Page 1. Carbaryl Adsorption on Calcium-Bentonite and Soils1 MI ALY, N. BAKRY, F. KISHK, AND AH EL... more Page 1. Carbaryl Adsorption on Calcium-Bentonite and Soils1 MI ALY, N. BAKRY, F. KISHK, AND AH EL-SEBAE2 ABSTRACT Adsorption of carbaryl on Ca-bentonite, and two Egyptian soils, a Nile alluvial and a highly calcareous soil, was carried out at different temperatures. ...
Abstract- Soil vermiculite clays of varying tetrahedral nd octahedral composition and cation exch... more Abstract- Soil vermiculite clays of varying tetrahedral nd octahedral composition and cation exchange capacity (CEC) were examined for their ability to fix K § in both the wet and dry states. Fixation capacity, expressed as per cent of the CEC, in the wet state was fairly high for most samples but it was enhanced greatly upon drying the K saturated samples. This enhancement indicated that each sample contained a number of vermiculite species with different CECs. The vermiculite clays, as a group, exhibited a much higher fixation capacity at a much lower CEC than those of the coarse grained vermiculites. This enhanced fixation is believed ue to the diocta-hedral nature of the coarse grained vermiculites. In samples of nearly equal CECs only those con-taining AP § in tetrahedral positions exhibited an enhanced fixation capacity in the dry state but not in the wet state. In was remarkable to find that the state of oxidation of crystal structure iron strongly affected the fixation and t...
Soil vermiculite clays of varying tetrahedral and octahedral composition and cation exchange capa... more Soil vermiculite clays of varying tetrahedral and octahedral composition and cation exchange capacity (CEC) were examined for their ability to fix K § in both the wet and dry states. Fixation capacity, expressed as per cent of the CEC, in the wet state was fairly high for most samples but it was enhanced greatly upon drying the K saturated samples. This enhancement indicated that each sample contained a number of vermiculite species with different CECs. The vermiculite clays, as a group, exhibited a much higher fixation capacity at a much lower CEC than those of the coarse grained vermiculites. This enhanced fixation is believed due to the dioctahedral nature of the coarse grained vermiculites. In samples of nearly equal CECs only those containing AP § in tetrahedral positions exhibited an enhanced fixation capacity in the dry state but not in the wet state. In was remarkable to find that the state of oxidation of crystal structure iron strongly affected the fixation and the CEC. Re...
Sources of the agricultural soil pollution in Egypt include the utilization of agrochemicals, the... more Sources of the agricultural soil pollution in Egypt include the utilization of agrochemicals, the reuse of agricultural drainage water, the recycling of the partially treated wastewater, the contaminated air, and the improper disposing of solid wastes. These various sources pose a real threat to the sustainable agricultural system and human health. In this chapter, we reviewed the sources and fate of the organic and inorganic pollutants in Egyptian soils. In brief, we explained sorption, mobility, and degradation properties of contaminants and their rules for realizing proper management of contaminated soils. Also, we reviewed the status of soils contamination with heavy metals and pesticides. Notably, the fate of the contaminants in soils depends on its characteristics and soil properties as well as the surrounding environmental condition. Therefore, the management of contaminated soils is a site-specific process. Such management can be ensured through prevention, remediation, and adaptation approaches. The literature review revealed the need to develop and implement a national plan for preventing soil pollution in the newly reclaimed areas. Besides, the necessity for providing a well-defined Egyptian guideline for managing contaminated sites in old agricultural lands.
