Ograniczanie wyników
Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 88

Liczba wyników na stronie
first rewind previous Strona / 5 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  sediment
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 5 next fast forward last
EN
Samples of water, sediment and two native plants (Eichhornia crassipes and Ceratophyllum demersum), collected seasonally from eight sites, were analyzed to investigate the level of contamination with metals (Fe, Mn, Ni, Co, Zn, Cu, Cr, Pb and Cd) in the Nile River in the Cairo region, using heavy metal pollution and contamination indices in the case of water, and the geoaccumulation index, the pollution load index, the enrichment factor and the potential ecological risk factor in the case of sediment. The results clarified that the levels of metals among three compartments were in order: sediments > plants > water. The Nile water in Cairo is not critically polluted by the studied metals and the metal pollution index for most sites does not exceed the critical limit (< 100). Sediment samples showed a clear accumulation of Mn, Ni and Cd when compared with benchmarks cited by the Environmental Protection Agency (EPA), especially during low flow seasons. The contribution of Cd to the ecological risk assessment was about 80%, while the contribution of Ni was about 10%, reflecting that these elements originated primarily from anthropogenic sources. Eichhornia crassipes and Ceratophyllum demersum have a higher accumulation capacity for Mn, Cu and Fe compared to the other studied metals.
EN
Heavy metals like cadmium (Cd) and lead (Pb) are pollutants that are toxic, difficult to decompose and accumulate in biota. One of the biota that lives in the waters is mullet fish. This fish is demersal, has a relatively long life period, has a specific tolerance to the aquatic environment and highly consumable in Indonesia. Therefore need to know the metal content of Cd and Pb in water, sediments and mullet fish and their relationship in Indonesia. The study used a survey method with purposive random sampling at four stations, three replications. The study was conducted from June to November 2019. Analysis of data was descriptive, F-test and correlation. The results showed that the heavy metal content of Cd and Pb between stations in the water media, sediment and in mullet fish there was a significant difference. The highest Cd and Pb were showed in station III, coming from the oil industry, domestic waste and transportation activities. The heavy metal content of Cd and Pb in water, sediment and mullet fish (Planiliza subviridis) in the Donan River, Cilacap shows results exceeding the allowed threshold and danger to human health.
EN
The Ecotourism Mangrove Forest at Wonorejo in East Coast Surabaya area is one of large mangrove forests inside in the metropolitan city in Indonesia. There are many ecological values of the mangrove forest in most tropical countries such as sea fisheries, place of sea and coastal animals, sea and brackish water quality protecting the endangered mangrove coastlines and development of human life. The role of mangrove in increasing the sea and brackish water quality can be shown through many processes such as cycling of nutrients, particulate matter and some pollutants in water and sediment around the mangrove plants. One of the inorganic pollutants that can be removed by mangrove are heavy metals, such as chromium (Cr). The Wonorejo River is one of the rivers that receive the disposal of wastewater in Surabaya East Coast area. Large quantitites of wastewater from industries and households were released to this river. The concentration of Cr at the Wonorejo Estuary reached 0.0325 mg/L and 2.7761 mg/L in sediments. The purpose of this research was to determine the potency of Cr accumulation by Avicennia alba that was grown for ten years at Wonorejo Ecotourism Mangrove Forest. The sampling activities were conducted using a transect quadrat sampling method with a 10x10 m dimension. The sediment and mangrove root samples were extracted before being analysed using an atomic absorption spectrophotometer (AAS). The results showed that the Cr accumulation by roots of A. alba reached 25.4 ± 1.6 to 55.3 ± 1.1. The BCF value in A. alba were 0.32 ± 0.01 to 0.83 ± 0.5 with the concentration Cr in sediment were 60 ± 1.4 to 79.3 ± 1.1. A. alba showed potential as a moderate accumulator for Cr. In conclusion, A. alba can be considered for use in phyto-monitoring and phytoremediation of Cr in coastal areas.
