Sediment Concentration Research Articles

Factors influencing the variation of the Sepik-Ramu River system's sediment plume off the north coast of New Guinea

The Sepik-Ramu River system (SRRs) is a principal contributor of terrestrial materials to the pelagic waters of the tropical Western Pacific, boasting the highest sediment discharge in New Guinea. However, this system's sediment outflow and dispersal patterns are not well-documented. This study seeks to address this gap by analyzing the estuarine sediment plumes, which are the key indicators of the marine dispersion of terrestrial materials. Utilizing Moderate Resolution Imaging Spectroradiometer (MODIS) images from 2010 to 2020 and applying the Novoa17 algorithm, we examined the distribution and temporal evolution of the sediment plume of the SRRs estuary. The sediment plume was categorized into two distinct zones: core and diffuse, based on suspended sediment concentration (SSC) levels. Our findings reveal significant seasonal variations of these sediment plumes in the nearshore. The plume area expands during the wet season and contracts during the dry season, respectively, with core and diffuse plumes sharing similar change characteristics. The diffuse plume primarily extends northeast in the wet season and subsequently shifts northwest in the dry season, and the core plume consistently points to the northeast. The study further explores the driving factors and mechanisms behind these patterns, identifying river discharge as the primary influence on the core plume and sea surface winds and coastal currents as determinants of the diffuse plume's behavior. Interannual variations in the plume characteristics were found to be influenced by the El Niño-Southern Oscillation (ENSO), which indirectly affects plume dynamics through its impact on regional precipitation. During El Niño events, characterized by drier conditions and reduced discharge, the plume SSC and area typically decrease. During La Niña events, the plume's SSC and area typically increase, except for the 2011 super La Niña's negative anomaly, caused by the rain belt's excessive westward shift.

Differences in sediment provenance from rainfall and snowmelt erosion in the Mollisol region of Northeast China

AbstractDifferences in erosion patterns inevitably lead to different soil loss processes. However, the differences in sediment sources between rainfall and snowmelt erosion are not well studied. To address this gap, a study was conducted in a small agricultural catchment (3.5 km2) using the fingerprinting technique to quantify the various sources contributing to sediment, as well as determine the magnitude of sediment total nitrogen (TN), total phosphorus (TP), total potassium (TK) and soil organic matter (SOM) loads from three sources (cultivated land, unpaved roads and gullies) during the rainy season and spring thawing period. Sediment sources from 17 rainfall erosion and seven snowmelt erosion events of varying magnitudes were compared. The Collins and Bayesian mixing models, coupled with geochemical tracers (Cs, V, Cd, Pb and Ag), were applied to assess the contribution proportion of individual sediment sources to suspended sediment. According to the results obtained from the Bayesian mixing model with higher accuracy, cultivated land, unpaved roads and gullies contributed 60.3% (load‐weighted mean contribution [LMC] = 82.8%), 11.0% (LMC = 6.5%) and 28.7% (LMC = 10.7%) of the sediment in the rainy season, respectively. Cultivated land was the dominant sediment source for rainfall erosion, with high rainfall erosivity and sediment concentration. However, for snowmelt erosion, gullies were the primary sediment source (LMC = 66.2%), followed by cultivated land (LMC = 19.8%) and unpaved roads (load‐weighted = 14.0%). Meanwhile, in the spring thawing period, the contributions of unpaved roads to sediment were higher than in the rainy season. During the rainy season, the greatest contributions of TN, TP, TK and SOM were observed from cultivated land, with respective LMC values of 94.2%, 89.4%, 81.1% and 94.8%. With the increase of sediment contribution from gullies in the spring thawing period, its LMC of TN, TP, TK and SOM increased to 42.6%, 58.3%, 65.0% and 38.0%, respectively. The results of the study could be useful for understanding the processes of soil erosion, clarifying the driving mechanism of compound erosion, developing the compound erosion prediction model and optimizing the spatial configuration of erosion control measures.

