Sediment Samples Research Articles

Determination of Radiological Hazards Associated with the use of Oba-Ile River Sediments as Building Material

This study was conducted to determine the radioactivity level in the sediment samples collected from Oba-Ile River, Olorunda Local Government Area of Osun State, Nigeria and evaluate the radiological hazards associated with the use of the river sediments as building material. Twenty four (24) sediment samples were obtained along three different points within the River for a period of eight months. The activity concentration of 40K in the sediment sample ranged from 273.36 ± 5.41 Bqkg-1 to 1662.41± 28.19 Bqkg-1with an average concentration 892.22 ± 14.66 Bqkg-1. The values of 232Th in the sediment samples ranged between 27.22 ± 5.12 Bqkg-1 to 186.14 ± 6.22 Bqkg-1 with an average concentration 87.95 ± 7.91 Bqkg-1. The values of 238U ranged from 12.61 ± 2.01 Bqkg-1 to 241.12 ± 5.91 Bqkg-1 with an average 62.83 ± 3.18 Bqkg-1. The radiological hazards due to natural radionuclides content, such as absorbed dose rate (DR), annual effective dose rate (AEDE),excess lifetime cancer risk (ELCR), internal radiation hazard (Hin) and external radiation hazard (Hex) in the sediment samples were calculated. The calculated radiological parameters were compared with recommended safety limits and internationally approved values.

Current evaluation of radiation hazards from sediments of Manzala Lake, Egypt

AbstractSurface sediment samples were collected from 12 different sites in Manzala Lake for measuring 238U, 226Ra, 232Th and 40K. Those elements were measured using High Purity Germanium (HPGe) detector. The concentrations of radionuclides were within the UNSCEAR limits. Various indices were applied to detect the environmental and human risk assessment for example activity utilization index, external hazard index and others. Environmental Risk from Ionising Contaminants: Assessment and Management (ERICA) tool was applied and showed no considered biological hazards. The results showed that concentrations of radionuclides in sediments of Manzala Lake were within the safe limits for further uses.

Isolation of Bacillus Velezensis from Leepuram Sea Sediment and Its Bioactive Compound and Antimicrobial Activity

Research into marine bacteria in India for their potential active chemicals is essential for the creation of medications derived from marine sources. The objective of this research was to collect Bacillus velezensis from Leepuram Sea Sediment, test their antibacterial efficacy with the agar diffusion method, and find secondary metabolites by GC-MS spectroscopy.Traditional microbiological methods and phylogenetic analysis of 16S rRNA sequences were used to successfully identify Bacillus velezensis from sediment samples obtained in the Leepuram Sea, Kanyakumari. Using the agar well diffusion method, we tested the isolated metabolites for their antibacterial activity against Gram-positive and Gram-negative bacteria. The results showed that the extract had a strong antibacterial effect, inhibiting the growth of harmful bacteria with zones of inhibition as large as 19 mm for E. coli and Pseudomonas.Bacillus velezensis produces secondary metabolites with pharmacological potential, according to this study. These metabolites may have useful uses in biocontrol, agriculture, and medicine. The implications of these results for human health and the creation of new antimicrobial drugs are likely to grow substantially when more worldwide research is carried out.

Augmenting Seafloor Characterization via Grain Size Analysis with Low-Cost Imagery: Minimizing Sediment Sampler Biases and Increasing Habitat Classification Accuracy

Bottom-grab samplers have long been the standard to describe nearshore marine habitats both qualitatively and quantitively. However, sediment samplers are designed to collect specific grain sizes and therefore have biases toward those sediments. Here, we discuss seafloor characterizations based on grain size analysis alone vs. grain size analysis augmented with quantitative benthic imagery. We also use both datasets to inform a prevalent benthic habitat classification system. The Coastal and Marine Ecological Classification Standard (CMECS) was used to test this hypothesis. CMECS was adopted by the federal government to standardize habitat classification in coastal U.S. waters. CMECS provides a hierarchal framework to define and interpret benthic habitats but does not prescribe specific sampling methods. Photography has been utilized for many decades in benthic ecology but has rarely been employed in habitat classification using CMECS. No study to date has quantitatively examined the benefit of incorporating benthic imagery into the classification of biotopes using CMECS. The objective of this study is to classify a roughly 1 km2 subtidal area within Herring Cove in Provincetown, MA with CMECS and quantify the benefit of augmenting classification with low-cost imagery. A benthic habitat survey of the study area included grab sampling for grain-size analysis and invertebrate taxonomy, benthic imagery, water quality sampling at 24 sampling stations, and acoustic mapping of the study area. Multivariate statistical analyses were employed to classify biotic communities and link environmental and biological data to classify biotopes. The results showed that benthic imagery improved the classification and mapping of CMECS components. Furthermore, the classification of habitats and biotopes was improved using benthic imagery data. These findings imply that the incorporation of low-cost benthic imagery is warranted in coastal benthic biotope classification and mapping studies and should be regularly adopted. This study has implications for coastal benthic ecologists classifying benthic habitats within the CMECS framework.

