نتایج جستجو برای: cr and mn to extremely polluted for zn
تعداد نتایج: 20266744 فیلتر نتایج به سال:
concentrations of six heavy metals including cr, mn, ni, pb, v and zn were determined in topsoil (from 47 grid cells), surface water (4 streams) and groundwater (8 wells and 4 qanats) from an agriculturalarea located at south part of the iranian capital, near the tehran oil refinery. concentrations of the elementswere measured using flame and flameless atomic absorption spectrometry. based on t...
Concentrations and distributions of trace metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in surficial sediments of the Cochin backwaters were studied during both monsoon and pre-monsoon periods. Spatial variations were in accordance with textural charaterstics and organic matter content. A principal component analysis distinguished three zones with different metal accumulation capacity: (i) hi...
Concentrations of the elements Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, N, Ni, P, Pb, and Zn were measured in needles and bark of Taxus baccata from the urban environment of Wrocław, Poland, and from a control site relatively free from pollution. In Wrocław the concentrations of N, P, K, and Mg in needles were significantly higher than in bark, but concentrations of Cd, Co, Cr, Cu Fe, Ni, and Zn were...
The objective of this study was to investigate the concentration and spatial distribution patterns of six potentially toxic heavy metal elements (Mn, Zn, Cr, Pb, Cu and Ni) in bus station dusts in the Xifeng district of Gansu province, NW China. The contents were analyzed for Mn, Zn, Cr, Pb, Cu and Ni by using S8 TIGER Brochures wavelength dispersive X-ray fluorescence spectrometry. Geoaccumula...
Geochemical sediment of the tropical Pinang River, Malaysia was carried out with the aim at documenting elemental concentrations and pollution level assessment. Concentration of selected heavy metals (Cu, Cd, Cr, Pb, Zn and Mn), rare earth elements, TOC and grain size distribution of sediments were determined at 100 m sampling interval along the river. Sediment size showed a positive correlatio...
During a period of 60 days assays were carried out with the moss Pohlia nutans transplanted from an uncontaminated control site to a dump consisting of a heavily polluted mine and smelter wastes located near wałbrzych in southwestern Poland. within the same period also samples of native P. nutans growing on the dump substrate were collected together with the same species from a control site. Co...
introduction we can obtain useful information about aquatic systems by studying heavy metals in surface sediments. marine sediments can bring out the aquatic contamination. due to heavy metal toxicity, hard biodegradation and easy bioaccumulation in aquatic ecosystems, various indices have been developed such as sediment quality guidelines (sqgs), enrichment factor (ef), pollution load index (i...
Background and Objective: Air quality and distribution of trace elements in the Tehran metropolis were evaluated using transplants of the epiphytic lichen Ramalina sinensis. Materials and Methods: Thalli of R. sinensis were collected from a non-contaminated area and transplanted in the six urban sites of Tehran for six months. After the end of the exposure period, the content of twelve element...
The Bolesław-Bukowno mining area in Poland is highly polluted by elements such as Zn, Pb, Cd and As. The reactivity and mobility of toxic elements such as Tl are poorly known. Here, we studied by sequential extraction the mobility of As, Cd, Co, Cr, Cu, Mn, Mo, Pb, Tl and Zn in sediments from two water reservoirs near Bukowno. Results show that available As, Co, Mn, Pb and Zn are found in carbo...
the present study investigated construct equivalence of multiple choice (mc) and constructed response (cr) item types across stem and content equivalent mc and cr items (item type ‘a’), non-stem-equivalent but content equivalent mc and cr items (item type ‘b’), and non-stem and non-content equivalent mc and cr items (item type ‘c’). one hundred seventy english-major undergraduates completed mc ...
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