Overbank Flow, Sediment Transport, and Channel Morphology in the Lower Yellow River: A Review

As a prerequisite and foundation for studying the evolution mechanism of river channels, an in-depth understanding of the cross-sectional morphology adjustment is required. As a starting point, it is crucial to systematically summarize and generalize the research findings on channel morphological adjustment obtained to date, particularly in the context of the significant changes in the water and sediment conditions of large rivers that have occurred worldwide. This paper provides a comprehensive review of the research findings on the three following aspects of the Lower Yellow River: the transverse distribution of overbank flow velocity, the transverse distribution of suspended sediment concentration, and the morphological adjustment of the river cross-section. There are various equations available to predict the lateral depth–average flow velocity distribution. These equations are classified into the two following categories: empirical and theoretical formulas. Theoretical formulas are obtained through consideration of the cross-sectional morphology, accounting for inertial force terms caused by secondary flow, and momentum transfer between the main channel and its floodplain. Similarly, empirical equations and theoretical formulas for sediment concentration transverse distribution are also summarized, given the different influencing factors and assumptions. We also discuss the morphological adjustment of river cross-sections based on the analysis of measured data, mathematical model calculation, and the physical model test. In particular, we propose the idea of revealing channel cross-section morphology evolution mechanisms from the theoretical level of water and sediment movement and distribution. This review aims to enhance understanding of overbank flow, sediment transport, and channel morphology in the Lower Yellow River and may also serve to some extent as a reference for the evolution and management of channels in other rivers.

Twin Satellites HY-1C/D Reveal the Local Details of Astronomical Tide Flooding into the Qiantang River, China

This article extracts the Qiantang River tidal bore, analyzing the water environment characteristics in front of the tidal line of the Qiantang River tidal bore and behind it. The Qiantang River tidal bore Index (QRI) was established using HY-1C, HY-1D, and Gao Fen-1 wide field-of-view (GF-1 WFV) satellite data to precisely determine the location and details of the Qiantang River tidal bore. Comparative analyses of the changes on the two sides of the Qiantang River tidal bore were conducted. The results indicate the following: (1) QRI enhances the visibility of tidal bore lines, accentuating their contrast with the surrounding river water, resulting in a more vivid character. QRI proves to be an effective extraction method, with potential applicability to similar tidal lines in different regions. (2) Observable roughness changes occur at the tidal bore location, with smoother surface textures observed in front of the tidal line compared to those behind it. There is a discernible increase in suspended sediment concentration (SSC) as the tidal bore passes through. (3) This study reveals the mechanism of water environment change induced by the Qiantang River tidal bore, emphasizing its significance in promoting vertical water body exchange as well as scouring the bottom sediments. This effect increases SSC and surface roughness.

Spatial distribution of trace and rare earth elements of bottom sediments in Lake Ostrowite, Bory Tucholskie National Park, Poland

AbstractLake pollution has attracted concerns worldwide; especially the excessive accumulation of trace elements (TEs) and rare earth elements (REEs) in bottom sediments can pose a serious threat to ecosystem health. However, there is still a knowledge gap on the level of sediment pollution in lakes isolated from the direct impact of pollution sources, their spatial variability, and also on the factors influencing this state. The aim of this study is to investigate the level and spatial variability of TEs and REEs concentrations, as well as to determine their source and the factors determining their distribution in the bottom sediments of Lake Ostrowite. Lake Ostrowite is the largest and deepest water body located in the Bory Tuholskie National Park (in northern Poland), which completely isolates the lake from the direct impact of pollution sources. The study covered analyses of 32 surface samples of bottom sediments. The concentrations of 24 TEs and 14 REEs were determined using inductively coupled plasma mass spectrometry (ICP‐QQQ‐MS). The assessment of the enrichment of bottom sediments in TEs and REEs employed geochemical background values (GBV) that provided the basis for the calculation of relative concentrations and geochemical indices. The determination of their sources and supply routes was based on the cluster analysis and principal component analysis. The obtained results point to the enrichment of the bottom sediments with TEs and REEs. Relative concentration values of TEs and REEs in reference to geochemical background values were in ranges from 0.01 to 7.31, at an average of 0.99, and from 0.03 to 4.29, averaging 1.76, respectively. The enrichment factor values show moderately severe enrichment of sediments at the study sites. This was primarily determined by the concentrations of Ag (from the TEs group) and Lu (from the REEs group). The metal pollution index values showed an approximate spatial distribution of points in terms of the presence of TEs and REEs. The lowest concentrations of TEs and REEs occurred on the eastern shore of the western basin of Lake Ostrowite. TEs and REEs concentrations in sediments are positively correlated with the content of organic matter and depth and negatively correlated with distance of the sampling point from the river outflow from Lake Ostrowite. On the eastern shore of the western basin, TEs and REEs concentrations are additionally shaped by wind, predominantly from the western direction. With water wave action, organic matter is transported to the central part of the western basin, where it is accumulated. Since the lake is isolated from point and nonpoint pollution sources, relevant from a biogeochemical point of view are dry and wet depositions from the atmosphere as well as aquatic vegetation, shoreline vegetation, forest litter, soil, and groundwater.

