Search results for: sediment contamination

Authors: Redhouane Ghernaout, Amira Fredj, Boualem Remini

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Suspended sediment transport is a serious problem worldwide, but it is much more worrying in certain regions of the world, as is the case in the Maghreb and more particularly in Algeria. It continues to take disturbing proportions in Northern Algeria due to the variability of rains in time and in space and constant deterioration of vegetation. Its prediction is essential in order to identify its intensity and define the necessary actions for its reduction. The purpose of this study is to analyze the concentration data of suspended sediment measured at Wadi El-Abtal Hydrometric Station. It also aims to find and highlight regressive power relationships, which can explain the suspended solid flow by the measured liquid flow. The study strives to find models of artificial neural networks linking the flow, month and precipitation parameters with solid flow. The obtained results show that the power function of the solid transport rating curve and the models of artificial neural networks are appropriate methods for analysing and estimating suspended sediment transport in Wadi Mina at Wadi El-Abtal Hydrometric Station. They made it possible to identify in a fairly conclusive manner the model of neural networks with four input parameters: the liquid flow Q, the month and the daily precipitation measured at the representative stations (Frenda 013002 and Ain El-Hadid 013004 ) of the watershed. The model thus obtained makes it possible to estimate the daily solid flows (interpolate and extrapolate) even beyond the period of observation of solid flows (1985/86 to 1999/00), given the availability of the average daily liquid flows and daily precipitation since 1953/1954.

Keywords: suspended sediment, concentration, regression, liquid flow, solid flow, artificial neural network, modeling, mina, algeria

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Authors: Krishna Kumar Singh, Praveen Jain

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The collection of storm water runoff and forcing it into the groundwater is the need of the hour to sustain the ground water table. However, the runoff entraps various types of sediments and other floating objects whose removal are essential to avoid pollution of ground water and blocking of pores of aquifer. However, it requires regular cleaning and maintenance due to the problem of clogging. To evaluate the performance of filter system consisting of coarse sand (CS), gravel (G) and pebble (P) layers, a laboratory experiment was conducted in a rectangular column. The effect of variable thickness of CS, G and P layers of the filtration unit of the recharge shaft on the recharge rate and the sediment concentration of effluent water were evaluated. Medium sand (MS) of three particle sizes, viz. 0.150–0.300 mm (T1), 0.300–0.425 mm (T2) and 0.425–0.600 mm of thickness 25 cm, 30 cm, and 35 cm respectively in the top layer of the filter system and having seven influent sediment concentrations of 250–3,000 mg/l were used for the experimental study. The performance was evaluated in terms of recharge rates and clogging time. The results indicated that 100 % suspended solids were entrapped in the upper 10 cm layer of MS, the recharge rates declined sharply for influent concentrations of more than 1,000 mg/l. All treatments with a higher thickness of MS media indicated recharge rate slightly more than that of all treatment with a lower thickness of MS media respectively. The performance of storm water infiltration systems was highly dependent on the formation of a clogging layer at the filter. An empirical relationship has been derived between recharge rates, inflow sediment load, size of MS and thickness of MS with using MLR.

Keywords: groundwater, medium sand-mixed storm water filter, inflow sediment load

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Authors: Sz. Klátyik, B. Darvas, M. Mörtl, M. Ottucsák, E. Takács, H. Bánáti, L. Simon, G. Gyurcsó, A. Székács

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Environmental and health safety of condiments used for spicing food products in food processing or by culinary means receive relatively low attention, even though possible contamination of spices may affect food quality and safety. Contamination surveys mostly focus on microbial contaminants or their secondary metabolites, mycotoxins. Chemical contaminants, particularly pesticide residues, however, are clearly substantial factors in the case of given condiments in the Capsicum family including spice paprika and chilli. To assess food safety and support the quality of the Hungaricum product spice paprika, the pesticide residue status of spice paprika and chilli is assessed on the basis of reported pesticide contamination cases and non-compliances in the Rapid Alert System for Food and Feed of the European Union since 1998.

Keywords: spice paprika, Capsicum, pesticide residues, RASFF

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Authors: G. O. Avwiri, E. O. Agbalagba, C. P. Ononugbo

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Activity concentrations of natural radionuclides (226Ra, 232Th and 40K) in the soil, sediment and water of oil producing communities in Delta and Rivers States were determined using γ-ray spectrometry. The mean soil/sediment activity concentration of 226Ra, 232Th and 40K in onshore west in Delta state is 40.2±5.1Bqkg-1, 29.9±4.2Bqkg-1 and 361.5±20.0Bqkg-1 respectively, the corresponding values obtained in onshore east1 of Rivers state is 20.9±2.8Bqkg-1, 19.4±2.5Bqkg-1and 260.0±14.1Bqkg-1 respectively. While the mean activity concentration of 226Ra, 232Th and 40K in onshore east2 of Rivers state is 29.3±3.5Bqkg-1, 21.6±2.6Bqkg-1 and 262.1±14.6Bqkg-1 respectively. These values obtained show enhanced NORMs but are well within the world range. All the radiation hazard indices examined in soil have mean values lower than their maximum permissible limits. In drinking water, the obtained average values of226Ra, 228Ra and 40K is 8.4±0.9, 7.3±0.7 and 29.9±2.2Bql-1 respectively for well water, 4.5±0.6, 5.1±0.4 and 20.9±2.0Bql-1 respectively for borehole water and 11.3±1.2, 8.5±0.7 and 32.4±3.7Bql-1 respectively for river water in onshore west. For onshore east1, average activity concentration of 226Ra, 228Ra and 40K is 8.3±1.0, 8.6±1.1 and 39.6±3.3Bql-1 respectively for well water, 3.8±0.8, 4.9±0.6 and 35.7±4.1Bql-1 respectively for borehole water and 5.5±0.8, 5.4±0.7 and 36.9±3.8Bql-1 respectively for river water. While in onshore east2 average value of 226Ra, 228Ra and 40K is 10.1±1.1, 8.3±1.0 and 50.0±3.9Bql-1 respectively for well water, 4.7±0.9, 4.0±0.4 and 28.8±3.0Bql-1 respectively for borehole water and 7.7±0.9, 6.1±0.8 and 27.1±2.9Bql-1 respectively for river water and the average activity concentrations in the produced water226Ra, 228Ra and 40K is 5.182.14Bql-1, 6.042.48Bql-1 and 48.7813.67Bql-1 respectively. These values obtained are well above world average values of 1.0, 0.1 and 10Bql-1 for 226Ra, 228Ra and 40K respectively, those of the control site values and most reported values around the world. Though the hazard indices (Raeq, Hex, Hin) examined in water is still within the tolerable level, the committed effective dose estimated are above ICPR 0.1 mSvy-1 permissible limits. The overall results show that soil and sediment in the area are safe radiologically, but the result indicates some level of water pollution in the studied area.

