Metal Concentrations In Sediments Research Articles

Implications of Heavy Metal Accumulation in Fish Feed, Water, Sediment, and Different Fish Species in a Polyculture System.

Heavy metal bioaccumulation in organisms is primarily a result of dietary uptake. The current study examines the concentrations of heavy metals (Pb, Cd, Cr, and Cu) in fish feed, water, sediment, and three fish species (Catla catla, Labeo rohita, and Cyprinus carpio) from different feeding zones in a polyculture pond system. Furthermore, associated human health risks were also evaluated. The fish samples (n = 25 for each species) were collected from 10 different fish ponds in the Kohat district, Pakistan. Heavy metals were determined using an atomic absorption spectrometer. Results revealed higher concentrations of heavy metals in sediment, followed by water. However, the concentration of heavy metals in fish feed was lower than the standard limits. In the case of fish, the bottom feeder (C. carpio) notably exhibited higher (P < 0.05) levels of heavy metals than the column feeder (L. rohita) and surface feeder (C. catla) fish. Moreover, in the liver of all fish species, the bioaccumulation of heavy metals was higher, followed by the gills. Principal component analysis (PCA) demonstrated a strong correlation of heavy metals in C. carpio gills, flesh, feed, and pond water, while the heavy metals in the liver correlated with the detected metals in sediment. The human health risk analysis shows that bottom feeder fish had higher estimated daily intake (EDI), target hazard quotient (THQ), and hazard index (HI) values (> 1). Consequently, the exposed population may experience adverse health effects. The findings of this study suggest that the bottom feeder (C. carpio) bioaccumulates a higher concentration of heavy metals than column (L. rohita) and surface feeder (C. catla) in the polyculture system.

Urbanization effects on growth and otolith asymmetry in Chrysichthys nigrodigitatus and Oreochromis niloticus within tropical coastal lagoon watersheds

In this study, we investigated the growth dynamics and otolith shape asymmetry of two fish species, Chrysichthys nigrodigitatus (CN) and Oreochromis niloticus (ON), within urbanized watersheds of the southern lagoon system, Nigeria. Using the von Bertalanffy growth model (VBGM), in addition to sediment metal concentration indices such as the average shale content, index of geoaccumulation (Igeo), contamination factor (CF), pollution load index (PLI), and potential ecological risk (PER) index, contamination levels were classified, and ecological risks were assessed. Notably, a lower growth potential (t0) was observed in CN at Ikorodu than at Epe, with similar trends for ON in the Epe during the dry season. Otolith asymmetry patterns, particularly in the CN at Ikorodu and ON in the Epe during the dry season, exhibited distinct ecological variations, indicating heightened stress levels at Ikorodu. Sediment analyses revealed moderate to strong contamination (Cd, Pb, Ni, and Cr) in both Lagos Lagoon (Ikorodu) and Epe Lagoon, with Ikorodu exhibiting notably high to moderate contamination levels according to the CF index. Elevated PLI values for Cd and Pb in Ikorodu, in addition to greater PER, indicated increased risk, with Cd posing a high risk (61.42%) and Pb posing a moderate risk (49.50%). Additionally, the reduced asymptotic length in the Epe during the dry season suggests that Chrysichthys nigrodigitatus is adaptable to seasonal variations, while divergent growth patterns in both areas indicate the existence of trade-off mechanisms in response to changing conditions. Habitat-specific otolith asymmetry and metal contamination underscore species adaptability, with wider stressor variability in Lagos than in Epe. Furthermore, multidimensional scaling analysis highlights the intricate relationship between otolith shape variables and environmental factors, emphasizing the need for tailored conservation efforts in urbanized watersheds.

