Evaluation of metal accumulation in Terme River sediments using ecological indices and a bioindicator species

Metal pollution assessment in the surface sediments of a river system in Türkiye: Integrating toxicological risk assessment and source identification

This study investigates potentially toxic elements (PTEs) in the surface sediments of the Abdal River system, a critical water source for Samsun province, Türkiye, due to the presence of the Çakmak Dam. PTE concentrations, measured in mg/kg, show significant variability: Hg (0.03) < Cd (0.26) < As (10.98) < Pb (13.88) < Cu (48.61) < Ni (62.45) < Zn (70.97) < Cr (96.28) < Mn (1015) < Fe (38357). Seasonal variations were observed, in particular increased concentrations of As, Cd and Pb in summer (p < 0.05). Contamination and ecological risk indices (mHQ, EF, Igeo, CF, PLI, Eri, mCd, NPI, PERI, MPI, and TRI) indicate moderate to low levels of contamination, suggesting potential ecological effects. Health risk assessments suggest minimal risks to human health from sediment PTEs. Statistical analyses (PCC, PCA and HCA) improve the understanding of the sediment environment and contamination sources, while the coefficient of variation assists in source identification.

Appraisal of metallic accumulation in the surface sediment of a fish breeding dam in Türkiye: A stochastical approach to ecotoxicological risk assessment

This study examines the levels and patterns of potentially toxic elements (PTEs) in surface sediment of Almus Dam Lake (ADL), a key fish breeding site in Türkiye. PTE concentrations in sediment were ranked: Hg (0.05 ± 0.01) < Cd (0.16 ± 0.01) < Pb (9.34 ± 1.42) < As (18.75 ± 15.65) < Cu (63.30 ± 15.17) < Ni (72.64 ± 20.54) < Zn (86.66 ± 11.95) < Cr (108.35 ± 36.40) < Mn (1008 ± 151) < Fe (53,998 ± 6468), with no significant seasonal or spatial differences. Ecological risk indices (mHQ, EF, Igeo, CF, PLI, Eri, mCd, NPI, PERI, MPI, and TRI) showed low contamination levels. Health risk assessments, including LCR, HQ, and THI, indicated minimal risks to humans from sediment PTEs. Statistical analyses (PCA, HCA, SCC) identified natural, transportation, and anthropogenic PTE sources, with slight impacts from agriculture and fish farming. This research underlines contamination status of ADL and emphasizes the need for targeted management strategies, offering critical insights for environmental safeguarding.

Ecological and public health risk assessment of potentially toxic elements in the surface sediments of the Pasur river estuary, Bangladesh

Potentially toxic elements (PTEs) in the surface sediments of the Pasur river estuary was investigated to assess its distribution, potential sources, and current dangers to ecological and public health. The Pasur River is a tidal, meandering, perennial river in south-western Bangladesh with a considerable number of fisheries and industrial activities. Sediment samples were collected from seven sampling points from January to December 2022 to assess the contamination level of six potentially toxic elements (Pb, Cr, Cd, As, Cu and Zn). Flame Atomic Absorption Spectrophotometer was utilized to detect the concentration of PTEs by following some sequential analytical procedure. Concentration of PTEs followed the reducing trend of Zn > Cr > Pb > As > Cu > Cd with the mean value of 61.04 > 49.15 > 26.58 > 10.28 > 6.28 > 1.59 mg/kg, respectively. The principle component and cluster analyses justified the anthropogenic source of the studied PTEs. The mean values of contamination factor (CF), geo-accumulation index (Igeo) and enrichment factor (EFc) showed that Pb and Cd were highly responsible for sediment (uncontaminated to moderate) contamination. Pollution load index (PLI) indicated higher pollution of sediments near the port areas. Potential ecological risk index (PERI) indicated low to moderate risks due to the contaminated sediment. However, the contamination of sediment was not associated with the non-carcinogenic (HQderm and HI < 1) and carcinogenic (CRderm < 10-6) risks due to the dermal contact. Although the risks were within the tolerable limit, regular monitoring is suggested to reduce the risk of PTEs contamination.