Keywords: radioactivity, soil, sediment and water, Niger Delta, gamma detector

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Authors: Amir Hedjripour

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The required dewatering configuration for a contaminated sediment dam is discussed to meet no-spill criteria for a defined Average Recurrence Interval (ARI). There is an option for the sediment dam to pump the contaminated water to another storage facility before its capacity is exceeded. The system is subjected to a range of storm durations belonging to the design ARI with concurrent dewatering to the other storage facility. The model is set up in 1-minute time intervals and temporal patterns of storm events are used to de-segregate the total storm depth into partial durations. By running the model for selected storm durations, the maximum water volume in the dam is recorded as the critical volume, which indicates the required storage capacity for that storm duration. Runoff from upstream catchment and the direct rainfall over the dam open area are calculated by taking into account the time of concentration for the catchment. Total 99 different storm durations from 5 minutes to 72 hours were modelled together with five dewatering scenarios from 50 l/s to 500 l/s. The optimised dam/pump configuration is selected by plotting critical points for all cases and storage-dewatering envelopes. A simple economic analysis is also presented in the paper using Present-Value (PV) analysis to assist with the financial evaluation of each configuration and selection of the best alternative.

Keywords: contaminated water, optimisation, pump, sediment dam

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Authors: M. Fertouna Bellakhal, M. Bellakhal, A. Dhib, A. Fathalli, S. Turki, L. Aleya

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Study of dinoflagellate cysts is a precious tool to get information about environment and water quality in many aquatic ecosystems. The distribution of Alexandrium pacificum cysts, in Bizerta lagoon located in North of Tunisia, was made based on sediment samples analysis from 123 equidistant stations delimiting 125 km² surfaces. Sediment characteristics such as percentage of water, organic matter, and particle size were analyzed to determine the factors that influence the distribution of this dinoflagellate. In addition, morphological examination and ribotyping of vegetative forms from microalgal cultures made from cyst germination confirmed the identity of the species attributed to A. pacificum. A correlation between the abundance of A. pacificum cysts and the percentage of water and sediment organic matter was recorded. In addition, the sedimentary fraction < 63μm was found to be potentially favorable for the installation and initiation of the Alexandrium pacificum efflorescence at the Bizerte lagoon. The mapping of cysts in this aquatic ecosystem has also allowed us to define distinct areas with specific abundance with closed relationship with shellfish aquaculture stations located within the lagoon.

Keywords: Alexandrium pacificum, cysts, Dinoflagellate, microalgal culture

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Authors: Hayyan I Al Taweil

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Background: The most common of bacterium in kitchen sponges and cutting surfaces which can play a task within the cross-contamination of foods, fomites and hands by foodborne pathogens. Aims and Objectives: This study investigated the incidence of bacterium in kitchen Sponge, and cutting surfaces. Material and methods: a complete of twenty four kitchen Sponges were collected from home kitchens and therefore the numbers of mesotrophic microorganism, coliform microorganism, E. coli, Salmonella, genus {pseudomonas|bacteria genus} and staphylococci in every kitchen Sponges were determined. Microbiological tests of all sponges for total mesophilic aerobic microorganism, S. aureus, Pseudomonas, Salmonella spp., and E. coli were performed on days 3, 7, and 14 by sampling. The sponges involved in daily use in kitchens countenosely with the dishwasher detergent a minimum of doubly daily Results: Results from the overall mesophilic aerobic microorganism, indicate a major increase within the variety of log CFU/ml. the amount of E. coli was reduced, Salmonella spp. was stabled, S. aureus was enhanced from the sponges throughout fourteen days. Genus Pseudomonas was enhanced and was the dominant micro flora within the sponges throughout fourteen days.

Keywords: Kitchen Sponges, Microbiological Contamination, Disinfection; cutting surface; , Cross-Contamination

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Authors: Zhang Hui, Wu Caiqiu, Yuan Xuyin, Qiu Jie, Zhang Hanpei

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The heavy metal contaminations were determined with a detailed soil survey in roadside soils along Shenyang-Dalian Highway of Liaoning Province (China) and Pb, Cu, Cd, Ni and Zn were analyzed using the atomic absorption spectrophotometric method. The average concentration of Pb, Cu, Cd, Ni and Zn in roadside soils was determined to be 43.8, 26.5, 0.119, 32.1, 71.3 mg/kg respectively, and all of the heavy metal contents were higher than the background values. Different heavy metal distribution regularity was found in different land use type of roadside soil, there was an obvious peak of heavy concentration at 25m from road edge in the farmland, while in the forest and orchard soil, all heavy metals gradually decreased with the increase of distance from road edge and conformed to the exponential model. Furthermore, the heavy metal contents of heavy metals except Cd were markedly increased compared with those in 1999 and 2007, and the heavy metals concentrations of Shenyang- Dalian Highway were considered medium or low in comparison with those in other cities around the world. The assessment of heavy metal contamination of roadside soils illustrated a common low pollution for all heavy metal and recommended that more attention should be paid to Pb contamination in roadside soils in Shenyang-Dalian Highway.