Health risk assessment in sediment cores: A preliminary study in Erdek and Bandırma Bays, Türkiye

The contents of heavy metals in the core sediments of Erdek and Bandırma Bays were investigated to determine the pollution level, metal distribution and the associated human risks. It is very important to assess the concentration level of metal pollutants and health risk to adults and children. Therefore, metal analysis, contamination degree (Cdeg), modified contamination degree (mCdeg), toxic unit (TU), toxic risk index (TRI), modified hazard quotient (mHQ), and human risk assessment were carried out. The measured metals in the sediments were in the range of Al: 0.71-6.5%, Fe: 0.73-6.7%, Mn:100-923mg/kg, As: 0.5-28mg/kg, Co: 0.1-21mg/kg, Cr: 31-595mg/kg, Cu: 0.1-58mg/kg, Ni: 11-196mg/kg, Pb: 3-72mg/kg, V: 19-159mg/kg, Zn: 6-255mg/kg, Hg: 0.03-1mg/kg. Based on the Igeo, the mean values were < 0, except for Hg in cores MD72 (0.1), BD1 (0.9), and ER1 (0.2), which means that both bays are “unpolluted to moderately contaminated” with Hg. The mean mCdeg values of Erdek and Bandırma Bays sediments were very low contaminated with selected metals. The mean values of ΣTUs values for the cores (BK1, MD72, BD1 and ER1) ranged from 2.8-1.0, 4.9-0.5, 5.8-0.5, and 2.9-0.7, respectively. The mHQ-Hg and -Ni values indicated moderate to considerable significant contamination to living organisms, while it was for -Zn, -Cu, and –Pb indicated low to very low contamination to living organisms. There was no toxic risk to the marine ecosystem according to the TRI value (<5). Based on the human risk assessment using to the Hazard Quotient (HQ) that recommended by the US EPA, there are no adverse health effects by ingestion and dermal contact. Moreover, there are no non-carcinogenic and carcinogenic harm to adults and children. The results of this study will serve as a preliminary baseline human health risk assessment for Bandırma and Erdek Bays.

HEAVY METALS ASSESSMENT AND ASSOCIATED POTENTIAL HEALTH RISK OF BUILDING SEDIMENT DEPOSITION IN OKPARE CREEK, NIGERIA

Heavy metals concentrations in sediments may pose significant threats to human health and well-being of the general ecosystem. Therefore, it's crucial to conduct a thoughtful assessment of sediment characteristics with regards to heavy metal concentration as a raw material for building in the studied area. Twenty sediment samples were collected (five each fromlocalities) and analysed using atomic absorption spectrophotometer (AAS). The highest concentrations of Zn, Cu, Cd, Cr, Pb, V, Fe and Ni were 6.33, 2.65, 0.45, 1,201, 0.38, 0.00, 1026.39 and 0.65 mg/kg respectively in each of the four localities. The results exceeded both recommended limit and other scientist report of similar environment. Also, the health risk impacts computed were all higher than limits. These high values may be attributed tothe nature of the area geological formation, application of fertilizer to the farmlands and petroleum exploration and production activities. Cd stood out as the main culprit for potential ecological risks. The average contamination level, as indicated by I-geo values ranging from 0.28 to 0.79 mg/kg, raisedconcerns, especially at locality 1. Across the board, I-geo values remained generally low (&lt; 2). Cd and Pb, with an I-geo value of about 1, significantly impacted sediment pollution. Average EF values were from 0.02 to 5.76 which revealed that human activities heavily influenced the sediment, marking them as significantly enriched with observed heavy metals. In particular, Cd played a major role in the sediment's enrichment, indicating a high level of environmental impact.

