Department of Marine Pollution

The corrosion inhibition efficiencies of some triazole, oxadiazole and thiadiazole derivatives for steel in presence of acidic medium have been studied by using AM1, PM3, MINDO/3 and MNDO semi-empirical SCF molecular orbital methods. Geometric structures, total negative charge on the molecule (TNC), highest occupied molecular energy level (EHOMO), lowest unoccupied molecular energy level (ELUMO), core–core repulsion (CCR), dipole moment (μ) and linear solvation energy terms, molecular volume (Vi) and dipolar-polarization (π*), were correlated to corrosion inhibition efficiency. Four equations were proposed to calculate corrosion inhibition efficiency. The agreement with the experimental data was found to be satisfactory; the standard deviations between the calculated and experimental results ranged between ±0.03 and ±4.18. The inhibition efficiency was closely related to orbital energies (EHOMO and ELUMO) and μ. The correlation between quantum parameters and experimental inhibition efficiency has been validated by single point calculations for the semi-empirical AM1 structures using B3LYP/6-31G** as a higher level of theory. The proposed equations were applied to predict the corrosion inhibition efficiency of some related structures to select molecules of possible activity from a presumable library of compounds.

Biosorption of heavy metals can be an effective process for the removal of toxic chromium ions from wastewater. In this study, the batch removal of toxic hexavalent chromium ions from aqueous solution, saline water and wastewater using marine dried green alga Ulva lactuca was investigated. Activated carbon prepared from U. lactuca by acid decomposition was also used for the removal of chromium from aqueous solution, saline water and wastewater. The chromium uptake was dependent on the initial pH and the initial chromium concentration, with pH ∼1.0, being the optimum pH value. Langmuir, Freundlich, Redlich-Peterson and Koble-Corrigan isotherm models were fitted well the equilibrium data for both sorbents. The maximum efficiencies of chromium removal were 92 and 98% for U. lactuca and its activated carbon, respectively. The maximum adsorption capacity was found to be 10.61 and 112.36 mg g −1 for dried green alga and activated carbon developed from it, respectively. The adsorption capacities of U. lactuca and its activated carbon were independent on the type of solution containing toxic chromium and the efficiency of removal was not affected by the replacing of aqueous solution by saline water or wastewater containing the same chromium concentration. Two hours were necessary to reach the sorption equilibrium. The chromium uptake by U. lactuca and its activated carbon form were best described by pseudo second-order rate model. This study verifies the possibility of using inactivated marine green alga U. lactuca and its activated carbon as valuable material for the removal of chromium from aqueous solutions, saline water or wastewater.

The corrosion inhibition efficiencies of some triazole, oxadiazole and thiadiazole derivatives for steel in presence of acidic medium have been studied by using AM1, PM3, MINDO/3 and MNDO semi-empirical SCF molecular orbital methods. Geometric structures, total negative charge on the molecule (TNC), highest occupied molecular energy level (E HOMO ), lowest unoccupied molecular energy level (E LUMO ), core-core repulsion (CCR), dipole moment (µ) and linear solvation energy terms, molecular volume (V i ) and dipolar-polarization (π * ), were correlated to corrosion inhibition efficiency. Four equations were proposed to calculate corrosion inhibition efficiency. The agreement with the experimental data was found to be satisfactory; the standard deviations between the calculated and experimental results ranged between ±0.03 and ±4.18. The inhibition efficiency was closely related to orbital energies (E HOMO and E LUMO ) and µ. The correlation between quantum parameters and experimental inhibition efficiency has been validated by single point calculations for the semi-empirical AM1 structures using B3LYP/6-31G ** as a higher level of theory. The proposed equations were applied to predict the corrosion inhibition efficiency of some related structures to select molecules of possible activity from a presumable library of compounds.

The concentrations of nine heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pd and Zn) in the labile and total fractions of muddy and sandy sediment samples collected from twelve sites in Suez Gulf during April 1999 were studied to evaluate the pollution status of the Suez Gulf. The enrichment factors (EF) for each element were calculated. There are extremely high concentrations of Cd, Ni, Pb and slightly concentration of Cr and Cu in both muddy and sandy sediments. The concentration of Zn was moderately high and can be considered as seriously contaminate Metal pollution index (MPI) shows high values ranged between 46 to 156 and 40 to 232 for both sandy and muddy sediments, respectively. Concentrations of heavy metals were normalized against iron for total fraction in both of sandy and muddy sediments. Principal component analysis (PCA) was studied on the data matrix obtained and represented three-factor model explaining 92.22% for labile and 88.82% for total fractions of muddy sediment. The main source of contamination is the offshore oil fields and industrial wastes. This is largely a result of ineffective and inefficient operation equipment, illegal discharge of dirty ballast water from tankers and lack of supervision and prosecution of offenders.