Deltaic marsh accretion under episodic sediment supply controlled by river regulations and storms: Implications for coastal wetlands restoration in the Yellow River Delta

Sediment supply has long been recognized as a critical factor affecting salt marsh evolutions. Subject to fluctuating river discharges and coastal hydrodynamics, sediment supply to deltaic marshes are episodic rather than continuous. To evaluate the impacts of episodic sediment delivery under river regulations and storm events on deltaic marsh accretion, a 5-month (April 18th to September 4th, 2021) field campaign was conducted at a Spartina alterniflora marsh of the Yellow River Delta, China. Nine storm events and the Water-Sediment Regulation Scheme (WSRS) coinciding with a freshwater diversion were captured. It was found that the two phases of the WSRS differed greatly in their contribution to marsh accretion. During the Water-Regulation Phase (WRP), marsh accretion rates showed little difference with pre-WRP periods. However, the subsequent Sediment-Regulation Phase (SRP) contributed to ∼15 % of annual accretion within only 4 days, suggesting the SRP was more effective in nourishing deltaic marshes with sediment. Further analyses indicated that the higher accretion during SRP was attributed to both higher sediment concentrations and more favorable sediment pathways, influenced by delta-scale river-tide interactions. Observations also showed that storm events contributed to half of the marsh accretion during the non-WSRS period when the fluvial sediment supply was very low. During storms, wave-induced intertidal resuspension acted as the major sediment sources. Under favorable conditions (onshore wind, high water levels, high waves), tidal-averaged sediment delivery to marshes underwent as much as fifty-fold increase compared with the calm period. The observed marsh dynamics suggested that marsh sedimentations depended on not only the seaward sediment concentrations, but also the sediment transport pathways. For deltaic marsh restoration practices, we proposed that marsh-orientated schemes which align river regulations with favorable meteorological and hydrodynamic conditions, could potentially make better use of fluvial sediment for deltaic marsh nourishment.

Relationship between hydro-environmental variables and Coilia nasus catch in a highly turbid macrotidal estuary in Japan

The effect of estuarine hydro-environmental parameters and tidal phases on the fish catch in the macrotidal Chikugo River estuary was investigated. This study focuses on the catch data of Etsu (Coilia nasus) fish, obtained during their spawning season from 2009 to 2020, employing traditional fishing techniques at a site situated 14.6–16 km upstream from the river mouth. It analyses various hydro-environmental parameters and identifies optimal ranges of environmental parameters. The optimal range of salinity (0.04–0.2) and suspended sediment concentration (SSC, 16–118 mg/L) indicated a higher fish catch at the saltwater-freshwater interface and upstream of the estuarine turbidity maximum (ETM) zone. By developing a generalized additive model (GAM) to analyze the relationship between CPUE and environmental parameters, the study assesses the relative importance of each variable in explaining CPUE variance. GAM exhibited a reasonable predictive capability (R2 = 0.509) and indicated the relative importance of each variable (SSC-24.69%, salinity-21.81%, temperature-24.41%, discharge-9.16%, and MTR-19.91%) in explaining the CPUE variance. Additionally, it aims to verify the maturity status and spawning migration patterns of C. nasus fish through standard-length distribution analysis during the spawning season. The standard-length distribution and comparison with previous literature confirmed that fishes caught by the fisherman belong to the category of matured fishes aged 2–3 years. The results indicated that the high CPUE of matured C. nasus at the upstream of ETM and freshwater-saltwater interface was related to the spawning migration and not to their feeding behaviour at the ETM. This research contributes to fisheries management strategies and conservation efforts in the Chikugo River estuary by providing valuable guidance for habitat restoration, informing fishing regulations, and understanding the behaviour of C. nasus.

