysts, which are not yet completely exhausted can be utilized as regener... more Spent vanadium oxide catalysts, which are not yet completely exhausted can be utilized as regenerated catalysts. The present paper shows that the acid-extracted V 2 O 5 from partially deactivated vanadium oxide catalysts for o-xylene oxidation is suitable for the synthesis of fresh catalysis samples. The catalytic activity and selectivity have been tested in a laboratory flow apparatus and found to be very close to those of the industrial catalyst.
The thermal stability, activity and selectivity of a series of V2O5-ZrO2 catalyst samples towards... more The thermal stability, activity and selectivity of a series of V2O5-ZrO2 catalyst samples towards o-xylene oxidation to phthalic anhydride have been investigated. It has been established that the phthalic anhydride content yield reaches about 55 mol.% in samples containing 7 and 10 wt.% V2O5. The selectivity of the catalyst with 7 wt.% V2O5-ZrO2 has been compared to that of commercially available V2O5-TiO2 (anatase). The investigations have been performed within two temperature ranges. At low temperatures (below 410°C) the V2O5-TiO2 (anatase) catalyst shows a better selectivity to phthalic anhydride than the V2O5-ZrO2 catalyst does. At high temperatures, the V2O5-ZrO2 catalyst is more selective with respect to the main product of partial oxidation due to the positive effect of the ZrO2 support. Even when the temperature rises up to 550°C and the time of exploitation becomes 50 h, the selectivity of V2O5-ZrO2 decreases slightly and remains above 50 mol.%, whereas with the V2O5-TiO2 (...
The total content of fat soluble vitamins and their percentages in the recommended daily intake f... more The total content of fat soluble vitamins and their percentages in the recommended daily intake for humans per 100 g portion, fatty acids composition, the atherogenic (IA) and thrombogenicity (IT) indices in two freshwater fish species – Common carp (Cyprinus carpio) and European catfish (Sillurus glanis) were investigated. Retinol contents in fresh edible tissues of the Common carp and European catfish were found to be 30.8 ± 3.4 mg/100 g wet weight (ww) for the Common carp 30.8 ± 3.4 µg/100 g ww and 1.9 ± 0.1 µg/100 g ww for the European catfish, cholecalciferol contents 14.8 ± 1.0 and 3.1 ± 0.1 µg/100 g ww, and α-tocopherol contents 2764.5 ± 44.0 and 2182.5 ± 31.5 µg/100 g ww, respectively. The sum of monounsaturated FA accounted for 50.02% (catfish) and 23.15% (carp). Polyunsaturated FA (PUFA) showed a higher level in the carp (36.75%) and a lower one in the catfish (21.64%). Both fishes are good sources of cholecalciferol in terms of the recommended daily intake of vitamins est...
Abstract The changes in industrial vanadium oxide catalysts for the oxidation of sulphur dioxide,... more Abstract The changes in industrial vanadium oxide catalysts for the oxidation of sulphur dioxide, leading to their deactivation have been studied by various chemical and physicochemical methods (chemical and X-ray analysis, IR and Moessbauer spectroscopy etc.). Chemical changes in the active phase and support and the accumulation of catalytic poisons and iron compounds are considered to be more important factors than changes in the catalyst physical properties.
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Quality Assurance and Safety of Crops & Foods, 2013
Persistent organochlorine pollutants like polychlorinated biphenyls (PCBs) and dichloro diphenyl ... more Persistent organochlorine pollutants like polychlorinated biphenyls (PCBs) and dichloro diphenyl trichloroethane residues (DDTs) can still be a problem for the aquatic environment and human health. The levels of DDTs and PCB congeners were determined in fish from the Bulgarian Black Sea coast. Four fish species with different feeding behaviour, goby (Neogobius cephalargoides), sprat (Sprattus sprattus sulinus), horse mackerel (Trachurus Mediterraneus ponticus) and shad (Alosa pontica pontica) were sampled from the Bulgarian Black Sea coast during 2007-2010. The DDT and PCB residues were measured in clean fish extracts by gas chromatography with mass detection. The main metabolite p,p'-dichloro diphenyl dichloroethylene was the most frequently detected compound in all fish species and was present in much higher concentrations than the other DDTs (ranging from 119.32 to 1,324.44 ng/g fat). PCBs were found in all fish species at concentrations ranging between 135.1 ng/g fat in horse mackerel and 990.8 ng/g f...
The wide application of V in the steel-producing industry is based on the strong effect of traces... more The wide application of V in the steel-producing industry is based on the strong effect of traces of V on the properties of Fe alloys. The introduction of 0.15-0.20% V strongly increases the strength, plasticity and wear resistance of the alloys. The aims of the present study were to obtain ferrovanadium from HC1 solutions after precipitation of V followed by
ABSTRACT In spite of a worldwide reduction in the utilization of organochlorine pesticides (OCPs)... more ABSTRACT In spite of a worldwide reduction in the utilization of organochlorine pesticides (OCPs), they are still a problem for the aquatic environment and human health. The Black Sea is still being polluted with persistent chemicals, including OCPs. Aquatic organisms (sprat, scad, bluefish, shad, belted bonito, goby, and black mussel) with different feeding behaviours were sampled on a seasonal basis from the Bulgarian region of the Black Sea, and the concentrations of 13 OCP residues were determined. Although many of the OCPs were not detected in the samples, in all samples 1,1,1-trichloro-2,2-bis(4- chlorophenyl) ethane (DDT) was present mainly in the form of its metabolites 1,1-dichloro-2,2-bis(4-chlorophenyl) ethane (DDD) and 1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene (DDE). Only about 12% of the total DDT was present as the parent compound pp-DDT, which suggests that it was not being used recently in the region. The total DDT concentrations were generally below 150 μgkg−1 fresh weight, but higher levels — up to 354 μgkg−1 fresh weight — were also measured for fish species with a high fat content. Between-species differences were observed, even when the concentrations were presented on a fat-level basis. DDT concentrations did not show any significant changes over the 2-yr sampling period. Fish sampled in the northern areas of the Bulgarian Black Sea coast seemed to contain higher DDT levels than those from the southern areas, suggesting a major (historical) influence of the Danube River. For permanent monitoring purposes, the utility of Black Sea gobies and scad should be considered.
... 2009 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria. V2O5-ZrO2 catalyst for sel... more ... 2009 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria. V2O5-ZrO2 catalyst for selective oxidation of o-xylene to phthalic anhydride: *II. ... Medical University, 55 Marin Drinov St., 9002 Varna, Bulgaria. Received May 15, 2008; Revised January 15, 2009. ...
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