Estuarine Samples Research Articles

Enhancement of per- and Polyfluoroalkyl Substances (PFAS) quantification on surface waters from marinas in the douro river, Portugal

PFAS, known as "forever" compounds, are prevalent in various environments, including soils and aquatic systems, due to extensive usage. Surface waters in several European countries, especially marinas and ports with high boat traffic, require further study as potential contamination sources. Reliable methods for the extraction and quantification of these emergent compounds are essential. This study aimed to improve an existent solid phase extraction method to analyse marinas and ports’ surface waters with variable salinities (2, 9 and 17 PSU). The objectives were to: 1) optimise the solid phase extraction method, considering matrix salinity effects and cross-contaminations, 2) validate the extraction and quantification method of 18 EPA 537.1 PFAS in estuarine surface waters, using the Ultra-High Performance Liquid Chromatography – Quadrupole Time – Of – Flight – Tandem Mass spectrometry, and 3) apply the optimised method for PFAS quantification in three Portuguese marinas. All ICH criteria were successfully validated considering 9 PSU. Limits of quantification ranged from 117.80 ng/L to 385 ng/L, except for PFHpA (645.85 ng/L). PFAS levels (PFOA, HFPO-DA, PFBS, PFHxS and PFOS) were relatively low, reaching a maximum of 0.32 ng/L only for the PFOA. In Freixo marina, total average concentrations were slightly higher (∑PFAS = 1.02 ng/L) when compared to the ones found in Cais da Ribeira Port (∑PFAS = 0.94 ng/L) and Afurada marina (∑PFAS = 0.81 ng/L). PFOS concentrations are below the limit values set by the Environmental Quality Standards (36000 ng/L of PFOS for inland surface water, respectively), similar to other Portuguese river studies. This study enabled the development of a precise and reliable extraction and quantification method to quantify PFAS in estuarine surface waters, particularly from marinas. This method can be readily applied to analyse PFAS in other estuarine samples.

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.

Simultaneous determination of picomolar level of dissolved silver with other key trace metals in seawater samples using solid phase extraction and isotope dilution methods

Simultaneous determination of dissolved silver (dAg) with other key GEOTRACES trace metals is difficult because dAg in seawater tends to form negatively charged chloride species that result in only 75% recovery efficiency with commonly used NOBIAS PA-1 chelating resins. In this study, we developed a method using solid phase extraction coupled with isotope dilution that enables full quantification (97.9 ± 2.1%) of dAg along with other major trace metals including cadmium (Cd), copper (Cu), manganese (Mn), nickel (Ni), and lead (Pb) (recovery efficiency = 100% to 102%) in seawater samples. Seawater samples were first spiked with Ag-109 and allowed to reach isotopic equilibrium before extraction using NOBIAS PA-1 chelating resin. Then, dAg isotope ratios (Ag-109/Ag-107) before and after solid phase extraction were determined and used to quantify dAg. Determination of dAg with dissolved Cd, Cu. Mn, Ni, and Pb in reference seawater material CASS-6 resulted in deviations of between 1.0% and 8.8% from the consensus values, which are well within the standard error of measurement. We then successfully determined the concentrations of dissolved Cd (0.05–0.2 nM), Cu (0.5–13 nM), Mn (10–140 nM), Ni (2–12 nM), Pb (5–110 nM), and Ag (10–40 pM) in Otsuchi Bay, Japan and its surrounding rivers. Evaluation of the behavior of dAg under a salinity gradient using estuarine samples collected from Samunsam River, Malaysia shows increasing dAg concentration with salinity (R2 = 0.68), which suggests release of sedimental Ag under high ambient chloride concentrations. Our new method enables rapid and simultaneous measurements of dAg with other key GEOTRACES trace metals in a single analysis, which is expected to expedite analysis and increase availability of oceanic dAg data globally.