Keywords: heavy metal contamination, roadside, highway, Nemerow Pollution Index

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Authors: Fiona S. Motswaiso, Kengo Nakamura, Takeshi Komai

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Heavy metals may occur naturally in rocks and soils, but elevated quantities of them are being gradually released into the environment by anthropogenic activities such as mining. In order to address issues of heavy metal water and soil pollution, a distinction needs to be made between natural and anthropogenic anomalies. The current study aims at characterizing the spatial distribution of trace elements and evaluate site-specific geochemical background concentrations of trace elements in the mine soils examined, and also to discriminate between lithogenic and anthropogenic sources of enrichment around a copper-nickel mining town in Selibe-Phikwe, Botswana. A total of 20 Soil samples, 11 river sediment, and 9 river water samples were collected from an area of 625m² within the precincts of the mine and the smelter. The concentrations of metals (Cu, Ni, Pb, Zn, Cr, Ni, Mn, As, Pb, and Co) were determined by using an ICP-MS after digestion with aqua regia. Major elements were also determined using ED-XRF. Water pH and EC were measured on site and recorded while soil pH and EC were also determined in the laboratory after performing water elution tests. The highest Cu and Ni concentrations in soil are 593mg/kg and 453mg/kg respectively, which is 3 times higher than the crustal composition values and 2 times higher than the South African minimum allowable levels of heavy metals in soils. The level of copper contamination was higher than that of nickel and other contaminants. Water pH levels ranged from basic (9) to very acidic (3) in areas closer to the mine/smelter. There is high variation in heavy metal concentration, eg. Cu suggesting that some sites depict regional natural background concentrations while other depict anthropogenic sources.

Keywords: contamination, geochemical baseline, heavy metals, soils

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Authors: Tiao Chang, Ivan Caballero, Hong Zhou

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Streams carry water and sediment naturally by maintaining channel dimensions, pattern, and profile over time. Watershed erosion as a natural process has occurred to contribute sediment to streams over time. The formation of channel dimensions is complex. This study is to relate quantifiable and consistent channel dimensions at the bankfull stage to the corresponding watershed erosion estimation by the Revised Universal Soil Loss Equation (RUSLE). Twelve sites of which drainage areas range from 7 to 100 square miles in the Hocking River Basin of Ohio were selected for the bankfull geometry determinations including width, depth, cross-section area, bed slope, and drainage area. The twelve sub-watersheds were chosen to obtain a good overall representation of the Hocking River Basin. It is of interest to determine how these bankfull channel dimensions are related to the soil erosion of corresponding sub-watersheds. Soil erosion is a natural process that has occurred in a watershed over time. The RUSLE was applied to estimate erosions of the twelve selected sub-watersheds where the bankfull geometry measurements were conducted. These quantified erosions of sub-watersheds are used to investigate correlations with bankfull channel dimensions including discharge, channel width, channel depth, cross-sectional area, and pebble distribution. It is found that drainage area, bankfull discharge and cross-sectional area correlates strongly with watershed erosion well. Furthermore, bankfull width and depth are moderately correlated with watershed erosion while the particle size, D50, of channel bed sediment is not well correlated with watershed erosion.

Keywords: watershed, stream, sediment, channel

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Authors: Kali Prasad Sarma

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Indiscriminate disposal of municipal solid waste (MSW) in open dumping site is a common scenario in developing countries like India which poses a risk to the environment as well as human health. The objective of the present investigation was to find out the concentration of heavy metals (Pb, Cr, Ni, Mn, Zn, Cu, and Cd) and other physicochemical parameters of leachate and soil collected from an open dumping site of Tezpur town, Assam, India and its associated potential ecological risk. Tezpur is an urban agglomeration coming under the category of Class I UAs/Towns with a population of 105,377 as per data released by Government of India for Census 2011. Impact of the leachate on the groundwater was also addressed in our study. The concentrations of heavy metals were determined using ICP-OES. Energy dispersive X-Ray (SEM-EDS) microanalysis was also conducted to see the presence of the studied metals in the soil. X-Ray diffraction analysis (XRD) and Fourier Transform Infrared (FTIR) spectroscopy were also used to identify dominant minerals present in the soil samples. The trend of measured heavy metals in the soil samples was found in the following order: Mn > Pb > Cu > Zn > Cr > Ni > Cd. The assessment of heavy metal contamination in the soil was carried out by calculating enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (Cfi), degree of contamination (Cd), pollution load index (PLI) and ecological risk factor (Eri). The study showed that the concentrations of Pb, Cu, and Cd were much higher than their respective average shale value and the EF of the soil samples depicted very severe enrichment for Pb, Cu, and Cd; moderate enrichment for Cr and Zn. Calculated Igeo values indicated that the soil is moderate to strongly contaminated with Pb and uncontaminated to moderately contaminated with Cd and Cu. The Cfi value for Pb indicates a very strong contamination level of the metal in the soil. The Cfi values for Cu and Cd were 2.37 and 1.65 respectively indicating moderate contamination level. To apportion the possible sources of heavy metal contamination in soil, principal components analysis (PCA) has been adopted. From the leachate, heavy metals are accumulated at the dumping site soil which could easily percolate through the soil and reach the groundwater. The possible relation of groundwater contamination due to leachate percolation was examined by analyzing the heavy metal concentrations in groundwater with respect to distance from the dumping site. The concentrations of Cd and Pb in groundwater (at a distance of 20m from dumping site) exceeded the permissible limit for drinking water as set by WHO. Occurrence of elevated concentration of potentially toxic heavy metals such as Pb and Cd in groundwater and soil are much environmental concern as it is detrimental to human health and ecosystem.