The residues of seven polycyclic aromatic hydrocarbons (PAHs) pollutants in microlayer and subsurface seawater samples collected from Alexandria coast, Egypt, were analyzed by gas chromatography-electron-impact mass spectrometry-selected ion monitoring mode (GC-MS-SIM). The pollutants studied were, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene and benzo[a]pyrene. Total PAH levels in microlayer ranged from 103 to 523 ng/l, while it ranged in subsurface samples from 13 to 120 ng/l. The Western Harbor location recorded the highest level of PAHs pollutant over all the other location for both subsurface and microlayer waters. The two major PAHs in microlayer water at the Western Harbor were fluorene and phenanthrene, making up 27% and 20% of the total PAHs, while the two major PAHs in subsurface water at the Eastern Harbor were phenanthrene and fluoranthene recording up 21% each of the total PAHs. The total PAH levels were generally in the nano-gram per liter for microlayer and subsurface seawater samples. The dominant PAHs in both subsurface and microlayer samples were fluoranthene, pyrene and benzo[a]pyrene. The microlayer enrichment factor at AlexandriaÕs Mediterranean coast was ranged from 29 for fluorene to 3 for phenanthrene and benzo[a]pyrene which showed PAHs concentration in the microlayer with an average of five times more than the total PAH in the subsurface samples.

The residues of 17 organochlorine pollutants were analyzed in bivalve Brachiodontes sp. collected from 11 different locations in April 2000 along the Egyptian Red Sea coast. The pollutants studied were 10 individual polychlorinated biphenyl (PCB) congeners, a,a,a-hexachlorocyclohexane (HCHs), cyclodienes (heptachlor, heptachlorepoxide, aldrin, dieldrin) and dichlorodiphenyltrichloroethanes (DDTs) (p,p 0 -DDE, p,p 0 -DDD and p,p 0 -DDT). The concentration of total DDTs ranged between 125 and 772 ng/g of wet weight whereas the concentration of the PCBs, HCHs and cyclodienes ranged from 6.7 to 66.4 ng/g; 16.2 to 183.4 ng/g and 8.8 to 221.6 ng/g of wet weight, respectively. The levels are low to moderate in relation to the published data from other coastal areas. The present results indicate low to moderate PCBs and pesticides contamination in the investigated mussels except DDTs.

The purpose of this study is to suggest an efficient process, which does not require a huge investment for the removal of direct dye from wastewater. Activated carbon developed from agricultural waste material was characterized and utilized for the removal of Direct Navy Blue 106 (DNB-106) from wastewater. Systematic studies on DNB-106 adsorption equilibrium and kinetics by low-cost activated carbons were carried out. Adsorption studies were carried out at different initial concentrations of DNB-106 (50, 75, 100, 125 and 150 mg l −1 ), contact time (5-180 min), pH (2.0, 3.0, 4.7, 6.3, 7.2, 8.0, 10.3 and 12.7) and sorbent doses (2.0, 4.0 and 6.0 g l −1 ). Both Langmuir and Freundlich models fitted the adsorption data quite reasonably (R 2 > 97). The maximum adsorption capacity was 107.53 mg g −1 for 150 mg l −1 of DNB-106 concentration and 2 g l −1 carbon concentration. Various mechanisms were established for DNB-106 adsorption on developed adsorbents. The kinetic studies were conducted to delineate the effect of initial dye concentration, contact time and solid to liquid concentration. The developed carbon might be successfully used for the removal of DNB-106 from liquid industrial wastes.

