Influence of Sediment Grain Size on Elutriate Toxicity of Inorganic Nanomaterials

2009 ◽  
Vol 44 (3) ◽  
pp. 201-210 ◽  
Author(s):  
Maria Alice Santos ◽  
Regina T.R. Monteiro ◽  
Christian Blaise ◽  
François Gagné ◽  
Kimberly Bull ◽  
...  
Keyword(s):  
Grain Size ◽  
Fine Particles ◽  
Toxicity Testing ◽  
Silica Sand ◽  
Sediment Grain Size ◽  
Artificial Sediment ◽  
Chemical Structures ◽  
Copper Zinc ◽  
Bioassay Data ◽  
Toxic Potential

Abstract Knowledge concerning the ecotoxic effects of nanomaterials, chemical structures with novel properties owing to their small sizes (1 to 100 nm), is wanting and deserves to be documented more fully. In this study we conducted testing with the MARA (microbial array for risk assessment) assay-an 11 microbial species 96-well microplate toxicity test measuring growth inhibition-to determine the toxic potential of four metallic nanopowders (MNPs): copper zinc iron oxide, samarium (III) oxide, erbium (III) oxide, and holmium (III) oxide. MTC (microbial toxicity concentration) endpoint values showed a range of toxicity responses generated by individual strains that was MNP-specific. Cluster analysis undertaken with the (n = 11) MTC values of the four MNPs, reflecting a toxic fingerprint proper to each nanochemical, indicated that their modes of action may be different. Experiments were also conducted with an artificial sediment, composed of varying concentrations of silica sand and kaolin (fine particles < 0.004 mm), spiked with each MNP to assess the contribution of fine particles on the resulting elutriate toxicity. The latter was shown to increase as fines contents decreased, except for CuZnFeO where no particular trends were observed. Toxicity testing was then undertaken with each MNP spiked into natural Saint Lawrence River freshwater sediments displaying low, medium, and high fines contents. Once again, analogous results to those obtained with the artificial sediment experiments were observed for MNP elutriate toxicity. Overall, MARA bioassay data indicate that MNP toxicity can be modulated by sediment grain size and that resulting adverse effects on aquatic biota will in part depend on such sediment characteristics.

scholarly journals The grain size distribution of settled sediment within storage reservoir Otmuchów

2017 ◽  
Vol 49 (1) ◽  
pp. 3-14
Author(s):  
Robert Głowski ◽  
Robert Kasperek
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Fine Particles ◽  
Satellite Image ◽  
Walking Distance ◽  
Sediment Grain Size ◽  
Storage Reservoir ◽  
Storage Reservoirs ◽  
Reservoir Length

Abstract The grain size distribution of settled sediment within storage reservoir Otmuchów. The river Nysa Kłodzka is flowing through the flat-reduction Otmuchów. There are localized two storage reservoirs Otmuchów and Nysa. The first of these reservoirs have been constructed in the period 1928-1933 and the filling was completed in 1934. Reservoir Nysa was completed in 1971. Both reservoirs are located within walking distance of each other, creating since 1971 cascade. Reservoir Otmuchów is located above the Nysa reservoir what cause, that in the bowl of the Otmuchów reservoir, the significant part of transported by Nysa Kłodzka sediments is deposited. When established after the 1997 flood damming levels, summer and winter, the length of the reservoir Otmuchów is suitably from 4.5 to 5 km. At the maximum impoundment level and a maximal capacity of 130.45 million m3 the reservoir length reach approx. 7 km. From the analysis of the satellite image can be seen advancing silting of the reservoir Otmuchów especially in the estuary zone of the Nysa Kłodzka. Obtained archival data about changes of the sediment grain size distribution in the longitudinal reservoir profile cover only the region of the still capacity extending a distance of 3 km from the cross-section of the dam. In this zone the fine particles of the suspended load with characteristic diameters ranging from 0.030 to 0.088 mm were embedded. In 2010, the authors presented the results of preliminary analysis of the silting process of the reservoir Otmuchów. The authors pointed out that there is a lack of the data about the dimension of the particles embedded in the usable capacity and flood capacity reserve (above 3 km from the dam) causing visible on satellite photo silting. This paper presents the results of the sediment grain size distribution in the usable capacity of the reservoir and in the estuary region of the Nysa Kłodzka located in flood capacity reserve, obtained from the sediment samples analysis. Obtained results allowed to supplement the image of the particle size distribution of the sediment being deposited in the reservoir Otmuchów longitudinal profile and an evaluation of the parameters of mobility rubble with fixed diameters.