Keywords: groundwater, heavy metal contamination, leachate, open dumping site

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Authors: T. Garlan, I. Gabelotaud, S. Lucas, E. Marchès

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Production of a global sedimentological seabed map has been initiated in 1995 to provide the necessary tool for searches of aircraft and boats lost at sea, to give sedimentary information for nautical charts, and to provide input data for acoustic propagation modelling. This original approach had already been initiated one century ago when the French hydrographic service and the University of Nancy had produced maps of the distribution of marine sediments of the French coasts and then sediment maps of the continental shelves of Europe and North America. The current map of the sediment of oceans presented was initiated with a UNESCO's general map of the deep ocean floor. This map was adapted using a unique sediment classification to present all types of sediments: from beaches to the deep seabed and from glacial deposits to tropical sediments. In order to allow good visualization and to be adapted to the different applications, only the granularity of sediments is represented. The published seabed maps are studied, if they present an interest, the nature of the seabed is extracted from them, the sediment classification is transcribed and the resulted map is integrated in the world map. Data come also from interpretations of Multibeam Echo Sounder (MES) imagery of large hydrographic surveys of deep-ocean. These allow a very high-quality mapping of areas that until then were represented as homogeneous. The third and principal source of data comes from the integration of regional maps produced specifically for this project. These regional maps are carried out using all the bathymetric and sedimentary data of a region. This step makes it possible to produce a regional synthesis map, with the realization of generalizations in the case of over-precise data. 86 regional maps of the Atlantic Ocean, the Mediterranean Sea, and the Indian Ocean have been produced and integrated into the world sedimentary map. This work is permanent and permits a digital version every two years, with the integration of some new maps. This article describes the choices made in terms of sediment classification, the scale of source data and the zonation of the variability of the quality. This map is the final step in a system comprising the Shom Sedimentary Database, enriched by more than one million punctual and surface items of data, and four series of coastal seabed maps at 1:10,000, 1:50,000, 1:200,000 and 1:1,000,000. This step by step approach makes it possible to take into account the progresses in knowledge made in the field of seabed characterization during the last decades. Thus, the arrival of new classification systems for seafloor has improved the recent seabed maps, and the compilation of these new maps with those previously published allows a gradual enrichment of the world sedimentary map. But there is still a lot of work to enhance some regions, which are still based on data acquired more than half a century ago.

Keywords: marine sedimentology, seabed map, sediment classification, world ocean

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Authors: Santosh Kumar Biswal, Ramakar Jha

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Soil erosion is a slow and continuous process and one of the prominent problems across the world leading to many serious problems like loss of soil fertility, loss of soil structure, poor internal drainage, sedimentation deposits etc. In this paper remote sensing and GIS based methods have been applied for the determination of soil erosion and sediment yield. Tel River basin which is the second largest tributary of the river Mahanadi laying between latitude 19° 15' 32.4"N and, 20° 45' 0"N and longitude 82° 3' 36"E and 84° 18' 18"E chosen for the present study. The catchment was discretized into approximately homogeneous sub-areas (grid cells) to overcome the catchment heterogeneity. The gross soil erosion in each cell was computed using Universal Soil Loss Equation (USLE). Various parameters for USLE was determined as a function of land topography, soil texture, land use/land cover, rainfall, erosivity and crop management and practice in the watershed. The concept of transport limited accumulation was formulated and the transport capacity maps were generated. The gross soil erosion was routed to the catchment outlet. This study can help in recognizing critical erosion prone areas of the study basin so that suitable control measures can be implemented.

Keywords: Universal Soil Loss Equation (USLE), GIS, land use, sediment yield,

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Authors: Layan Moussa, Darine Salam, Samir Mustapha

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Heavy metal contamination in agricultural soils in Lebanon poses serious environmental and health problems. Intensive efforts are employed to improve existing quantification methods of heavy metals in contaminated environments since conventional detection techniques have shown to be time-consuming, tedious, and costly. The implication of hyperspectral remote sensing in this field is possible and promising. However, factors impacting the efficiency of hyperspectral imaging in detecting and quantifying heavy metals in agricultural soils were not thoroughly studied. This study proposes to assess the use of hyperspectral imaging for the detection of Ni in agricultural clay soil collected from the Bekaa Valley, a major agricultural area in Lebanon, under different contamination levels and soil moisture content. Soil samples were contaminated with Ni, with concentrations ranging from 150 mg/kg to 4000 mg/kg. On the other hand, soil with background contamination was subjected to increased moisture levels varying from 5 to 75%. Hyperspectral imaging was used to detect and quantify Ni contamination in the soil at different contamination levels and moisture content. IBM SPSS statistical software was used to develop models that predict the concentration of Ni and moisture content in agricultural soil. The models were constructed using linear regression algorithms. The spectral curves obtained reflected an inverse correlation between both Ni concentration and moisture content with respect to reflectance. On the other hand, the models developed resulted in high values of predicted R2 of 0.763 for Ni concentration and 0.854 for moisture content. Those predictions stated that Ni presence was well expressed near 2200 nm and that of moisture was at 1900 nm. The results from this study would allow us to define the potential of using the hyperspectral imaging (HSI) technique as a reliable and cost-effective alternative for heavy metal pollution detection in contaminated soils and soil moisture prediction.

