scholarly journals Improved geohydraulic characterization of river bed sediments based on freeze-core sampling – Development and evaluation of a new measurement approach

2015 ◽  
Vol 527 ◽  
pp. 133-141 ◽  
Author(s):  
Daniel Strasser ◽  
Hermann-Josef Lensing ◽  
Thomas Nuber ◽  
Dominik Richter ◽  
Simon Frank ◽  
...  
1996 ◽  
Vol 23 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Michael S. Adams ◽  
Hartmut Kausch ◽  
Thomas Gaumert ◽  
Karl-Ernst Krüger

SummaryWe review several studies and provide new data previously unpublished to show that there has been a substantial decline in pollution of German riverine waters since the beginning of German political reunification in 1989. This reduction is notable in the Elbe, which originates in eastern Germany and the Czech Republic. Pollutants such as many of the chlorinated hydrocarbons have fallen substantially in concentration, while others such as arsenic have declined only slightly. Total nitrogen has declined by only a small amount, but ammonium has fallen substantially, while nitrates have increased. Nitrification is no longer a significant drain on oxygen in the tidal stretch of the Elbe, but decomposition of algae from the middle Elbe is now a greater problem in the lower Elbe. The river-bed sediments of the middle Elbe have a higher species diversity. Fisheries are improving, and concentrations of pollutants in fish such as eel and bream have declined significantly. The river Werra has also improved in quality due to reduction in salt loadings from earlier potash mining.


1975 ◽  
Vol 12 (6) ◽  
pp. 1036-1040 ◽  
Author(s):  
Akira Kudo ◽  
D. C. Mortimer ◽  
J. Sanford Hart

The desorption rate of mercury from bed sediments was determined by a 10 week experiment. The rates ranged from 0.1 ng/cm2/day to 1.0 ng/cm2/day for Ottawa River bed sediments, depending on the environmental conditions. The rates decreased with an increase of exposure period to the water, but increased with an increase in the depth of bed sediments. The amount of mercury desorbed from bed sediments to overlying water was highly dependent on the volume (depth) of bed sediments. Calculations based on the experiment showed the half-lives of total mercury associated with bed sediments from as short as 2.1 years to as long as 1.8 × 102 years, depending on the depth of the bed sediments.


2013 ◽  
Vol 86 (1) ◽  
pp. 187-198 ◽  
Author(s):  
LÉO A. HARTMANN ◽  
LUCAS M. ANTUNES ◽  
LEONARDO M. ROSENSTENGEL

The Entre Rios mining district produces a large volume of amethyst geodes in underground mines and is part of the world class deposits in the Paraná volcanic province of South America. Two producing basalt flows are numbered 4 and 5 in the lava stratigraphy. A total of seven basalt flows and one rhyodacite flow are present in the district. At the base of the stratigraphy, beginning at the Chapecó river bed, two basalt flows are Esmeralda, low-Ti type. The third flow in the sequence is a rhyodacite, Chapecó type, Guarapuava subtype. Above the rhyodacite flow, four basalt flows are Pitanga, high-Ti type including the two mineralized flows; only the topmost basalt in the stratigraphy is a Paranapanema, intermediate-Ti type. Each individual flow is uniquely identified from its geochemical and gamma-spectrometric properties. The study of several sections in the district allowed for the identification of a fault-block structure. Blocks are elongated NW and the block on the west side of the fault was downthrown. This important structural characterization of the mining district will have significant consequences in the search for new amethyst geode deposits and in the understanding of the evolution of the Paraná volcanic province.


2008 ◽  
Vol 254 (1-2) ◽  
pp. 52-72 ◽  
Author(s):  
Joniell B. Borges ◽  
Youngsook Huh ◽  
Seulgi Moon ◽  
Hyeonjeong Noh

1998 ◽  
Vol 54 (3) ◽  
pp. 212-222 ◽  
Author(s):  
W. M. Daniels ◽  
W. A. House ◽  
B. V. Zhmud ◽  
J. E. Rae ◽  
A. Parker

2015 ◽  
Vol 85 ◽  
pp. 11-21 ◽  
Author(s):  
Zhongqiao Li ◽  
Francien Peterse ◽  
Ying Wu ◽  
Hongyan Bao ◽  
Timothy I. Eglinton ◽  
...  

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