Ecosystem degradation caused by factors such as improper natural resources management and contami... more Ecosystem degradation caused by factors such as improper natural resources management and contamination with agricultural, industrial, and domestic wastes often results in the creation of an unhealthy ecosystem, a main cause for the prevailing poverty and poor health in many parts of rural Egypt. In collaboration with members of the community in some villages of El-Fayoum province, an interdisciplinary research team is currently employing an ecosystem approach to arrive at an understanding of community health problems with a view to develop resource management interventions and policies aimed at enhancing community health and well-being. Participatory rural appraisal (PRA) and knowledge, attitudes, and practices (KAP) techniques were used to measure the perceptions of the community’s men and women of their health and environmental priorities, and to test their current state of knowledge and awareness of the health-related issues. The results indicate that these perceptions were gender-sensitive and were different from those of Ministry of Health. Spatial and temporal monitoring and assessment of the ecosystem components revealed considerable land and water resources degradation. Presence of water pools and waterways in the vicinity of the residential areas enhanced the risk of water-associated diseases. Although, the disease-carrying vectors of schistosomiasis and malaria were detected in the waterways, the incidence of the two diseases was relatively low in the main village in contrast to the situation in the nearby hamlets. Prevalence of schistosomiasis was substantially higher in these hamlets (20–30% compared to 2–3% in the main village). Such a highly infected community represents a continuous pool of reinfection of the waterways, an issue that needs to be further examined to determine its relation to the hamlets’ specific ecosystem characteristics. A high incidence of hepatitis C and soil transmitted-intestinal parasites were markedly detected. It is concluded that in addition to natural resources degradation, other potential health risk factors were identified including socioeconomic, cultural, and institutional factors. Further studies are being conducted to explore these potential risk factors and their links to human health and well-being.
Chemical and mineralogical analyses of the clay fraction of eleven soils containing a large amoun... more Chemical and mineralogical analyses of the clay fraction of eleven soils containing a large amount of vermiculite clay and representing a wide range of parent materials revealed that two types of vermiculite clays exist: (1) An aluminous type in which Al3+ substitutes for Si4+ in tetrahedral positions in the same order of magnitude as in the coarse grained vermiculites and micas, and with Al3+ as the dominant octahedral ion. (2) A silicious type in which only Si4+ occupies the tetrahedral positions, and with Fe3+ and Mg2+ as the dominant octahedral ions. The aluminous vermiculite clay was found to occur in soils derived from acid igneous rocks and is usally associated with mica, whereas the silicious type was found to occur in soils derived from basic igneous rocks which do not contain mica. Because of this close association of these two types to their parent material, it was concluded that the aluminous vermiculite is a product of alteration of mica whereas the silicious type is a product of synthesis from primary oxides of silica, alumina, iron, and magnesium. Both types of vermiculite clays tend to be dioctahedral in contrast to the trioctahedral nature of the coarse-grained vermiculite.
Oxidation of octahedral ferrous to ferric iron in soil vermiculite clays and biotites increases t... more Oxidation of octahedral ferrous to ferric iron in soil vermiculite clays and biotites increases the potassium-fixation capacity of vermiculites and increases the difficulty of replacing interlayer potassium in biotites. This unexpected effect is believed to be related to an increase in the attractive forces between potassium ions and oxygen ions of the surface layers which is brought about by a tilting of the dipole of the octahedral hydroxyl ions from a perpendicular position to an inclined position with respect to the cleavage plane.
To assess the status of copper in Egyptian soils, surface and subsurface soil samples were collec... more To assess the status of copper in Egyptian soils, surface and subsurface soil samples were collected from various geographical regions of Egypt and of various genesis. The samples were analyzed for the total Cu, water-soluble plus exchangeable as well as the acid-extractable and EDTA-extractable Cu. The total Cu varied between 3.5 and 72.3 ppm. Less than 2% of this copper was in the soluble plus exchangeable form. The highest values of total and soluble plus exchangeable copper were found in the alluvial soils while the sandy soils had the least amounts. This was attributed to the high clay and organic matter content of the alluvial soils in addition to the dominance of montmorillonitic clay minerals in their fine fraction. The calcareous soils showed intermediate values of total and soluble plus exchangeable Cu due to their lower organic matter and clay mineral content. The clay mineralogy of these soils revealed the dominance of illitic and kaolinitic minerals which are relatively poor in Cu and other trace elements. Because of their relatively higher organic matter content, the alluvial soils had a large percentage (up to 43%) of their total Cu in the EDTA extractable form. The calcareous soils, on the other hand, had a large percentage (up to 52%) of their Cu in the acid-extractable form. The EDTA extractable Cu was correlated with the organic matter content of the soils. Since the pH of the EDTA extract was found to be dependent on the CaCO3 content of the soils, it was suggested that the method be modified so that the final pH of the extract is constant for all soils.