Spatial distribution studies on sedimentary organic matter along the shoreline of Arabian Sea: insights from Kollam, Southwest Coast, India.

The present study was aimed at investigating the source, quality, and quantity of organic matter and labile fraction of biochemical constituents in the surficial sediments of Arabian Sea Shoreline at Kollam, India, which gives an input into the processes associated with the subsurface geochemistry pattern. About 15 surface sediment samples were collected from the five beaches for this study during January 2021. The samples were analyzed for CHN, total organic carbon (TOC), and labile fraction such as carbohydrates (CHO), proteins (PRO), and lipids (LIP). The TOC/TN ratio revealed that the source organic matter (OM) in the samples was primarily of marine origin and autochthonous, except TM3 at Thirumullavaram. Thirumullavaram is a sheltered beach, and it has low hydrodynamic process. The high organic matter content in TM3 (13.9) may be the originated from the terrestrial input. The hierarchical cluster analysis revealed that TM3 indicate that unique character to other stations. Principal component analysis revealed that three components accounted for 78% of the total variance. PC1 variance was associated with carbon-based organic compounds. PC2 was predominantly influenced by CHO and LOM, suggesting that PC2 may encompass variability associated with these nutritional profiles. PC3 was influenced by LIP and LIP/CHO, showing it may be a lipid-related component. The PRO to CHO ratio is < 1, exhibiting old aged organic matter deposited in sediments and the meso-oligotrophic status. The LIP to CHO ratio, recorded as < 1, exhibits the poor quality of energetic (food) OM in sediments. The sediment samples exhibit the following trend CHO > PRO > LIP.

Distribution of heavy metals in the sediments of Ganga River basin: source identification and risk assessment.

Sediment serves as a heavy metal store in the riverine system and provides information about the river's health. To understand the distribution of heavy metal content in the Ganga River basin (GRB), a total of 25-bed sediment and suspended particulate matter (SPM) samples were collected from 25 locations in December 2019. Bed sediment samples were analyzed for different physio-chemical parameters, along with heavy metals. Due to insufficient quantity of SPM, the samples were not analyzed for any physio-chemical parameter. The metal concentrations in bed sediments were found to be as follows: Co (6-20mg/kg), Cr (34-108mg/kg), Ni (6-46mg/kg), Cu (14-210mg/kg), and Zn (30-264mg/kg) and in SPM, the concentrations were Co (BDL-50mg/kg), Cr (10-168mg/kg), Ni (BDL-88mg/kg), Cu (26-80mg/kg), and Zn (44-1186mg/kg). In bed sediment, a strong correlation of 0.86 and 0.93 was found between Ni and Cr, and Cu and Zn respectively and no significant correlation exists between organic carbon and metals except Co. In SPM, a low to moderate correlation was found between all the metals except Zn. The risk indices show adverse effects at Pragayraj, Fulhar, and Banshberia. Two major clusters were formed in Hierarchal Cluster Analysis (HCA) among the sample points in SPM and bed sediment. This study concludes that the Ganga River at Prayagraj, Banshberia, and Fulhar River is predominately polluted with Cu and Zn, possibly posing an ecological risk. These results can help policymakers in implementing measures to control metal pollution in the Ganga River and its tributaries.

Forensic-geology-based magnetic analysis of beach sediments from the Shimokita Peninsula, Japan.

