نتایج جستجو برای: negative balance of underground water
تعداد نتایج: 21252620 فیلتر نتایج به سال:
BACKGROUND Between September 17 and October 3, 2009, hundreds of workers employed in a manufacturing factory in Shenzhen, a city in south China developed a sudden onset of acute gastroenteritis. A retrospective cohort study is designed to identify the risk factors and control this outbreak. METHODS Information on demographic characteristics, working place, the history of contact with a person...
recent droughts and indiscriminate use of ground water for agriculture, is the main problems of the especially desert country.water crisis has gripped all of country plains, and due tothe reduction of surface water resources and successive droughts, illegal exploitation of ground water resources is increasing.the knowledge of the water balance plains can be helped in the water resources managem...
Background and Objective: Rainfall and groundwater level are important parameters of DRASTIC index, thus their time-series were examined using time series analysis for Mahidasht plain vulnerability in Kermanshah Province. Materials and Methods: DRASTIC model is a quantitative model that seven parameters for transfer of pollution are considered including depth of water table, net recharge, aqui...
Background and Objectives: With increasing population, the process of contamination of water resources has intensified and humans need new and inexpensive ways to refine and improve water quality. Heavy metals are the environmental pollutants that originate mainly from industrial and agricultural activities and are found in all parts of the industrial communities. This research was conducted to...
underground economy affects important indexes such as formal gdp, unemployment, consumption, production and etc. therefore it is necessary to identify elements and factors which affect underground economy to restrict it. surveys and studies indicate the size of iran’s underground economy is high and taxes, quantity and quality of regulations and performance of formal economy are the important f...
in the present work, a simple and sensitive method was developed for determination of morphine and heroin using gold nanoparticles as resonance rayleigh scattering (rrs) and colorimetric technique’s probe. synthesized gold nanoparticles by sodium citrate reduction method have a negative charge layer on their surfaces because of self-assembled citrate anions on their surface. binding of morphin...
Studies about sediment erosion were mainly concentrated on the river channel sediment, the terrestrial sediment, and the underground sediment. The transport process of underground sediment is studied in the paper. The concept of the flush potential sediment is founded. The transport equation with stable saturated seepage is set up, and the relations between the flush potential sediment and wate...
constructionof underground dams is a practical solution to save groundwater in alluvium watersheds, particularly in arid and semi-arid regions where surface water scarcity is an environmental challenge. considering socio-economic and environmental benefits of underground dams, the accurate locating is the primary consideration for dam construction. the new technologies and methods are a step to...
Background and purpose: Fertilizer is one of the sources of heavy metal contamination in soil and underground water. The purpose of this study was to investigate the concentration of cadmium, lead and arsenic in paddy soil and underground water and its relationship with chemical fertilizer in Ghaemshahr City. Materials and methods: During the spring and summer in 2010, samples of soil were ran...
background: during recent years, overpopulation, increase of wastewater, and drop in water tables has led to high concentration of salts in underground water, which is an important environmental pollutant. if concentration of salt in drinking water exceeds the limits, it will be dangerous for health. the aim of this study was to measure physical and chemical parameters in drinking water of rura...
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