EN
Under hydrological uncertainty and to secure the potable water supply for the Fez city with more than one million and a half inhabitants, the competent authority intends to bring water from the Idriss 1st reservoir 30 km away, downstream the Inaouene watershed. The pollution risks as well as the contamination degree of surface water and sediments were assessed by monitoring the physicochemical characteristics of the water and sediment samples. The results revealed high values of chemical oxygen demand and chloride mainly linked to the uncontrolled liquid discharges. Calcium and magnesium showed also high concentrations that are due to the watershed geology, where carbonate rocks are dominant. The contents of some heavy metals remain relatively low and within the Moroccan standards. The metal contents in sediments show a low degree of the anthropogenic pollution. This led to conclude that the waters and sediments in the study area show relatively degraded quality and then could be used for water supply under continuous control.
EN
Purpose: Due to an increase in a number of bridges being constructed, scour depth around bridge piers is gradually being recognized as one of the possible reasons for bridge failure. According to [1] about 53% of bridge failures in the US were caused due to floods and corresponding scour in the rivers. Lots of work has been carried out around the single pier but in the case of group piers, the work is very less. Hence, it becomes necessary to calculate the actual scour depth around the bridge piers considering the close location of bridges as well. Design/methodology/approach: Recognizing the need for research in this direction, an experimental study was planned and conducted in the Hydraulics Laboratory of Civil Engineering Department of National Institute of Technology Kurukshetra, India. Experiments were conducted in a standard recirculating tilting bed water flume 15 m long, 0.4 m wide, and 0.60 m deep. The orientation of more than one pier, namely Tandem pattern was employed for the work. Two pier models, 62 mm and 42 mm diameter were used for the experimental study. The mobile bed used in the experiments had an average mean size, d50 = 0.23 mm, 0.30 mm and 0.50 mm. Findings: The outcomes of the ANN function and M5 model analysis have been used to compare with experimental results. From the earlier studies, it was concluded that, when the clear spacing between the pier models was greater than 0D the scour depth around the piers increase with a rapid rate. However, in the case of modelling techniques, M5 models show higher predictive accuracy than ANN models. Research limitations/implications: It is a significant area of research. However, the present study has been a time and facility- constrained study. Therefore, there is a large scope to conduct further studies on the subject, Different pattern i.e. Side by Side; Staggered and Group of piers can be adopted for further investigations. Originality/value: Sufficient work has been done by number of researchers around the single bridge pier. But due to rapid urbanization a number of bridges constructed in close proximity to each other which affects the scour depth of each other. Modelling techniques used in hydraulic engineering are not always effective in practice. The present study discusses the effect of spacing on scouring around piers in a tandem arrangement using experimental as well as modelling techniques. To predict the scour depth of the Tandem arrangement 89 laboratory data sets have been used.
EN
This study investigated the multifractality of streamfow data of 192 stations located in 13 river basins in India using the multifractal detrended fuctuation analysis (MF-DFA). The streamfow datasets of diferent river basins displayed multifractality and long-term persistence with a mean exponent of 0.585. The streamfow records of Krishna basin displayed least persistence and that of Godavari basin displayed strongest multifractality and complexity. Subsequently, the streamfow-sediment links of fve major river basins were evaluated using the novel multifractal cross-correlation analysis (MFCCA) method of cross-correlation studies. The results showed that the joint persistence of streamfow and total suspended sediments (TSS) is approximately the mean of the persistence of individual series. The streamfow displayed higher persistence than TSS in 60% of the stations while in majority of stations of Godavari basin the trend was opposite. The annual cross-correlation is higher than seasonal cross-correlation in majority of stations but at these time scales strength of their association difers with river basin.