Health and ecological risk assessment of heavy metals in water and sediments within a data scarce urban catchment in Tanzania – A case of Ngerengere River, Morogoro Municipality

Low-, middle- and high-income countries, exhibit indications of risks associated with water quality. The study investigated heavy metal concentrations in surface water and sediments within the Ngerengere River and its tributaries (Kikundi, Bigwa, and Morogoro) drain within in the Morogoro Municipality of Tanzania, an Urban Catchment Area (UCA) with limited available data mainly because of inadequate monitoring and reporting capabilities. Analysis of health and ecological risks associated with heavy metal pollution was also carried out using health risk assessments models, pollution indices, and multivariate analysis techniques. Between the dry and wet seasons of 2023, water and sediment samples from (13) sampling stations strategically established along the Ngerengere river and its tributaries were analyzed for six heavy metals (Pb, Cr, Ni, Cd, Cu and Zn) using the Atomic Absorption Spectrophotometer Model Perking Elmer 850 Graphite Furnace and Perking Elmer AS 800 Auto-sampler coupled with a computer interface for operational, displaying and reading the results. The calculated degree of water contamination (Cd) values in river water in both dry and wet seasons ranged from 0 to 6.803 indicating low and high degrees of contamination respectively. Heavy metal concentration in sediment decreases in the order of Zn>Ni>Cr>Cu>Cd>Pb. The non-cancer risk index (HI) via ingestion and dermal pathways in dry and wet seasons for both children and adult groups was <1 hence no non-cancer risk, However, cumulative dermal and ingestion exposure in both children and adults indicated potential cancer risk in dry and wet season. The analysis of ecological risks associated with heavy metal enrichment in the sediment indicated high enrichment of sediments with Cd, Ni and Zn. Conclusively, in wet months, risk indices tend to be low, while in dry months, they typically remain high.

Sources of suspended sediments in salt marsh creeks: Field measurements in China and the Netherlands

Marsh creeks are perceived as important conduits for transporting water and sediment between mudflats and marshes. In order to advance the understanding of the transport mechanisms in creeks, the source and ultimate sink of sediment which moves between mudflats and marshes through creek channels need further investigation. Therefore, two field campaigns were conducted in two intertidal systems with varying sediment availability. The water depth, flow velocity, suspended sediment concentration, and bed level change were measured simultaneously in a marsh creek and on the adjacent mudflat in Chongming Island (China) and in Paulina Saltmarsh (the Netherlands). Paulina Saltmarsh is much smaller, more frequently flooded, and has lower sediment concentration than Chongming. These contrasting conditions allow for a comparison of transport mechanisms and functioning of the creek. Both systems first show that the high suspended sediment concentration (SSC) measured in marsh creeks is mainly the consequence of sediment advection rather than local erosion. In addition, erosion in marsh creeks is usually limited during ebb tides, reducing the export of sediment through these creeks. However, differences have been observed between two systems. The measured SSC was highly asymmetric between flood and ebb tides in Chongming. Large peaks in SSC during the flood period can be observed for most tidal cycles. The marsh creeks in Chongming therefore function as conduits for sediment import. Additionally, there are distinct overbank and underbank tides in Chongming. Sediment was trapped and retained in creeks during underbank tides, which can then be eroded and transported to the marsh during subsequent overbank tides. We also observed that mudflats in Chongming quickly recovered after erosion. These mechanisms have not been observed in Paulina Saltmarsh, where net sediment export via the marsh creek was observed due to a lack of abundant sediment in suspension during flood tides. Furthermore, the remaining bed surface of mudflats after an erosion event was stronger than before, limiting further erosion in Paulina Saltmarsh. These findings from the two systems indicate that the role of creeks in sediment import/export depends on the availability of sediment from mudflats, shedding light on nourishment strategies for salt marshes.