The occurrences of various illegal activities on beaches require effective geological and environmental investigation methods. Among these methods, the room-temperature magnetic analysis of soils and sediments represents a nondestructive investigation method for various amounts, types, and grain sizes of magnetic minerals. Here, to verify the usefulness of magnetic analysis in forensic geology research, beach sediment samples from nine sites in the Shimokita Peninsula, Japan, were measured using magnetic analysis to determine the correlations between their concentration-dependent magnetic parameters and actual regional characteristics. The results revealed that the values of various parameters, namely the low-field magnetic susceptibility, anhysteretic remanent magnetization, and isothermal remanent magnetization (IRM), were relatively higher at sites near Ti and Fe sedimentary ore deposits. Further, thermomagnetometry results revealed that magnetite was the main magnetic carrier of the sediments. Moreover, pyrrhotite was detected around Ti-Fe mine sites. Furthermore, the results of the investigated parameters reflected the regional characteristics of the amount of magnetic minerals in the beach sediments. Low-temperature IRM curves and the magnetic grain size parameter also displayed sample-site-reflective characteristics. Thus, we believe that magnetic analysis represents an effective method for estimating the provenance of beach sediments in forensic geology research.

Morphodynamics drive the transport and accumulation of anthropogenic microparticles in tropical coastal depositional systems in southeastern Brazil.

A significant limitation in current coastal pollution research is that microplastics (<5 mm) comprise only a fraction of all anthropogenic microparticles (AMP, <5 mm) scale residues. Comprehensive AMP assessments, including those comprising semisynthetic, and modified natural compositions, are lacking. For instance, the accumulation of AMP in different coastal morphological features within a depositional system remains poorly known, fueling long-lasting debates about the distribution process of microparticles. Using a multi-proxy approach, we address mutual interactions between distinct surface morphologies (tidal flats, beaches, and foredunes) and transport and deposition dynamics of AMP. This issue was addressed by analyzing sediment and water samples collected at a marine protected area in the south coastal of São Paulo (Brazil). Here, we showed that AMP abundance in the tidal mudflat (18,500-20,500 particles/kg) was four times higher than in beach sands (4700-5900 particles/kg), while the lowest abundance was observed in foredune sands (4350 particles/kg). This can be attributed to the low-energy hydrodynamics of tidal flats associated with the cohesive behavior of muddy sediments, which consequently favor trapping and act as the main sink for AMP. Further, coastal processes (waves and currents) drive AMP onshore through sediment transport from the surfzone to the beach, from where the AMP becomes available for onshore eolian transport. Higher AMP abundance (85 particles/L) was observed in the marine water samples compared to the estuarine water samples (35 particles/L). Fibers <1 mm appeared as the predominant AMP in the sediment (99-100 %) and water (80-95 %) samples, primarily consisting of modified cellulose (73 %), dye signature only (16 %), and microplastics (11 %). Consequently, we argue that to fully comprehend the spatial distribution of AMP in coastal sediments and waters, it is crucial to analyze these microparticles from an integrated perspective, primarily considering the hydro-wind dynamics of different coastal morpho-sedimentary compartments combined with sediment grain size.

Heavy metal bioaccumulation based on seasonal monsoon impact in benthic macroinvertebrates of Korean streams.

This study investigates the influence of seasonal monsoon flooding on heavy metal contamination and bioaccumulation in benthic macroinvertebrate communities within a stream ecosystem. We analyzed sediment and benthic macroinvertebrate samples for eight heavy metals [zinc (Zn), chromium (Cr), nickel (Ni), lead (Pb), copper (Cu), arsenic (As), cadmium (Cd), and mercury (Hg)] ) before (BF) and after (AF) a major flooding event. Significant spatial and temporal variations in heavy metal concentrations were observed, with generally higher levels detected after the flood. Chironomidae consistently exhibited high bioaccumulation factors (BAFs) for several metals, highlighting their role as bioindicators. Notably, elevated Cu accumulation was observed in multiple species, including Radix auricularia (R. auricularia), Cipangopaludina chinensis malleata (C. c. malleata), and Palaemon spp. Non-metric multidimensional scaling (NMDS) analysis revealed shifting correlations between environmental variables and bioaccumulation patterns before and after flooding. Pre-flood, total nitrogen (TN) showed a strong positive correlation with Hg bioaccumulation, while post-flood, large sand content emerged as a more influential factor for Zn, Cr, Ni, and Pb bioaccumulation. Our findings emphasize the complex interplay between seasonal flooding, environmental factors, and heavy metal dynamics, with potential implications for ecological risk assessment and water quality management.