EN
In this study, we conducted a comparative analysis of the abundance and diversity of bacteria on the surface of the submerged macrophyte Myriophyllum spicatum, as well as in the surrounding water column and sediment in the low-salinity area of Hangzhou Bay, China. Bacterial clones from three clone libraries were classified into 2089 operational taxonomic units (OTUs), most of which affiliated with bacterial divisions commonly found in marine ecosystems. Alphaproteobacteria, Cyanobacteria and Gammaproteobacteria were the most abundant groups of bacteria on the surface of plants, in the water column and sediment, respectively. Epiphytic bacterial communities were more closely related to those in the sediment than bacterioplankton, and some species of epiphytic bacteria were found only on the surface of M. spicatum. The relative abundance of epiphytic bacterial genera associated with breakdown of organic compounds and with cellulose digestion was higher in October than that in July. These results suggested that bacterial communities on the surface of M. spicatum may originate from sediment bacterial communities and their specific structure was gradually formed on the surface of M. spicatum after being cultivated in low-salinity seawater.
EN
The seasonal patterns of the denitrifiers (denitrifying bacteria) in the sediment of Daya Bay, southern China, were examined using quantitative PCR and high-throughput MiSeq sequencing methods in spring, summer and winter. The abundance and diversity of nirS-encoding denitrifiers were much higher than that of nirK-encoding denitrifiers, indicating that the former probably dominated the denitrification processes in sediments of Daya Bay. The average abundance and diversity of nirS-encoding denitrifiers were much higher in spring than that in summer and winter, on the other hand, the abundance of nirK-encoding denitrifiers showed the opposite pattern. The species composition of nirS-encoding denitrifiers community in spring differed significantly from that in summer and winter, whereas, no significant difference existed between summer and winter. The dominant environmental drivers for the diversity of community species were NO2-, NO3- and DO concentrations. The abundances of dominant genera of nirS-encoding denitrifiers, Accumulibacter sp. and Cuprizvidus sp., were significantly higher in summer and winter than that in spring, and were negatively correlated with NO2-, NO3-, and DO concentrations ( p < 0.05). In contrast, the abundances of Azoarcus sp. and Halomonas sp., were highest in spring, and were positively correlated with NO3- and NO2- content (p < 0.05). For nirK-encoding denitrifiers, a significant difference in community composition was observed between spring and winter. No obvious correlation was found between community composition of nirK-encoding denitrifiers and environmental parameters.
PL
W artykule przedstawiono zagadnienia związane z biodegradacją osadów zdeponowanych w instalacjach wydobywczych i transportujących ropę naftową. Materiał badawczy stanowiły osady zdeponowane w różnych częściach instalacji. Zbadano skład osadów pod kątem zawartości substancji nieorganicznych i organicznych, grupowego składu węglowodorów ropopochodnych (węglowodory alifatyczne, aromatyczne, żywice, asfalteny) oraz zawartości węglowodorów ropopochodnych TPH. Na podstawie uzyskanych wyników stwierdzono, że badane osady składają się głównie z substancji organicznych, z czego zdecydowaną większość stanowią węglowodory alifatyczne. Wyjątkiem jest osad pobrany po tłokowaniu, w którym odnotowano stosunkowo duże zawartości węglowodorów aromatycznych, żywic i asfaltenów. Dla wszystkich osadów obliczono zawartość n-alkanów o długości łańcucha węglowego od n-C8 do n-C44. Szczególną uwagę zwrócono na podatność osadów na biodegradację pod wpływem biopreparatów opracowanych na bazie mikroorganizmów allochtonicznych. Szybkość biodegradacji substancji ropopochodnych analizowano wykorzystując zestaw OxiTop Control. Wzrost aktywności mikrobiologicznej w środowisku reakcyjnym pod wpływem dodatku biopreparatów świadczył o biodegradacji substancji organicznych zawartych w osadach. Na podstawie uzyskanych wyników testu respirometrycznego wytypowano biopreparat, pod wpływem którego biodegradacja zachodziła najbardziej efektywnie. Najbardziej skuteczny okazał się biopreparat IV, w wyniku działania którego uzyskano obniżenie zawartości węglowodorów alifatycznych o długości łańcucha węglowego n-C8 do n-C18 dla osadu najłatwiej biodegradowalnego (osad nr 5) o 59–37%. Natomiast w osadzie najtrudniej biodegradowalnym (osad nr 5) zanotowano spadek o 27–11%. Węglowodory z zakresu n-C19 do n-C30 również uległy biodegradacji w zadowalającym stopniu, tj. 35–14% w osadzie nr 5 oraz 11–6% w osadzie nr 4. Węglowodory zawierające powyżej 30 atomów węgla w cząsteczce uległy redukcji w granicach 13–3% w osadzie nr 5 i 6–2% w osadzie nr 4. Dla osadów surowych i osadów po przeprowadzeniu testu biodegradacji z wybranym biopreparatem, sporządzono wykresy ilustrujące zmianę zawartości n-alkanów w badanych próbkach.