The use of low-cost and eco-friendly adsorbents has been investigated as an ideal alternative to the current expensive methods of removing dyes from wastewater. Orange peel was collected from the local fields of orange trees and converted into a low-cost adsorbent. The present study deals with the removal of textile dyes from artificial textile dye effluent by activated carbons developed from orange peel. Direct Yellow 12 (DY-12) was used as the model compound due to its wide range of applications and high stability in the environment. The maximum removal was 96% for 125 mg l !1 of DY-12 concentration on 5 g l -1 carbon concentration. The effect of initial dye concentration (25-125 mg l !1 ), pH, contact time, and concentration of orange peel carbon (2.5-10.0 g l !1 ) have been studied at 27±2ºC. Several isotherm models, Langmuir, Freundlich, Koble-Corrigan, Redlich-Peterson, Tempkin, Dubinin-Radushkevich and generalized isotherm equations, were investigated and all of them were in good agreement with the experimental data except Redlich-Peterson. The results indicate that acidic pH (1.5) supported the adsorption of DY-12 on activated carbon developed from orange peel. Furthermore, adsorption kinetics of DY-12 was studied and the rate of sorption was found to conform to pseudo-second-order kinetics with correlation coefficients equal unity under all studied conditions. The maximum adsorption capacity calculated from the Langmuir isotherm model was 75.76 mg g !1 . The activated carbon obtained from orange peel via acid decomposition has been found to be an efficient material for dye removal from artificial textile dye effluent owing to its very low cost.

Ten organochlorine compounds were analyzed in four species of fish (Bouri Mugil spp., Denis Sparus auratus, Moza Boops boops and Mousa Pegusa lascaris), from four Egyptian governorates (South Sinai, Suez, Port-Said and Demietta). Although all fish studied are bottom or near-bottom feeders, remarkable variations between studied species were noticed. The grand total values recorded at the studied governorates were in descending order: Bouri > Denis > Moza > Mousa. The highest concentration of pesticides was recorded in Demietta governorate fish (20-211 ng/g of wet weight) and the p,p 0 -DDE dominated over the other p,p 0 -isomers in all studied fish, while dieldrin was the dominated in the studied cyclodiene compounds. However, hexachlorobenzene (HCB) occurred at all studied governorate fish except Mousa fish from South Sinai. Toxaphene was detected only in fish (Bouri, Denis, and Mousa) from Demietta governorate. Chlordane was not detected in any studied fish. The level of organochlorine pesticides contamination in fish from the studied governorates is relatively low and should not pose a health risk to consumers.

The corrosion inhibition efficiencies of some triazole, oxadiazole and thiadiazole derivatives for steel in presence of acidic medium have been studied by using AM1, PM3, MINDO/3 and MNDO semi-empirical SCF molecular orbital methods. Geometric structures, total negative charge on the molecule (TNC), highest occupied molecular energy level (EHOMO), lowest unoccupied molecular energy level (ELUMO), core–core repulsion (CCR), dipole moment (μ) and linear solvation energy terms, molecular volume (Vi) and dipolar-polarization (π*), were correlated to corrosion inhibition efficiency. Four equations were proposed to calculate corrosion inhibition efficiency. The agreement with the experimental data was found to be satisfactory; the standard deviations between the calculated and experimental results ranged between ±0.03 and ±4.18. The inhibition efficiency was closely related to orbital energies (EHOMO and ELUMO) and μ. The correlation between quantum parameters and experimental inhibition efficiency has been validated by single point calculations for the semi-empirical AM1 structures using B3LYP/6-31G** as a higher level of theory. The proposed equations were applied to predict the corrosion inhibition efficiency of some related structures to select molecules of possible activity from a presumable library of compounds.

Biosorption of heavy metals can be an effective process for the removal of toxic chromium ions from wastewater. In this study, the batch removal of toxic hexavalent chromium ions from aqueous solution, saline water and wastewater using marine dried green alga Ulva lactuca was investigated. Activated carbon prepared from U. lactuca by acid decomposition was also used for the removal of chromium from aqueous solution, saline water and wastewater. The chromium uptake was dependent on the initial pH and the initial chromium concentration, with pH ∼1.0, being the optimum pH value. Langmuir, Freundlich, Redlich-Peterson and Koble-Corrigan isotherm models were fitted well the equilibrium data for both sorbents. The maximum efficiencies of chromium removal were 92 and 98% for U. lactuca and its activated carbon, respectively. The maximum adsorption capacity was found to be 10.61 and 112.36 mg g −1 for dried green alga and activated carbon developed from it, respectively. The adsorption capacities of U. lactuca and its activated carbon were independent on the type of solution containing toxic chromium and the efficiency of removal was not affected by the replacing of aqueous solution by saline water or wastewater containing the same chromium concentration. Two hours were necessary to reach the sorption equilibrium. The chromium uptake by U. lactuca and its activated carbon form were best described by pseudo second-order rate model. This study verifies the possibility of using inactivated marine green alga U. lactuca and its activated carbon as valuable material for the removal of chromium from aqueous solutions, saline water or wastewater.