Contamination and ecological risk assessment of Cr, As, Cd and Pb in water and sediment of the southeastern Bay of Bengal coast in a developing country

Safe levels of heavy metals in the surface water and sediment of the eastern Bay of Bengal coast have not been universally established. Current study characterized heavy metals such as arsenic (As), chromium (Cr), cadmium (Cd) and lead (Pb) in surface water and sediments of the most important fishing resource at the eastern Bay of Bengal coast, Bangladesh. Both water and sediment samples were analyzed using inductively coupled plasma mass spectrometer. Considering both of the seasons, the mean concentrations of Cr, As, Cd, and Pb in water samples were 33.25, 8.14, 0.48, and 21.14 μg/L, respectively and in sediment were 30.47, 4.48, 0.20, and 19.98 mg/kg, respectively. Heavy metals concentration in water samples surpassed the acceptable limits of usable water quality, indicating that water from this water resource is not safe for drinking, cooking, bathing, and any other uses. Enrichment factors also directed minor enrichment of heavy metals in sediment of the coast. Other indexes for ecological risk assessment such as pollution load index (PLI), contamination factor (CF), geoaccumulation index (Igeo), modified contamination degree (mCd), and potential ecological risk index (PERI) also indicated that sediment of the coastal watershed was low contamination. In-depth inventorying of heavy metals in both water and sediment of the study area are required to determine ecosystem health for holistic risk assessment and management.

Pollution characteristics, sources and health risks assessment of potentially hazardous elements in sediments of ten ponds in the Saros Bay region (Türkiye)

Pollution of lentic ecosystems by potentially hazardous elements (PHE) due to human activities has become a global concern. In this study, the contents of eight PHEs in the sediments of 10 most important ponds located in the Saros Bay region (Türkiye) were evaluated. The contents of PHEs in the sediments of the ponds ranged from 0.14 mg/kg for Cd to 274 mg/kg for Mn. According to the enrichment factor (EF) results, ponds P3, P8 and P9 for Cd and pond P8 for Pb showed "moderate enrichment". However, the pollution load index (PLI) results indicated that all ponds were in a "baseline contamination" state due to the combined effect of all PHEs. Similarly, based on ecological risk assessment indices, no ecological risk from PHEs was identified. In addition, Cd, Zn, As, Cr, Cu and Pb contents in all ponds were found below threshold effect concentrations. The results of the health risk assessment indicated that non-carcinogenic and carcinogenic risks were not expected for recreational receptors due to exposure to the PHEs in the sediments via incidental ingestion and dermal contact. Correlation and cluster analysis results indicated that although agricultural activities contributed slightly to the As content, all PHEs mainly originated from natural sources.

Sediment-connected Potentially Toxic Element Contamination and Phytoremediation Potential of Native Aquatic Macrophytes along the Jajrood River, Tehran Province, Iran

This study was conducted to analyze Cu, Fe, and Pb contamination in sediments and also phytoremediation ability of bulrush (Typha Latifolia) and one-rowed water-cress (Nasturtium microphyllum) along the Jajrood River, Iran in 2022. In so doing, a total of 60 sediment and macrophyte samples were collected from four sites. The contents of the analyzed elements were determined using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Also, the values of pollution index (PI), pollution load index (PLI), bioconcentration factor (BCF), bioaccumulation factor (BAF), transfer factor (TF) and metal accumulation index (MAI) were calculated. The results demonstrated that the average contents of Cu, Fe, and Pb were lower than those in the background, which presumably demonstrated natural sources of these metals. The greatest concentrations of analyzed elements for all the sediment and macrophyte samples were observed in specimens collected from S4 located at the end of the river, indicating the impact of anthropogenic entries from upstream areas on elemental accumulation in downstream section of the river. The values of PI reflected slight contamination. The higher BCF and lower translocation TF values of Fe and Pb in T. Latifolia and also Cu in N. microphyllum imply that these species could be suitable for their phytostabilization of above-mentioned elements from the sediment. This study provides evidenceas to the efficiency of T. Latifolia and N. microphyllum in bioremediation of Cu, Fe, and Pb in contaminated aquatic environments.