The structure and arrangement of echinoid tubercles

1980 ◽  
Vol 289 (1033) ◽  
pp. 1-54 ◽  
Keyword(s):  
Grain Size ◽  
Fine Particles ◽  
Power Stroke ◽  
Test Surface ◽  
Spine Density ◽  
Sediment Grain Size ◽  
Effective Coverage ◽  
Locomotory Behaviour ◽  
Sand Dollars ◽  
And Function

Tubercles and spines of 33 species of extant irregular echinoids were studied to provide data for interpreting tubercle structure and arrangement in fossil echinoids. Tubercle morphology is analysed functionally. It is possible to infer much about the posture, movement and function of the associated spine from tubercle morphology. The development and direction of areole enlargement and the structure of the platform are the most important features in this respect. Surface stereom porosity is used to differentiate tubercles and miliaries, which bear either spines or pedicellariae, from granules, which have no such appendages. Tubercles of regular echinoids are usually radially symmetrical and can be broadly separated into fixed-pivot and sliding-pivot systems. In irregular echinoids, spines are usually modified for a particular function and tubercle morphology is correspondingly varied. The power stroke of the oral spines is radial in pygasteroids and holectypoids, whereas, in clypeasteroids and cassiduloids, it is posterior. This is reflected in their different burial and locomotory behaviour. Oral spine and tubercle arrangement in Cassidulus resembles that found in spatangoids and this again is reflected in its behaviour. Spine and tubercle differentiation becomes quite pronounced in certain clypeasteroids. It is argued that lunules and notches are modifications which allow sand dollars to feed on the organic-rich surface layer of sediment while remaining infaunal. Tubercle and spine diversity is most pronounced in the spatangoids and is described in detail for Echinocardium. Each group of spines with a particular function is associated with morphologically distinct tubercles. Tufts of spines are readily recognizable from the tubercle arrangement. The considerable variation in the arrangement of spines and tubercles within the anterior ambulacrum is thought to reflect the varying emphasis placed on adoral transportation of sediment. Fasciole arrangement shows no correlation with depth of burial or grain size of the substratum. Aboral tubercle density is correlated with sediment grain size. To maintain a water-filled space between the tip of the spines and the test surface, echinoids increase spine density and develop a uniform covering of spines with either distally swollen or spatulate tips. In spatangoids, a more effective coverage is achieved by development of curved or oblique aboral spines, and the aboral mucous coat prevents fine particles from falling between spines and clogging the burrow. The structure and arrangement of tubercles can be extremely useful in palaeobiological studies.

Change of quality indexes of premixes in the storage process

2020 ◽  
pp. 105-112
Author(s):  
Oksana Bitlian ◽  
Oksana Kravchenko ◽  
Tetiana Kodak ◽  
Andrii Onyshchenko ◽  
Tetiana Konks
Keyword(s):  
Raw Materials ◽  
Storage Process ◽  
Important Place ◽  
Inappropriate Use ◽  
Chemical Structures ◽  
Copper Zinc ◽  
Qualitative Responses ◽  
Chelating Compounds ◽  
Quality Indexes

The analysis of literature sources shows that the type and material from which the packaging is made has an important place in the system of factors which influence on the storage of feed products and also prevents reducing the quality of raw materials and finished products. Therefore, the purpose of our research is the technological justification of changing the quality indexes of premix samples with salts of trace elements of different chemical nature in the process of storage. For the solution of the tasks, common zootechnical and statistical methods of the research were used. The use of premixes in feeding pigs is based on the fact that they should be used taking into account the biogeochemical properties of the region for which they are calculated. Foods depending on regional properties have a special biochemical composition and excess or lack of individual substances should be offset by the composition of premix. Ignoring this provision necessarily leads to the inappropriate use of BAR, the misbalance of the diet in relation to the physiological needs and inefficiency of the industry. In turn, it requires the purchase and conservation of products for the period of use. Various chemical structures and structures of BAR during the storage process react differently and change qualitative indexes, which leads to a decrease in the productive activity of active substances. It was determined that the humidity of premixes varied within the limits of 12.0-13.0 %, which exceeded the normative, but was not critical, the highest acidity had premix with sulfuric acid salts (6.9 units), the least - premix with lysates (5.7 unit). According to the results of the study, positive qualitative responses were found for the presence of vitamins A, D and B2, macro- and micronutrients: potassium, magnesium, copper, zinc, cobalt, iodine. The above facts of changes in the properties of premixes in the process of storage must be taken into account when providing technological bases for feeding pigs in order to obtain high gains and the quality of manufactured products. Key words: premix, micro-and macro elements, combined fodders, fodder mixes, chelating compounds, feeding, using, pigs' livestock.

