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Purpose Riverbed sediment geochemistry provides useful information regarding metal contamination. To integrate sediment quality in river monitoring, within the WFD, the report of sediment quality to water quality managers must be expeditious. This study revisits the metal enrichment concept, applied to sediments from two mountain catchments, as a useful technique in river monitoring. Methods Riverbed sediment samples, collected at the end of the Dry and Wet Periods (DP, WP) were analysed for Cd, Cu, Pb, Zn, and Fe in fractions < 2 mm and < 63 µm. The metal enrichment factors (EFs) were referenced to distinct background values: average shale (AS), world rivers suspended sediments (WRSS) and Geochemical Atlas of Portugal (GAP). Results Cd, Cu, Pb and Zn contents are higher in the fraction < 63 µm, and at DP. The ranges of variation in fraction < 63 µm are (mg kg −1 ): a) River Vilariça, Cd (5–18 DP; 0.3 WP); Cu (103–341 DP; 22–218 WP); Pb —(24–55 DP; 11–42 WP); Zn (107–241 DP; 54–103 WP); b) River Vizela, —Cd (13–44 DP; 8–41 WP); Cu (267–444 DP; 18–168 WP); Pb —(44–132 DP; 20–42 WP); Zn (141–801 DP; 36–181 WP). Variations in metal contents are influenced by lithological, geomorphological, and microclimatic features, and anthropogenic pressures. EFs are higher when referenced to AS. In the River Vizela, the EFs reveal an enrichment of Cu, Pb and Zn relative to WRSS; Cd registers an enrichment relative to GAP. Conclusion Local/regional background, and EFs, are relevant when assessing environmental risks in freshwater systems: low EFs, when associated to natural enrichments, originate values of concern in terms of quality guidelines; high EFs may not imply risk to the fluvial environment. Using the fraction < 63 µm in river monitoring is considered adequate. In dynamic mountain streams, recent sediments and associated contaminants are retained, providing information on possible pollution sources. Identifying metals contamination (or natural enrichment) can help decision-makers to provide solutions for pollution sources.

Heavy metals in coastal ecosystems caused by the increased expansion of urbanization, industrialization, and agricultural practices have become a significant environmental risk to human well-being. This study evaluates and compares 17 sediment quality indices to examine the possible ecological and human health risks associated with heavy metal concentrations in the sediments of the Nador lagoon in Morocco. The concentration order of the HMs and sulfurs evaluated was S > Sr > Ba > V > Zr > Zn > Cr > Rb > La > Cu > Pb > Ni > Ce > Nd > Co > Sc > Nb > Ga > Th > Y > Hf. Sulfurs, Pb, Sr, and Nd exhibited concentrations that exceeded geochemical background values. The analysis of the sediment quality indices allowed us to understand that the Nador lagoon was moderately to strongly polluted by heavy metals originating from various anthropogenic activities. Results from the Sediment Quality Guidelines indicated a toxic response in the benthic organisms within the lagoon, while the ecological hazard analysis revealed a very high risk of heavy metal contamination in the ecosystem. The Hazard Index for non-carcinogenic values was below the limit, suggesting a lack of non-cancerous effects. However, Cu and Pb concentrations surpassed the Lifetime Cancer Risk range, indicating a potential cancer risk with prolonged exposure. Integrating our research into coastal management frameworks can contribute to the preservation and enhancement of these coastal ecosystems for future generations.

Heavy metal contamination in freshwater ecosystems poses a persistent threat to environmental and public health, particularly in urban regions with limited waste management infrastructure. This study assessed the concentration and spatial distribution of cadmium, lead, manganese, and zinc in the water and sediments of Telaje-Cabugan Creek, a tributary of the Tandag River in Surigao del Sur, Philippines. Water and sediment samples were collected from three designated sites and analyzed using atomic absorption spectroscopy. Physicochemical parameters, including pH, salinity, temperature, turbidity, and depth, were also recorded. Statistical methods, including one-way ANOVA and Pearson correlation, were used to assess spatial variations and environmental influences on metal concentrations. Results showed that only manganese was detected in water, while zinc, lead, and cadmium were present in sediments, with cadmium below the detection limit in both matrices. Zinc concentrations exceeded international sediment quality thresholds, indicating moderate pollution, while other metals remained within acceptable levels. No significant spatial differences were observed in heavy metal concentrations across the sampling sites. Correlation analysis revealed that manganese in sediments was significantly influenced by salinity and pH, suggesting environmental conditions can affect its mobility. The findings provide baseline data for local water quality management and highlight the need for integrated interventions to address diffuse sources of contamination in urban freshwater systems.