Assessment of human health hazard associated with heavy metal accumulation in popular freshwater, coastal and marine fishes from south-west region, Bangladesh

An analysis was conducted on both freshwater, coastal and marine fish species to evaluate the concentrations of heavy metals, with the aim of assessing their levels and examining the potential health risks for humans linked to the consumption of contaminated fish. This study estimate concentrations of Cr, Fe, Cu, As, Cd and Pb in 60 individuals belonging to 20 species (10 species for freshwater and another 10 for coastal and marine fishes) by using Atomic Absorption Spectrophotometer. Metal concentrations of Cr, Fe, and Pb in freshwater fishes and Cr, Fe, As, and Pb in marine fishes were exceeded the maximum allowable concentration (MAC). The Estimated Daily Intake (EDI), Average Pollution Load Index (APLI), Target Hazard Quotient (THQ), Hazard Index (HI) and Target Cancer Risk (TCR) of heavy metals were determined for the assessment of human health risk. Ranking order of the values of EDI for freshwater fishes, coastal and marine fishes were Cd > Fe > Pb > Cr > Cu > As and Cd > Fe > Pb > Cr > As > Cu. Highest APLI value of 8.14 (Puntius ticto) that is seriously polluted and 3.003 observed in Otolichthoides pama in freshwater and marine fishes, respectively. THQPb and THQAs for all the fish species were exceed the safe limit (THQ>1) suggesting potential health risk to consumers. The hazard index for both the fish samples were exceeded the USEPA (United States Environmental Protection Agency) permitted risk level (HI > 1). The target carcinogenic risk value for Cr and As were crossed the USEPA standard limit (TCR> 1E-04), which denotes that continuous consumption of studied fishes may cause health risk to the consumers. On the other hand, sensitivity analysis of freshwater, coastal and marine fishes indicates that all the metal concentrations were responsible factor for health risk.

Response of soil fungal community to chromium contamination in agricultural soils with different physicochemical properties

Chromium (Cr) contamination has been of great concern in agricultural soil health due to its persistence, toxicity and bioaccumulation. Fungi, as an essential regulator of soil remediation and biochemical processes, had an unclear response to Cr contamination. In this study, the composition, diversity and interaction mechanisms of fungal communities in agricultural soils from ten different provinces of China were investigated in order to elucidate the fungal community response to varying soil properties and Cr concentrations. The results showed that high concentrations of Cr led to substantial alterations in the fungal community composition. The complex soil properties had a far greater impact on the fungal community structure than the single factor of Cr concentration, with soil available phosphorus (AP) and pH being most influential. Function predictions based on FUNGuild indicated that high concentrations of Cr have a significant impact on certain functional groups of fungi, including mycorrhizal fungi and plant saprotroph. The fungal community tended to resist Cr stress by enhancing interactions and clustering among network modules, while generating new keystone taxa. This study allowed insights into the response of soil fungal community to Cr contamination in different agricultural soils from different provinces and provided a theoretical basis for soil Cr ecological risk assessment and the development of bioremediation techniques for Cr-contaminated soils.