Sulfur Vacancies in Pyrite Trigger the Path to Nonradical Singlet Oxygen and Spontaneous Sulfamethoxazole Degradation: Unveiling the Hidden Potential in Sediments.

Pharmaceutical residues in sediments are concerning as ubiquitous emerging contaminants. Pyrite is the most abundant sulfide minerals in the estuarine and coastal sediments, making it a major sink for pharmaceutical pollutants such as sulfamethoxazole (SMX). However, research on the adsorption and redox behaviors of SMX on the pyrite surface is limited. Here, we investigated the impact of the nonphotochemical process of pyrite on the fate of coexisting SMX. Remarkably, sulfur vacancies (SVs) on pyrite promoted the generation of nonradical species (hydrogen peroxide, H2O2 and singlet oxygen, 1O2), thereby exhibiting prominent SMX degradation performance under darkness. Nonradical 1O2 contributed approximately 73.1% of the total SMX degradation. The SVs with high surrounding electron density showed an advanced affinity for adsorbing O2 and then initiated redox reactions in the sediment electron-storing geobattery pyrite, resulting in the extensive generation of H2O2 through a two-electron oxygen reduction pathway. Surface Fe(III) (hydro)oxides on pyrite facilitated the decomposition of H2O2 to 1O2 generation. Distinct nonradical products were observed in all investigated estuarine and coastal samples with the concentrations of H2O2 ranging from 1.96 to 2.94 μM, while the concentrations of 1O2 ranged from 4.63 × 10-15 to 8.93 × 10-15 M. This dark-redox pathway outperformed traditional photochemical routes for pollutant degradation, broadening the possibilities for nonradical species use in estuarine and coastal sediments. Our study highlighted the SV-triggered process as a ubiquitous yet previously overlooked source of nonradical species, which offered fresh insights into geochemical processes and the dynamics of pollutants in regions of frequent redox oscillations and sulfur-rich sediments.

Toward a More Comprehensive Approach for Dissolved Organic Matter Chemical Characterization Using an Orbitrap Fusion Tribrid Mass Spectrometer Coupled with Ion and Liquid Chromatography Techniques.

Dissolved organic matter (DOM) represents one of the largest active organic carbon pools in the global carbon cycle. Although extensively studied, only <10% of DOM has been chemically characterized into individual dissolved compounds due to its molecular complexity. This study introduced a more comprehensive DOM characterization method by coupling both ion chromatography (IC) and liquid chromatography (LC) with high mass accuracy and resolution mass spectrometry. We presented a new on-the-fly mass calibration of the Orbitrap technique by utilizing the "lock mass" function in the Orbitrap Fusion Tribrid mass spectrometer (OT-FTMS), which assures high mass accuracy at every scan by a postcolumn introduction of internal labeled standards. With both IC and LC, tested unlabeled standards of amino acids, small peptides, and organic acids were consistently below 1.0 ppm mass error, giving the OT-FTMS the potential of reaching mass accuracy of the Fourier-transform ion cyclotron resonance mass spectrometer. In addition to mass accuracy, a pooled quality control sample (QC) was used to increase reproducibility by applying systematic error removal using random forest (SERRF). Using an untargeted mass spectrometry approach, estuarine DOM samples were analyzed by OT-FTMS coupled to IC in negative mode and LC in positive mode detection to cover a wide range of highly cationic to highly anionic molecules. As a proof of concept, we focused on elucidating the structures of three distinct DOM compound classes with varied acidities and basicities. In UPLC-OT-FTMS, a total of 915 compounds were detected. We putatively elucidated 44 small peptides and 33 deaminated peptides of these compounds. With IC-OT-FTMS, a total of 1432 compounds were detected. We putatively elucidated 20 peptides, 268 deaminated peptides, and 188 organic acids. Except for five compounds, all putatively elucidated compounds were uniquely detected in their corresponding chromatography technique. These results highlight the need for combining these two techniques to provide a more comprehensive method for DOM characterization. Application of the combined IC and LC techniques is not limited to DOM chemical characterization. It can analyze other complex compound mixtures, such as metabolites, and anthropogenic pollutants, such as pesticides and endocrine-disrupting chemicals, in environmental and biological samples.

