Wyniki wyszukiwania - Biblioteka Nauki

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Influence of land development on heavy metal forms in the Bobrza River ecosystem (Świętokrzyskie Province, Poland)

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Rabajczyk A.

Open Chemistry

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2011

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tom 9

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nr 2

326-336

EN

Metals are perceived as pollutants but they are also natural substances found in the environment. The surface water environment is under the influence of continuing industrial pollution/effluents. Therefore it is necessary to determine various metal forms present in each component of the water ecosystem. The study presents analysis for Cd, Cu, Cr, Fe, Mn, Ni, Zn and Pb content in the Bobrza River bottom deposits and water. The analysis of water and sediment samples from the Bobrza River taken from the littoral zone at three sampling points: the riverhead, i.e. the natural environment; Białogon - the acidic environment; and Sitkówka-Nowiny - the alkaline environment, were analyzed. Sample quality indicators were defined with pH value, conductivity, heavy metal content for water and suspended matter samples. The metal forms in river sediment were also analyzed. The sediment samples were subjected to Tessier’s five-stage sequential extraction procedure assisted by microwave radiation. Analyte concentration in water samples and in the extracts was determined with the use of F-AAS and GF-AAS techniques. The results obtained reveal a relationship between land development, the degree of metal bonding with suspended matter and metal forms found in river sediments.

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Pleistocene deposits in the Southern Egyptian Sahara: lithostratigraphic relationships of sediments and landscape dynamics at Bir Tarfawi

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Hill C. L. , Schild R.

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tom Vol. 34, Nr 1

23--38

EN

The sedimentological and lithostratigraphic record from north-central Bir Tarfawi documents the presence of Pleistocene basin-fill deposits. Three topographic basins were created as a result of deflation during climate episodes associated with lowering of the local groundwater table. In each case, the three deflational basins or topographic depressions were subsequently filled with sediments; these basin aggradations coincided with changes from arid climate conditions to wetter conditions and a rise in the groundwater table. The oldest and highest sedimentary remnant is associated with Acheulian artifacts and may reflect spring-fed pond and marsh conditions during a Middle Pleistocene wet climate episode. Lithofacies for a lower stratigraphic sequence (the “White Lake”) documents deposition in a perennial lake that varied in extent and depth and is associated with Middle Paleolithic artifacts. A third episode of deflation created a topographic low that has been filled with Late Pleistocene sediments that are associated with Middle Paleolithic artifacts and fossil remains. Lateral and vertical variations in the lithofacies of this basin-fill sequence and the sediments of the “grey-green” lake phases provide a record of changing hydrologic conditions. These hydrologic conditions appear to reflect variations in water-table levels related to groundwater recharge and, at times, local rains.

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Assessment of elemental contamination in the bottom sediments from a dam reservoir using a sequential extraction technique and chemometric analysis

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Dabioch M. , Kita A. , Zerzucha P. , Pytlakowska K.

Open Chemistry

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2013

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tom 11

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nr 12

1981-1995

EN

The concentration of elements in sediments is an important aspect of the quality of water ecosystems. The element concentrations in bottom sediments from Goczalkowice Reservoir, Poland, were investigated to determine the levels, accumulation and distribution of elements; to understand the contamination and potential toxicity of elements; and to trace the possible source of pollution. Sediments were collected from 8 sampling points. The functional speciation, mobility and bioavailability of elements were evaluated by means of modified Tessier sequential extraction. The element contents were measured by optical emission spectrometry with inductively coupled plasma. The experimental results were analyzed using chemometric methods such as principal component analysis and cluster analysis to elucidate the metal distributions, correlations and associations. The highest concentrations of most elements were found at the center of the reservoir. The distribution of metals in the individual fractions was varied. To assess the extent of anthropogenic impact indices, contamination factor, degree of contamination, metal pollution index and risk assessment code were applied. The calculated factors showed the highest contamination factor and the ability of chromium to be released from sediments. The degree of contamination showed that the area is characterized by a very high contamination. Strontium and manganese showed high potential ecological risk for sediments. [...]