Recent warming of the Kuroshio Current has promoted offshore sediment transport in the Yellow Sea

AbstractAs cross‐shelf gradients of most properties are typically much steeper than those in the alongshore direction, transport across isobaths tends to be inhibited, particularly at oceanic fronts where cross‐shelf gradients are markedly pronounced. Consequently, variations in cross‐shelf gradients may exert a significant influence on offshore transport; however, this influence is not yet well understood. This study employs reconstructed daily suspended sediment concentration (SSC) data from the Yellow Sea's offshore region to investigate the dynamics of offshore transport. Our analysis on an interannual scale shows that offshore SSC correlates more with temperature gradients at the oceanic front than with winter storms, despite the latter's vital role in causing frontal instability. The observed increase in offshore transport over the past two decades is likely connected to Kuroshio Current warming, which has strengthened the horizontal density gradient at the oceanic front, driving the strengthened offshore transport of coastal sediments during instability episodes.

Sustained increase in suspended sediments near global river deltas over the past two decades

River sediments play a critical role in sustaining deltaic wetlands. Therefore, concerns are raised about wetlands’ fate due to the decline of river sediment supply to many deltas. However, the dynamics and drivers of suspended sediment near deltaic coasts are not comprehensively assessed, and its response to river sediment supply changes remains unclear. Here we examine patterns of coastal suspended sediment concentration (SSC) and river sediment plume area (RPA) for 349 deltas worldwide using satellite images from 2000 to 2020. We find a global increase in SSC and RPA, averaging +0.46% and +0.48% yr−1, respectively, with over 59.0% of deltas exhibiting an increase in both SSC and RPA. SSC and RPA increases are prevalent across all continents, except for Asia. The relationship between river sediment supply and coastal SSCs varies between deltas, with as much as 45.2% of the deltas showing opposing trends between river sediments and coastal SSCs. This is likely because of the impacts of tides, waves, salinity, and delta morphology. Our observed increase in SSCs near river delta paints a rare promising picture for wetland resilience against sea-level rise, yet whether this increase will persist remains uncertain.

Microplastic analysis in sediments of the Elbe River by electrostatic separation and differential scanning calorimetry

This study presents the most extensive investigation of microplastic (MP) contents in sediment from the Elbe River. We employed electrostatic separation (ES) and differential scanning calorimetry (DSC) to overcome limitations of sample throughput and time-consuming analysis. In total 43 sediment samples were collected using a Van-Veen grab. Subsequently, coarse materials (d10 > 100 μm) and fine materials (d10 ≤ 100 μm) were enriched using ES and density separation. DSC was utilized for MP identification and quantification, based on the phase-transition signals of eight different polymers. MP presence was detected in 25 samples, with successful quantification in 12 samples. The MP content in coarse material samples from shoreline areas ranged from 0.52 to 1.30 mg/kg, while in fine material samples from harbor basins, it ranged from 5.0 to 44.6 mg/kg. The most prevalent polymers identified were LD-PE, HD-PE, PP, and PCL. These findings confirmed the suitability of DSC for analyzing MP in complex environmental samples. MP hotspots were identified in harbor basins, where natural sedimentation processes and increased anthropogenic activities contribute to MP accumulation. Additionally, industrial sewage potentially contributed to MP content in sediment samples. The highest pollution levels were observed in the middle Elbe, between the confluences of Mulde and Havel. Lowest MP contents were found in the lower Elbe, potentially influenced by tides. Future studies should focus on holistic investigations of selected river sections, encompassing sediment, water, and biota samples, rather than the entire catchment area. This approach would facilitate the generation of spatiotemporal data on MP distribution in freshwater streams. In addition, more research is needed to explore potential interactions between different MP and sediment types during DSC measurements.

