Estuarine Sediment Samples Research Articles

Understanding Zinc Transport in Estuarine Environments: Insights from Sediment Composition

Sediments are sources and sinks of heavy metals in water, and estuaries are heavily influenced by human production and life. Therefore, it is of great significance to study the composition of estuarine sediments and the relationship between their components to understand the transport and transformation pathways of heavy metals in the environment. In this research, we investigated the characteristics and patterns of Zn adsorption by organic–inorganic composites, organic–clay mineral composites, and iron oxide–clay mineral composites in eight estuarine sediment samples from Dianchi Lake. The results show that both Langmuir and Freundlich isothermal models can describe the adsorption behaviour of the adsorbent better. The order of the adsorption capacity of the three groups of samples for zinc was organic–inorganic composites > organic–clay mineral composites > iron oxide–clay mineral composites. Through FTIR and XRD analyses, the adsorption of Zn2+ on the three groups of samples was dominated by electrostatic attraction and coordination adsorption, accompanied by the occurrence of ion exchange and co-precipitation. After FTIR semi-quantitative analysis, it was found that the source of the differences in the high and low Zn adsorption of the three types of samples may be mainly due to the content of phenolic functional groups in the organic matter. This may be related to the low redox site of the phenolic hydroxyl group, which, as an electron donor, is susceptible to electrostatic attraction and complexation with heavy metal cations. The organic–inorganic composite has a higher adsorption capacity for Zn when the ratio of the active fraction of organic matter to the free iron oxide content is 0.65–0.70. In this range, the organic matter can provide enough negative charge without making the sample surface too dense. Iron oxides can also activate the sample by providing sufficient contact between the clay minerals and the organic matter. When this ratio is too high or too low, it will be unfavourable for Zn adsorption.

Isotopic and spectral signatures unravel the sources, preservation and degradation of sedimentary organic matter in the Dongzhai Harbor mangrove estuary, southern China

Sedimentary organic matter (SOM) production and transformation processes have a prominent role in regulating biogenic element cycling in mangrove ecosystems. However, aquaculture biodeposits can substantially affect source apportionments and biogeochemical processes of SOM within mangroves. In this study, natural stable isotopes (13C and 15N), spectral techniques, and hydrogeochemical analysis were used to elucidate the sources, preservation, and degradation of SOM across the Dongzhai Harbor (DZH) estuary, southern China, where aquaculture systems are extensive. Along the estuarine salinity gradient, sediment and bottom water samples were collected from the upper fluvial mangrove zones to the lower marine endmember. Results indicated that source contributions to SOM along the estuarine gradient were spatially heterogeneous. Aquaculture-derived organic matter was the largest contributor to the Sanjiang River (44.29 %) in the upper estuary, and terrestrial sources from C3 mangrove forests were highest in the Yanfeng East River (62.87 %) near the middle estuary. Farther seaward, marine plankton sources were elevated in the Dongzhai Harbor channel (64.15 %) and Yanfeng West River (48.83 %) of the lower estuary. The terrestrial/microbial humic-like component (C1), tryptophan-like component (C2), and soil-derived fulvic acid (C3) were identified from the samples using fluorescence excitation emission matrices and parallel factor analysis (EEM-PARAFAC). Results show that in the upper and middle estuary, SOM was preserved by sedimentation due to the abundance of fine-grained aquaculture-derived biodeposits, weak hydrodynamic conditions, and the formation of Fe/Mn-humus complexes. In contrast, in the lower estuary, SOM originated from marine plankton and was rapidly degraded via aerobic respiration. Moreover, correlations between δ13C and δ15N values vs C/N ratios further suggest progressive SOM degradation from initial diagenesis to post-depositional geochemical processes. This study provides new insights into aquacultural and environmental factors controlling SOM preservation and degradation within estuaries. The findings have implications for shoreline stability and the protection and restoration of estuarine mangrove wetlands.

Contaminants from a former Croatian coal sludge dictate the structure of microbiota in the estuarine (Raša Bay) sediment and soil.