scholarly journals Centennial Impacts of the East Asian Summer Monsoon on Holocene Deltaic Evolution of the Huanghe River, China

2021 ◽  
Vol 11 (6) ◽  
pp. 2799
Author(s):  
Yanping Chen ◽  
Wenzhe Lyu ◽  
Tengfei Fu ◽  
Yan Li ◽  
Liang Yi
Keyword(s):  
Grain Size ◽  
Yellow River ◽  
Asian Summer Monsoon ◽  
River Delta ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Sediment Grain Size ◽  
Huanghe River ◽  
Huanghe River Delta ◽  
The Huanghe River

The Huanghe River (Yellow River) is the most sediment laden river system in the world, and many efforts have been conducted to understand modern deltaic evolution in response to anthropological impacts. However, the natural background and its linkage to climatic changes are less documented in previous studies. In this work, we studied the sediments of core YDZ–3 and marine surface samples by grain-size analysis to retrieve Holocene dynamics of the Huanghe River delta in detail. The main findings are as follows: The mean value of sediment grain size of the studied core is 5.5 ± 0.9 Φ, and silt and sand contents are 5.2 ± 2.3% and 8.2 ± 5.3%, respectively, while the variance of clay particles is relatively large with an average value of 86.4 ± 8.5%. All grain-size data can be mathematically partitioned by a Weibull-based function formula, and three subgroups were identified with modal sizes of 61.1 ± 28.9 μm, 30.0 ± 23.9 μm, and 2.8 ± 1.6 μm, respectively. There are eight intervals with abrupt changes in modal size of core YDZ–3, which can be correlated to paleo-superlobe migration of the Huanghe River in the Holocene. Based on these observations, the presence of seven superlobes in the history are confirmed for the first time and their ages are well constrained in this study, including Paleo-Superlobes Lijin (6400–5280 yr BP), Huanghua (4480–4190 yr BP), Jugezhuang (3880–3660 yr BP), Shajinzi (3070–2870 yr BP), Nigu (2780–2360 yr BP), Qikou (2140–2000 yr BP), and Kenli (1940–1780 and 1700–1650 yr BP). By tuning geomorphological events to a sedimentary proxy derived from core YDZ–3 and comparing to various paleoenvironmental changes, we proposed that winter climate dominated Holocene shifts of the Huanghe River delta on millennial timescales, while summer monsoons controlled deltaic evolution on centennial timescales.

East Asian winter monsoon variation during the last 3000 years as recorded in a subtropical mountain lake, northeastern Taiwan

The Holocene ◽  
2021 ◽  
pp. 095968362110190
Author(s):  
Tsai-Wen Lin ◽  
Stefanie Kaboth-Bahr ◽  
Kweku Afrifa Yamoah ◽  
André Bahr ◽  
George Burr ◽  
...  
Keyword(s):  
Grain Size ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Winter Monsoon ◽  
Mountain Lake ◽  
Sediment Grain Size ◽  
Global Monsoon ◽  
Asian Winter Monsoon ◽  
The Past ◽  
Monsoon System

The East Asian Winter Monsoon (EAWM) is a fundamental part of the global monsoon system that affects nearly one-quarter of the world’s population. Robust paleoclimate reconstructions in East Asia are complicated by multiple sources of precipitation. These sources, such as the EAWM and typhoons, need to be disentangled in order to understand the dominant source of precipitation influencing the past and current climate. Taiwan, situated within the subtropical East Asian monsoon system, provides a unique opportunity to study monsoon and typhoon variability through time. Here we combine sediment trap data with down-core records from Cueifong Lake in northeastern Taiwan to reconstruct monsoonal rainfall fluctuations over the past 3000 years. The monthly collected grain-size data indicate that a decrease in sediment grain size reflects the strength of the EAWM. End member modelling analysis (EMMA) on sediment core and trap data reveals two dominant grain-size end-members (EMs), with the coarse EM 2 representing a robust indicator of EAWM strength. The downcore variations of EM 2 show a gradual decrease over the past 3000 years indicating a gradual strengthening of the EAWM, in agreement with other published EAWM records. This enhanced late-Holocene EAWM can be linked to the expansion of sea-ice cover in the western Arctic Ocean caused by decreased summer insolation.