EN
The article presents issues related to the biodegradation of sediments deposited in extraction and transporting crude oil installations. The research material were sediments deposited in various parts of the installation. The composition of sediments in terms of the content of inorganic and organic substances, group composition (aliphatic hydrocarbons, aromatic hydrocarbons, resins, asphaltenes) and the content of Total Petroleum Hydrocarbon (TPH) were examined. On the basis of the results obtained, it was concluded that the sediments studied consist mainly of organic substances, of which the vast majority are aliphatic hydrocarbons. The exception is the post-piston sediment, in which relatively high amounts of aromatic hydrocarbons, resins and asphaltenes were noted. The content of n-alkanes with carbon chain length from n-C8 to n-C44 was calculated for all sediments. Particular attention was paid to the susceptibility of sediments to biodegradation under the influence of biopreparations prepared on the basis of allochthonic microorganisms. The rate of biodegradation of petroleum derivatives was analyzed using the OxiTop Control set. The increase in microbial activity in the reaction environment under the addition of biopreparations attested to the biodegradation of organic substances contained in the sediments. On the basis of the results of the respirometric test, a biopreparation was selected, under which biodegradation took place most effectively. The most effective was biopreparation IV, as a result of which the reduction of aliphatic hydrocarbons with a carbon chain length of n-C8 to n-C18 for the most biodegradable sediment (sediment No. 5) by 59–37% was achieved, whereas the most difficult to biodegrade sediment (sediment No. 5) by 27–11%. Hydrocarbons from the range of n-C19 to n-C30 were also biodegradable to a satisfactory degree, i.e. 35–14% in the sediment No. 5 and 11÷6% in the sediment No. 4. Hydrocarbons containing more than 30 carbon atoms in the molecule were reduced within the limits of 13–3% in sediment No. 5 and 6–2% in sediment No. 4. For raw sediments and sediments after biodegradation test using the selected biopreparation, charts illustrating the change in the content of n-alkanes in the samples were made.
EN
The surface water quality and level of metal contents in the contamination of the Toplluha river sediment were determined by means of statistical techniques and pollution indicators. The samples of water and sediments were taken in five different locations along the Toplluha river in the spring period 2013 and 2019 using standard methods for analysis. International standards (WHO 2004) were used to assess the quality of water. The samples of water in some of the locations were above these criteria levels. The heavy metal contents in the sediment were in the following order: Cu > Zn > Cr > Ni > Pb > Cd. For the evaluation of the heavy metal content, some factors were applied: enrichment factor (EF), pollution load index (PLI) and index of geoccumulation (Igeo). Cu and Pb have a significance enrichment according to the calculated EF values. The Igeo index values for Cu and Zn were at a higher level. The PLI index values were at a progressive high level from stations S3 to S5. Therefore, the preliminary treatment of the discharging waters is indispensable.
EN
A study investigated physicochemical parameters in environmental matrices along the river Cerica waters. A corre- lation between the actual level of pollution of this river and its impact on the Drini i Bardhë River was determined. The extent of its pollution, was conducted following the identification of pollution sources, which consequently allowing to determine the necessary steps for their isolation. The monitoring of heavy metals, physicochemical parameters, nutrients was carried out in all country-sample (locations). In particular, there where are significant sources of pollution of surface waters, as a result of industrial activities and wastewater discharge. Determining of the locations and heavy metals concentrations was carried out in sediments and agricultural lands in this region, with the purpose to reflect the actual stat.