Analysis of four heavy metal concentrations in sediments from the Jiaozhou Bay, China by visible and near infrared spectroscopy (225–975 nm)

As an important component ofbiogeochemical cyclein coastal ecosystems, sediments are the sink of heavy metals. Therefore, distribution and dynamics of heavy metals in sediments could assess ecological quality and predict ecological risks. In the new era, rapid and green technology are highly needed, especially that could determine multi-parameters simultaneously. Here, we explored a new method to rapidly determine concentrations of heavy metals in sediments by visible and near infrared reflectance spectroscopy (VIRS).We sampled sediments in the Jiaozhou Bay, China, collected their reflectance spectra, and measured concentrations of four heavy metals (As, Cr, Cu, and Zn). Heavy metal models were established and evaluated using substances highly correlated with heavy metals. This study provides an effective reference for rapid analysis of As, Cr, Cu, and Zn simultaneously in sediments, at least in the Jiaozhou Bay, and for ecological environment protection and resource development of the Jiaozhou Bay.

The drivers of benthic macroinvertebrates communities along a subtropical river system: Sediments chemistry or water quality?

AbstractImpacts of metal pollution, either on water or in sediments within aquatic systems have been a serious challenge globally. Little is known about the ecological impacts of metal pollution on benthic macroinvertebrates species in sub–tropical river systems. The aim of this study was to examine benthic macroinvertebrates community composition in relation to sediment metal concentrations and other physicochemical variables in the Mutshundudi River system. Benthic macroinvertebrates sampling and community composition analysis, sediment collection, processing, metal analysis and assessment of water variables in the river system were done across two seasons at 12 sampling sites. The river was categorized into three segments: upstream, midstream and downstream. The results from geo‐accumulation (Igeo) values showed that sediments were loaded with Na, Zn, and B in all river segments. In comparison with South African water quality guidelines for aquatic ecosystems, water quality ranged from good at upstream sites because of low anthropogenic activities to very poor in downstream sites because of high anthropogenic activities. Sediments from the Mutshundudi River showed significant differences on high concentrations of metals (i.e., Mg, K, Na, and Cu) and seasonal variations. Both water quality and sediment chemistry were considered the driving factors of benthic macroinvertebrates, since species densities and composition reduced with a decline in water and sediment quality during both cool–dry and hot–wet seasons. Continuous build‐up of the metal contaminants, such as Mg, K, Na, and Cu in river sediments may pose adverse impacts on macroinvertebrate community structure.

Sediment metals content in upstream Citarum river, West Java Province, Indonesia

Study of metal content in sediments is important for monitoring condition of Citarum river. This study aims to determine several metal namely Fe, Cu, Mn, Zn, Ni, Cr, Cd, Pb, Hg, and As in upstream Citarum river sediments. Research was conducted in the Cirasea sub-watershed, namely Gunung Wayang, Babakan Village, Cikitu Village, Wangi Sagara, Puncak Cae, Koyod, Andir, and Nanjung. Sediment samples were taken once a month from September to November 2022. Several physico-chemical parameter were carried insitu and laboratory. Sediment metal analysis was carried out using the ICP-OES (Inductively Coupled Plasma - Optical Emission Spectrometry) technique. Metal concentrations were compared with standards and the relationship between metal parameters and physico-chemical parameters was analyzed by PCA (Principal Component Analysis). Metals that were not found in all stations were Hg and Cd. The metal found with the largest concentration was Fe, otherwise metal found with the smallest concentration was As. Based on PCA, there are three groups based on metals and physico-chemical parameters. Advanced metal analysis needs to be carried out in the Citarum river from upstream to downstream to determine water quality of Citarum river.

Комплексная оценка экологического состояния участка трансграничной реки Нарвы

A comprehensive study of the ecological state on the transboundary Narva River (Russia –Estonia border) downstream of Ivangorod, Kingisepp District, Leningrad Region, was carried out. It included the determination of chemical indicators of pollution of the natural river water, with an emphasis on some heavy metals content in water, sediments and soft tissues of local filter-feeding mollusks; the latter were used as bioindicators of river pollution in this location. Zn was determined in maximum concentrations in bottom sediments, then Cu, to a lesser extent Pb, Cd and Ni. The coefficient of metal bioconcentration calculated in soft tissues of mollusks showed maximum for Zn and Cu, to a lesser extent for Pb, Cd and minimum for Ni. However, such values have no negative effect on local biota as shown by physiological testing of bivalves from study site. The functional assessment of bivalves by non-invasive cardiac rhythm recording made it possible to characterize their functional status and adaptive capabilities as good. The relative abundance of hydrocarbon-oxidizing bacteria in the digestive tract of mollusks from the Narva River has been determined as an indicator of environmental pollution by oil products. It was noted that the number of hydrocarbon-oxidizing bacteria does not exceed the values characteristic of the reference waters of the Eastern Gulf of Finland. Based on the totality of the studies, it was concluded that the river waters in the studied location can be characterized as slightly polluted and its ecological status as of a good quality.