Integrated Assessment of Metal Contamination of Soils, Sediments, and Runoff Water in a Dry Riverbed from a Mining Area Under Torrential Rain Events

Dry riverbeds can transport mining waste during torrential rain events, disseminating pollutants from mining areas to natural ecosystems. This study evaluates the impact of these mine wastes on soils, sediments, and runoff/pore water in the La Carrasquilla dry riverbed (southeastern Spain). An integrated approach utilizing geochemical and mineralogical techniques was employed, analyzing water, soil, and sediment samples from both the headwater and mouth of the riverbed. Soil profiles and pore water were collected at 30 cm, 60 cm, and 90 cm deep, alongside sediment and runoff water samples. The assessment of metal(loid) contamination focused on arsenic, cadmium, chromium, copper, iron, nickel, manganese, zinc, and lead, utilizing sequential extraction to evaluate metal partitioning across soil phases. Various pollution indices, including the contamination factor (Cf), pollution load index (PLI), potential ecological risk index (RI), and metal(loid) evaluation index (MEI), were employed to classify contamination levels. The highest level of contamination was reported in the headwater, which suggested anthropogenic activities linked to the presence of mining residues as the major source of metal(loid)s. However, an active deposition of As, Cd, Cu, Fe, Mn, and Zn was reported in the topsoil at the mouth. In the headwater, a quartz and muscovite-rich zone exhibited the highest Cf for Pb (1022), primarily bound to the soil residual fraction (62.8%). At the headwater and mouth, pore water showed higher concentrations of sulfate, Ca, Na, Cl, Mg, and Mn and higher salinity than acceptable limits for drinking water or irrigation established by the World Health Organization. Runoff-water metal concentrations surpassed established guidelines, with MEI values indicating significant contamination by cadmium (36.1) and manganese (19.0). These findings highlight the considerable ecological risk of Pb and underscore the need for targeted remediation strategies to mitigate environmental impacts in the Mar Menor coastal lagoon.

Spatial distribution of heavy metal contamination and risk indices of surface sediments in high-altitude lakes.

Lake ecosystems in northern Pakistan are the most critical resources that maintain and regulate water flow for downstream agricultural, domestic, industrial, and ecological processes. One consequence of these processes is that ecosystems deposit heavy metals (HMs), where lake stagnant conditions result in high vulnerability of water resources. For this purpose, the present study examined HMs such as cadmium (Cd), chromium (Cr), cobalt (Co), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) concentrations in high-altitude lakes (HAL) sediments of Mansehra district, northern Pakistan. Sediment samples were collected from the five HAL. This study used HM concentrations in lake sediments for the pollution factors such as contamination factor (Cf), pollution load index (PLI), sediment pollution index (SPI), ecological risk assessment (ERA), and risk index (RI). Among HMs, Fe showed the uppermost levels of 1410mg/kg in lake sediment, while Cd with lowermost levels of 1.05mg/kg. Results revealed that most HM concentrations in HAL sediments were within the threshold of sediments quality guidelines (SQGs), except for Cd. Among lakes, the sediments of Siri Lake showed higher contamination of HMs than others. Siri Lake sediments also showed higher Cf, PLI, ERA, and RI values than others. The majority of HMs in HAL sediments showed no contamination, except for Cd (considerable) and Pb (moderate) levels to the exposed aquatic ecosystem. This study revealed that 95% of sediment samples in HAL were noted low to medium-level risks to the exposed aquatic communities. Statistical and geospatial analyses revealed that geogenic sources of contamination are a significant contributor to HM contamination of HAL sediments compared to others.

Ecological risks caused by neonicotinoid pesticides in sediments: A case study of freshwater basins in China.