Risk assessment and source apportionment for metals in sediments of Kaptai Lake in Bangladesh using individual and synergistic indices and a receptor model

Metal enrichment in lake sediments originating from multiple sources can threaten both the aquatic ecosystem and human health. Therefore, assessment of the eco-environmental risks and potential sources of metals in the sediments is essential for effective lake management. Here, we analyzed the sediment metal contents of Kaptai Lake, the largest lake in Bangladesh for the first time with this study. The results indicated that only Cr and Ni contents among the metals studied exceeded the probable effect concentrations (PEC) at 25.42 % and 55.93 % of the sampling stations, respectively. All metals at most sampling stations showed low contamination and low ecological risk based on the individual indices (geoaccumulation index, contamination factor, ecological risk factor, enrichment factor and modified hazard quotient). There was no significant risk from the combined metals in the sediments of the lake according to the synergistic indices (toxic risk index, Nemerow risk index, ecological risk index, Nemerow pollution index and pollution load index). Organic matter and silt were significant sediment parameters that favored the accumulation of Cr, Fe, Cu, Pb and Mn. In the absolute principle component scores-multiple linear regression model (APCS-MLR), five potential sources of metals were identified in the sediments: Zn, Mn, Co and Cd mainly from natural sources and to a lesser extent from agricultural and aquacultural activities, Ni, Cr and Fe from parent materials, Pb and Cu mainly from natural sources and to a lesser extent from vehicle emissions, Hg and U from lithogenic sources, and As from natural sources. This study will improve our knowledge of the sedimentary metal contents of Kaptai Lake and provide helpful information for developing effective lake management and pollution control strategies.

Evaluating potential ecological risks of emerging toxic elements in lacustrine sediments: A case study in Lake Fuxian, China

The fragile ecosystems of plateau lakes are in face of ecological risks from emerging toxic elements. Beryllium (Be) and thallium (Tl) have been considered priority control metals in recent years owing to their persistence, toxicity, and bioaccumulation. However, the toxic factors of Be and Tl are scarce and ecological risks of them in the aquatic environment were seldom investigated. Hence, this study developed a framework for calculating the potential ecological risk index (PERI) of Be and Tl in aquatic systems and used it to assess the ecological risks of Be and Tl in Lake Fuxian, a plateau lake in China. The toxicity factors of Be and Tl were calculated to be 40 and 5, respectively. In sediments of Lake Fuxian, the concentrations of Be and Tl were between 2.18 and 4.04 mg/kg and 0.72-0.94 mg/kg, respectively. The spatial distribution indicated that Be was more abundant in the eastern and southern regions, and Tl had higher concentrations near the northern and southern banks, consistent with the distribution of anthropogenic activities. The background values were calculated as 3.38 mg/kg and 0.89 mg/kg for Be and Tl, respectively. In comparison with Be, Tl was more enriched in Lake Fuxian. The increasing Tl enrichment has been attributed to anthropogenic activities (e.g., coal burning and non-ferrous metal production), especially since the 1980s. Generally, Be and Tl contamination has decreased over the past several decades, from moderate to low, since the 1980s. The ecological risk of Tl was low, whereas Be might have caused low to moderate ecological risks. In the future, the obtained toxic factors of Be and Tl in this study can be adopted in assessing the ecological risks of them in sediments. Moreover, the framework can be employed for the ecological risk assessment of other newly emerging toxic elements in the aquatic environment.

Occurrence, geochemical characteristics, enrichment, and ecological risks of rare earth elements in sediments of "the Yellow river-Estuary-bay" system

Recent studies have suggested that rare earth elements (REEs) are contaminants of emerging concern. Moreover, the understanding of the occurrence and risks of REEs in river-estuary-bay systems is limited. The present study investigated the distributions, geochemical characteristics, and ecological risks of Y and 14 REEs (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) in sediments from the Yellow River to its estuary and adjacent Laizhou Bay. The average total concentrations of Y and REEs in the sediments generally increased from the Yellow River (149 mg/kg) to the estuary (165 mg/kg) and Laizhou Bay (173 mg/kg). In the estuarine core sediments, the concentrations of Y, light REEs (LREEs), and heavy REEs (HREEs) were in the ranges of 19.5-31.4 mg/kg, 58.6-156 mg/kg, and 12.3-19.1 mg/kg, respectively, from the 1700s to 2018, showing no obvious increasing or decreasing trends. The surface and core sediments from the river to the bay were characterized by obvious fractionation between LREEs and HREEs. In sediments, Fe minerals and clay are believed to promote the accumulation of REEs, especially HREEs. The enrichment levels of REEs generally increased from the middle reaches of the Yellow River to the bay, and Gd, Tb, Dy, Ho, Yb, and Lu were the most enriched elements in the sediments. Lu had moderate potential ecological risks in sediments of "the Yellow River-estuary-bay" system, and other REEs had relatively low ecological risks. The potential ecological risk indices of Y and REEs ranged from 78.7 to 144, showing increasing trends from the Yellow River to its estuary and adjacent bay, which should raise concerns regarding emerging contaminant management around estuarine and coastal regions.