Assessments of heavy metal contaminations of surface water and sediment of Pülümür Stream (Türkiye)

The primary considerations within aquatic ecosystems are water and sediment quality, rendering it imperative to assess their concentrations, pollution levels, origins, and ecological hazards. In this study, heavy metal concentrations in surface waters and sediments of the Pülümür Stream were investigated to assess the level, distribution, source of pollution and the associated human risks. Water and sediment samples from the river were collected monthly from February 2021 to January 2022 and examined using the Inductively Coupled Plasma Mass Spectrometry (ICP– MS) technique. Metal concentrations in the sediment followed a decreasing or derivative sequence of Fe > Al > Mn > Ni > Cr > Zn > Cu > Pb > As >Cd > Hg. The ecological indices of the stream water have low degrees of contamination by heavy metals. Igeo and EF showed that most of the sites are moderately to highly polluted due to Ni, and Cr, while PLI and PERI showed a progressive deterioration of the environment at site 9. Moreover, the modified hazard quotient (mHQ) indicates low ecological risk for Cu, Pb, Zn, Cd, Hg metals, while Ni, As and Cr reach high pollution at sediment sites. Pearson correlation analysis revealed that the presence of Zn, Cu, Pb, Hg, and Mn metals in the sediment analysis has a lithogenic source, and As, Ni, Cd, and Cr accumulate due to human activities, mainly domestic and agricultural irrigation wastes and mining wastes, all of which affect the aquatic environment. According to this study, more attention should be paid to the comprehensive monitoring of metals in the water and sediment for both aquatic biota and human risk of the Pülümür River.

Linkages Between Mineral Element Composition of Soils and Sediments With Hyporheic Zone Dissolved Organic Matter Chemistry Across the Contiguous United States

AbstractThe hyporheic zone is a hotspot for biogeochemical cycling where interactions with mineral metals preserve the release and biodegradation of organic matter (OM). A small fraction of OM can still be exchanged between localized sediments and the overlying water column, and recent evidence suggests there exists a longitudinal structuring in sediment dissolved OM (DOM) chemistry across the continental United States (CONUS). In this study, we tested a hypothesis that water extractable sediment DOM chemistry could be explained by sediment metal contents and integrative watershed scale features at the CONUS scale. Crowdsourced samples were characterized for high resolution mass spectrometry and coupled with sediment metals determined via x‐ray fluorescence as well as with land cover and soil elemental information obtained from national databases. Our results highlight weak relationships between DOM chemistry and elemental composition at the CONUS scale indicating limited transferability of organo‐metal linkages into multi‐scale hydrobiogeochemical models.

Threat of heavy metal pollutants and parasites to freshwater fish with special reference to their risk of cancer to humans in Egypt