Neonicotinoid insecticides (NNIs) are extensively used in agricultural production in China due to their selective neurotoxicity towards target insects. In recent years, the rapid development of agriculture has increased the use and residue of NNIs. Consequently, the sediment environment, serving as the ultimate sink, is significantly impacted by NNIs. Upon release into the environment, NNIs can enter the human body through the food chain, posing potential ecological and human health risks. This study analyzed 79 sediment samples from two major river basins in North and South China, the Liaohe River basin in Liaoning Province and the Jianjiang River basin in Guangdong Province. The content, composition, distribution, and source of eight NNIs were analyzed, and assess the ecological and human health risks of the target compounds in these regions. The results indicated that the average concentration of NNIs in the sediments of the Jianjiang River basin (2.34 μg/kg) is slightly higher than that of the Liaohe River basin (2.32 μg/kg), and the sources of NNIs in the two areas were different, with differences in the sources of NNIs likely attributable to varying types of agricultural production. The risk assessment revealed that the ecotoxicological and public health risks were more pronounced in the Jianjiang River basin compared to the Liaohe River basin, underscoring the critical need for surveillance and management of hazardous substances like NNIs. The insights findings from this study can provide scientific guidance for the risk evaluation and environmental management of NNIs.

Land-Use Impacts on Soil Erosion: Geochemical Insights from an Urban Drinking Catchment, South-Central Chile

We investigate the influence of land use and land cover (LU/LC) changes on soil erosion and chemical weathering processes within the Nonguén watershed in the Coastal Cordillera of south-central Chile. The watershed is divided into three sub-basins, each characterized by distinct LU/LC patterns: native forest and exotic plantations. A comprehensive geochemical analysis, including trace elements and lithium (Li) isotopes, was conducted on river water and suspended sediment samples collected from streams within these sub-basins to assess how land management practices, particularly plantation activities, influence the geochemical composition of river systems. Our results show that sub-basins dominated by exotic plantations exhibit significantly higher concentrations of major and trace elements in suspended sediments compared to sub-basins dominated by native forests. The elevated trace element concentrations are primarily attributed to increased physical erosion due to forestry activities such as clear-cutting and soil disturbance, which enhance sediment mobilization. Notably, concentrations of elements such as Fe, Al, and As in plantation-dominated sub-basins are raised to ten times higher than in native-dominated sub-basins. In contrast, sub-basins with native forest cover exhibit lower levels of sediment transport and trace element mobilization, suggesting that native vegetation exerts a stabilizing effect that mitigates soil erosion. Despite the substantial differences in sediment transport and element concentrations, Li isotopic data (δ7Li) show minimal fractionation across the different LU/LC types. This indicates that land use changes impact the chemical weathering processes less compared to physical erosion. The isotopic signatures suggest that physical erosion, rather than chemical weathering, is the dominant process influencing trace element distribution in plantation-dominated areas. The study provides critical insights into how forestry practices, specifically the expansion of exotic plantations, accelerate soil degradation and affect the geochemical composition of river systems. The increased sediment loads, and trace element concentrations observed in plantation-dominated sub-basins, raise concerns about the long-term sustainability of forest management practices, particularly regarding their impacts on water quality in urban catchment areas. These results are of significant relevance for environmental management and policy, as they underscore the need for more investigation and sustainable land use strategies to minimize soil erosion and preserve water resources in regions undergoing rapid LU/LC changes.

Interpreting depositional environments from modern floodplain sediments using optically stimulated luminescence

We investigate how luminescence signals imprinted on fluvial sediments vary depending on the depositional environment and vary through time in the same river. We collected sediment samples from four geomorphically distinct locations on the modern floodplain and modern point bar on the Buffalo River in northwest Arkansas, USA, in order to determine if different depositional environments are associated with distinct bleaching characteristics in the sediments. Our analysis revealed that all samples from different depositional environments yielded ages consistent with modern deposition. The samples collected from the floodplain and bar head contained a higher proportion of grains with residual doses, indicative of incomplete bleaching during transport, while samples from the mid‐bar and bar tail appeared well bleached. Our results are particularly intriguing for two significant reasons. First, they highlight distinct equivalent dose distributions in different depositional environments. Second, they shed light on an intriguing relationship: despite generally well‐bleached modern floodplain samples, ancient sediments from corresponding terraces displayed equivalent dose (De) distributions that suggest partial bleaching in some cases. This research contributes to the growing body of work that seeks to establish a relationship between luminescence properties and sediment transport processes and offers valuable insight into how luminescence signals vary locally in modern fluvial deposits, which can help guide the interpretation of older fluvial deposits.

