نتایج جستجو برای: accumulation igeo sediment

تعداد نتایج: 184755  

2005
S. L. Yang J. Zhang J. P. Smith S. B. Dai A. Gao P. Li

[1] On the basis of estimates of sediment accumulation in reservoirs, the impact of 50,000 dams on sediment supply and intertidal wetland response in the Yangtze River catchment is examined. The total storage capacity of reservoirs is 200 10 m, or 22% of the Yangtze annual runoff. The sediment accumulation rate in reservoirs has increased from 0 in 1950 to >850 10 t/yr in 2003. Although sedimen...

2005
ROLF AALTO WILLIAM DIETRICH Rolf Aalto

The Strickland River is the primary sediment source for the Fly River system, a large tropical river that ranks in the global top 20 for both water and sediment discharge. Over the past decade the Strickland sediment discharge has been gauged at many locations. Comprehensive studies are now underway to study the delivery, transport, and storage of sediment throughout this system. A key question...

2016
Yongfu Wu Xinwei Lu Xiufeng Han Yan Zhou

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...

Journal: :Annual research & review in biology 2022

Mining is an activity that involves the use of chemicals and results in unsustainable dangerous conditions for miners, their families, community surrounding ecosystem. This study was done to assess metallic contamination soils sediments Bétaré-Oya gold artisanal mine district, East-Cameroon. A total thirty (30) samples exploited soils, control were taken from mining sites Lom, Mbal Mali. The co...

2011
P. J. Dillon H. E. Evans

Phosphorus retention (TPacc) was determined in 7 lakes in Ontario, Canada from mass balances and from the direct measurement of phosphorus accumulation in the sediments. Phosphorus retentions determined using the mass balance technique ranged between 20 ± 3.9 and 94 ± 23 mg/m/yr and were slightly lower than those calculated by multiplying sediment total phosphorus (TP) concentrations by sedimen...

2014
Elizabeth A. Canuel Rebecca M. Dickhut Steven A. Kuehl

Our objectives are to examine sediment PAH distributions in environments representing contrasting depositional regimes within the York River, VA, a sub-estuary of the Chesapeake Bay. Our study utilizes a suite of geochemical tools to quantify sediment processes influencing the distribution of dissolved and solid-phase PAHs. These tools will enable us to quantify particle residence times in surf...

Journal: :The Science of the total environment 2009
Bryce E Johnson Bradley K Esser Dyan C Whyte Priya M Ganguli Carrie M Austin James R Hunt

The Walker Creek intertidal delta of Tomales Bay, California is impacted by a former mercury mine within the watershed. Eleven short sediment cores (10 cm length) collected from the delta found monomethylmercury (MMHg) concentrations ranging from 0.3 to 11.4 ng/g (dry wt.), with lower concentrations occurring at the vegetated marsh and upstream channel locations. Algal mats common to the delta'...

Journal: :محیط زیست طبیعی 0
لیلا دواشی دانشجوی کارشناسی ارشد محیط زیست دانشکدۀ منابع طبیعی و کویرشناسی، دانشگاه یزد حمیدرضا عظیم زاده دانشیار دانشکدۀ منابع طبیعی و کویرشناسی ـ پژوهشکدۀ مناطق خشک و بیابانی، دانشگاه یزد

increasing in concentration of heavy metals such as lead, cadmium, nickel, chromium and zinc cause considerable harmful effects on soil and environment. these elements are also hazardous to health of humans and wildlife. petrochemical plants and refineries pollution increase the amount of carcinogenic and tratogenic compounds in environment. the main goal of recent paper is the studying of soil...

Journal: :Environmental toxicology and chemistry 2013
Wei Luo Yonglong Lu Tieyu Wang Peiru Kong Wentao Jiao Wenyou Hu Junmei Jia Jonathan E Naile Jong Seong Khim John P Giesy

Cadmium (Cd) and zinc (Zn) in surface water, sediment, carp, and crab samples collected from upstream and downstream regions of coastal watersheds along the Chinese Northern Bohai and Yellow Seas were analyzed to provide a comprehensive understanding and assessment of their environmental concentrations and bioaccumulations. The results showed that downstream waters contaminated with Zn would ha...

2015
Daniel Barlow

At present there is a poor understanding of changes in rates of erosion over long time periods and in the link between erosion and sediment delivery in Britain. Using a catchment study approach sediment accumulation rates in cores from the three lakes Semer Water, Gormire and Hornsea Mere have been used to reconstruct changes in sediment yield over time periods of up to 10 000 years, and estima...

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