Grain size analysis and ecological risk assessment of metals in the sediments of Konsin River and Igboho dam reservoir, Oyo State, Nigeria, under agricultural disturbances

A large amount of agrochemicals and organic manures are applied on agricultural lands which is one of the major pathways of metal contamination in sediments. The present study was an attempt to appraise the grain-size of sediments and metal status of the Konsin River and Igboho dam reservoir sediments using several indexes as contamination factor (CF), degree of contamination (DC), geo-accumulation index (I_geo), enrichment factor (EF), potential ecological risk index (PERI), pollution load index (PLI), and statistical analysis. A total of seven sampling sites were chosen based on prevalent anthropogenic features and analyzed for the concentration of metals, viz., Cd, Cr, Pb, Mn, Fe, Cu, and Zn. The finding from this study showed high presence of very rough grains at the upstream and sand particles at the downstream. The average values of Cd, Cr, Pb, Mn, Fe, Cu, and Zn range from 0.00 - 2.00, 19.50 - 49.90, 20.80 - 65.30, 593.90 - 2532.90, 22,133.60 - 46,058.60, 19.60 - 66.10, and 81.60 - 191.30 mg/kg, respectively. The concentrations of metals in the sediments followed the increasing order of Cd < Cu < Cr < Pb < Zn < Mn < Fe. The observation from this study showed higher affinity of metals to less particle size. The mean concentrations of Cd, Cr, Pb, Mn, Fe, Cu, and Zn were above the toxicity reference value. The I_geo and EF indicated that most of the sites were moderately to strongly polluted due to Cd while the calculated PLI showed progressive deterioration of the environment in most sites. The Pearson's correlation analysis revealed that the presence of metals in the sediments were from anthropogenic and unidentified sources. The status of metals in the study area portends a serious ecological threat to the sediment biota and occupants of the agrarian communities that depend on the water and its produce for survival.

Potentially hazardous elements in sediments and Ceratophyllum demersum: an ecotoxicological risk assessment in Miliç Wetland, Samsun, Türkiye

Potentially hazardous elements (PHEs) are non-biodegradable and accumulate in places like water, soil, and plants where they endanger environmental health. There are a considerable number of wetlands having both national and worldwide importance in Türkiye. Regarding PHE accumulation, sediments and Ceratophyllum demersum were examined in the Miliç Wetland (MW), situated in a basin with intense hazelnut and rice farming, which is next to the international highway on the Central Black Sea Coast of Türkiye. The quantification of PHEs in the study subjects was undertaken using a validated inductively coupled plasma-mass spectrometry (ICP-MS) method, and mean concentrations (mg/kg) of PHEs in the sediments were in the order of Al (13,133) > Fe (10,790) > Mn (205.84) > Cu (17.95) > Cr (16.40) > Zn (15.55) > Ni (11.74) > Pb (9.17) > Co (6.30) > As (2.07) > Cd (0.19). The ecotoxicological risk was assessed using sediment quality guidelines (SQGs) and certain geological indices, indicating mostly low ecological risk, low pollution, and no hazardous risk. Based on the modified hazard quotient (mHQ) classification of values, Ni showed low contamination, while Cd, Pb, As, and Cu displayed very low contamination, and Zn presented minor contamination. The findings of total lifetime cancer risk (LCR), hazard quotient (HQ), and hazard index (HI) identified that exposure of adults or children to sediments containing PHEs would not represent a major health risk. As a recommendation, it is necessary to avoid the direct entrance of agricultural pesticides and fertilizers to enhance the sediment quality of the MW. Since the highway was constructed close to MW, this is considered a significant source of human-caused pollution. Consequently, all PHEs analyzed, except for Cd, displayed a bioconcentration factor (BCF) value of more than 1000, indicating that Ceratophyllum demersum is a promising plant for phytoremediation in PHE-polluted ecological systems involving wetlands, and it can efficiently be employed as an indicator species in biological screening investigations.