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Dinoflagellate cysts and benthic foraminifera from surface sediments of Svalbard fjords and shelves as paleoenvironmental indicators

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Telesiński M. M. , Pospelova V. , Mertens K. N. , Kucharska M. , Zajączkowski M.

Oceanologia

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2023

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tom Vol. 65 (4)

571--594

EN

Due to the Arctic amplification effect, the Svalbard archipelago is an important area for studying ongoing environmental changes. However, its marine ecosystem is extremely complex. In this study, we analyze modern assemblages of dinoflagellate cysts (dinocysts) and benthic foraminifera from surface sediment samples around Svalbard. We use multivariate statistical analyses to examine relationships between environmental conditions (summer and winter sea surface temperature and salinity, sea-ice cover, etc.) and both microfossil groups to evaluate their use as proxies for reconstructions of the marine environment in the region. Our results show that the most important factor controlling the environment around Svalbard is the Atlantic Water which mostly impacts the western coast, but its influence reaches as far as the eastern coast of Nordaustlandet. However, on a local scale, such factors as the sea-ice cover, the presence of tidewater glaciers, or even the morphology and hydrology of fjords become increasingly important. We found that two dinocyst species, cysts of Polarella glacialis and Echinidinium karaense, can be considered regional winter drift ice indicators. The relationships between environmental parameters and benthic foraminiferal assemblages are much more difficult to interpret. Although statistical analysis shows a correlation of benthic foraminiferal species with various environmental parameters, this correlation might be somewhat coincidental and caused by other factors not analyzed in this study. Nevertheless, the use of two complementary microfossil groups as (paleo)environmental indicators can provide a more comprehensive picture of the environmental conditions.

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Distribution and Source Fingerprinting of Total Petroleum Hydrocarbons in Sediments of the River Niger at Okpu and Iyiowa-Odekpe Axes in South-Eastern, Nigeria

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Chokor A. A.

World News of Natural Sciences

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2022

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tom 42

151-168

EN

The assessment of total petroleum hydrocarbons (TPH) status as well as the aliphatic profiles of sediments from the Okpu and Iyiowa-Odekpe segments of the River Niger in South-Eastern Nigeria was conducted during the year 2021 – 2022. Composites samples taken from sediments at five (5) different locations (ST-A, ST-B, ST-C, ST-D, & ST-E) for the months of June, September, December, and February, were extracted with dichloromethane (DCM) using soxhlet extractor followed by a silica gel clean up and fractionation into aliphatic and aromatic fractions. Analysis of aliphatic fraction (Total Aliphatic Hydrocarbons –TAH - and aliphatic components) were done with gas chromatography-flame ionization detector (GC-FID); while the polycyclic aromatic hydrocarbons (PAHs) were determined with gas chromatography-mass spectrometry (GC-MS). The summations of TAHs and PAHs gave the TPHs concentrations that ranged from 108.04 – 1091.46mg/Kg with a mean of 440.0234 ± 54.78mg/Kg. The mean value for the raining season (515.10±281.73 mg/Kg) was significantly higher than that of the dry season (364.94 ± 205.54 mg/Kg). The range of values were also much higher than the Nigerian Department of Petroleum Resources (DPR) target value of 50mg/Kg but considerably much lower than the intervention value (5,000mg/Kg) set by the same body. Source diagnostic indices of aliphatic hydrocarbons gave range of: even to odd numbered n-alkane ratio (0.7183 – 1.7184), carbon preference index – CPI (0.65041 – 1.4520), sum of low molecular weight to high molecular weight n-alkane (1.0559 – 8.8077), nC31/nC19 (0.16867 – 1.1461), sum of long chain hydrocarbons to short chain hydrocarbons (0.1686 – 1.1470), and pristane/phytane ratio (0.6523 – 2.5284); suggesting that the TPHs in sediments were from mixed origin – anthropogenic and biogenic. Inputs from biogenic sources were however, dominated by marine sources. Developmental plans and actions that will reduce these anthropogenic inputs are necessary to protect the aquatic lives and sustain public health.