Croatian superhigh-organic-sulfur Raša coal had been mined for nearly 400 years. The release of hazardous trace elements (HTEs) and toxic organic pollutants (TOPs) into the local environment by coal mining, preparation, and combustion activities has resulted in pollution. In this study, the diversity and composition of microbial communities in estuarine sediment and soil samples as well as community function responses to the pollutants were investigated. The results showed that PAH degradation does occur following 60 years of natural attenuation, the location is still heavily polluted by polycyclic aromatic hydrocarbons (PAHs) and HTEs. Microbial analyses have shown that high concentrations of PAHs have reduced the diversity and abundance of microbial communities. The pollution exerted an adverse, long-term impact on the microbial community structure and function in the brackish aquatic ecosystem. Microorganisms associated with the degradation of PAHs and sulfur-containing compounds have been enriched although the diversity and abundance of the microbial community have reduced. Fungi which are believed to be the main PAH degrader may play an important role initially, but the activity remains lower thereafter. It is the high concentrations of coal-derived PAHs, rather than HTEs, that have reduced the diversity and abundance of microbial communities and shaped the structure of the local microbiota. This study could provide a basis for the monitoring and restoration of ecosystems impacted by coal mining activities considering the expected decommission of a large number of coal plants on a global scale in the coming years due to growing global climate change concerns.

Porous-polymer monolith decorated with dithizone for greener visual and spectrophotometric sensing of Hg(II)

This paper describes a hydrophobic porous polymer monolith for visual and spectrophotometric determination of Hg(II). The monolith was synthesized in the coffins of 2.0 mm i.d. transparent polypropylene ink-pen tubes using stearyl methacrylate (SMA) as the functional monomer and ethylene glycol dimethacrylate (EDMA) as the crosslinker by fast UV-mediated polymerization. The poly(SMA-co-EDMA) monolith retained dithizone, an anchor for the Hg(II) and colorimetric reagent. Besides the monolith's fast preparation, the polypropylene transparency enabled the naked-eye visualization of all color changes occurring in the solid phase extraction steps (conditioning, loading, washing and elution). This feature also enabled the unprecedented use of a simple ruler for detection since the distance occupied by Hg(II) inside the column was linearly related to Hg(II) concentration. Loading the column with 12.0 mL of sample and elution with 1.0 mL of ethanol contributed to the green analytical chemistry and provided a detection limit of 7.9 µg L−1, which was enough to determine Hg(II) in certified estuarine sediment (ERM-CC580) and urine samples. A sample volume of 45 mL provides a detection limit of 0.59 μg L−1, allowing the detection of trace Hg(II) levels in the Billings reservoir waters, an anthropized water reservoir located in the São Paulo Metropolitan Area of São Paulo State (Brazil), thus attending the maximum concentration levels preconized by the United States Environmental Protection Agency (1.0 µg L−1) and World Health Organization (6.0 µg L−1). The proposed method is simple, cheap and can be easily implemented in field measurements for sample trials.

Microplastics in estuarine water and sediment in Mauritius

The aim of this study was to quantify the distribution of MPs from four estuaries in Mauritius. Estuarine surface water and sediment samples were collected once over four weeks. The mean abundances of MPs in surface water and sediments were in the range of 249–412 particles.L−1 and 74–235 particles.kg −1 dry weight, respectively. Fibres shared a higher proportion in both surface water (52%) and sediment samples (81%). MPs in the size range of 24–250μm (53 %) were found in abundance in surface water samples while MP of sizes 500–1500μm (36%) in sediment samples. Cotton polyamide type of MPs were dominated in both surface water (33%) and sediment (44%) followed by polyethylene (28%) and polypropylene (22%), respectively. The results of this study provide an important baseline reference for evaluating the abundance of MPs in the Southern African regions and in the Indian Ocean.

Bioactive potential of Aspergillus sp. isolated from Uppanar estuarine sediment samples against plant pathogens

In the present study, fungal strains were isolated from the sediment samples collected from the Uppanar estuary, Cuddalore district, Tamil Nadu and evaluated their potential for antifungal activity against a panel of plant fungal pathogens. Isolates were screened qualitatively for their antifungal activity and from the results, the HK-05 strain was selected for further study. The potential strain was identified as Aspergillus sp. using morphological observation under the microscope. Antimicrobial activity screening showed that the isolate Aspergillus sp. HK-05 was inhibitory to the different plant fungal pathogens tested, such as Sclerotium rolfsii (21 mm), Macrophomina phaseolina (28 mm), Phytophthora infestans (24 mm), Fusarium oxysporum (18 mm) and Colletotrichum musae (25 mm). The results suggested that Aspergillus sp. could combat diseases caused by plant pathogenic fungal strains. Furthermore, an in-depth study is underway on bio-guided extraction and identification of active molecules, which would identify individual components and lead to the isolation of the active molecule in future.