Page 1. Carbaryl Adsorption on Calcium-Bentonite and Soils1 MI ALY, N. BAKRY, F. KISHK, AND AH EL... more Page 1. Carbaryl Adsorption on Calcium-Bentonite and Soils1 MI ALY, N. BAKRY, F. KISHK, AND AH EL-SEBAE2 ABSTRACT Adsorption of carbaryl on Ca-bentonite, and two Egyptian soils, a Nile alluvial and a highly calcareous soil, was carried out at different temperatures. ...
Abstract- Soil vermiculite clays of varying tetrahedral nd octahedral composition and cation exch... more Abstract- Soil vermiculite clays of varying tetrahedral nd octahedral composition and cation exchange capacity (CEC) were examined for their ability to fix K § in both the wet and dry states. Fixation capacity, expressed as per cent of the CEC, in the wet state was fairly high for most samples but it was enhanced greatly upon drying the K saturated samples. This enhancement indicated that each sample contained a number of vermiculite species with different CECs. The vermiculite clays, as a group, exhibited a much higher fixation capacity at a much lower CEC than those of the coarse grained vermiculites. This enhanced fixation is believed ue to the diocta-hedral nature of the coarse grained vermiculites. In samples of nearly equal CECs only those con-taining AP § in tetrahedral positions exhibited an enhanced fixation capacity in the dry state but not in the wet state. In was remarkable to find that the state of oxidation of crystal structure iron strongly affected the fixation and t...
Soil vermiculite clays of varying tetrahedral and octahedral composition and cation exchange capa... more Soil vermiculite clays of varying tetrahedral and octahedral composition and cation exchange capacity (CEC) were examined for their ability to fix K § in both the wet and dry states. Fixation capacity, expressed as per cent of the CEC, in the wet state was fairly high for most samples but it was enhanced greatly upon drying the K saturated samples. This enhancement indicated that each sample contained a number of vermiculite species with different CECs. The vermiculite clays, as a group, exhibited a much higher fixation capacity at a much lower CEC than those of the coarse grained vermiculites. This enhanced fixation is believed due to the dioctahedral nature of the coarse grained vermiculites. In samples of nearly equal CECs only those containing AP § in tetrahedral positions exhibited an enhanced fixation capacity in the dry state but not in the wet state. In was remarkable to find that the state of oxidation of crystal structure iron strongly affected the fixation and the CEC. Re...
Sources of the agricultural soil pollution in Egypt include the utilization of agrochemicals, the... more Sources of the agricultural soil pollution in Egypt include the utilization of agrochemicals, the reuse of agricultural drainage water, the recycling of the partially treated wastewater, the contaminated air, and the improper disposing of solid wastes. These various sources pose a real threat to the sustainable agricultural system and human health. In this chapter, we reviewed the sources and fate of the organic and inorganic pollutants in Egyptian soils. In brief, we explained sorption, mobility, and degradation properties of contaminants and their rules for realizing proper management of contaminated soils. Also, we reviewed the status of soils contamination with heavy metals and pesticides. Notably, the fate of the contaminants in soils depends on its characteristics and soil properties as well as the surrounding environmental condition. Therefore, the management of contaminated soils is a site-specific process. Such management can be ensured through prevention, remediation, and adaptation approaches. The literature review revealed the need to develop and implement a national plan for preventing soil pollution in the newly reclaimed areas. Besides, the necessity for providing a well-defined Egyptian guideline for managing contaminated sites in old agricultural lands.