Keywords: heavy metals, hyperspectral imaging, moisture content, soil contamination

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Authors: Muluneh Ademe, Zeleke Mekonnen

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Objective: to determine the level of bacterial contamination of reused insulin syringes among diabetic patients. Method: A facility based cross-sectional study was conducted among diabetic patients. Data on socio-demographic variables, history of injection syringe reuse, and frequency of reuse of syringes were collected using predesigned questionnaire. Finally, the samples from the syringes were cultured according to standard microbiological techniques. Result: Eighteen diabetic patients at Jimma University Hospital participated. A total of 83.3% of participants reused a single injection syringe for >30 consecutive injections, while 16.7% reused for >30 injections. Our results showed 22.2% of syringes were contaminated with methicillin-resistant Staphylococcus aures. Conclusion: We conclude reuse of syringe is associated with microbial contamination. The findings that 4/18 syringes being contaminated with bacteria is an alarming situation. A mechanism should be designed for patients to get injection syringes with affordable price. If reusing is not avoidable, reducing number of injections per a single syringe and avoiding needle touching with hand or other non-sterile material may be an alternative to reduce the risk of contamination.

Keywords: diabetes mellitus, Ethiopia, subcutaneous insulin injection, syringe reuse

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Authors: Armel Zacharie Ekoa Bessa, Annick Kwewouo Janpou

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Sediments collected along the beaches of the Atlantic Ocean in Africa were analyzed by geochemical proxies such as the ICP-MS technique to determine their heavy metal contamination and related ecological risks. Several metals were selected and show a decreasing trend: Fe > Mn > Ni > Cu > Co > Zn > Cr > Cd. Several pollution indices have been calculated, including the enrichment factor (EF), whose values are generally higher than 1. 5; the geo-accumulation index (I-geo), with values of some elements (Co, Ni and Cu) in the sediments of the study area being higher than 0, and other metals (Zn, Cr, Fe and Mn) being lower than 0; the contamination factor (CF), where the values of all the selected elements are between 1 and 3; and the pollution load index (PLI), where the values in almost all the study sites are higher than 1. These results show moderate contamination of the investigated sediments with heavy metals. The potential ecological risk assessment (Eri and RI) suggests that this part of the African coast is a low to a slight risk area. Statistical analyses indicate that heavy metals have shown fairly similar trends with anthropogenic and natural sources. This study shows that this coastal area is not highly concentrated in heavy metals and reveals that the Atlantic coast of Africa would be moderately polluted by the metals studied, with a low to moderate ecological risk.

Keywords: heavy metals, pollution, atlantic ocean, sediments

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Authors: Saeed Zeinali, Nasser Talebbeydokhti, Mehdi Saeidian, Shahrad Vosough

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In this article, bathymetry changes have been studied as a case study for Larak Island, located in The South of Iran. The advanced 2D model of Mike21 has been used for this purpose. A simple procedure has been utilized in this model. First, the hydrodynamic (HD) module of Mike21 has been used to obtain the required output for sediment transport model (ST module). The ST module modeled the area for tidal currents only. Bed level changes are resulted by series of modeling for both HD and ST module in 3 months time step. The final bathymetry in each time step is used as the primary bathymetry for next time step. This consecutive procedure been continued until bathymetry for the year 2020 is obtained.

Keywords: bed level changes, Larak Island, hydrodynamic, sediment transport

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Authors: Roberta Guerra, Juan Pablo Pozo Hernandez

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Surface sediments from the coastal lagoon of Pialassa Piomboni in the NW Adriatic Sea were collected and analysed and the potential ecological risks in the area were assessed based on the acid-volatile sulphide (AVS) model. The AVS levels are between 0.03 and 8.8 µmol g-1, with the average at 3.1 µmol g-1. The simultaneously extracted metals (∑SEM), which is the molar sum of Cd, Cu, Ni, Pb, and Zn, range from 0.3 to 6.6 µmol g-1, with the average at 1.7 µmol g-1. Most of the high ∑SEM concentrations are located in the southern area of the lagoon. [SEM]Zn had the comparatively high mean concentration (1.4 µmol g-1), and a maximum value of 6.1 µmol g-1, respectively. Concentrations of [SEM]Cd, [SEM]Cu, [SEM]Ni, and [SEM]Pb were consistently lower, with maximum values of 0.007 µmol g-1, 1.4 µmol g-1, 0.3 µmol g-1 and 0.2 µmol g-1, respectively. Compared to other metals, [SEM]Zn was the dominant component in all samples and accounted for approximately 31 - 93% of the ∑SEM, whereas the contribution of Cd – the most toxic metal studied – to ∑SEM was no more than 1%. According to the USEPA evaluation method, the sediment samples can be divided into the three following categories: category 1, adverse biological effects on aquatic life may be expected when ([SEM]–[AVS])/fOC > 3000; category 2, adverse effects on aquatic life are uncertain when ([SEM]–[AVS])/fOC = 130 to 3,000; and category 3, no indication of adverse effects when ([SEM]–[AVS])/fOC < 130. Most of the surface sediments of the Pialassa Piomboni lagoon (>90%) had no adverse biological effects according to the criterion proposed by the USEPA; while adverse effects were uncertain in few stations (~2%).