12
Content available remote Po stronie przewodów tłocznych w pompowniach ścieków
PL
W artykule zostały rozważone trzy tematy dotyczące pompowania ścieków: zawory zwrotne, wpływ drobnych kamieni oraz grubego żwiru na opory przepływu w pionowym przewodzie oraz tworzenie się odorantów w czasie ciśnieniowego transportu ścieków. Opisano wielkości prędkości przepływu, które otwierają zawory zwrotne w pompowni i scharakteryzowano niektóre wartości. Następnie przy pomocy równań opisano wpływ drobnych kamieni i grubego żwiru na opory przepływu przez przewody ciśnieniowe. Na końcu podano wskazówki co do metod ograniczania uciążliwości zapachowej transportowanych ścieków.
EN
Three subjects belonging to pumping of sewage have been considered: non-return valves, the impact of small stones and coarse gravel on the flow resistance in a vertical pipe and the formation of odorants during pressure sewage transport. The flow velocities that open the non-return valves in the pumping station are described and some values are characterized. Then, the equations describe the effect of small stones and coarse gravel on the flow resistance through pressure lines. Finally, instructions on how to reduce the odour nuisance of transported sewage are given.
EN
The effect of instream vegetation growth has largely been ignored by hydrological and geomorphological research in river environments, which focused instead on the function of riparian vegetation as a regulator of bank stability or as a buffer for dissolved and particulate matter entering the channel from the hillside. However, in many lowland streams, instream vegetation can be very intensive, resulting in high biomass levels during the growing season. Instream plants have a significant influence on the dynamics of flow, sediment, and nutrients. Plant growth can cause increased frictional resistance to flow and can have a short-to medium-term effects on the geomorphology of the channel. Additionally, plant development influences the velocity of river flow, affects sedimentation dynamics and increases flood risk. To achieve a balance between flooding and ecological management of rivers in the presence of vegetation, a reliable method is required to predict the resistance of channels. In the current study, a two-dimensional hydrodynamic and morphodynamic model is developed and applied using a new scaling expression of shear stress based on vegetation characteristics. These first attempts at field simulations showed qualitatively acceptable results and demonstrated the effectiveness of the model in predicting hydraulic parameters in the presence of vegetation. This model is useful in predicting the effect of vegetation on stream flow and river morphology, as well as in managing flood hazards and stream ecology.
EN
Acid volatile sulphide (AVS), one of the most reactive phases in sediments, is a crucial link in explaining a dynamic biogeochemical cycle in a marine ecosystem. Research gaps exist in describing the spatial variation of AVS and interconnections with sediment covariates in the Eastern Upper Gulf of Thailand. Measurements of AVS and auxiliary parameters followed the standard protocol. A comparison of ordinary kriging (OK), cokriging (CK), and regression kriging (RK) performance was evaluated based on the mean absolute error (MAE) and root mean square error (RMSE). The concentrations of AVS ranged from 0.003 to 0.349 mg g−1 sediment dry weight. Most parameters contained short range spatial dependency except for oxidation-reduction potential (ORP) and pH. The AVS tended to be both linearly and non-linearly related to ORP and readily oxidisable organic matter (ROM). The RK model, using inputs from the tree-based model, was the most robust of the three kriging methods. It is suggested that nonlinear interactions should be taken into account when predicting AVS concentration, and it is expected that this will further increase the model accuracy. This study helps establish a platform for ecological health and sediment quality guidelines.