Rapid determination of total metals: synergic effect of ultrasound energy and ionic liquids on the digestion of sediment samples

PurposeThe aim of this study was to develop a new and rapid sample digestion procedure for metal extraction using ultrasonic energy together with a combination of an ionic liquid and mineral acids as extractants.MethodsA fixed mass of sediment (about 0.50 g) was extracted with a combination of low volumes of NaHCO3, HCl, HNO3, HF and the ionic liquid Bmim[BF4]. Afterwards, the mixture was sonicated for 20 min. After neutralizing the hydrofluoric acid excess, the extracts were filtered and measured by ICP OES where Cd, Cr, Cu, Ni, Pb and Zn were determined.ResultsThe recoveries in certified reference materials ranged from 92 to 102% for LGC-6137, from 88 to 98% for IAEA SL-1 and from 81 to 98% for MURST-ISS-A1, with a good precision (relative standard deviation (RSD) < 10.0% for all the certified reference materials). The new digestion procedure was successfully applied to the determination of metals in estuarine sediment samples, with a satisfactory precision (RSD < 9.5%). The results showed no significant statistical differences compared to those obtained by the conventional digestion procedure (with an α-error of 0.05).ConclusionThis approach has led to satisfactory results in the determination of the total metal concentrations for most of the elements studied using shorter analysis times than the conventional procedure, and small volumes of hydrofluoric acid. The new pretreatment method made it possible to satisfactorily assess the total metal concentrations in estuarine sediments.

Complete Genome Sequence of Bacillus safensis Strain 3A, a Heavy Metal-Resistant Bacterium Isolated from Contaminated Estuarine Sediment in Brazil.

Bacillus safensis 3A was isolated from a contaminated estuarine sediment sample with mine tailing from the Samarco dam disaster, which occurred in 2015 in Minas Gerais State, Brazil. We report here a draft genome sequence (3.6 Mb) of this bacterial strain. B. safensis exhibited strong resistance to heavy metals.

Isolation, Screening and Antimicrobial Activity of Aeromonas hydrophila from Spoiled Vegetables and Biochemical Analysis of Estuarine Microbial Sediments

Background: Aeromonas hydrophila is a heterotrophic, Gram-negative, rod-shaped, facultative anaerobic, non-spore forming bacteria that are autochthonous and widely dispersed in marine environments. The study aims at investigating the screening of Aeromonas hydrophila from spoiled vegetables and the sediment sample collected from three different estuaries located in the Bay of Bengal (Vedharanyam, Parangipettai and Pichavaram, Tamilnadu, India) for the presence of enzymes and antimicrobial activities. Objective: Isolation, enzyme screening, antimicrobial activity of Aeromonas hydrophila from spoiled vegetables and three different estuarine microbial sediment samples for the purpose of biochemical and enzymatic analysis. Methods: The bioactive compound produced by this strain was purified by using thin-layer chromatography. Results: The purified isolate of Aeromonas hydrophila strain produces good antimicrobial activity against Aspergillus niger, Candida albicans, Staphylococcus, Klebsiella and pseudomonas species. Conclusion: These isolates producing amylase, protease, lipase, and gelatinase enzymes, which are commercially very important and used in many industries and other biochemical sectors.

The Response of Estuarine Ammonia-Oxidizing Communities to Constant and Fluctuating Salinity Regimes.

Aerobic nitrification is a fundamental nitrogen biogeochemical process that links the oxidation of ammonia to the removal of fixed nitrogen in eutrophicated water bodies. However, in estuarine environments there is an enormous variability of water physicochemical parameters that can affect the ammonia oxidation biological process. For instance, it is known that salinity can affect nitrification performance, yet there is still a lack of information on the ammonia-oxidizing communities behavior facing daily salinity fluctuations. In this work, laboratory experiments using upstream and downstream estuarine sediments were performed to address this missing gap by comparing the effect of daily salinity fluctuations with constant salinity on the activity and diversity of ammonia-oxidizing microorganisms (AOM). Activity and composition of AOM were assessed, respectively by using nitrogen stable isotope technique and 16S rRNA gene metabarcoding analysis. Nitrification activity was negatively affected by daily salinity fluctuations in upstream sediments while no effect was observed in downstream sediments. Constant salinity regime showed clearly higher rates of nitrification in upstream sediments while a similar nitrification performance between the two salinity regimes was registered in the downstream sediments. Results also indicated that daily salinity fluctuation regime had a negative effect on both ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) community’s diversity. Phylogenetically, the estuarine downstream AOM were dominated by AOA (0.92–2.09%) followed by NOB (0.99–2%), and then AOB (0.2–0.32%); whereas NOB dominated estuarine upstream sediment samples (1.4–9.5%), followed by AOA (0.27–0.51%) and AOB (0.01–0.23%). Analysis of variance identified the spatial difference between samples (downstream and upstream) as the main drivers of AOA and AOB diversity. Our study indicates that benthic AOM inhabiting different estuarine sites presented distinct plasticity toward the salinity regimes tested. These findings help to improve our understanding in the dynamics of the nitrogen cycle of estuarine systems by showing the resilience and consequently the impact of different salinity regimes on the diversity and activity of ammonia oxidizer communities.

