نتایج جستجو برای: urmia lake sediments
تعداد نتایج: 69393 فیلتر نتایج به سال:
Groundwater resources are considered as a largest reservoir of available freshwater in the world. According to the importance and scarcity of this precious resource, studying the groundwater quality changes is very important. Declines in water level of Urmia lake has led to increase in the salinity of water in this lake. In this paper, water level reduction effects were studied on qualitative c...
Nature has always proven that it is able to overcome its problems. However, human manipulation has led to environmental degradations. The dryness of a thousand-year Urmia Lake (a brinewater lake in Iran) is an example of environmental degradation that happened due to successive droughts and construction of dams on the basin of this lake. This study examines methods for the revival of Urmia Lake...
Sediment from two Georgia Piedmont impoundments and soil from the Georgia Piedmont Bt horizon were incubated with an easily consumable organic carbon substrate in an anaerobic environment to observe iron reduction and phosphorus release. 97% of porewater iron in the Bt horizon soil, 96% of porewater iron in Lake Lanier sediments, and 93% of porewater iron in Lake Oglethorpe sediments was reduce...
this study investigated the impact of internal nitrogen and phosphorus loading on water qualityof lake chaohu, china. results showed that the overall mean concentration of tn and tp in lake water was1.09±0.84 and 0.15±0.84 (sd) mg/l, respectively, indicating lake chaohu was highly eutrophic during thestudy period. mean benthic flux of nh4 +, no3 -, and po4 3- were 3.56±1.52 mg n/m2/d, -0.14±0.4...
this study investigated the impact of internal nitrogen and phosphorus loading on water qualityof lake chaohu, china. results showed that the overall mean concentration of tn and tp in lake water was1.09±0.84 and 0.15±0.84 (sd) mg/l, respectively, indicating lake chaohu was highly eutrophic during thestudy period. mean benthic flux of nh4 +, no3 -, and po4 3- were 3.56±1.52 mg n/m2/d, -0.14±0.4...
Diel pH changes in lake waters resulting from high photosynthetic activity may regulate water-soluble P concentration (WSP) and P sorption by suspended sediments in shallow eutrophic lakes. Laboratory studies were conducted to determine the pH effect on P fractions and P sorption kinetics in oxidized sediment suspensions from two subtropical lakes (Lake Apopka and Lake Okeechobee, Florida). The...
Recently, hypoxia has become serious in Lake Biwa due to progressing of global warming. In this study, we determined Mn and As concentrations and their speciation in lake bottom water and sediments in June and December to elucidate their geochemical behaviors. Lake bottom water and sediment samples were collected from seven stations in the northern basin of Lake Biwa. In sediments, clear enrich...
The sediments from the Coari lake, a "terra firme" lake sculpted into Plio-Pleistocene deposits, and the Acará lake, a flooding-type lake developed on Quaternary sediments in the floodplain of the mid-Solimões river, in the western Amazônia, Brazil, were studied to investigate the environmental condition of their developing. This study includes mineral composition, geochemistry, Pb isotope, pal...
The BCR (European Communities Bureau of Reference) three-step sequential extraction procedure was applied to fractionate heavy metals in the sediment of Taihu Lake. For the determination of total metal concentration of the sediments, sample digestion was achieved by using HF/H2O2/HNO3 (2/1/1) acid mixture in a microwave-irradiated closed vessel system. The concentrations of Cd, Ni, Cr, Zn, Cu a...
The reduction in the use of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) has opened the way for the introduction of novel brominated flame retardants (NBFRs) in place of the banned formulations. Important representatives of this group are decabromodiphenyl ethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), hexabromobenzene (HBB), and pentabromoethylbenzen...
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