EN
The present work was designed to assess the contamination level in the coastal of Annaba, following the spectrophotometric determination of the level of some metallic elements (Fe, Cu, Pb, Zn, Ni and Cd) in the sediments along an increasing bathymetric gradient (10 m and 20 m), as well as in the biological indicator grey mullet (Mugil cephalus) muscle. During the winter period (2014), 12 surface sediment samples, and a total of 24 fish were collected. Once the samples are dried, crushed and sieved, 0.5 g dry weight of each sample was added to concentrated acids. The results showed that the levels of some metals are superior to the recommended guideline values, and consequently the sediment of this bay is contaminated by iron, lead and copper. The contamination index (CI) showed a general tendency in the concentration of the studied metals as follows: Fe > Pb > Cu > Zn > Ni > Cd, since the most studied metals occurred at higher concentration in depth (20 m). However, the average concentrations of metals in fishes were found to be as the following order: Fe > Zn > Pb > Cu > Ni > Cd. The consumption of fish from some contaminated sites can be dangerous because concentrations of lead, cadmium and zinc exceed the international standards. Moreover, the strong positive correlation observed between the metallic elements of sediments and fishes confirm that these metals resulted from the similar sources of the anthropic activities, such as domestic, port, industrial and agricultural waste discharges. This is confirmed by the determined of pollution load index (PLI) parameter. Conclusively, a regular monitoring program of heavy metal is recommended for protecting these organisms, and to reduce the environmental risks.
PL
W pracy oceniono poziom zanieczyszczenia strefy przybrzeżnej w okolicach Annaby na podstawie spektrofotometrycznych analiz metali (Fe, Cu, Pb, Zn, Ni and Cd) w osadach na różnej głębokości (10 i 20 m) i w mięśniach cefala pospolitego (Mugil cephalus) jako organizmu wskaźnikowego. W okresie zimowym (2014 r.) zebrano 12 próbek osadów powierzchniowych i łącznie 24 ryby. Po wysuszeniu, pokruszeniu i przesianiu próbek do stężonych kwasów dodano 0,5 g suchej masy każdej próbki. Wyniki dowodzą, że stężenie niektórych metali przekracza dopuszczalne normy, a osady w zatoce są zanieczyszczone żelazem, ołowiem i miedzią. Wskaźnik zanieczyszczenia (CI) kształtował się następująco: Fe > Pb > Cu > Zn > Ni > Cd, przy czym większe stężenie większości metali notowano na głębokości 20 m. Średnie stężenie metali w mięśniach ryb układało się natomiast w porządku: Fe > Zn > Pb > Cu > Ni > Cd. Konsumpcja ryb z niektórych skażonych stanowisk może być niebezpieczna, ponieważ stężenie ołowiu, kadmu i cynku przekracza międzynarodowe standardy. Ponadto, silna dodatnia korelacja między stężeniem metali w osadach i w rybach dowodzi, że metale te pochodzą z tych samych antropogenicznych źródeł takich jak zrzuty ścieków bytowych, portowych, przemysłowych i rolniczych. Potwierdza to oznaczony wskaźnik ładunku zanieczyszczeń (PLI). W podsumowaniu zaleca się wdrożenie regularnego programu monitoringu w celu ochrony organizmów wodnych i ograniczenia ryzyka środowiskowego.
EN
Various activities such as farming, industry, household waste, fish pond, and fishery can possibly affect the estuarine and coastal ecosystem. Demak waters, located to the east of Tanjung Emas Semarang, become an influential element of fishery industry that mostly produces anchovies and shrimps. This research was aimed at (1) analyzing the spatial distribution of heavy metal Pb and Cd in the surface water and sediment; and (2) investigating the abundance of coliform in Demak waters. Moreover, in this research, water pollution index was also analyzed and compared to other polluted water areas. It was found that the Pb content ranged from 0.6037 to 0.6647 mg·1–1 whereas the Cd content ranged from 0.064 to 0.1707 mg·1–1. Both lead and cadmium contents had surpassed the water quality standard. The Pb content in sediment ranged from 0.563 to 0.6823 mg·kg-1 whereas the Cd content reached 0.0047 to 0.0577 mg·kg-1. It showed that this sediment was not polluted by Pb and Cd. The analysis of water pollution index revealed that the pollution level found in Morosari, Rejo, Tuntang, and Lohbener estuary was low. On the other hand, Wedung and Serang estuary were heavily polluted. Compared to some previous studies, most of Pb and Cd contents in Demak waters were greater. However, lead and cadmium content in sediment was lower.