Microplastics distribution and contamination from the Cochin coastal zone, India

Microplastics are small plastic fragments less than 5 mm in diameter, and microplastic pollution is an emerging threat in our day to day life. Microplastic pollution was estimated in water, sediment and fish samples from selected stations along the Cochin estuary and nearby coastal areas in Kochi. The estuarine water and sediment samples recorded a larger number of microplastics than in beach samples with a mean abundance of 751.7 ± 452.21 particles/m3 and 1340 ± 575.22 particles/kg, respectively. Study stations near to the busiest city locations showed significantly high levels of microplastic pollution (p < 0.001). A total number of 46 fishes belonging to five species were dissected, from which nine microplastics were isolated. All of the isolated plastic materials were identified as secondary microplastics. Among different types, fibres were abundant in all the sampling sites. Selected particles were identified with Fourier Transform Infrared Spectroscopy analysis as cellophane, polystyrene, polyethylene, polypropylene, and nylon. The study found that the water and sediment samples from the Cochin estuary are seriously polluted with microplastics, and this is the first attempt to compare the microplastic pollution status of the Cochin estuary with the associated beaches.

Simple and cost-effective method for microplastic quantification in estuarine sediment: A case study of the Santos and São Vicente Estuarine System

Sediment is a useful environmental compartment in the evaluation and monitoring of microplastics (i.e., plastic particles between 1 ​μm and 5 ​mm in length) in aquatic environments, since 70% of plastic waste is deposited on the ocean floor, in riverbeds, and on the bottom of estuaries. The techniques typically used to separate and quantify microplastics require extensive sample preparation and are often ineffective for estuarine sediment samples. In this study, we present a new method for separating and quantifying microplastics found in estuarine sediment samples. This procedure involves sediment collection, drying, sieving (2.0, 1.0, 0.5 and 0.25 ​mm mesh sizes), and stereomicroscopic examination of the samples retained in each sieve. The results were measured as microplastic abundance (particles g-1 of sediment). This method allows researchers to estimate total microplastic abundance and distribution at the sieve meshes tested, calculate thread/fiber and fragment proportions, and separate microplastic samples for subsequent Py-GC/MS analysis in order to identify their respective compositions. This method was found to be effective in precluding the need for solvents and reducing the amount of time required for sample preparation. For these reasons, this method is more cost-effective and generates less environmental impact than those currently available.

The efficiency of sequential extraction of phosphorus in soil and sediment: insights from the oxygen isotope ratio of phosphate

Phosphorus (P) occurs in different chemical forms in soil and sediment, and they play different ecological and environmental roles. Thus, separation and quantification of different P pools are essential to the understanding of P dynamics in the environment. Over the past decades, different sequential extraction methods have been used concurrently. However, systematic evaluation of different extraction methods is lacking, making choice of methods and comparisons between results difficult. We compared the oxygen isotope compositions (δ18OP) of different phosphate pools that were extracted by two major extraction methods, Hedley (Hedley et al., Soil Sci Soc Am J 46:970-976, 1982) and SEDEX methods (Ruttenberg, Limnol Oceanogr 37:1460-1482, 1992), for both a soil and an estuarine sediment sample. Additionally, Ag3PO4 and KH2PO4 standards were used to test the fidelity of the extraction and purification procedure. The purity of the precipitated Ag3PO4 was also examined. The δ18OP values have large differences among phosphate pools for the soil extracted by the Hedley method and for the sediment extracted by the SEDEX method. The δ18OP values of Ag3PO4 and KH2PO4 standards after extraction, purification, and/or re-precipitation are similar to their original δ18OP values. The XRD patterns of the precipitated Ag3PO4 are identical to that of Ag3PO4 standard. The residual carbon and nitrogen contents in the precipitated Ag3PO4 are low. The Hedley method has good efficiency for separating isotopically distinct Pi pools (different sources/bioavailability) in the soil samples, while the SEDEX method has good efficiency for separating isotopically distinct Pi pools (different sources/bioavailability) in sediments that are more marine in character such as for the estuarine sample. The extraction and purification processes do not alter δ18OP, and the precipitated Ag3PO4 has high purity.