Relationships between multibeam backscatter, sediment grain size and Posidonia oceanica seagrass distribution

2010 ◽  
Vol 30 (18) ◽  
pp. 1941-1950 ◽  
Author(s):  
Giovanni De Falco ◽  
Renato Tonielli ◽  
Gabriella Di Martino ◽  
Sara Innangi ◽  
Simone Simeone ◽  
...  
Keyword(s):  
Grain Size ◽  
Posidonia Oceanica ◽  
Sediment Grain Size

scholarly journals Flow Characteristics and Grain Size Distribution of Granular Gangue Mineral by Compaction Treatment

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Ran Yuan ◽  
Dan Ma ◽  
Hongwei Zhang
Keyword(s):  
Weight Loss ◽  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Water Flow ◽  
Fine Particles ◽  
Flow Characteristics ◽  
Test System ◽  
Chemical Components ◽  
Gangue Mineral

A test system for water flow in granular gangue mineral was designed to study the flow characteristics by compaction treatment. With the increase of the compaction displacement, the porosity decreases and void in granular gangue becomes less. The main reason causing initial porosity decrease is that the void of larger size is filled with small particles. Permeability tends to decrease and non-Darcy flow factor increases under the compaction treatment. The change trend of flow characteristics shows twists and turns, which indicate that flow characteristics of granular gangue mineral are related to compaction level, grain size distribution, crushing, and fracture structure. During compaction, larger particles are crushed, which in turn causes the weight of smaller particles to increase, and water flow induces fine particles to migrate (weight loss); meanwhile, a sample with more weight of size (0–2.5 mm) has a higher amount of weight loss. Water seepage will cause the decrease of some chemical components, where SiO2 decreased the highest in these components; the components decreased are more likely locked at fragments rather than the defect of the minerals. The variation of the chemical components has an opposite trend when compared with permeability.

scholarly journals Remote sensing of underwater vegetation using single-beam acoustics

2009 ◽  
Vol 67 (3) ◽  
pp. 594-605 ◽  
Author(s):  
Victor Quintino ◽  
Rosa Freitas ◽  
Renato Mamede ◽  
Fernando Ricardo ◽  
Ana Maria Rodrigues ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Grain Size ◽  
Algal Biomass ◽  
Sediment Grain Size ◽  
Coastal System ◽  
Single Beam ◽  
Acoustic Data ◽  
Sediment Types ◽  
Caulerpa Prolifera ◽  
Sandy Sediments

Abstract Quintino, V., Freitas, R., Mamede, R., Ricardo, F., Rodrigues, A. M., Mota, J., Pérez-Ruzafa, Á., and Marcos, C. 2010. Remote sensing of underwater vegetation using single-beam acoustics. – ICES Journal of Marine Science, 67: 594–605. A single-beam, acoustic, ground-discrimination system (QTC VIEW, Series V) was used to study the distribution of underwater macrophytes in a shallow-water coastal system, employing frequencies of 50 and 200 kHz. The study was conducted in Mar Menor, SE Spain, where the expansion of Caulerpa prolifera has contributed to the silting up of the superficial sediments. A direct relationship was identified between algal biomass and sediment-fines content. Acoustic information on sediment grain size and data on algal biomass were obtained in muddy and sandy sediments, including vegetated and non-vegetated seabed. Non-vegetated muddy areas were created by diving and handpicking the algae. The multivariate acoustic data were analysed under the null hypotheses that there were no acoustic differences between bare seabeds with contrasting superficial sediment types or among low, medium, and high algal-biomass areas, having in mind that grain size can act as a confounding factor. Both null hypotheses were rejected, and the results showed that 200 kHz was better than 50 kHz in distinguishing cover levels of algal biomass. The relationship between the 200-kHz acoustic data and algal biomass suggests utility in modelling the latter using the former.

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