CRISPR‐based environmental DNA detection for a rare endangered estuarine species

AbstractEnvironmental DNA (eDNA) methods complement traditional aquatic monitoring surveys and are especially advantageous for rare and listed species to detect spatial and temporal distribution patterns. However, improvements in ease of use and portability could increase the utility of eDNA methods, leading to more widespread application, including expanding its role in management decision‐making processes. We describe the development of an eDNA detection assay for delta smelt (Hypomesus transpacificus), an endangered fish in the San Francisco Estuary, using SHERLOCK (Specific High‐Sensitivity Enzymatic Reporter Unlocking). SHERLOCK is a clustered regularly interspaced short palindromic repeats (CRISPR)‐based diagnostic tool with the ability to detect species‐specific genetic variants, making it ideal for genetic‐based taxonomic identification of any organism. Because of its high sensitivity and specificity, SHERLOCK is adaptable to eDNA detection in water samples. Here, we describe adaptation of a delta smelt SHERLOCK assay for use with estuarine water eDNA samples. This version of the assay exhibits increased sensitivity compared to the original delta smelt SHERLOCK protocol (new limit of detection approximately three copies per reaction compared to ~300 in original assay) and successfully detected delta smelt eDNA in both experimental and natural contexts. Overall, our results demonstrate that SHERLOCK eDNA detection offers managers an alternative, isothermal methodology, and highlights some challenges for detection of rare, endangered species at low abundance.

Metagenomic analysis of microbial communities and antibiotic resistant genes in the Tijuana river, and potential sources

The Tijuana River is a transborder river that flows northwest across the border from Baja California in Mexico into Southern California before discharging into the Pacific Ocean. The river is frequently contaminated with raw sewage due to inadequate sanitary infrastructure in Tijuana. To assess the type and degree of microbial contamination, water samples were collected monthly from a near-border and an estuarine site from August 2020 until May 2021. A portion of each sample was used for epifluorescent microscopy and DNA was extracted directly from the rest for shotgun metagenomic sequencing. After sequence quality checking and processing, we used the rapid taxonomic identifier tool Kaiju to characterize the microbial diversity of the metagenomes and matched the sequences against the Comprehensive Antibiotic Resistance Database (CARD) to examine antimicrobial resistance genes (ARGs). Bacterial and viral-like particle (VLP) abundance was consistently higher in the near-border samples than in the estuarine samples, while alpha diversity (within sample biodiversity) was higher in estuarine samples. Beta-diversity analysis found clear compositional separation between samples from the two sites, and the near-border samples were more dissimilar to one another than were the estuarine sites. Near-border samples were dominated by fecal-associated bacteria and bacteria associated with sewage sludge, while estuarine sites were dominated by marine bacteria. ARGs were more abundant at the near-border site, but were also readily detectable in the estuarine samples, and the most abundant ARGs had multi-resistance to beta-lactam antibiotics. SourceTracker analysis identified human feces and sewage sludge to be the largest contributors to the near-border samples, while marine waters dominated estuarine samples except for two sewage overflow dates with high fecal contamination. Overall, our research determined human sewage microbes to be common in the Tijuana River, and the prevalence of ARGs confirms the importance of planned infrastructure treatment upgrades for environmental health.