The environmental condition of an estuarine ecosystem disturbed by pesticides

Knowledge regarding the concentration levels resulting from the use of agricultural pesticides may indicate the nature of the controls necessary to reduce environmental and human health risks to an acceptable level. Therefore, the main goal of the present work was to assess the spatial and temporal occurrence of 35 pesticides in the River Sado estuary (Portugal) in 2017 and evaluate its environmental condition, as data for estuarine ecosystems is scarce. Since pesticides are very susceptible to matrix effects promoted by environmental samples, to attain the main goal, we developed a fast and almost solvent-free environmentally friendly method with a good performance for both estuarine surface water and sediment samples. Quantified residues were determined mostly during summer, in line with the pesticide application period. Five herbicides (alachlor, bentazon, metobromuron, metribuzin and triclopyr) were measured in the water before and after the production season, suggesting a long-term aquatic exposure. Sediment samples were less contaminated, since a lower number of quantified pesticides were found in the study area, in lower frequencies and lower concentrations. No potential high adverse effects of the use of agricultural pesticides were expected on the aquatic organisms of the Sado estuary, even considering the potential combination effect of pesticide mixtures.

Evaluation of a data-processing method for target and non-target screening using comprehensive two-dimensional gas chromatography coupled with high-resolution time-of-flight mass spectrometry for environmental samples

We evaluated the possibility of semi-automatic target and non-target screening by comprehensive two-dimensional gas chromatography coupled with high-resolution time-of-flight mass spectrometry (GC×GC-HRToFMS) by using estuarine sediment samples. Two-way screening consisting of compound-based (target screening) and data-based (non-target screening) analyses was performed by using two original software programs, including mass-spectral deconvolution software based on non-negative matrix factorization, the NIST Mass Spectral Library, and an in-house accurate mass spectral library with a retention index (RI) for the 1st column. Target screening detected 47 organohalogen compounds, including polychlorinated biphenyls, polybrominated diphenyl ethers and organochlorine pesticides, in the sediment sample. Among about 54,000 peaks detected in the non-target screening, 53.6% showed match factors (MF) of ≥ 700 in an automatic mass spectral library search using the peak-top mass spectra. Both mass error of molecular ions and RI error were calculated automatically for the first-hit compounds in the library search; 0.03% of peaks passed all criteria, namely MF ≥ 700, mass error ≤± 20 ppm, RI error ≤ ± 20, and intensity of molecular ion ≥ 10,000. Two compounds—a phosphorus flame retardant and a brominated phenol—were tentatively identified in the non-target screening process. The advantages of semi-automatic GC×GC-HRToFMS data processing with the two original software programs is its simplicity, high reproducibility, and shortened time for processing a large volume data. The results suggest that an In-source HiRes search—i.e. library matching using accurate mass spectra—is useful and could be applied for non-target screening using high-resolution MS in the future.

Adapting metabarcoding-based benthic biomonitoring into routine marine ecological status assessment networks

The use of genomic approaches to assist with biodiversity estimations is an alternative to traditional biomonitoring, which is very time-consuming and costly. In response to the high demand for quick community descriptions, DNA metabarcoding can simultaneously assign taxonomy to hundreds of samples rapidly and at low cost. However, the technique has not routinely been incorporated into biomonitoring network programs yet. Here, we applied DNA metabarcoding methodologies at stations within the monitoring network of the Basque Water Agency, the competent authority for the application of the European Water Framework Directive in this region. We characterized the benthic macroinvertebrate communities from 18 estuarine and coastal sediment samples using morphology and metabarcoding-based taxonomic identification and evaluated the performance of several versions of the AZTI’s Marine Biotic Index (AMBI). Although metabarcoding detected 112 taxa against the 206 taxa identified through morphology, we showed that metabarcoding leads to similar biomonitoring conclusions compared with traditional techniques. Using the abundance and biomass of those taxa detected from morphological methodologies, we found a significant positive correlation with the number of reads obtained with metabarcoding approaches. The metabarcoding-based index derived from read counts, gAMBI, and the morphology-based index derived from individuals’ biomass, (B)AMBI, showed the best correlation and revealed excellent agreement at determining the ecological status of the stations analyzed. We calculated that, for the analysis of the 51 stations included in the Basque monitoring network, metabarcoding was 55% less costly and 72% less time consuming. The results of our study are relevant to policy makers and researchers in the field of ecological assessment and will contribute to the quick implementation of DNA metabarcoding to intensive monitoring programs.