In-situ radiogenic heat production in the Cenozoic sediments of the North sea

Radioactive decay is a significant heat source in sedimentary basins. Spectral gamma ray logs from the North Sea well 1/2-2 were used to obtain the uranium, thorium and potassium concentrations in the Cenozoic sediments beneath the well. On average, the sediments contain 1.86 ± 0.37% potassium, 10.12 ± 2.55 ppm thorium and 2.74 ± 1.54 ppm uranium. Abnormally high, up to 8 ppm, uranium concentrations were measured in the transition zones between the Nordland and the Hordaland Group and in the Sele Formation of the Rogaland Group.The estimated heat production rate, of all in-situ radioactive isotopes, is, on average, 1.281 ± 0.35 μW/m3. About 12% (0.143 ± 0.31 μW/m3) can be contributed to potassium, 46% (0.570 ± 0.14 μW/m3) to thorium and 42% (0.567 ± 0.31 μW/m3) to uranium. The estimated radiogenic heat rates vary significantly across the main stratigraphic units. On average, radiogenic heat production is more intensive in shale-dominated material (1.33 ± 0.31 μW/m3) than in sand-rich sediments (0.84 ± 0.36 μW/m3). High heat production rates are very closely related to high uranium concentration. In the “hottest” (2.012 ± 0.27 μW/m3) unit, the Sele Formation, the uranium accounts for about 69% of the generated heat, while the thorium and the potassium contribute with 24% and less than 7%, respectively. In the ”coldest” (0.782 ± 0.35 μW/m3) unit, the Forties, the relative contribution of uranium is only about 36% and that of potassium and thorium are about 18% and 46%, respectively.The radiogenic heat rates in the Cenozoic sediments should be integrated in future evaluations of the geothermal potential in the North Sea.

Assessment of the Ra-226 and Ra-228 Content in the Bottom Sediments of the Kolva and Usa Rivers (Bolshezemelskaia Tundra of the Nenets Autonomous Region and the Komi Republic)

An assessment was made of the content of natural radionuclides Ra-226 and Ra-228, as well as petroleum products, in the bottom sediments of the Kolva and Usa rivers (Bolshezemelskaia tundra of the Nenets Autonomous Region and the Komi Republic). The values of the specific activities of the studied radionuclides, their isotope ratios, the concentration of petroleum products are obtained, and the correlation dependences of the specific activities of Ra-226 and Ra-228 on the concentration of petroleum products are established. It has been demonstrated that certain sections of the Kolva river are characterized by increased content of Ra-226 in bottom sediments. It was concluded that the likely source of radionuclide entry into bottom sediments is the entry of oil and gas waste into surface waters.

Comparative Study and Evaluation of Sediment Deposition and Migration Characteristics of New Sustainable Filter Media in Micro-Irrigation Sand Filters

The quartz sand filter medium used in micro-irrigation media filters has the disadvantages of short filtration cycle, surface filtration, and mining pollution. Selecting resources as new filter media is essential to improve the performance of the media filter and boost sustainable development. In this study, the traditional quartz sand filter medium and two new filter media were selected, and their corresponding filtration performances were comparatively studied. The influence of the type, particle size, and height of the filter medium on filtration performance was evaluated. The sediment content and distribution based on the size of particles in quartz sand, crushed glass, and glass bead filter layers was measured and analyzed. The hydraulic performance of different filter columns was analyzed. The results showed that for a given particle size, quartz sand exhibits the best sediment retention ability. This promoted the aggregation of small sediment particles into larger ones, whereas the crushed glass and bead glass filter layers promoted the splitting of large sediment particles into smaller ones, which enabled the reduction of blockage during the micro-irrigation process. The filtration rate of the quartz sand filter column exhibited the least fluctuation relative to crushed glass and glass bead filter media, and the pressure in each column exhibited a linear incremental change. In summary, glass microbeads are not suitable as filter material, crushed glass is suitable for general micro-irrigation systems, and quartz sand is suitable for micro-irrigation systems with elaborate filtration requirements. The findings of this study can provide theoretical guidance for the selection of the micro-irrigation filter material.