A rapid and portable fluorescence spectroscopy staining method for the detection of plastic microfibers in water

We propose a simple technique for microplastic detection based on their interaction with a hydrophilic and anionic fluorescent dye 1,3,6,8 pyrene tetrasulfonate (PTSA). Synthetic microfibers derived from surgical face masks (an abundantly generated plastic waste post COVID) were considered as model microplastics. The interactions between microfibers and the dye were studied as a function of physiological parameters (pH, contact time and temperature), external agents, dye dosage and polymer variants. A pocket-sized photometer (by Lovibond Tintometer group) was employed for the detection and further validated using advanced equipment set-ups (fluorescence microscope, Fourier transform infrared spectroscopy and benchtop spectrofluorometer). Risk assessment studies were conducted on Artemia salina as a model organism. As a risk mitigation strategy, dye recovery followed by sunlight mediated degradation were performed. The detection study was performed in real water samples collected from fresh, estuarine and seawater samples spiked with microfibers. As an outcome, an optimized standard operational conditions were determined for the effective detection of synthetic microfibers. The data obtained could have scientific and industrial impact, in particular for experts working in the broad arena of clean water, who are specifically interested in developing cost-effective solutions for effective detection and biomonitoring of emerging pollutants.

Smartphone-based detection of nitrate in seawater samples with the resorcinol method: Comparison with the vanadium reduction method

The presence of nitrate (NO3−) in the aquatic environment has raised a major concern for scientists and environmental managers. In this study, a smartphone-based resorcinol method was developed for the determination of NO3− in seawater. Simple custom-made devices were used in the method, and the reaction temperature, reaction time, and smartphone camera settings were optimized. Salinity variation did not show any major impact on the determination of NO3− using the proposed method, and hence the incorporation of a correction factor was also not required. The detection limit for this method was observed to be 1.3 µM, and the working range was observed to be 5–60 µM, with a relative standard deviation of 0.7% (5 µM, n = 7), which was adequate for the determination of NO3− in most estuarine and coastal seawater samples. The proposed method was compared with the frequently used vanadium chloride (VCl3) reduction method under the same experimental conditions, and both methods were found to be beneficial. The proposed method procedure was simple and easy to use. It was successfully applied for the determination of NO3− in seawater samples, and the results showed that it was practical and can be used potentially for on-site analysis.

A differential titration method for determining the dissociation characteristics of natural organic acids in the coastal zone

Characterizing the concentrations and equilibrium characteristics of organic acid/base pairs is essential for quantifying CO2-system components and their behaviors and interactions in organic-rich coastal environments. Relatively few studies have been devoted to characterization of titratable organics, and their contributions to total alkalinity are frequently implicitly or explicitly considered negligible. In this work, novel potentiometric titration procedures were developed to quantify the concentrations and dissociation constants of river-derived titratable organics and thereby their alkalinity (Org-Alk) contributions to the total alkalinity (TA) of coastal seawater. The overall approach was to compare the titration properties of two paired solutions of identical salinity (S ≈ 5): (a) a sample of “estuarine” water formulated as a mixture of organic-rich river water plus open-ocean seawater and (b) an organics-free “baseline” approximation of that estuarine water, formulated as a mixture of dilute aqueous sodium chloride plus open-ocean seawater. Acid was incrementally added to both solutions, and the resulting two titration curves were then compared to provide direct visualization and quantification of the contributions of organics to TA. In other words, at any given pH, the difference in acid added to the two solutions (with a small correction for silicate alkalinity) indicates acid uptake by titratable organics in the estuarine sample. This procedure was performed for four replicate samples at 15, 25, and 35 °C. Our titrations indicated the presence of three types of titratable organics. The dominant type had a concentration of approximately 200 μmol∙kg−1 and a well-defined dissociation constant (pK) that did not vary with temperature: pKOrg2(average) = 6.33 ± 0.01. The second type had a concentration of approximately 110 μmol∙kg−1 and a moderately well-defined and high pK: 8.56 ≤ pKOrg3 ≤ 9.32. The third type had a concentration of approximately 40 μmol∙kg−1 and a low, poorly defined pK: 4.1 ≤ pKOrg1 ≤ 6.1. Inference of this third type was required to eliminate systematic residuals that were otherwise present in our fitted titration data (residuals = direct observations – model predictions). These data allow for a summation of TA contributions from organic constituents that may contribute (especially in coastal waters) but are typically uncharacterized. Such data are required for rigorous CO2-system models that rely on inputs of the commonly used data pair of TA and dissolved inorganic carbon (DIC). Studies of CO2 system behavior in the coastal zone clearly require two types of alkalinity titrations – one that includes a summation of inorganic and organic components (i.e., conventional titrations), and a second CO2-free titration in which the concentrations and pK characteristics of organic acids are quantified.