Understanding how pollution and parasite infection work together to stress their hosts' health raises the possibility of a danger to aquatic life and humans. This study examined two freshwater fish species, Clarias gariepinus, and Oreochromis niloticus, at El-Abbasa Fish farm in Sharkia Governorate of Egypt. to determine their heavy metal content, parasite frequency, and potential health risks. Parasitological investigations revealed higher parasite prevalence in C. gariepinus, with trematodes being the most prevalent. Histopathological examinations displayed severe alterations in infected fish, including gill necrosis, intestinal damage, liver degeneration, and muscle necrosis. Moreover, heavy metal analysis. Heavy metals levels in water, Fe, Zn, Pb, Cu, As, and Cd levels were 0.95 ± 0.04, 0.75 ± 0.03, 0.14 ± 0.02, 0.09 ± 0.01, 0.07 ± 0.01, and 0.03 ± 0.01 mg/L, respectively. Sediment samples showed Cd as the lowest (2.38 ± 0.94 μg/g dry wt. basis) and Fe as the highest (241.01 ± 6.39 mg/kg dry wt. basis). The sequence of heavy metal concentrations in both water and sediment was Fe > Zn > Pb > Cu > As > Cd. Significant differences were found among metals in water and sediment (p < 0.05). Heavy metal concentrations in fish tissues followed the order liver > muscles > gills > intestine Iron was the most abundant, while cadmium was the lowest is the order in which bio-accumulation factors (BAF) between water and fish tissues followed a descending order: BAF-Liver < BAF-Gills < BAF-Intestine < BAF-Muscles. The sequence of heavy metal accumulation in tissues was BAF-Fe > BAF-Pb > BAF-Cd > BAF-As > BAF-Cu > BAF-Zn, indicating varying degrees of accumulation across different metals and tissues and bio-sedimentation (BSF) of metals in fish tissues are the order of heavy metal concentration within tissues was BSF-Cd > BSF-As > BSF-Fe > BSF-Zn > BSF-Cu > BSF-Pb. Additionally, data were recoded to reflect histological changes in several fish organs. The estimated daily intake of heavy metals (EDI-HMs) was far lower than the permissible tolerated daily intake (PTDI) limits, which were set by international authorities at 70 kg of body weight. As the hazard index value is below 1, the THQ and HI associated with the consumption muscle of fish demonstrate negligible non-carcinogenic harm to residents' health. Contrarily, As, and Cd pose a cancer threat for kids and adults who eat muscular fish, and it needs to be viewed as a warning sign from the perspective of data indices and human health.

Characteristics of heavy metals in surface sediments of the Van Don-Tra Co coast, northeast Vietnam

Eighteen surface sediment samples were collected from the Van Don-Tra Co coast, northwestern Gulf of Tonkin, for analyzing the concentration of heavy metals (Zn, Cr, As, Cu, Ni, Pb, Co, and Cd) and grain size. The statistical and contamination indices of heavy metals were calculated to evaluate the extent of pollution caused due to heavy metals and their potential harm to the environment. According to the analysis results, the contamination of heavy metals in the study area were higher than the background concentrations, except for Pb. The heavy metal concentrations in the study area followed the descending order of Zn > Cr > As > Cu > Ni > Pb > Co > Cd. The concentrations of heavy metals do not correlate with clay content, and almost heavy metals were non-correlated with silt and sand contents, except for Cr, implying that the grain size does not control heavy metals concentration in surface sediments in the region. The results of pollution indices imply that the contamination in the environment was due to excess accumulation of Cd, in contrast to that of Zn. The ecological pollution risk shows an increased risk of heavy metal pollution. According to the statistical index, the contamination of heavy metals in surface sediments in the study area could come from the same sources under the same environmental conditions and is related to the source of sedimentary material from the mainland near the study area.

The predictive model of hydrobiological diversity in the Asana-Tumilaca basin, Peru based on water physicochemical parameters and sediment metal content