Keywords: sediment quality, heavy metals, coastal lagoon, bioavailability, SEM, AVS

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Authors: M. Budakoglu, M. Karaman, A. Abdelnasser, D. Kiran, M. Kumral

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About 50 mg lake sediment was digested in two steps. While first stage was completed with 6 ml 37% HCl, 2 ml 65% HNO3 and 1 ml 38-40% HF in an pressure and temperature controlled Teflon beaker using Berghoff Microwave™ at average 135°C, digestion procedure was completed with the addition of 6 ml 5% boric acid solution. REE contents of sediment samples were determined by Perkin Elmer DRC II ICP-MS in Geochemistry Research Laboratories (JAL/GRL) of Faculty of Mines, Istanbul Technical University. Chondrite-normalized REE patterns of Lake Acıgöl sediments show generally high abundance of REE compared to chondritic concentrations, with particular enrichment in LREE [(La/Lu)N = 4.85-19.90], [(La/Lu)N = 7.09-15.14], [(La/Lu)N = 9.42-15.52] and [(La/Lu)N = 7.69-15.63] for the surface sediment and 0-10 cm-, 10-20 cm- and 20-30 cm-subsurface sediments respectively. Also these samples showed flat HREE normalized to chondrite as (La/Sm)N ranging from 2.98 to 4.8 for surface sediments and for subsurface sediments from 3.28 to 3.97 (0-10 cm), 3.57 to 3.94 (10-20 cm) and 3.36 to 3.94 (20-30 cm) while (Gd/Yb)N ranging from 2.14 to 2.93, from 2.03 to 2.76, from 2.26 to 2.79 and from 2.05 to 2.76 from the surface and subsurface sediments respectively. Moreover, their REE profiles are similar to profiles of the continental collision basin (CCB) with negative Eu anomalies. In addition, their REE patterns illustrate generally low abundance of REE compared to concentrations of NASC, PAAS and UCC with very slight enrichment of LREE and positive Eu* anomalies. Therefore there is no comparable between our samples of surface and subsurface sediments and these types of international sediments.

Keywords: chondrite-normalized REE patterns, hypersaline lake, surface sediments, subsurface sediments, Lake Acıgöl, Turkey

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Authors: Mohammad Mokhtari, Gires Usup, Zaidi Che Cob

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Bacteria communities as mediators of the biogeochemical process are the main component of the mangrove ecosystems. Crab burrows by increasing oxic-anoxic interfaces and facilitating the flux rate between sediment and tidal water affect biogeochemical properties of sediments. The effect of fiddler crab burrows on the density and diversity of bacteria were investigated to elucidate the effect of burrow on bacterial distribution. Samples collected from the burrow walls of three species of fiddler crabs including Uca paradussumieri, Uca rosea, and Uca forcipata. Sediment properties including grain size, temperature, Redox potential, pH, chlorophyll, water and organic content were measured from the burrow walls to assess the correlation between environmental variables and bacterial communities. Bacteria were enumerated with epifluorescence microscopy after staining with SYBR green. Bacterial DNA extracted from sediment samples and the community profiles of bacteria were determined with Terminal Restriction Fragment Length Polymorphism (T-RFLP). High endemism was observed among bacterial communities. Among the 152 observed OTU’s, 22 were found only in crab burrows. The highest bacterial density and diversity were recorded in burrow wall. The results of ANOSIM indicated a significant difference between the bacterial communities from the three species of fiddler crab burrows. Only 3% of explained bacteria variability in the constrained ordination model of CCA was contributed to depth, while much of the bacteria’s variability was attributed to coarse sand, pH, and chlorophyll content. Our findings suggest that crab burrows by affecting sediment properties such as redox potential, pH, water, and chlorophyll content induce significant effects on the bacterial communities.

Keywords: bioturbation, canonical corresponding analysis, fiddler crab, microbial ecology

Procedia PDF Downloads 132

Authors: Mahfoud Benzerzour, Mouhamadou Amar, Nor-edine Abriak

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In this study, a sediment was used as a secondary raw material in cement substitution with prior treatment. The treatment adopted is a physical treatment involving grinding and separation to obtain different fractions, using a dry method (1 mm, 250µm, 120µm) and washing method (250µm and 120µm). They were subsequently heat treated at temperatures of 650°C, 750°C and 850°C for 1 hour and 3 hours, in order to enable chemical activation by decarbonation or by pozzolanic activation of the material. Different characterization techniques were performed. The determination of main physical and chemical characteristics was obtained through multiple tests: particle size distribution, specific density, the BET surface area, the initial setting time and hydration heat calorimetry Langavant. The chemical tests include: ATG analysis, X-ray diffractometry (XRD) and X-ray fluorescence (XRF) which were used to quantify the fractions, phases and chemical elements present. Compression tests were performed conforming NF EN 196-1 French standard, over terms of 7 days - 14 days - 28 days and 60 days on all formulated mortars: reference mortar based on 100% CEM I 52.5N binder and cement substituted mortars with 8% and 15% by treated sediment. This clearly evidenced contribution due to the chemical activity which was confirmed by calorimetry monitoring and strength investigation.

Keywords: sediment, characterization, grinding, heat treatment, substitution

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Authors: Rajkumar Ghosh

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Fluoride contamination in water and its subsequent impact on agricultural practices is a growing concern in various regions worldwide, including North 24 Parganas, West Bengal, India. This study aimed to investigate the extent of fluoride contamination in the region's water sources and evaluate its effects on crop production and quality. A comprehensive survey of water sources, including wells, ponds, and rivers, was conducted to assess the fluoride levels in North 24 Parganas. Water samples were collected and analyzed using standard methods, and the fluoride concentration was determined. The findings revealed significant fluoride contamination in the water sources, surpassing the permissible limits recommended by national and international standards. To assess the effects of fluoride contamination on crops, field experiments were carried out in selected agricultural areas. Various crops commonly cultivated in the region, such as paddy, wheat, vegetables, and fruits, were examined for their growth, yield, and nutritional quality parameters. Additionally, soil samples were collected from the study sites to analyse the fluoride levels and their potential impact on soil health. The results demonstrated the adverse effects of fluoride contamination on crop growth and yield. Reduced plant height, stunted root development, decreased biomass accumulation, and diminished crop productivity were observed in fluoride-affected areas compared to uncontaminated control sites. Furthermore, the nutritional composition of crops, including micronutrients and mineral content, was significantly altered under high fluoride exposure, leading to potential health risks for consumers. The study also assessed the impact of fluoride on soil quality and found a negative correlation between fluoride concentration and soil health indicators, such as pH, organic matter content, and nutrient availability. These findings emphasize the need for sustainable soil management practices to mitigate the harmful effects of fluoride contamination and maintain agricultural productivity. Overall, this study highlights the alarming issue of fluoride contamination in water sources and its detrimental effects on crop production and quality in North 24 Parganas, West Bengal, India. The findings underscore the urgency for implementing appropriate water treatment measures, promoting awareness among farmers and local communities, and adopting sustainable agricultural practices to mitigate fluoride contamination and safeguard the region's agricultural ecosystem.