Five sediment cores from the fresh water region of the Vembanad wetland system were studied for the trace element contents The average concentration of iron, manganese, nickel, copper, zinc, cadmium, lead, mercury and chromium were determined. The core samples were collected using gravity type corer, digested with a mixture of nitric acid and perchloric acid and analyzed by atomic absorption spectrophotometry. Heavy metals such as iron, copper, nickel and zinc reported enrichment towards the surface of the core sediment sample collected from the centre of the lake. Lead, cadmium and mercury showed uniform distribution through out the core. Quality of the sediments were evaluated based on sediment quality guidelines, pollution load index, sum of toxic units and with effect range low/effect range median and threshold effect level/probable effect level values of Environmental Protection Agency guidelines. The degree of contamination for each station was determined. The concentration of different heavy metals has been compared with the world average concentration of shale values. Results of the analysis showed that Vembanad lake is facing serious metal pollution with increased rate of deposition.

PurposeThis study aims to identify a suitable sediment compartment for sediment quality monitoring by: (a) studying the concentration of trace metals (Cd, Cu, Ni, Pb and Zn) in the bed, bank and suspended sediment compartments of the Ravensbourne River to establish any differences in trace metal concentrations with compartment; (b) determining the influence of sediment particle size fractions (< 63 μm and 63 μm–2 mm), organic matter and mineralogy on any differences; and (c) examining if metal concentration in each sediment compartment complies with the draft UK sediment quality guidelines.Materials and methodsHere, we make a comparison of metal concentrations in the bed, bank and suspended sediment compartments of the Ravensbourne River collected using different sampling techniques. We distinguished between two particle size fractions—the < 63 μm fraction (suspended, bed and bank sediment) and the 63 μm–2 mm fractions of bed and bank material with the aim of comparing concentrations between the two fractions. Particle size analysis, metal speciation, organic matter content by loss on ignition and mineralogy using X-ray diffraction were also carried out on each sediment compartment.Results and discussionThe results showed variations in trace metal concentrations with sediment compartment and with particle size. The mineralogical characteristics were comparable for all sediment compartments, and the relationships between organic matter content and metal concentrations were significant in the majority of the bank sediment samples. There were no significant differences (p > 0.05) in the concentrations of metals between the suspended sediment and the < 63 μm bed sediment fraction, but there was a significant difference (p < 0.05) between the suspended sediment and the < 63 μm bank sediment fraction. There were also significant differences between the concentrations of metals in the < 63 μm and the 63 μm–2 mm fractions. Generally, the Ravensbourne River did not comply with the draft UK sediment quality guidelines for the metals analysed.ConclusionsThis study shows the importance of identifying a suitable sediment compartment to sample for compliance with sediment quality standards. The bed and suspended sediments are the most widely used sediment compartments for sediment monitoring, but collecting sufficient mass of the < 63 μm sediment fraction for monitoring presents a challenge for urban gravel bed rivers like the Ravensbourne River. It seems appropriate to establish individual monitoring regimes for different rivers.

PurposeRiver impoundments disrupt natural water flow patterns and sediment distribution throughout the impacted reach, which often results in a damaging effect on aquatic ecosystems. Dam removal can release sediments that may contain fugitive agricultural nutrients and organochlorine pesticide residues (OCPRs).MethodsSediment samples from an impoundment on the Oostanaula Creek (HUC 03,565,432) in Athens, Tennessee, were obtained, as were surface soil samples from the agricultural watershed. A subset of cores were used for simulated weathering, and all samples were extracted and analyzed for nutrients and OCPRs.ResultsThe impoundment sediments tested low in P and K, but sediment pore water contained elevated concentrations of NO3, NH4, and SO4 relative to reservoir water. Endrin aldehyde and p,p’-DDD were commonly detected in sediment and soil, while aldrin, dieldrin, and p,p’-DDE occurred in a smaller number of samples. When detected, dieldrin and endrin aldehyde frequently exceeded the threshold effect concentration (TEC), but never exceeded the probable effect concentration (PEC) in the sediment samples; p,p’-DDD always exceeded TEC and exceeded PEC in 49% of the sediment samples. The concentrations of NO3 and NH4 in the weathered sediment leachates were similar to those in the reservoir water, and NH4 became the dominant cation in leachates at the conclusion of simulated weathering. Weathering decreased sediment p,p’-DDD concentrations to less than the PEC; however, the concentrations of other OCPRs were not influenced.ConclusionThe dam sediments may have harmful effects on sediment-dwelling organisms and a long-term impact on stream reclamation following low-head dam removal.

