Surface sediments were collected from Lake Manzala, the Mediterranean coastal wetland located to the east of the Nile Delta, Egypt, to assess the effect of drain effluent on the spatial variations of sedimentary chara...Surface sediments were collected from Lake Manzala, the Mediterranean coastal wetland located to the east of the Nile Delta, Egypt, to assess the effect of drain effluent on the spatial variations of sedimentary characteristics and heavy metal pollution. Grain-size compositions, textures, and heavy metal distribution patterns in sediments are presented using GIS technique. Results of the analysis of the sediment showed a clear effect of drain effluent, with an increase in fine fractions and homogeneous suspensions in transportation mode. Lake sediments were dominated by sandy mud textures, and mode of transportation was homogeneous sus- pension and rolling. Spatial distribution of heavy metals (Fe, Mn, Zn, Cu, Ni, Cr, and Pb) was studied in the lake’s surficial sediments, along with their relationship to drain effluent and their contamination status in the ecological system. Heavy metal pollution status was assessed by means of accepted sediment quality guidelines and contamination assessment methods (contamination factor, con- tamination degree, modified contamination degree, geo-accumulation, and enrichment factor). Among the determined heavy metals, Pb had the most ecological risk. Generally, the heavy metals in the surface sediments indicated pollution risk ranging from moderate to considerable, particularly, in those sites facing drains and inlets that had the highest toxic effluent. The results were interpreted by statistical means. A cluster analysis defined areas facing drain discharge and inlets as separated groups. ANOVA indicated that most of the sedimentation and studied metals directed this clustering.展开更多
Contamination with heavy metals is one of the most serious problems in the aquatic environments. In Egypt, Manzala Lake is suffering from this problem. The objective of this work was to assess heavy metals pollutants ...Contamination with heavy metals is one of the most serious problems in the aquatic environments. In Egypt, Manzala Lake is suffering from this problem. The objective of this work was to assess heavy metals pollutants and their spatial distribution in Manzala Lake using GIS technique. Georeferenced water and sediment samples were randomly collected from the lake. The detected heavy metals were: Fe, Pb, Cu, Cd, Cr, Zn and Co. The obtained results indicated that the highest concentrations of heavy metals were observed in the northeastern and the southern parts of the lake nearby drains. This could be attributed to industrial, agricultural and municipal wastes coming through the drains especially Bahr El-Baqar drain and the industrial wastes coming from Port Said drains. From the geo-accumulation index, it was noticed that the lake is more polluted with cadmium and lead in the hydrosoils samples. All metals in water are within the EPA standard limit except for cadmium. Geostatistics provides effective methods to quantify the contaminated waters and sediments which support decision-making about redevelopment scenarios or remediation techniques.展开更多
The African catfish, Clarias gariepinus, is generally considered to be one of the most important tropical catfish species for aquaculture purposes. Parasitological investigation was performed in two hundred naturally ...The African catfish, Clarias gariepinus, is generally considered to be one of the most important tropical catfish species for aquaculture purposes. Parasitological investigation was performed in two hundred naturally collected fish samples during the period of February to December 2014. The prevalence of gastrointestinal helminth parasites infecting C. gariepinus was investigated. A total of 249 helminth parasites belonging to four genera were recovered from 130 (65%) examined fish samples. They were digenea Orientocreadium batrachoides, cestode Polyonchobothrium clariae, and nematode Procamallanus laevionchus and Camallanus polypteri. Majority of the recorded parasites were found in the intestine. Female fish samples had higher prevalence rate 72 (90%) than males 58 (48.33%), and there was no significant difference (P > 0.05) in infestation rate between the two sexes. The relationship of host size (weight/length) and parasite infection showed that there was no significant difference in the parasitic infection among three classes, although fish of larger sizes had more infections. In addition, this study determines the effect of fish age on the prevalence and intensity of gastrointestinal parasites.展开更多
文摘Surface sediments were collected from Lake Manzala, the Mediterranean coastal wetland located to the east of the Nile Delta, Egypt, to assess the effect of drain effluent on the spatial variations of sedimentary characteristics and heavy metal pollution. Grain-size compositions, textures, and heavy metal distribution patterns in sediments are presented using GIS technique. Results of the analysis of the sediment showed a clear effect of drain effluent, with an increase in fine fractions and homogeneous suspensions in transportation mode. Lake sediments were dominated by sandy mud textures, and mode of transportation was homogeneous sus- pension and rolling. Spatial distribution of heavy metals (Fe, Mn, Zn, Cu, Ni, Cr, and Pb) was studied in the lake’s surficial sediments, along with their relationship to drain effluent and their contamination status in the ecological system. Heavy metal pollution status was assessed by means of accepted sediment quality guidelines and contamination assessment methods (contamination factor, con- tamination degree, modified contamination degree, geo-accumulation, and enrichment factor). Among the determined heavy metals, Pb had the most ecological risk. Generally, the heavy metals in the surface sediments indicated pollution risk ranging from moderate to considerable, particularly, in those sites facing drains and inlets that had the highest toxic effluent. The results were interpreted by statistical means. A cluster analysis defined areas facing drain discharge and inlets as separated groups. ANOVA indicated that most of the sedimentation and studied metals directed this clustering.
文摘Contamination with heavy metals is one of the most serious problems in the aquatic environments. In Egypt, Manzala Lake is suffering from this problem. The objective of this work was to assess heavy metals pollutants and their spatial distribution in Manzala Lake using GIS technique. Georeferenced water and sediment samples were randomly collected from the lake. The detected heavy metals were: Fe, Pb, Cu, Cd, Cr, Zn and Co. The obtained results indicated that the highest concentrations of heavy metals were observed in the northeastern and the southern parts of the lake nearby drains. This could be attributed to industrial, agricultural and municipal wastes coming through the drains especially Bahr El-Baqar drain and the industrial wastes coming from Port Said drains. From the geo-accumulation index, it was noticed that the lake is more polluted with cadmium and lead in the hydrosoils samples. All metals in water are within the EPA standard limit except for cadmium. Geostatistics provides effective methods to quantify the contaminated waters and sediments which support decision-making about redevelopment scenarios or remediation techniques.
文摘The African catfish, Clarias gariepinus, is generally considered to be one of the most important tropical catfish species for aquaculture purposes. Parasitological investigation was performed in two hundred naturally collected fish samples during the period of February to December 2014. The prevalence of gastrointestinal helminth parasites infecting C. gariepinus was investigated. A total of 249 helminth parasites belonging to four genera were recovered from 130 (65%) examined fish samples. They were digenea Orientocreadium batrachoides, cestode Polyonchobothrium clariae, and nematode Procamallanus laevionchus and Camallanus polypteri. Majority of the recorded parasites were found in the intestine. Female fish samples had higher prevalence rate 72 (90%) than males 58 (48.33%), and there was no significant difference (P > 0.05) in infestation rate between the two sexes. The relationship of host size (weight/length) and parasite infection showed that there was no significant difference in the parasitic infection among three classes, although fish of larger sizes had more infections. In addition, this study determines the effect of fish age on the prevalence and intensity of gastrointestinal parasites.