Wide Riparian Zones Inhibited Trace Element Loss in Mining Wastelands by Reducing Surface Runoff and Trace Elements in Sediment.

The diffusion of trace elements in mining wastelands has attracted widespread attention in recent years. Vegetation restoration is an effective measure for controlling the surface migration of trace elements. However, there is no field evidence of the effective riparian zone width in mining wastelands. Three widths (5 m, 7.5 m, and 10 m) of Rhododendron simsii/Lolium perenne L. riparian zones were constructed in lead-zinc mining wastelands to investigate the loss of soil, cadmium (Cd), copper (Cu), arsenic (As), lead (Pb), and zinc (Zn). Asbestos tiles were used to cut off connections between adjacent plots to avoid hydrological interference. Plastic pipes and containers were used to collect runoff water. Results showed that more than 90% of trace elements were lost in sediment during low coverage and heavy rainfall periods. Compared with the 5 m riparian zone, the total trace element loss was reduced by 69-85% during the whole observation period in the 10 m riparian zone and by 86-99% during heavy rain periods in the 10 m riparian zone, which was due to reduction in runoff and concentrations of sediment and trace elements in the 10 m riparian zone. Indirect negative effects of riparian zone width on trace element loss through runoff and sediment concentration were found. These results indicated that the wide riparian zone promoted water infiltration, filtered soil particles, and reduced soil erosion and trace element loss. Riparian zones can be used as environmental management measures after mining areas are closed to reduce the spread of environmental risks in mining wastelands, although the long-term effects remain to be determined.

ASPERGILLOSIS IN BROILER CHICKEN IN TUNJUK VILLAGE, TABANAN DISTRICT, TABANAN REGENCY, BALI

In the development of broiler farming in Indonesia, it is necessary to be aware of diseases that often attack livestock, namely Aspergillosis fungal infection. This case study aims to confirm the diagnosis in the death of 30-day-old broiler chickens of male sex who experienced clinical symptoms of lethargy, nasal discharge, shortness of breath, swollen eyelids, and difficulty eating for 3 days so that they were separated from the rest of the chicken population obtained at one of the farms located in Tunjuk Village, Tabanan District, Tabanan Regency, Bali. Examination of case animals included signaling, anamnesis, epidemiological data, clinical symptoms, anatomical pathology and histopathology examination, bacteriology and mycology examination, and parasitology examination. The results of the anatomical pathology examination showed congestion in the brain, petechie in the ventriculus, hemorrhage in the intestines, hemorrhage in the lungs with white nodules and white nodules in the kidneys. Histopathological examination found septa hyphae and conidiophore. In the mycological examination, the case animals identified Aspergillosis in the lung and kidney organs grown on SDA (Sabouraud Dextose Agar) media and observation under a microscope using 10% KOH dye and methylene blue. In the bacteriological examination, samples of lung and intestinal organs were cultured on general Nutrient Agar (NA) media, followed by selective Eosin Methylene Blue Agar (EMBA) media, primary tests, gram staining, biochemical tests and sugar tests until the results showed that there was a secondary infection of Klebsiella sp in the lung organ samples. The results of the examination related to parasites in the feces of case chickens by qualitative methods, namely natif (direct), sedimentation concentration, and buoyancy concentration were confirmed not to be found worm eggs or coccidia. From this case study it can be concluded that the case chicken was infected with Aspergillosis. Prevention of the spread of Aspergillosis should be done by improving farm management such as housing sanitation and good husbandry methods to prevent the risk of livestock experiencing the disease.