Environmental effects of acid mine drainage and rehabilitation options at closed mine site: a case study.

Irregular waste storage at closed mine sites poses severe environmental problems. This study evaluates the concentrations and effects of trace elements released into the environment by mining activity by analyzing soil, water, and sediment samples taken from a copper mining site. According to the data, acidic mine drainage was the main cause of the high concentrations of trace elements in the soil and sediments, including arsenic (As), cadmium (Cd), lead (Pb), and copper (Cu). The concentrations of As, Cd, Pb, and Cu in soil and sediments were 2734-times, 1189-times, 157-times and 32 times higher, respectively, in comparison to the background values of averaged concentrations of these elements in the upper crust. Geological and statistical studies indicate that the primary constituents of these pollutants are chalcopyrite and pyrite derivatives present in the primary rock structure. Using water analysis data from 2011 to 2020, the release of essential trace element into water was investigated to monitor the environmental effects of acidic mine drainage (AMD) from the closed Kuvarshan copper mine in the Artvin region of Turkey. This study demonstrates that trace elements concentrations may change according to local and seasonal factors and highlights the importance of conducting routine environmental monitoring studies.

Recent Findings on the Pollution Levels in the Romanian Black Sea Ecosystem: Implications for Achieving Good Environmental Status (GES) Under the Marine Strategy Framework Directive (Directive 2008/56/EC)

This study provides a comprehensive evaluation of contamination levels in the Romanian Black Sea within the framework of the Marine Strategy Framework Directive (MSFD). Over the course of five oceanographic expeditions between 2020 and 2022, data were gathered from 70 stations in transitional, coastal, shelf, and offshore waters of the Black Sea. Analyses were conducted on water, sediment, and biota samples for key contaminants: heavy metals (HMs), polycyclic aromatic hydrocarbons (PAHs), and persistent organic pollutants (POPs) such as organochlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs). The assessment identified contamination hotspots near riverine inputs, urban runoff, harbor activities, and industrial discharges. Offshore waters also showed measurable pollutant levels, likely from diffuse sources and atmospheric deposition. The key findings reveal the widespread contamination of HMs, PAHs, and POPs across the Romanian Black Sea, with concentrations in certain areas exceeding acceptable environmental thresholds, highlighting ongoing challenges for regional pollution management. PAHs were prevalent in both nearshore and offshore regions, while OCPs and PCBs were detected across various matrices, with significant concentrations observed in water and biota samples. The study emphasizes the importance of integrated assessments within the MSFD framework, suggesting that future evaluations should complement the “one out-all out” (OOAO) approach with multi-metric tools, to enhance the robustness of pollution status reporting. Despite improvements in some areas, contamination remains a critical challenge, requiring strengthened regulations, improved waste management, and increased regional cooperation to mitigate the ongoing risks to marine ecosystems. The findings provide valuable data for the upcoming national MSFD assessment cycle (2018–2023) and highlight the need for sustained monitoring and coordinated efforts to ensure long-term marine sustainability.

Effect of Plasma Treatment on Self-Cleaning Features of Acrylic Paint/TiO2-Coated Surfaces for Environmental Pollutant Removal

This study investigates the characterization and performance of self-cleaning TiO2 surfaces synthesized through a one-step preparation process, followed by enhancement via plasma treatment. The process involved coating aluminum foil with an acrylic paint mixture containing nanoparticles of different mass compositions and subsequent plasma treatment using a continuous plasma arc. Scanning electron microscopy revealed the morphology of the treated surfaces, showing an increase in surface area of plasma-treated materials. Energy-dispersive X-ray spectroscopy revealed changes in oxygen and titanium in acrylic paint/TiO2 surfaces as the TiO2 content increased, indicating successful TiO2 incorporation. Raman spectroscopy showed that the bulk structure of self-cleaning acrylic paints is mainly preserved after plasma treatment. Alternating current impedance spectroscopy assessed that plasma treatment reduced agglomeration and increased active sites, especially for the acrylic paint/TiO2 surfaces with 0.5 mg/cm3 TiO2. The contact angle measurements indicated that plasma treatment enhanced the superhydrophobic characteristics and potential self-cleaning abilities of produced acrylic paint/TiO2 surfaces. The efficacy of these plasma-treated surfaces in self-cleaning was evaluated by testing their performance against puddle sediment and automotive oil samples. The study demonstrated that plasma treatment positively impacted the self-cleaning ability of the acrylic paint/TiO2 surfaces, particularly those with 0.5 mg/cm3 TiO2. This enhancement was attributed to the formation of functional groups, improved water repellency, and possible increases in surface area, which collectively contribute to the sustainable self-cleaning properties of the treated surfaces.

