نتایج جستجو برای: degree of contamination
تعداد نتایج: 21171351 فیلتر نتایج به سال:
Background and Aim : Contamination of the surface soils of the urban ecosystem with heavy metals poses potential ecological risks. In this research, a preliminary investigation was carried out to evaluate the potential ecological risk of cadmium and lead contamination in urban park soils in Assadabed City, Iran. Materials and Methods : Soil samples were taken from the urban parks of Asad...
all analytical methods are generally based on the measurement of a parameter or parameters which are somehow related to the concentration of the species.an ideal analytical method is one in which the concentration of a species can be measured to a high degree precision and accuracy and with a high sensitivity. unfortunately finding such a method is very difficult or sometimes even impossible.in...
The current paper determines heavy metals in sediments of six freshwater wetlands of greater Dhaka district from November 1999 to September 2000. The sampling took place in summer, rainy season, and winter, wherein for each season five soil samples were collected from the wetland at a depth of 0 – 15 cm. To assess the status of heavy metal pollution in the sediments, geo-accumulation factor (Ig...
The current paper determines heavy metals in sediments of six freshwater wetlands of greater Dhaka district from November 1999 to September 2000. The sampling took place in summer, rainy season, and winter, wherein for each season five soil samples were collected from the wetland at a depth of 0 – 15 cm. To assess the status of heavy metal pollution in the sediments, geo-accumulation factor (Ig...
for several years, researchers in familiarity of efl teachers with post-method and its role in second and foreign language learners’ productions have pointed out that the opportunity to plan for a task generally develops language learners’ development (ellis, 2005). it is important to mention that the critical varies in language teaching was shown is the disappearances of the concept of method ...
abstract cooperative learning refers to small groups of learners working together as a team to solve a problem, complete a task, or accomplish a common goal. in a cooperative environment one’s success is directly related to the success of other members because the focus on the individual shifts towards the group. to test the effectiveness of the method, using jigsaw technique, a study was cond...
Background: The pollution of the aquatic environment with heavy metals has become a worldwide problem during recent years, due to their potential toxic effects and ability to bio-accumulate in aquatic ecosystems. Heavy metals are sensitive indicators for monitoring changes in the aquatic environment. Methods: In this study, total concentrations of Cr, Pb, Cu, Zn, and Fe were measured in water...
an increase in heavy metal pollution in the soils of arak due to industrialization and urbanization has become an environmental problem. the region hosts several industrial facilities which are the main source for hazardous wastes which include electric, metal, automotive supply industry, food, machinery, and chemicals. soil samples were collected from these industrial areas in the central and ...
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