17
Content available The studies on check dam restoration effectiveness
EN
A check dam is a hydraulic structure, which is constructed in order to limit river sediment transport. A sedimentation reservoir is created upstream from the body of the dam, where river sediment is constantly accumulated. These structures were constructed starting in the early 20th century in upstream parts of mountain streams in the Polish part of the Carpathian Mountains. At present, the reservoirs of most check dams are already fully filled with sediment and the impact of these structures on the ecosystems of streams is unfavorable. Moreover, the dams that have not been renovated are in poor technical condition. In the paper two cases of check dam lowering and restored is discussed and the one hypothetical case of gradual check dam lowering is presented and discussed as well. The cases of Krzczonówka and Trzebuńka, where the method of removing sediment from reservoirs was different, showed that the sudden change of „established” hydrodynamic conditions for decades is not favorable for the stream. The results of hypothetic simulation of gradual check dam lowering for the case of Isepnica Stream leads to the conclusion that lowering the construction of check dam and removing sediment from its reservoir in a way that does not have a drastic impact on the hydrodynamic balance of the stream channel is possible. However, as it was shown in the case of Isepnica Stream, it is very complicated task.
EN
The continuity of sediment transport in many catchment-river-sea systems worldwide has been disturbed by anthropogenic interferences. These interferences alter the sediment balance and result either in a surplus or lack of sediment, and with mostly negative, impacts to the economy, development and infrastructure, and environment. The main issues discussed related to surplus or lack of sediment belongs to: i) siltation of reservoirs with negative effects on hydropower production or water storage, and ii) erosion at downstream reaches where sediments are essential for channel formation and aquatic habitats. Both problems are recognized in Poland, however, only dealt with when they cause local economic problems. The paper focuses on examples of sustainable sediment managements in catchment-river-sea systems, and presents the idea of combining the Macromodel DNS with the SWAT module. The resulting modelling and analytical tool can be considered very valuable in sediment quantity management.
EN
Lake Mariut is suffering from pollution as it receives industrial effluents and a mix of sewage from different drains, often lacking treatment systems. Sequential extraction procedures were applied for the speciation of heavy metals (Fe, Mn, Zn, Cu and Pb) and P in the lake sediment to evaluate their potential bioavailability. Total concentrations of metals had low values compared with the sediment quality guidelines. The chemical speciation data for Mn and Zn indicate a potential pollution level since the non-residual fractions contain up to 77.6 and 64.9% (respectively) of the total metal content. However, Fe, Cu and Pb are mostly linked to the inert fraction. Risk assessment of metals was carried out using the mobility factor, the contamination factor, the risk assessment code and the enrichment factor. All the analytical approaches indicated the accumulation of pollutants exceeding the adsorptive capacity of Lake Mariut sediments. The organic phosphorus fractions dominated in the sediment accounting for 51.4%, while the most abundant form of inorganic phosphorus was Ca-bound phosphorus. The rank order of P fractions was HCl-P > NaOH-P > BD-P > NH4Cl-P > Res-P. The decrease both in the dissolved oxygen level in the lake water and the Fe:P ratio in the lake sediment resulted in the high contribution of the phosphorus fractions to the overlying water.
EN
Due to the limited water exchange, lagoons are particularly prone to eutrophication. The consumption of oxygen in this process, coupled with simultaneous enrichment of bottom sediments with organic matter, reinforces the occurrence of anaerobic conditions and methanogenic growth. Methanogenic archaea activities cause depolymerization of organic compounds accumulated in sediments. As a result of such ecosystem transformation, methane might be produced and emitted from this basin. Chemical studies conducted in 2010 were focused on methane content in the surface bottom sediments in the Polish part of the Vistula Lagoon. The results showed that the highest methane concentration occurs in the southwestern part of this basin (6.45 mmol dm-3), while the lowest one in the southeastern part (7.1 × 10-3 mmol dm-3). Molecular studies were focused on specific methanogenic archaea gene identification. The comparison of nucleotide sequences of “mcrA gene” clones obtained from genomic DNA isolated from the Vistula Lagoon sediments indicates a similarity to the yet uncultivated archaea, but also to archaea from the Methanosarcinales and Methanomicrobiales orders.
first rewind previous Strona / 5 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.