Keywords: agricultural ecosystem, water treatment, sustainable agricultural, fluoride contamination

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Authors: Cherdvong Saengsupavanich

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Human utilizes coastal resources as well as deteriorates them. Coastal tourism may degrade the environment if poorly managed. This research investigated the shoreline change at Koa Toa Island, one of the most famous tourist destinations. Aerial photographs and satellite images from three different periods were collected and analyzed. The results showed that the noticeable shoreline change before and after the tourism on the island had expanded. Between 1995 and 2002 when the tourism on Koh Toa Island was not intensive, sediment deposition occurred along most of the coastline. However, after the tourism had grown during 2002 to 2015, the coast evidently experienced less deposition and more erosion. The erosion resulted from less land-based sediment being provided to the littoral system. If the coastline of Koh Toa Island is not carefully sustained, the tourism will disappear along with the beautiful beach.  

Keywords: coastal engineering and management, coastal erosion, coastal tourism, Koh Toa Island, Thailand

Procedia PDF Downloads 279

Authors: Flavio O. Torres, Maria J. Castilla, Rodrigo A. Augsburger, Pedro I. Cachana, Katherine S. Reyes

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In this paper, we present a scene-based nonuniformity correction method using a modified recursive least square algorithm with a feedback system on the updates. The feedback is designed to remove impulsive noise contamination images produced by a recursive least square algorithm by measuring the output of the proposed algorithm. The key advantage of the method is based on its capacity to estimate detectors parameters and then compensate for impulsive noise contamination image in a frame by frame basics. We define the algorithm and present several experimental results to demonstrate the efficacy of the proposed method in comparison to several previously published recursive least square-based methods. We show that the proposed method removes impulsive noise contamination image.

Keywords: infrared focal plane arrays, infrared imaging, least mean square, nonuniformity correction

Procedia PDF Downloads 116

Authors: L. Mouzai, M. Bouhadef

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Raindrops and overland flow both are erosive parameters but they do not act by the same way. The overland flow alone tends to shear the soil horizontally and concentrates into rills. In the presence of rain, the soil particles are removed from the soil surface in the form of a uniform sheet layer. In addition to this, raindrops falling on the flow roughen the water and soil surface depending on the flow depth, and retard the velocity, therefore influence shear velocity and Manning’s factor. To investigate this part, agricultural sandy soil, rainfall simulator and a laboratory soil tray of 0.2x1x3 m were the base of this work. Five overland flow depths of 0; 3.28; 4.28; 5.16; 5.60; 5.80 mm were generated under a rainfall intensity of 217.2 mm/h. Sediment concentration control is based on the proportionality of depth/microtopography. The soil loose is directly related to the presence of rain splash on thin sheet flow. The effect of shear velocity on sediment concentration is limited by the value of 5.28 cm/s. In addition to this, the rain splash reduces the soil roughness by breaking the soil crests. The rainfall intensity is the major factor influencing depth and soil erosion. In the presence of rainfall, the shear velocity of the flow is due to two simultaneous effects. The first, which is horizontal, comes from the flow and the second, vertical, is due to the raindrops.

Keywords: flow resistance, laboratory experiments, rainfall simulator, sediment concentration, shear velocity, soil erosion

Procedia PDF Downloads 169

Authors: M. Cynthya, V. Prabhawathi, D. Mukesh

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Food contamination occurs during post process handling. This leads to spoilage and growth of pathogenic microorganisms in the food, thereby reducing its shelf life or spreading of food borne diseases. Several methods are tried and one of which is use of antimicrobial packaging. Here, papain, a protease enzyme, is covalently immobilized with the help of glutarldehyde on polyurethane and used as a food wrap to protect food from microbial contamination. Covalent immobilization of papain was achieved at a pH of 7.4; temperature of 4°C; glutaraldehyde concentration of 0.5%; incubation time of 24 h; and 50 mg of papain. The formation of -C=N- observed in the Fourier transform infrared spectrum confirmed the immobilization of the enzyme on the polymer. Immobilized enzyme retained higher activity than the native free enzyme. The efficacy of this was studied by wrapping it over S. aureus contaminated cottage cheese (paneer) and cheese and stored at a temperature of 4°C for 7 days. The modified film reduced the bacterial contamination by eight folds when compared to the bare film. FTIR also indicates reduction in lipids, sugars and proteins in the biofilm.

