scholarly journals Organic Matter and Grain-Size Distribution of the Modern Bottom Sediments in the Balaklava Bay (the Black Sea)

2019 ◽  
Vol 25 (6) ◽  
Author(s):  
N. A. Orekhova ◽  
E. I. Ovsyany ◽  
K. I. Gurov ◽  
M. A. Popov ◽  
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...  
2008 ◽  
Vol 37 (4) ◽  
Author(s):  
Mirosław Skorbiłowicz ◽  
Elżbieta Skorbiłowicz

The distribution of lead, zinc, and chromium in fractions of bottom sediments in the Narew River and its tributariesThe purpose of the paper was to evaluate the distribution of lead, zinc and chromium contents in different grain fractions of bottom sediments in the Narew River and some of its tributaries. This study also aimed to determine which fractions are mostly responsible for bottom sediment pollution. The studies of the Narew and its tributaries (the Supraśl, Narewka, and Orlanka) were conducted in September 2005 in the upper Narew catchment area. The analyzed bottom sediments differed regarding grain size distribution. The studies revealed the influence of the percentage of particular grain fractions present on the accumulation of heavy metals in all bottom sediments.


2004 ◽  
Vol 5 (1) ◽  
pp. 43
Author(s):  
K.G. PEHLIVANOGLOU ◽  
G. TRONTSIOS ◽  
A. TSIRAMBIDES

The Thermaikos Gulf constitutes the NW part of the North Aegean Sea and is limited eastward from the Chalkidiki Peninsula and westward from the Pieria Prefecture. Its plateau covers an area of 3,500 km2. The mechanisms responsible for the grain size distribution into the Gulf, the clay mineralogy and the chemistry of some bottom sediments from the outer Thermaikos Gulf, are examined. Source mixing during transportation, flocculation, differential settling processes and organic matter appear to be the main mechanisms for the distribution of clay minerals in shallow waters. All grain size fractions studied present a wide range of values confirming the extreme variations of the discharged load and the variability in marine processes. Plagioclases predominate over K-feldspars, while quartz is the most abundant mineral present. In addition, micas, chlorites, amphiboles and pyroxenes exist as primary and/or accessory minerals in all samples. Among clay minerals, illite predominates over smectite and smectite over chlorite (+ kaolinite). The ordered interstratified phase of I/S, with 30-35% S layers, is present in the 2-0.25µm fraction. The randomly interstratified phase of I/S, with 50% S layers, is present in the <0.25& micro; m fraction. On average the clay mineral content of the studied samples is: 48% I, 23% S, 17% Ch (+K) and 12% others for the 2-0.25µm fraction and 50% I, 30% S and 20% Ch (+K) for the <0.25 µm fraction. All these minerals are the weathering products of the rocks from the drainage basins of the rivers flowing into the Gulf, as well as of the Neogene and Quaternary unconsolidated sediments of the surrounding coasts. The terrigenous input, the water mass circulation and, to a lesser extent, the quality of the discharged material and the differential settling of grains, control the grain size distribution within the outer Thermaikos Gulf. The chemical composition of the analysed samples is generally in agreement with their mineral composition and signifies their terrigenous origin presenting discretely clastic character.


Author(s):  
E. A. Tikhonova ◽  

As part of the 113th cruise of the R/V “Professor Vodyanitsky”, research was conducted on organic pollution of bottom sediments in the coastal areas of Crimea and the Caucasus, as well as the water area in front of the Kerch Strait. Concentration of chloroformextractable substances was determined by the weight method and that of petroleum hydrocarbons was determined using infrared spectrometry. Both in 2020 and 2016 (the 83d cruise of the R/V “Professor Vodyanitsky”), properties of the bottom sediments of the Crimean and Caucasian coasts were typical of the marine soils of this region. This indicates that the studied water areas are generally in good condition. In accordance with the regional classification of bottom sediment pollution, the maximum concentrations of chloroform-extractable substances obtained for both the Black Sea and the Sea of Azov coast indicate pollution level III (23% of analysed samples). These values were found in bottom sediments in the Sevastopol water area (225 mg·100 g-1), in the coastal area of Cape Tarkhankut (120 mg·100 g-1) and Karadag (120 mg·100 g-1), the southern part of the Sea of Azov (125 mg·100 g-1) and Tuapse (110 mg·100 g-1). The content of chloroform-extractable substances in bottom sediments off the Black Sea coast of the Caucasus and the Sea of Azov coast is slightly lower than that off the Crimean coast. Pollution level II is assigned to bottom sediments in 46 % of the samples, with an average concentration of 72 mg·100 g-1 of air-dry solids. The rest (31 %) of the studied area was classified as conditionally clean (pollution level I, i. e. less than 50 mg·100 g-1). There has been a slight increase in the concentration of petroleum hydrocarbons in the bottom sediments of both the Black Sea and the Sea of Azov and their share in the total amount of chloroformextractable substances. In general, the level of pollution of bottom sediments by organic matter remained unchanged if compared with previous years, in particular with the data from 2016


Cerâmica ◽  
2001 ◽  
Vol 47 (304) ◽  
pp. 204-207 ◽  
Author(s):  
S. R. Teixeira ◽  
S. A. de Souza ◽  
C. A. I. Moura

Plasticity and the grain-size distribution of the raw material used to make structural bricks and roof tiles are very important to the production process. These two parameters and the mineral composition will define the quality and properties of the final product: color, mechanical resistance, water absorption, cracks, swell and shrink during drying and firing the ceramic pieces etc. In the Brazilian ceramic industry it is very common to mix together two or more different kinds of raw material to achieve the ceramic mass with the desired grain-size distribution. The objective of this work was to characterize the raw material collected at the floodplains of the Paraná and Paranapanema Rivers and the ceramic mass used by the ceramic industry in western São Paulo State, Brazil. Particle size distribution, organic matter and X-ray diffraction were used to study this material. The textural analysis indicates that the raw materials have the clay fraction ranging from 38.2% to 66.3%, the silt from 22.2% to 49.7% and the sand from 3.1% to 34.1%. The results indicate that all mixed raw materials have more clay in its composition than would be necessary. The organic matter ranges from 5 to 7%. All samples have kaolinite and many of them have smectites, HIV and mica. Gibbsite, iron and titanium oxides, and quartz are also identified. One of the samples (yellow) is rich in goethite.


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