Sediment quality criteria (SQC) of heavy metals (copper, lead, zinc and cadmium) for surface sediment have been developed to evaluate sediment contamination in the Xiang-jiang River of China using the equilibrium partitioning approach. USEPAs fresh water quality criteria [criterion continuous concentration (CCC), criterion maximum concentration (CMC)] were referenced to derive sediment quality criteria (SQC-low and SQC-high) of the Xiang-jiang River. The toxicological implications of SQC-low and SQC-high were similar with CCC and CMC, which were used to protect benthic organisms from short-term- and long-term exposure to pollutants. Sediment Pollution Index method was established based on the SQC-low and SQC-high values to evaluate sediment quality qualitatively and quantitatively. The evaluation method was applied to the Xiang-jiang River, and the result indicated that the cadmium contamination in the sediments was of concern; especially, in the Zhu-zhou, Yue-yang, and the middle and downstream reaches of Heng-yang section.

Purpose The main purpose of this study was to evaluate temporal and regional variability of contamination by heavy metals (HMs) in river sediments using their enrichment factors (EFs) and benchmarking according to sediment quality guidelines (SQGs). The Zlin region in the Czech Republic (Morava and Drevnice River basins) represents a model area where several regionally specific ecological risk assessment studies have recently been conducted with a focus on organic pollution, eco-toxicity, geological, and geochemical characteristics. Materials and methods Four consecutive sediment sampling campaigns were undertaken in spring and autumn 2005–2006. Aqua-regia leachable content of Cd, Co, Cr, Cu, Ni, Pb, Sb, V, and Zn in surface sediments from 14 sites was analyzed using ICP-MS, and Hg content was analyzed using AMA-254 analyzer. EFs were calculated to identify the human impact on pollution in the area. Comparisons to SGQs were conducted to identify the areas and HMs of greatest risk. Results and discussion Calculation of EFs contributed to the effective clustering of HMs. Median EFs of Co, Ni, and V ranged from 0.9 to 1.4 at all sites indicating concentrations very close to natural geological background levels. There was greater enrichment at locally polluted sites, the highest in the cases of Cd, Sb, Hg, and Cr. Widespread influence of diffuse HM sources (traffic, agriculture, and urban wastes) was apparent from elevated concentrations of Pb, Cu, and Zn at all sites. EF values also helped to identify the greatest temporal changes and shifts in HMs contamination between adjacent sites caused by 50-year recurrence interval floods in early spring 2006. The impact was most apparent in downstream sites; namely directly below the confluence of the two major rivers. Conclusions The overall contamination of HMs in the region was classified as low-to-moderate with significantly contaminated sub-areas. The study showed relatively stable spatial distributions of HMs, indicating potential sources of pollution. Cu was identified as the HM of greatest risk. The study emphasizes the necessity of considering both environmental circumstances and background HM occurrence to prevent misinterpretation of the pollution situation. The use of EFs which include grain size proxy normalization and HM background levels, along with the comparison of the detected concentrations to SQGs, proved an efficient way to identify hazardous contamination from anthropogenic sources.

Surface sediments in the fraction < 63 μm collected from eight stations along the north coastline of Izmit Bay, north-eastern Marmara Sea, Turkey, were analyzed for major (organic carbon, Al, Ba, Fe and Mg) and trace (As, Cd, Co, Cr, Cu, Mo, Ni, Pb and Zn) elements by using inductively coupled plasma atomic emission spectrometry (ICP-AES). Sediments heavily contaminated are evaluated by the Sediment Quality Guidelines (SQG) of US EPA. The results were compared with the marine sediment quality standards (SQS), as well as literature values reported to assess the pollution status of the sediments. The enrichment factors (EFs) were calculated to evaluate actual level of contamination for all the elements using the earth crust as reference matrix, based on elemental values by Mason which show a normal pattern near to unity. The analysis revealed two groups of elements: (i) Arsenic, Cd, Pb, and Zn are the most enriched elements; (ii) Barium, Co, Cr, Cu, Fe, Mg, Mo and Ni are at background levels. The results show that road traffic run-offs, paint industries and coal combustion are among the most significant sources.