The hydrobiological diversity in the basin depends on biotic and abiotic factors. A predictive model of hydrobiological diversity for periphyton and macrobenthos was developed through multiple linear regression analysis (MLRA) based on the physicochemical parameters of water (PPW) and metal content in sediments (MCS) from eight monitoring stations in the Asana-Tumilaca Basin during the dry and wet seasons. The electrical conductivity presented values between 47.9 and 3617 μS/cm, showing the highest value in the Capillune River due to the influence of geothermal waters. According to Piper's diagram, the water in the basin had a composition of calcium sulfate and calcium bicarbonate-sulfate. According to the Wilcox diagram, the water was found to be between good and very good quality, except for in the Capillune River. The Shannon–Wiener diversity indices (H′) were 2.62 and 2.88 for periphyton, and 2.10 and 2.44 for macrobenthos, indicating moderate diversity; for the Pielou's evenness index (J′), they were 0.68 and 0.70 for periphyton, and 0.68 and 0.59 for macrobenthos, indicating similar equity, in the dry and wet seasons, respectively, for both indices. In the model there were three cases, where the first two cases only worked with PPW or MCS, and case 3 worked with PPW and MCS. For case 3, the predicted values for H′ and J′ of periphyton and macrobenthos concerning those observed presented correlation coefficients of 0.7437 and 0.6523 for periphyton and 0.9321 and 0.8570 for macrobenthos, respectively, which were better than those of cases 1 and 2. In addition, principal component analysis revealed that the As, Pb, and Zn contents in the sediments negatively influenced the diversity, uniformity, and richness of the macrobenthos. In contrast, Cu and Cr had positive impacts because of the adaptation processes.

Content of heavy metals in bottom sediments of drained Kakhovka Reservoir

The article highlights the ecological danger of the destruction of the Kakhovka HPP dam and the draining of the Kakhovka Reservoir. The results of experimental studies of the content of mobile compounds and gross forms of heavy metals in five samples of bottom sediments taken from the bottom of drained reservoirs taken on the territory of the Kushugum community of the Zaporizhia district of the Zaporizhia region. Two samples were taken from the bottom of the former flood zone (Balabyne village), 2 samples — from the bottom of the former limestone quarry, which was connected to the floodplain of the Dnipro (Kushugum village) and 1 sample taken from the open area of the Kakhovka Reservoir (Malokaterynivka village). Based on the results of the research, it was established that the maximum permissible limit (for soil) of mobile compounds of lead (from 2.0 to 4.1 times), zinc (from 2.4 to 5.4 times), cadmium (from 1.9 to 2.5 times) was exceeded. and nickel (from 1.04 to 2.2 times) in all investigated bottom sediment samples. Exceeding the MPC (soil) for the content of gross forms of lead was found in five bottom sediment samples (from 1.1 to 1.5 times). Exceedings of the MPC of the soil by the content of gross forms of cadmium and manganese and mobile compounds of copper, nickel, cobalt and manganese were not detected. The maximum limit for the content of mobile compounds of iron and gross forms of zinc, copper, nickel, cobalt and iron is not regulated. The highest degree of contamination of bottom sediments by the content of: mobile compounds and gross forms of lead and nickel was found in samples taken from the bottom of a former limestone quarry (Kushugum village, Zaporizhzhia region); zinc — in a sample taken from the bottom of the former flood zone in the territory of the town of Balabyne and a sample taken from the open area of the Kakhovka Reservoir in the territory of the town of Malokaterynivka; cadmium — in the samples taken from the bottom of the former limestone quarry in the territory of the town of Balabyne and the sample taken from the open area of the Kakhovka Reservoir in the territory of the town of Malokaterynivka. According to the results of the correlation analysis, an extremely strong dependence was established between the content of mobile compounds of heavy metals and their gross forms — for cobalt (r=0.96), cadmium (r=0.92), nickel (r=0.91), lead (r=0.88) and zinc (r=0.84).

Ecological Status of Algeciras Bay, in a Highly Anthropised Area in South-West Europe, through Metal Assessment-Part I: Abiotic Samples.