Imbalance of sediment transport in a meso-tidal bay: effect of tidal pumping and residual circulation

In-situ mooring systems with acoustic Doppler current profilers were installed in the western (TM01) and eastern (TM02) parts of Yeosu Bay from September 3 to October 2, 2021, to understand the controlling mechanisms of suspended sediment transport. In the bay, freshwater from the Seomjin River freely exchanges with seawater from the open sea. Over the mooring period, current flows were mainly dominated by ebb tides. Power spectral density analysis of the suspended sediment concentration (SSC) exhibited a quarter-diurnal (6.21 h) frequency at TM01 and a semi-diurnal (12.42 h) frequency at TM02. The results suggested that SSC variations in the western part were driven primarily by local sediment resuspension, while they were influenced predominantly by horizontal advection in the eastern part. Differences in SSC variation at the two stations could be due to the physical properties of the bed sediments (TM01: sandy mud containing shell fragments, TM02: mud). Such current flows and SSC variations over the tidal cycles caused an imbalance of sediment transport. At TM01, the sediment fluxes were dominantly seaward due to tidal pumping (88% of the total) and the discharge of suspended sediments in the surface layer by residual circulation. At TM02, landward sediment fluxes were driven primarily by the residual current (73% of the total). Although the suspended sediment fluxes tended to be compensated and balanced mutually by circulation over the entire period, the suspended sediment fluxes at TM02 were approximately twice higher than those at TM01. This was caused by the difference in SSC asymmetry between flood and ebb at the two stations. The mechanisms controlling the transport of suspended sediment could vary spatially, and the relative contribution of tidal pumping and residual circulation could result in an imbalance of sediment transport.

The fate of pharmaceuticals and personal care products (PPCPs) in sewer sediments:Adsorption triggering resistance gene proliferation

In recent years, large quantities of pharmaceuticals and personal care products (PPCPs) have been discharged into sewers, while the mechanisms of PPCPs enrichment in sewer sediments have rarely been revealed. In this study, three PPCPs (tetracycline, sulfamethoxazole, and triclocarban) were added consecutively over a 90-day experimental period to reveal the mechanisms of PPCPs enrichment and the transmission of resistance genes in sewer sediments. The results showed that tetracycline (TC) and triclocarban (TCC) have higher adsorption concentration in sediments compared to sulfamethoxazole (SMX). The absolute abundance of Tets and suls genes increased in sediments under PPCPs pressure. The increase in secretion of extracellular polymeric substances (EPS) and the loosening of the structure exposed a large number of hydrophobic functional groups, which promoted the adsorption of PPCPs. The absolute abundance of antibiotic resistance genes (ARGs), EPS and the content of PPCPs in sediments exhibited significant correlations. The enrichment of PPCPs in sediments was attributed to the accumulation of EPS, which led to the proliferation of ARGs. These findings contributed to further understanding of the fate of PPCPs in sewer sediments and opened a new perspective for consideration of controlling the proliferation of resistance genes.

Chemical, biochemical, and bioactivity studies on some soda lakes, Wadi El-Natrun, Egypt

Wadi El-Natrun is one of the most observable geomorphological features in the North-Western Desert of Egypt; it contains several old saline and saline soda lakes. This study investigates physicochemical and biochemical characteristics and estimates the total phenolic content (TPC), total flavonoid content (TVC), and bioactivities of sediment, cyanobacteria, and brine shrimp (Artemia salina) in soda lakes, i.e., El-Hamra Lake 1 (H1) and El-Hamra Lake 2 (H2). These soda lakes are unique extreme ecosystems characterized by high pH (> 9.3), high alkalinity, and salinity. Some extremophilic microorganisms are hosted in this ecosystem. The results revealed that the chemical water type of studied lakes is soda-saline lakes according to the calculated percentage sequence of major cations and anions. Sodium ranked first among major cations with an abundance ratio of e% 58, while chloride came first among anions with an abundance ratio of e% 71, and bicarbonate and carbonate occupied the last rank with an abundance of 6%. The biochemical investigations showed that TPC and TVC are present in concern contents of sediment, cyanobacteria, and brine shrimp (A. salina) which contribute 89% of antioxidant capacity and antimicrobial activities. Thus, this study helps better understand the chemical and biochemical adaptations in soda lake ecosystems and explores natural sources with potential applications in antioxidant-rich products and environmental conservation efforts.