Determination of denudation rates by the measurement of meteoric 10Be in Guadiana river sediment samples (Spain) by low-energy AMS

The concentration of meteoric 10Be in estuarine sediment samples has been measured by Spanish Accelerator for Radionuclides Analysis (SARA) at CNA and subsequently used to assess the denudation rate in Guadiana river basin together with the sediment budget method, on both sides of the frontier between Spain and Portugal. The two methods yielded coincident results. The estimation by the 10Be method gave the denudation rate of (0.76 ± 0.10) × 10−2 cm/y. After correcting for an approximate 80% attenuation of the sediment discharge into the ocean, caused by the river dams, the sediment budget method yielded the rate of (0.77 ± 0.17) × 10−2 cm/y.

Biochemical Mechanisms and Microorganisms Involved in Anaerobic Testosterone Metabolism in Estuarine Sediments.

Current knowledge on the biochemical mechanisms underlying microbial steroid metabolism in anaerobic ecosystems is extremely limited. Sulfate, nitrate, and iron [Fe (III)] are common electron acceptors for anaerobes in estuarine sediments. Here, we investigated anaerobic testosterone metabolism in anaerobic sediments collected from the estuary of Tamsui River, Taiwan. The anaerobic sediment samples were spiked with testosterone (1 mM) and individual electron acceptors (10 mM), including nitrate, Fe3+, and sulfate. The analysis of androgen metabolites indicated that testosterone biodegradation under denitrifying conditions proceeds through the 2,3-seco pathway, whereas testosterone biodegradation under iron-reducing conditions may proceed through an unidentified alternative pathway. Metagenomic analysis and PCR-based functional assays suggested that Thauera spp. were the major testosterone degraders in estuarine sediment samples incubated with testosterone and nitrate. Thauera sp. strain GDN1, a testosterone-degrading betaproteobacterium, was isolated from the denitrifying sediment sample. This strain tolerates a broad range of salinity (0–30 ppt). Although testosterone biodegradation did not occur under sulfate-reducing conditions, we observed the anaerobic biotransformation of testosterone to estrogens in some testosterone-spiked sediment samples. This is unprecedented since biotransformation of androgens to estrogens is known to occur only under oxic conditions. Our metagenomic analysis suggested that Clostridium spp. might play a role in this anaerobic biotransformation. These results expand our understanding of microbial metabolism of steroids under strictly anoxic conditions.

Method for organically bound tritium analysis from sediment using a combustion bomb

The method consisted in combustion, using a Parr bomb type 1121, of a sediment - tritium free promoter mixture. The proper ratio sediment to promoter in our experiments was between 1:3 and 1:2, higher ratio resulting in unreliable results, due to incomplete combustion of the sample. The described method was used to measure the estuarine sediment sample from the 2nd International OBT Intercomparison Exercise, the average reported value being 163±12Bqkg−1 dry matter (k=2).

A novel extraction-based procedure for the determination of trace elements in estuarine sediment samples by ICP-MS

The study proposes a simple and fast extraction-based procedure for the determination of trace elements in estuarine sediment samples by inductively coupled plasma mass spectrometry (ICP-MS). The extraction conditions were optimized using a central composite design. Optimum results were obtained when 100mg of sediment sample was used followed by ultrasound-assisted extraction for 15min with 7.50molL−1 HF (1mL HF) and 3.50molL−1 HNO3 (1mL HNO3 65%m/m). Calibration against aqueous standards was carried out with rhodium as an internal standard. The method was successfully applied for the quantitative extraction of As, Cd, Co, Cr, Cu, Ni, Pb, Sn, V and Zn. Detection limits ranging from 0.02 to 0.1μgg−1 and relative standard deviation lower than 8% were obtained. The method accuracy was assessed by using three certified reference materials and comparing the results from the extraction procedure with those obtained following microwave-assisted digestion of the samples; no statistical differences, based on t-test at a confidence level of 95%, were detected. The proposed method showed to be simple and fast and can be applied for sediment samples with the elimination of the sample digestion step prior to analysis.