The ecological status of Algeciras Bay (South-west Europe), highly influenced by anthropogenic activities, was assessed by monitoring Zn, Cd, Pb, and Cu in water and sediment samples. Total contents and metal fractions with different availabilities and their spatial-seasonal distribution were determined. The trend in water and sediment contents were Zn > Pb ≈ Cu > Cd, without significant seasonal variations. Sites 3 and 4, closest to industrial activities, had the highest metal concentrations, mainly in sediments. Cd showed low partition coefficient in water, indicating higher bioavailability. Total metal content in sediments exceeded the threshold effect level for Cu and were close to Pb. The BCR procedure revealed the highest availabilities for Cd and Pb, due to its higher content in exchangeable and reducible fractions. Higher Pb levels (21.4 ± 5.1 mg/kg) were found in sediments of this bay compared with other ecosystems. Pollution indexes for sediment quality revealed that site 3 was the most polluted (CF = 7.12 and Igeo = 2.25). For an integrative study of the ecological status of this significant bay, these results have been complemented with the metal evaluation in benthic and benthopelagic fish tissues in Ecological status of Algeciras Bay, in a highly anthropised area in south-west Europe, through metal assessment-Part II: Biotic samples.

Assessment and Review of Heavy Metals Pollution in Sediments of the Mediterranean Sea

The impact of marine sediment pollution is crucial for the health of the seas, particularly in densely populated coastal areas worldwide. This study assesses the concentration and distribution of heavy metals in the marine sediments of the main regions of the Mediterranean Sea. The results underscore high concentrations of mercury (Hg), nickel (Ni), and copper (Cu), whereas chromium (Cr), zinc (Zn), cadmium (Cd), barium (Ba), and vanadium (V) exhibit moderate values. To assess the heavy metal results, sediment quality guidelines and pollution indices (Igeo and Geochemical Signal Type-GST) were employed, revealing a consistent trend of decreasing concentrations from the coastal zone to the open sea. Principal Component Analysis (PCA) emphasizes the significant roles of Cu, Zn, Ba, and Cr in sediment chemistry. The study suggests that the distribution patterns of heavy metals are linked to wastewater discharges in coastal areas, requiring effective management strategies to ensure the health of the Mediterranean Sea.

Morphodynamics and heavy metal accumulation in an artificially built near-natural river (Inde, Germany)

Heavy metals in riverine sediments threaten fluvial ecosystems worldwide. Sediment cascades transporting the compounds downstream lead to pollution stress downstream from the original input source. In regulated rivers, artificially built reaches with re-activated morphodynamics and morphological structures may become typical sink areas for contaminants. Therefore, a thorough understanding of transport mechanisms and accumulation dynamics is the key to managing enhanced heavy metal concentrations in alluvial sediments. In this study, we investigate a morphologically diverse 12 km-long river reach of the Inde River in Germany, that was relocated in 2005 due to an open-pit lignite mine. As the Inde catchment is a former industrial hotspot (beginning in the Iron Age; golden age at the end of the nineteenth century), the floodplain sediments that accumulated since the construction of the Neue Inde are enriched in heavy metals. The structures and sediments of the relocation are recycled repeatedly, causing the mixing of contaminated and uncontaminated sediments. The Neue Inde is an important sediment trap, especially due to the river’s intense regulation immediately upstream. Thereby, the input of sediments enriched in heavy metals into the receiving waters, the Rur River, is limited. So far, it is unclear whether there is a threshold of sediment storage that, if exceeded, turns the Neue Inde from a sink to a source. The morphodynamical development of artificially built river reaches mainly depends on the restoration design in terms of initially built morphological structures and the width of the river corridor.