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.

Isolasi dan Skrining Aktivitas Antibakteri Fungi Tanah Muara Desa Katialada Gorontalo Lokasi Satu terhadap Staphylococcus aureus

The emergence of antibiotic resistance becomes a barrier in controlling infectious diseases, so it is necessary to find new alternative antibiotics. This study aimed to explore the potential of estuarine soil fungals secondary metabolites isolated from Katialada Village Gorontalo Location One and test their antibacterial activity against Staphylococcus aureus. The antibacterial parameter observed was the percent inhibition of ethyl acetate extracts against Staphylococcus aureus. The estuarine soil samples were cultured in PDA media producing five single fungal isolates differentiated based on color morphology, texture, and shape coded IS2-BTG-4.1.1, IS2-BTG-4.1.2, IS1-BTG-4.2, IS2-BTG4.3.1, and IS2-BTG-4.3.2. Those five samples were fermented using PDB media and the fermented products were extracted with ethyl acetate. The extracts were screened for its compound using a TLC plate and antibacterial testing with a single concentration of 100 g/mL in the microdilution method. The screening results showed that the five ethyl acetate extracts contained terpenoid compounds and code IS2-BTG-4.3.2 also had alkaloids. Based on the antibacterial test results, the five ethyl acetate extracts had growth inhibitory activity on the Staphylococcus aureus, with the percentage showed by IS2-BTG-4.1.1 50,2% ± 14,8%, IS2-BTG-4.1.2 35,6% ± 12,9%, IS1-BTG-4.2 13,0% ± 7,3%, IS2-BTG-4.3.1 13,6% ± 6,0%, and IS2-BTG-4.3.2 by 12,4% ± 9,2%.

Prevalence and Distribution of Potentially Human Pathogenic Vibriospp. on German North and Baltic Sea Coasts.

Global ocean warming results in an increase of infectious diseases including an elevated emergence of Vibrio spp. in Northern Europe. The European Centre for Disease Prevention and Control reported annual periods of high to very high risks of infection with Vibrio spp. during summer months along the North Sea and Baltic Sea coasts. Based on those facts, the risk of Vibrio infections associated with recreational bathing in European coastal waters increases. To obtain an overview of the seasonal and spatial distribution of potentially human pathogenic Vibrio spp. at German coasts, this study monitored V. cholerae, V. parahaemolyticus, and V. vulnificus at seven recreational bathing areas from 2017 to 2018, including the heat wave event in summer 2018. The study shows that all three Vibrio species occurred in water and sediment samples at all sampling sites. Temperature was shown to be the main driving factor of Vibrio abundance, whereas Vibrio community composition was mainly modulated by salinity. A species-specific rapid increase was observed at water temperatures above 10°C, reaching the highest detection numbers during the heat wave event with abundances of 4.5 log10 CFU+1/100 ml of seawater and 6.5 log10 CFU+1/100 g of sediment. Due to salinity, the dominant Vibrio species found in North Sea samples was V. parahaemolyticus, whereas V. vulnificus was predominantly detected in Baltic Sea samples. Most detections of V. cholerae were associated with estuarine samples from both seas. Vibrio spp. concentrations in sediments were up to three log higher compared to water samples, indicating that sediments are an important habitat for Vibrio spp. to persist in the environment. Antibiotic resistances were found against beta-lactam antibiotics (ampicillin 31%, cefazolin 36%, and oxacillin and penicillin 100%) and trimethoprim-sulfamethoxazole (45%). Moreover, isolates harboring pathogenicity-associated genes such as trh for V. parahaemolyticus as well as vcg, cap/wcv, and the 16S rRNA-type B variant for V. vulnificus were detected. All sampled V. cholerae isolates were identified as non-toxigenic non-O1/non-O139 serotypes. To sum up, increasing water temperatures at German North Sea and Baltic Sea coasts provoke elevated Vibrio numbers and encourage human recreational water activities, resulting in increased exposure rates. Owing to a moderate Baltic Sea salinity, the risk of V. vulnificus infections is of particular concern.