Biomonitoring of Alterations in Fish That Inhabit Anthropic Aquatic Environments in a Basin from Semi-Arid Regions

Industrial, agricultural, and urban areas can be sources of pollution and a cause of habitat fragmentation. The Conlara River located in the northeast of San Luis Province suffers different environmental pressures along its course from urban to agro-industrial areas. The present study aims to assess the water quality of the Conlara basin by evaluating how metals and pesticide contamination as well as physicochemical parameters relate to physiological stress in Jenynsia multidentata. Samplings were carried out in four sites characterized by a growing gradient of anthropic impact from the springs to the final sections of the river, starting with tourism passing through urban areas and ending with large agricultural areas (from S1 to S4) during both the dry and wet seasons. A total of 27 parameters were determined (11 physicochemical, 9 heavy metals, and 7 pesticides) in surface waters. Biomarkers (CAT, TBARS, ChE, and MN) showed significant physiological and cytological alterations in J. multidentata depending on the hydrology season. The combination of physicochemical parameters, metals, and pesticide levels allowed typification and differentiation of the sites. Some metal (Cr, Mn, Pb, and Zn) and pesticide (α-BHC, chlorpyrifos, permethrin and cypermethrin, and endosulfan α) levels recorded exceeded the recommended Argentinian legislation values. A principal component analysis (PCA) allowed detection of differences between both seasons and across sites. Furthermore, the differences in distances showed by PCA between the sites were due to differences in the presence of physicochemical parameters, metals, and pesticides correlated with several biomarkers' responses depending on type of environmental stressor. Water quality evaluation along the Conlara River shows deterioration and different types of environmental stressors, identifying zones, and specific sources of pollution. Furthermore, the biomarkers suggest that the native species could be sensitive to anthropogenic environmental pressures.

Spatial-temporal distribution and pollution indices of heavy metals in the Turnasuyu Stream sediment, Turkey

The potential contamination levels and human health risk of heavy metals in sediment of the Turnasuyu Stream in Ordu, Turkey, were evaluated comprehensively by taking seasonal samples from three different locations. The order of the mean heavy metals (HMs) concentrations (mg/kg) were as follows: Fe > Al > Mn > Pb > Zn > Cu > Co > Cr > Ni > Cd > As. All HM levels, except Cd and Pb, were in the minimum enrichment range as assessed by the sediment enrichment factor (EF). Similar low contamination levels for all HM, except Pb and Cd, were also observed when the contamination factor (CF) and geo-accumulation index (I_geo) were taken into account. The low risk of the study area has also been confirmed by the ecological risk index (E_rⁱ) values. The probable human health risk assessment has been performed, and the lifetime cancer risk (LCR) values for adults were found as negligible with values below 10^-6. In addition, the hazard index (HI) and total hazard index (THI) results were both higher in children than in adults. The Pearson correlation coefficient (PCC) revealed the highest correlation between Cd and Pb (0.85). When the ecological indexes and statistical results are evaluated together, it is thought that the presence of HMs in the sediment may be due to lithological reasons as well as anthropogenic activities such as quarrying, municipal, agricultural, and domestic discharges in the region. Mitigation measures should be taken in accordance with the standards within the river basin to prevent the potential risks of pollution.