Physicochemical Characterisation of Water and Sediment of the Semimechanized Artisanal Gold Mining Environment of the Béké Locality

This paper aims to investigate the level of pollution of water, sediment, and soil due to semimechanized artisanal gold mining in Béké, Adamawa region of Cameroon. For this purpose, water and sediment samples were collected and analyzed. In order to achieve this goal, several research studies and field observations were carried out. Questionnaires were also used to complement field investigations. All these enabled the identification of the potential sources of impacts on the human, physical, and biological environment. Three soil samples (S1, S5, and S7) were collected on the same spot with the water sample and analyzed to assess the intensity of soil contamination. The water samples (W1–S9) were characterized physically, chemically, and microbiologically to evaluate the water quality contamination. The results of the physicochemical analysis of the water samples showed that the rivers in this zone are moderately acidic (with pH values ranging from 5.11 to 6.37) and slightly mineralized (with sample W2 collected from the Béké river having an iron concentration of 6.7 g/L). The pattern of mean trace metal concentration in sediments was Fe &gt; Mn &gt; Cr &gt; Pb &gt; Cu &gt; Zn. According to pollution indices, the contamination degree (CD) varied from 4.03 to 4.56 corresponding to low contamination. The index of ecological risk (Eri) for all the trace metals was low (Eri ≤ 40) and the geoaccumulation index (Igeo) ranged between uncontaminated and moderately contaminated (Igeo 0-1). The result of our field investigations and analysis shows that the semimechanized artisanal gold mining in the locality of Béké has very significant environmental consequences such as land degradation, deforestation, water pollution, and landscape modification.

Neurological risks arising from the bioaccumulation of heavy metal contaminants: A focus on mercury.

This study investigated the concentrations of heavy metals in the water sources of the upstream region of the Huangpu River, the Yangtze River Estuary, and various areas in Shanghai, as well as the heavy metal concentrations in the blood of Shanghai residents. It aimed to analyze the heavy metal elements absorbed by the human body and the resulting pathological effects. The results revealed that surface water primarily contains five heavy metals: copper (Cu), lead (Pb), zinc (Zn), arsenic (As), and mercury (Hg), while water sediments primarily contain seven heavy metals: Cu, cadmium (Cd), Pb, chromium (Cr), Zn, As, and Hg. The main heavy metals present in the human body are Pb, Hg, As, and Cd. By reviewing previous articles, it was found that heavy metal concentrations in human blood are higher than those in surface water, suggesting uncertainties in the heavy metal content of surface water and its tendency to settle at the bottom. Furthermore, a comparison of heavy metal content in sediments revealed that Hg is the most readily absorbed heavy metal by the human body and is also a toxic environmental pollutant. Within the cell, Hg is highly toxic to mitochondria and may cause oxidative stress and neurodegenerative disease. This study concludes that water sediments serve as the major source of pollution in the human body and pose significant health risks, thereby necessitating the implementation of effective preventive measures.

Risk assessment of Cr, As, and Sb to aquatic communities at the water-sediment interface in the lower Yellow River, China, integrated with the Diffusive Gradients in Thin‐films technique

The dynamic concentrations of labile metals/metalloids, measured by the Diffusive Gradients in Thin-films (DGT) technique, can be used for evaluating the toxicity risk of heavy metals to aquatic organisms in sediments. In this study, the different potential risks of the three sediment compartments, overlying water (W), sediment- water interface (SWI) and sediment (S) were independently assessed by studying the concentrations of Cr, As, and Sb in the sediment and water from the lower Yellow River. Total concentrations of these elements and bioavailable concentrations, using DGTs, were explored and probabilistic risk assessment (PRA) based on a Monte Carlo model was performed. The results show that the total heavy metal concentrations in sediment and overlying water were spatially variable due to influences of natural geography and sediment distribution. The trace elements mean concentrations using DGT were 1.68, 1.69 and 0.73 μg·L−1 for Cr, 0.61, 0.51 and 0.39 μg·L−1 for As, and 0.78, 1.16, and 0.41 μg·L−1 for Sb in W, SWI and S, respectively. Among them, the DGT-labile concentration of As displayed a large spatial variability, indicating a close association with anthropogenic activities. The risk quotient (RQ) categories for single heavy metal toxicity demonstrated to be moderate risk for Cr and almost no risk for As and Sb. The combined biotoxicity probability assessment of the three heavy metals showed that they would cause almost no harmful effects to benthic organisms in the whole ecosystem of the Yellow River.