Ecosystem degradation caused by factors such as improper natural resources management and contami... more Ecosystem degradation caused by factors such as improper natural resources management and contamination with agricultural, industrial, and domestic wastes often results in the creation of an unhealthy ecosystem, a main cause for the prevailing poverty and poor health in many parts of rural Egypt. In collaboration with members of the community in some villages of El-Fayoum province, an interdisciplinary research team is currently employing an ecosystem approach to arrive at an understanding of community health problems with a view to develop resource management interventions and policies aimed at enhancing community health and well-being. Participatory rural appraisal (PRA) and knowledge, attitudes, and practices (KAP) techniques were used to measure the perceptions of the community’s men and women of their health and environmental priorities, and to test their current state of knowledge and awareness of the health-related issues. The results indicate that these perceptions were gender-sensitive and were different from those of Ministry of Health. Spatial and temporal monitoring and assessment of the ecosystem components revealed considerable land and water resources degradation. Presence of water pools and waterways in the vicinity of the residential areas enhanced the risk of water-associated diseases. Although, the disease-carrying vectors of schistosomiasis and malaria were detected in the waterways, the incidence of the two diseases was relatively low in the main village in contrast to the situation in the nearby hamlets. Prevalence of schistosomiasis was substantially higher in these hamlets (20–30% compared to 2–3% in the main village). Such a highly infected community represents a continuous pool of reinfection of the waterways, an issue that needs to be further examined to determine its relation to the hamlets’ specific ecosystem characteristics. A high incidence of hepatitis C and soil transmitted-intestinal parasites were markedly detected. It is concluded that in addition to natural resources degradation, other potential health risk factors were identified including socioeconomic, cultural, and institutional factors. Further studies are being conducted to explore these potential risk factors and their links to human health and well-being.
Chemical and mineralogical analyses of the clay fraction of eleven soils containing a large amoun... more Chemical and mineralogical analyses of the clay fraction of eleven soils containing a large amount of vermiculite clay and representing a wide range of parent materials revealed that two types of vermiculite clays exist: (1) An aluminous type in which Al3+ substitutes for Si4+ in tetrahedral positions in the same order of magnitude as in the coarse grained vermiculites and micas, and with Al3+ as the dominant octahedral ion. (2) A silicious type in which only Si4+ occupies the tetrahedral positions, and with Fe3+ and Mg2+ as the dominant octahedral ions. The aluminous vermiculite clay was found to occur in soils derived from acid igneous rocks and is usally associated with mica, whereas the silicious type was found to occur in soils derived from basic igneous rocks which do not contain mica. Because of this close association of these two types to their parent material, it was concluded that the aluminous vermiculite is a product of alteration of mica whereas the silicious type is a product of synthesis from primary oxides of silica, alumina, iron, and magnesium. Both types of vermiculite clays tend to be dioctahedral in contrast to the trioctahedral nature of the coarse-grained vermiculite.
Oxidation of octahedral ferrous to ferric iron in soil vermiculite clays and biotites increases t... more Oxidation of octahedral ferrous to ferric iron in soil vermiculite clays and biotites increases the potassium-fixation capacity of vermiculites and increases the difficulty of replacing interlayer potassium in biotites. This unexpected effect is believed to be related to an increase in the attractive forces between potassium ions and oxygen ions of the surface layers which is brought about by a tilting of the dipole of the octahedral hydroxyl ions from a perpendicular position to an inclined position with respect to the cleavage plane.
To assess the status of copper in Egyptian soils, surface and subsurface soil samples were collec... more To assess the status of copper in Egyptian soils, surface and subsurface soil samples were collected from various geographical regions of Egypt and of various genesis. The samples were analyzed for the total Cu, water-soluble plus exchangeable as well as the acid-extractable and EDTA-extractable Cu. The total Cu varied between 3.5 and 72.3 ppm. Less than 2% of this copper was in the soluble plus exchangeable form. The highest values of total and soluble plus exchangeable copper were found in the alluvial soils while the sandy soils had the least amounts. This was attributed to the high clay and organic matter content of the alluvial soils in addition to the dominance of montmorillonitic clay minerals in their fine fraction. The calcareous soils showed intermediate values of total and soluble plus exchangeable Cu due to their lower organic matter and clay mineral content. The clay mineralogy of these soils revealed the dominance of illitic and kaolinitic minerals which are relatively poor in Cu and other trace elements. Because of their relatively higher organic matter content, the alluvial soils had a large percentage (up to 43%) of their total Cu in the EDTA extractable form. The calcareous soils, on the other hand, had a large percentage (up to 52%) of their Cu in the acid-extractable form. The EDTA extractable Cu was correlated with the organic matter content of the soils. Since the pH of the EDTA extract was found to be dependent on the CaCO3 content of the soils, it was suggested that the method be modified so that the final pH of the extract is constant for all soils.
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