Assessment of the level of heavy metals contamination via sediments quality indices of the Koudiet Medouar Dam and its tributary (Batna, Algeria)

The present study assesses the level of heavy metals concerning sediment from the Koudiet Medouar dam. This dam is intended for the production of drinking water and irrigation. In order to assess the level of contamination of the dam by toxic metals, 216 sediment samples were taken at nine stations upstream and downstream of the dam from 2012 to 2014. At the same time, the physical characteristics of the water and the physicochemical parameters of the sediments were determined. The results, expressed by the mean ± standard deviation, are for water: temperature, 15.5 ± 7 °C; potential of hydrogen, 8.05 ± 0.36; conductivity, 1125 ± 228 μS/cm. For sediments the values are potential of hydrogen, 8.55 ± 0.22; conductivity, 730 ± 347 μS/cm; carbonates, 49.18 ± 18.1%; fraction less than 63 μm 27.06 ± 6.95%; organic matter 3.02 ± 1.2%. Trace metal concentrations followed the order: Mn > Zn > Cr > Cu > Co > Ni > Pb > Cd. The strong correlation among trace metal indicates that these elements have common sources suggesting their association with silted sands. The geo-accumulation index, contamination factors, degree of contamination, and sediment pollution index reveal a polymetallic contamination dominated by two or more elements in which Cd, Cr, and Cu are of greatest concern. The levels of trace metals in the sediments record high concentrations upstream of the dam, especially in the second station of the village, near the dam. Our results reflect the footprint of anthropogenic inputs of cadmium, chromium, and copper resulting from agricultural activities by runoff water and soil erosion as well as domestic water discharges.

Bacterial Diversity in Deep-Sea Sediment of West Pacific Nodule Province

Dense polymetallic nodule fields are found in different areas of the Pacific and Indian Oceans. However, limited knowledge exists about microbial diversity, processes and functions in deep-sea polymetallic nodule sediments. This study investigated microbial diversity, composition and function in sediments from various locations and depths in a western Pacific polymetallic nodule province. Sediment cores were collected, DNA extracted, and the V3–V4 regions of the 16S rRNA gene were sequenced using Illumina MiSeq. The test results show that the abundance and diversity of microbial communities in sediments from different sites vary significantly. The dominant microbial communities at the family level in the three sediment samples were all mainly Marinobacteraceae and Alcanivoracaceae. Sediment samples from core 1 had similar microbial structures and microbial community functions. Surface sediment had higher species richness, diversity and evenness than the middle layer. The dominant phylum at different depths was consistent. There was significant spatial heterogeneity in the microbial community within sediments from polymetallic nodule regions. This study expands on our knowledge of the spatial and vertical distribution of microbial community diversity beneath polymetallic nodules in deep-sea settings.

Leptolaimus petrelense n. sp. (Plectida: Leptolaimidae), a new nematode species from the Petrel lagoon, central Chile

Summary During a survey on the biodiversity of nematodes in the Petrel lagoon (central Chile), a population of Leptolaimus was found in sediment samples. Morphological, morphometric and molecular data indicated that the recovered nematode is a new species. This nematode belongs to the group in which the males only have four pre-cloacal tubular supplements present, and females have no supplements. The new species can be separated from the other species of the group by the length of both males and females (843-1060 μm), the tail length (118-208 μm), the shape of the gubernaculum, and the arrangement of the caudal setae in males (a pair of ventral precloacal setae at level of spicules, a pair of dorsal post-cloacal setae, two subventral and two subdorsal caudal pairs. The differences from closely related species L. gerlachi, L. praeclarus, L. octavus, L. hydrothermalis, L. vipriensis, and L. hadalis are discussed. The recovered population is described herein as Leptolaimus petrelense n. sp.