The corrosion inhibition efficiencies of some triazole, oxadiazole and thiadiazole derivatives for steel in presence of acidic medium have been studied by using AM1, PM3, MINDO/3 and MNDO semi-empirical SCF molecular orbital methods. Geometric structures, total negative charge on the molecule (TNC), highest occupied molecular energy level (E HOMO ), lowest unoccupied molecular energy level (E LUMO ), core-core repulsion (CCR), dipole moment (µ) and linear solvation energy terms, molecular volume (V i ) and dipolar-polarization (π * ), were correlated to corrosion inhibition efficiency. Four equations were proposed to calculate corrosion inhibition efficiency. The agreement with the experimental data was found to be satisfactory; the standard deviations between the calculated and experimental results ranged between ±0.03 and ±4.18. The inhibition efficiency was closely related to orbital energies (E HOMO and E LUMO ) and µ. The correlation between quantum parameters and experimental inhibition efficiency has been validated by single point calculations for the semi-empirical AM1 structures using B3LYP/6-31G ** as a higher level of theory. The proposed equations were applied to predict the corrosion inhibition efficiency of some related structures to select molecules of possible activity from a presumable library of compounds.

The concentrations of nine heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pd and Zn) in the labile and total fractions of muddy and sandy sediment samples collected from twelve sites in Suez Gulf during April 1999 were studied to evaluate the pollution status of the Suez Gulf. The enrichment factors (EF) for each element were calculated. There are extremely high concentrations of Cd, Ni, Pb and slightly concentration of Cr and Cu in both muddy and sandy sediments. The concentration of Zn was moderately high and can be considered as seriously contaminate Metal pollution index (MPI) shows high values ranged between 46 to 156 and 40 to 232 for both sandy and muddy sediments, respectively. Concentrations of heavy metals were normalized against iron for total fraction in both of sandy and muddy sediments. Principal component analysis (PCA) was studied on the data matrix obtained and represented three-factor model explaining 92.22% for labile and 88.82% for total fractions of muddy sediment. The main source of contamination is the offshore oil fields and industrial wastes. This is largely a result of ineffective and inefficient operation equipment, illegal discharge of dirty ballast water from tankers and lack of supervision and prosecution of offenders.

The residues of seven polycyclic aromatic hydrocarbons (PAHs) pollutants in microlayer and subsurface seawater samples collected from Alexandria coast, Egypt, were analyzed by gas chromatography-electron-impact mass spectrometry-selected ion monitoring mode (GC-MS-SIM). The pollutants studied were, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene and benzo[a]pyrene. Total PAH levels in microlayer ranged from 103 to 523 ng/l, while it ranged in subsurface samples from 13 to 120 ng/l. The Western Harbor location recorded the highest level of PAHs pollutant over all the other location for both subsurface and microlayer waters. The two major PAHs in microlayer water at the Western Harbor were fluorene and phenanthrene, making up 27% and 20% of the total PAHs, while the two major PAHs in subsurface water at the Eastern Harbor were phenanthrene and fluoranthene recording up 21% each of the total PAHs. The total PAH levels were generally in the nano-gram per liter for microlayer and subsurface seawater samples. The dominant PAHs in both subsurface and microlayer samples were fluoranthene, pyrene and benzo[a]pyrene. The microlayer enrichment factor at AlexandriaÕs Mediterranean coast was ranged from 29 for fluorene to 3 for phenanthrene and benzo[a]pyrene which showed PAHs concentration in the microlayer with an average of five times more than the total PAH in the subsurface samples.

The residues of 17 organochlorine pollutants were analyzed in bivalve Brachiodontes sp. collected from 11 different locations in April 2000 along the Egyptian Red Sea coast. The pollutants studied were 10 individual polychlorinated biphenyl (PCB) congeners, a,a,a-hexachlorocyclohexane (HCHs), cyclodienes (heptachlor, heptachlorepoxide, aldrin, dieldrin) and dichlorodiphenyltrichloroethanes (DDTs) (p,p 0 -DDE, p,p 0 -DDD and p,p 0 -DDT). The concentration of total DDTs ranged between 125 and 772 ng/g of wet weight whereas the concentration of the PCBs, HCHs and cyclodienes ranged from 6.7 to 66.4 ng/g; 16.2 to 183.4 ng/g and 8.8 to 221.6 ng/g of wet weight, respectively. The levels are low to moderate in relation to the published data from other coastal areas. The present results indicate low to moderate PCBs and pesticides contamination in the investigated mussels except DDTs.

