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Lafrance P Villeneuve JP Mazet M Ayele J Fabre B 《Environmental pollution (Barking, Essex : 1987)》1991,72(4):331-344
The quantitative determination of pesticide binding to dissolved humic substances is relevant to both water treatment operation using activated carbon adsorption process and the application of transport models that predict the environmental distribution patterns of a given hydrophobic contaminant. In this study and in a first set of experiments, the extent of binding between (i) three pesticides of environmental concern, aldicarb, lindane and pentachlorophenol, and (ii) dissolved commercial humic acid and soil extracted fulvic acid, was determined using dialysis experiments and water solubility enhancement tests. In a second set of experiments, the influence of dissolved humic substances or pesticide on the retention of the other co-adsorbate onto activated carbon was investigated in binary systems. It was found that association was negligible for aldicarb and that the pesticide sorption onto activated carbon was not affected by humic acid (8.5 mg liter(-1) DOC). The association constants K for lindane and pentachlorophenol were identical in the presence of fulvic acid (logK=4.1) but lower than that observed with humic acid. In the presence of humic acid, binding affinity for pentachlorophenol (logK=4.6) was higher than the one observed for lindane (logK=4.4), despite its much higher water solubility. This observation suggests that the aromatic character of the pentachlorophenol molecule contributes to association interactions with humic acid. From co-adsorption experiments onto activated carbon it was found that fulvic acid (7.7 mg litre(-1) DOC) slightly enhances sorption kinetics of pentachlorophenol. Lindane (1 mg litre(-1)) does not affect sorption kinetics for fulvic acid but markedly enhances both the sorption kinetics and adsorptive capacity for humic acid. Activated carbon retention of dissolved humic substances or pesticide appears to be enhanced by the association potential that exists between these co-adsorbates in some binary systems. 相似文献
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Fenta Ayele Almaw Yasuda Hiroshi Shimizu Katsuyuki Haregeweyn Nigussie 《Regional Environmental Change》2017,17(4):1229-1240
Regional Environmental Change - Climate variability and human activities are two major drivers influencing changes in streamflow response of a watershed, and thus assessing their relative effect is... 相似文献
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TEKLEMARIAM AYELE2
This is a study of the changing settlement and land use patterns of the Konso in three peasant associations in southwestern Ethiopia and an evaluation of their attitudes toward government-sponsored villagization in the lowlands. Over the years, the Konso have moved spontaneously from the overpopulated highlands toward lower elevations and have recently begun to cultivate on the Yanda plain, but without settling there. Fear of tropical diseases, armed conflict with pastoralists and the Konso perception of lowland living continue to be powerful deterrents to settlement in the lowlands. Major objectives of the government villagization programme are unlikely to be achieved in the Konso area and may instead lead to disaster unless this programme is drastically revised to provide suitable conditions for resettlement and to meet the specific needs of the population. 相似文献
This is a study of the changing settlement and land use patterns of the Konso in three peasant associations in southwestern Ethiopia and an evaluation of their attitudes toward government-sponsored villagization in the lowlands. Over the years, the Konso have moved spontaneously from the overpopulated highlands toward lower elevations and have recently begun to cultivate on the Yanda plain, but without settling there. Fear of tropical diseases, armed conflict with pastoralists and the Konso perception of lowland living continue to be powerful deterrents to settlement in the lowlands. Major objectives of the government villagization programme are unlikely to be achieved in the Konso area and may instead lead to disaster unless this programme is drastically revised to provide suitable conditions for resettlement and to meet the specific needs of the population. 相似文献
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Ayele Hailu Sheferaw Atlabachew Minaleshewa 《Environmental science and pollution research international》2021,28(12):14233-14252
Environmental Science and Pollution Research - Lake eutrophication and water quality deterioration have become a major environmental problem in urban areas and fertilized basins in developing... 相似文献
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This study analyses the relation of forest cover and stream flow on the 266 km2 Koga watershed in a headwater of Blue Nile Basin using both observed hydrological data and community perception. The watershed
declined from 16% forest cover in 1957 to 1% by 1986. The hydrological record did not reveal changes in the flow regime between
1960 and 2002 despite the reduction in forest area. This agrees with the perception of the downstream community living near
the gauging station. The upstream community, however, reported both decreases in low flows and increases in high flows shortly
after the forest cover was reduced. The upstream deforestation effect appeared to have been buffered by a wetland lower in
the watershed. This study concludes that community perception can be a complement to observational data for better understanding
how forest cover influences the flow regime. 相似文献
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Abstract This study examined trends in population redistribution and residential land use changes in northeast Scotland during 1988 to 2003. We utilised a geographical information system (GIS) tool to bring together data from interrelated sources and to analyse population settlement and land use changes at detailed spatial scale. This analysis revealed that substantial land conversion had taken place in the region; particularly conversion of agricultural lands to built-up and residential areas. It also drew attention to policy conflicts, discrepancies between policy rhetoric and policy implementations. More specifically, it was shown that substantial farm land conversion had taken place in suburban areas and rural Aberdeenshire with little change in the size of derelict land in Aberdeen City. The reason given for this was that it was costly to rehabilitate and reuse derelict lands and this conflicted with the objective of providing affordable housing in the City region. The implication of this study is that if the declared policy objectives of integrated and sustainable land use and transport policies are to be achieved, then local authorities may need to cooperate to minimise conflicts between economic and environmental objectives. 相似文献
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