An automated analyzer for the simultaneous determination of silicate and phosphate in seawater

Accurate and automated determination methods for silicate and phosphate are in high demand to improve understanding of biogeochemistry and ecology in dynamic and complex estuarine-coastal ecosystems. Here, a portable automated analyzer is reported for the simultaneous determination of silicate and phosphate in water samples with varying salinity. After comprehensive optimization of the chemical reactions and flow manifold, the system demonstrated limits of detection of 0.09 and 0.05 μmol L−1 for silicate and phosphate, respectively, exhibiting linearity at concentrations up to 400 and 200 μmol L−1 with automated dilution, achieving relative standard deviations (n = 11) of 0.27% (20 μmol L−1 silicate), 0.51% (5 μmol L−1 phosphate) and 0.80% (1 μmol L−1 phosphate). Compared with similar automated flow analyzers, the system exhibited advantages, such as low consumption of reagents (10–20 μL/sample), portability (4.8 kg), rapid start-up (5 min), reliability (automated analysis of quality control sample) and applicability within a broad salinity range (from 0 to 35) allowing analysis of dynamic estuarine and seawater samples. The system was successfully applied to a routine monitoring program by a national marine station and is potentially suitable for installation on different observation platforms for on-line and real-time underway analysis of nutrients in coastal areas.

Detection, Quantification, and Simplified Wastewater Surveillance Model of SARS-CoV-2 RNA in the Tijuana River.

The COVID-19 pandemic and the detection of SARS-CoV-2 RNA in sewage has expanded global interest in wastewater surveillance. However, many underserved communities throughout the world lack improved sanitation and use informal combined sanitary and storm sewer systems. Sewage is transported via open channels, ditches, and rivers, where it mixes with surface water and/or stormwater. There is a need to develop better methods for the surveillance of pathogens such as SARS-CoV-2 RNA in this context. We developed a simplified surveillance system and monitored flow rates and concentrations of SARS-CoV-2 RNA in the Tijuana River at two locations downstream of the United States–Mexico border in California, United States. SARS-CoV-2 RNA was detected in the upstream location on six out of eight occasions, two of which were at concentrations as high as those reported in untreated wastewater from California sanitary sewer systems. The virus was not detected in any of the eight samples collected at the downstream (estuarine) sampling location, despite the consistent detection of PMMoV RNA. Synchrony was observed between the number of cases reported in Tijuana and the SARS-CoV-2 RNA concentrations measured with the CDC N1 assay when the latter were normalized by the reported flow rates in the river.

Application of Chitosan, Ferric Chloride and Aluminium Sulphate in the Removal of Heavy Metals from Coastal, Estuarine and Industrial Wastewater

