نتایج جستجو برای: natural and anthropogenic sources
تعداد نتایج: 16910230 فیلتر نتایج به سال:
this studyinvestigated therelations between examinees’ academic knowledge and theirperformanceonreading section of ielts and toefl (ibt) through using generalizabilitytheory. g-theory was utilized to investigate the effects of subtest, test items, participants and academic background on the reliability of ielts and toefl (ibt) score. tosamplethe subjectsofthissurvey,a placement testwasadministe...
Arsenic is one of the heavy metals and nearly all its compounds, especially organic compounds, are toxic. The wide spectrum of diseases caused by this element has led to evaluation of the toxicity of different arsenic species and identification of the major natural and anthropogenic pollution sources of it in the nature. Mining activities are among the main sources of anthropogenic pollution of...
The concentrations of sixteen elements and organic carbon were determined in 78 marine sediment samples collected from the Iranian coastal waters of the Persian Gulf. Nine transects perpendicular to the coastline were sampled. Sixteen elements, including As, Ba, Cd, Co, Cu, Mn, Ni, Pb, Zn (trace metals) and Ca, Fe, Mg, Na, P, S, Si (major metals), were determined by Inductively Coupled Plasma M...
This study presents a 17-years air quality database comprised of different parameters corresponding to the largest city in the south of Spain (Seville) where atmospheric pollution is frequently attributed to traffic emissions and is directly affected by Saharan dust outbreaks. We identify the PM10 contributions from both natural and anthropogenic sources in this area associated to different air...
concentrations of eight metals namely, cr, mn, fe, co, ni, cu, zn and pb were examined in the surface sediments of discharge channels of six industries in lagos using x-ray fluorescence spectrometry.these channels drain into the isolo canal which empties into the lagos lagoon and eventually into the atlantic ocean. this study was conducted to detect any contamination levels within the sediment...
The research results indicated that wet and dry dust deposition is a function of geographical characteristics. The seasonal wet and dry dust deposition and Fine Particles (PM 2.5) correlation in Iran with elevation, latitude and longitude results that the maximum correlation belongs to height, followed by latitude and longitude; meanwhile height and latitude are strongly and reversely correlate...
concentrations of heavy metals (ni, co, zn, cd, pb and cu) in the reservoir of shahid rajaeidam, one of the main water reservoirs in north part of iran, were determined using a differential pulse polarography(metrohm 797 va) and compared with the national and international specified maximum contaminant levels(mcl) for different purposes of water use. the results showed that concentrations of cd...
sediment core samples can provide useful information about aquatic environment. sedimentation rate, climate changes and heavy metal concentration are among the most important studies that are carried out on sediment cores. in this study, a sediment core of 70cm with aim of metal concentration investigation is collected from central part of the zarivar lake in the vicinity of the marivan city in...
Background and purpose: Soil contamination resulted from either natural or anthropogenic factors reduces environmental quality. The aim of this study was to evaluate the geoaccumulation, contamination factor, and principal component analysis indices to estimate topsoil contamination in Aran-Bidgol town. Materials and methods: 135 topsoil samples were collected from Aran-Bidgol town and the m...
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