The purpose of this study is to suggest an efficient process, which does not require a huge investment for the removal of direct dye from wastewater. Activated carbon developed from agricultural waste material was characterized and utilized for the removal of Direct Navy Blue 106 (DNB-106) from wastewater. Systematic studies on DNB-106 adsorption equilibrium and kinetics by low-cost activated carbons were carried out. Adsorption studies were carried out at different initial concentrations of DNB-106 (50, 75, 100, 125 and 150 mg l −1 ), contact time (5-180 min), pH (2.0, 3.0, 4.7, 6.3, 7.2, 8.0, 10.3 and 12.7) and sorbent doses (2.0, 4.0 and 6.0 g l −1 ). Both Langmuir and Freundlich models fitted the adsorption data quite reasonably (R 2 > 97). The maximum adsorption capacity was 107.53 mg g −1 for 150 mg l −1 of DNB-106 concentration and 2 g l −1 carbon concentration. Various mechanisms were established for DNB-106 adsorption on developed adsorbents. The kinetic studies were conducted to delineate the effect of initial dye concentration, contact time and solid to liquid concentration. The developed carbon might be successfully used for the removal of DNB-106 from liquid industrial wastes.

The use of low-cost and eco-friendly adsorbents has been investigated as an ideal alternative to the current expensive methods of removing dyes from wastewater. Orange peel was collected from the local fields of orange trees and converted into a low-cost adsorbent. The present study deals with the removal of textile dyes from artificial textile dye effluent by activated carbons developed from orange peel. Direct Yellow 12 (DY-12) was used as the model compound due to its wide range of applications and high stability in the environment. The maximum removal was 96% for 125 mg l !1 of DY-12 concentration on 5 g l -1 carbon concentration. The effect of initial dye concentration (25-125 mg l !1 ), pH, contact time, and concentration of orange peel carbon (2.5-10.0 g l !1 ) have been studied at 27±2ºC. Several isotherm models, Langmuir, Freundlich, Koble-Corrigan, Redlich-Peterson, Tempkin, Dubinin-Radushkevich and generalized isotherm equations, were investigated and all of them were in good agreement with the experimental data except Redlich-Peterson. The results indicate that acidic pH (1.5) supported the adsorption of DY-12 on activated carbon developed from orange peel. Furthermore, adsorption kinetics of DY-12 was studied and the rate of sorption was found to conform to pseudo-second-order kinetics with correlation coefficients equal unity under all studied conditions. The maximum adsorption capacity calculated from the Langmuir isotherm model was 75.76 mg g !1 . The activated carbon obtained from orange peel via acid decomposition has been found to be an efficient material for dye removal from artificial textile dye effluent owing to its very low cost.

Ten organochlorine compounds were analyzed in four species of fish (Bouri Mugil spp., Denis Sparus auratus, Moza Boops boops and Mousa Pegusa lascaris), from four Egyptian governorates (South Sinai, Suez, Port-Said and Demietta). Although all fish studied are bottom or near-bottom feeders, remarkable variations between studied species were noticed. The grand total values recorded at the studied governorates were in descending order: Bouri > Denis > Moza > Mousa. The highest concentration of pesticides was recorded in Demietta governorate fish (20-211 ng/g of wet weight) and the p,p 0 -DDE dominated over the other p,p 0 -isomers in all studied fish, while dieldrin was the dominated in the studied cyclodiene compounds. However, hexachlorobenzene (HCB) occurred at all studied governorate fish except Mousa fish from South Sinai. Toxaphene was detected only in fish (Bouri, Denis, and Mousa) from Demietta governorate. Chlordane was not detected in any studied fish. The level of organochlorine pesticides contamination in fish from the studied governorates is relatively low and should not pose a health risk to consumers.

ABSTRACT The concentrations of certain heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pd and Zn) in the total and labile fractions of muddy sediment samples collected from eleven sites in Lake Burullus in January 2003 were investigated in order to evaluate the pollution status of the Lake. The metal contents were determined by means of Atomic Absorption Spectrophotometer (AAS) using MESS-2 certified reference material (National Research Council of Canada).