Keywords: cheese, papain, polyurethane, Staphylococcus aureus

Procedia PDF Downloads 445

Authors: N. Santatriniaina, J. Deseure, T. Q. Nguyen, H. Fontaine, C. Beitia, L. Rakotomanana

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Nowadays, with the increasing of the wafer's size and the decreasing of critical size of integrated circuit manufacturing in modern high-tech, microelectronics industry needs a maximum attention to challenge the contamination control. The move to 300 mm is accompanied by the use of Front Opening Unified Pods for wafer and his storage. In these pods an airborne cross contamination may occur between wafers and the pods. A predictive approach using modeling and computational methods is very powerful method to understand and qualify the AMCs cross contamination processes. This work investigates the required numerical tools which are employed in order to study the AMCs cross-contamination transfer phenomena between wafers and FOUPs. Numerical optimization and finite element formulation in transient analysis were established. Analytical solution of one dimensional problem was developed and the calibration process of physical constants was performed. The least square distance between the model (analytical 1D solution) and the experimental data are minimized. The behavior of the AMCs intransient analysis was determined. The model framework preserves the classical forms of the diffusion and convection-diffusion equations and yields to consistent form of the Fick's law. The adsorption process and the surface roughness effect were also traduced as a boundary condition using the switch condition Dirichlet to Neumann and the interface condition. The methodology is applied, first using the optimization methods with analytical solution to define physical constants, and second using finite element method including adsorption kinetic and the switch of Dirichlet to Neumann condition.

Keywords: AMCs, FOUP, cross-contamination, adsorption, diffusion, numerical analysis, wafers, Dirichlet to Neumann, finite elements methods, Fick’s law, optimization

Procedia PDF Downloads 472

Authors: Nashaat Mazrui, Oarabile Mogobe, Barbara Ngwenya, Ketlhatlogile Mosepele, Mangaliso Gondwe

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Over the last several decades, the world has seen a rapid increase in activities such as deforestation, agriculture, and energy use. Subsequently, trace elements are being deposited into our water bodies, where they can accumulate to toxic levels in aquatic organisms and can be transferred to humans through fish consumption. Thus, though fish is a good source of essential minerals and omega-3 fatty acids, it can also be a source of toxic elements. Monitoring trace elements in fish is important for the proper management of aquatic systems and the protection of human health. The aim of this study was to determine concentrations of trace elements in sediment and muscle tissues of Clarias gariepinus at Lake Ngami, in the Okavango Delta in northern Botswana, during low floods. The fish were bought from local fishermen, and samples of muscle tissue were acid-digested and analyzed for iron, zinc, copper, manganese, molybdenum, nickel, chromium, cadmium, lead, and arsenic using inductively coupled plasma optical emission spectroscopy (ICP-OES). Sediment samples were also collected and analyzed for the elements and for organic matter content. Results show that in all samples, iron was found in the greatest amount while cadmium was below the detection limit. Generally, the concentrations of elements in sediment were higher than in fish except for zinc and arsenic. While the concentration of zinc was similar in the two media, arsenic was almost 3 times higher in fish than sediment. To evaluate the risk to human health from fish consumption, the target hazard quotient (THQ) and cancer risk for an average adult in Botswana, sub-Saharan Africa, and riparian communities in the Okavango Delta was calculated for each element. All elements were found to be well below regulatory limits and do not pose a threat to human health except arsenic. The results suggest that other benthic feeding fish species could potentially have high arsenic levels too. This has serious implications for human health, especially riparian households to whom fish is a key component of food and nutrition security.

Keywords: Arsenic, African sharp tooth cat fish, Okavango delta, trace elements

Procedia PDF Downloads 155

Authors: Nasreen Jeelani, Huining Shi , Di An, Lu Xia, Shuqing An

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Heavy metals contamination in aquatic ecosystem is a major environmental problem since its accumulation along the food chain pose public health risk. The concentration of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in soil and plants species collected from different streams of Suoxu River, China was investigated. This aim was to define the level of pollutants in Suoxu River, find which plant species exhibits the greatest accumulation and to evaluate whether these species could be useful for phytoremediation. While total soil Cd, Cr, Cu, Ni, Pb, and Zn concentrations varied, respectively, from 0.09 to 0.23 , 58.6 to 98, 9.72 to 80.5, 15.3 to 41, 15.2 to 27.3 and 35 to 156 (mg-kg-1), those in plants ranged from 0.035 to 0.49, 2.91 to 75.6, 4.79 to 32.4, 1.27 to 16.1, 0.62 to10.2, 18.9 to 84.6 (mg-kg-1), respectively. Based on BCFs and TFs values, most of the studied species have potential for phytostabilization. The plants with most effective in the accumulation of metals in shoots are Phragmatis australis (TF=2.29) and Iris tectorum (TF =2.07) for Pb. While Chenopodium album, (BCF =3.55), Ranunculus sceleratus, (BCF= 3.0), Polygonum hydropiper (BCF =2.46) for Cd and Iris tectorum (BCF=2.0) for Cu was suitable for phytostabilization. Among the plant species screened for Cd, Cr, Cu, Ni, Pb and Zn, most of the species were efficient to take up more than one heavy metal in roots. Our study showed that the native plant species growing on contaminated sites may have the potential uses for phytoremediation.

Keywords: heavy metals, huaihe river catchments, sediment, plants

Procedia PDF Downloads 325

Authors: Kaarthik K., Harshini S., Karthika M., Kripanandhini T.

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Water is an essential part of living organisms. Major water pollution is caused due to contamination of industrial wastewater in the river. The most important step in bringing wastewater contaminants down to levels that are safe for nature is wastewater treatment. The contamination of river water harms both humans who consume it and the aquatic life that lives there. We introduce a new cloud-based industrial IoT paradigm in this work for real-time control and monitoring of wastewater. The proposed system prevents prohibited entry of industrial wastewater into the plant by monitoring temperature, hydrogen power (pH), CO₂ and turbidity factors from the wastewater input that the wastewater treatment facility will process. Real-time sensor values are collected and uploaded to the cloud by the system using an IoT Wi-Fi Module. By doing so, we can prevent the contamination of industrial wastewater entering the river earlier, and the necessary actions will be taken by the users. The proposed system's results are 90% efficient, preventing water pollution due to industry and protecting human lives.

Keywords: sensors, pH, CO₂, temperature, turbidity

Procedia PDF Downloads 78