Water quality in water bodies is subjected to the natural degradation process of eutrophication and has adverse effect on social development. Most of the water bodies in Kochi, Alappuzha and Kottayam shrunk considerably due to the aggressive rapid urbanization process and overpowering invasion. This study aims at assessing the physic-chemical parameters of coastal, estuarine and industrial wastewater samples and application of chitosan in removal of heavy metals. A study was conducted to determine the physico-chemical parameters of water of 5 different water bodies and 2 industries in Ernakulam, Kottayam and Alappuzha named Periyar River, Fort Kochi beach, Poonithura Canal, Vembanadu Lake, Vettikattumukku pond in Kottayam, and two seafood industries in Cochin from March to May, 2021. The selected parameters were water temperature, color, salinity, pH, Dissolved Oxygen (DO), concentration of nutrients (Nitrite, Phosphate and Silicate) and concentration of alkali metals (Sodium, Potassium and Calcium). This analytical study would improve the socio eco features of these water bodies by employing utility-based restoration plans. Heavy metals are naturally occurring elements, which are found throughout the earth’s crust, most environmental contamination and human exposure and majority of them are carcinogenic. We removed the heavy metals for reducing the toxicity of wastewater in eco-friendly and cheaper way using chitosan, aluminium sulphate and ferric chloride. Under different pH conditions, adsorption of chromium and copper ions by chitosan was investigated. Amount of chromium and copper absorbed or the efficiency of heavy metal removal by chitosan, alum and ferric chloride were determined using ICP-AES. Among Chromium and Copper, Cu can be efficiently removed from the water using chitosan at higher pH. Ferric chloride is more efficient in removing heavy metals than Aluminium sulfate at the same pH.

Lanthanoid analysis in seawater by seaFAST-SP3™ system in off-line mode and magnetic sector high-resolution inductively coupled plasma source mass spectrometer

Analysis of lanthanoids in seawater is challenging due to the complex matrix (∼35 g L−1 TDS) and low dissolved concentrations (in ng L−1). A 4-step strict analytical protocol and state-of-the-art technology were implemented and validated in this study. The 4-steps method involves the 1) sample filtration and acidification (pH<2); 2) pre-concentration by the matrix separation system, 3) off-line injection of the eluted sample; and 4) determination of lanthanoids by high-resolution inductively coupled plasma mass spectrometer (HR-ICP-MS). Since there are no certified values for lanthanoids in seawater are available, the method validation was done by analyzing SLEW-3 (estuarine water reference samples) and comparing with other reports and artificial seawater (100 ng L−1 lanthanoid multi-element standard solutions). SLEW-3 recovery varied from 78.6% to 106% and in artificial samples it ranged from 87 to 110%. Low recovery can be explained by complex organic in seawater, because the UV oxidation was not performed in the acidified samples. The variation was ≤10%, except for Gd, Tb, and Yb (11–13.75%). Blanks varied between 0.01 and 0.07 ng L−1, except for La and Ce (0.13–0.21 ng L−1). Blanks represent <5% SLEW-3 values and <1% synthetic seawater. The procedural detection limit varied from 0.01 to 0.03 ng L−1.•Lanthanoids as geochemical tracers in seawaters•A 4-step strict analytical protocol and state-of-the-art technology for lanthanoids analyses in seawaters•Sample pre-concentration system for matrix separation for the detection of ultra-low lanthanoids levels

When river water meets seawater: Insights into primary marine aerosol production

The impact of inorganic salts and organic matter (OM) on the production of primary marine aerosols is still under debate. To constrain their impact, we investigated primary aerosols generated by a sea-spray generator chamber using surface water samples from rivers, estuaries, and seas that were collected along salinity gradients in two temperate Korean coastal systems and one Arctic coastal system. Salinity values showed an increasing trend along the river–estuary–coastal water transition, indicating the lowest amount of inorganic salts in the river but the highest amount in the sea. In river samples, the lowest number concentration of primary aerosol particles (1.01 × 103 cm−3) was observed at the highest OM content, suggesting that low salinity controls aerosol production. Moreover, the number concentration of primary aerosols increased drastically in estuarine (1.13 × 104 cm−3) and seawater (1.35 × 104 cm−3) samples as the OM content decreased. Our results indicate that inorganic salts associated with increasing salinity play a much larger role than OM in aerosol production in river-dominated coastal systems. Laboratory studies using NaCl solution supported the conclusion that inorganic salt is a critical factor in modulating the particles produced from river water and seawater. Accordingly, this study highlights that inorganic salts are a critical factor in modulating the production of primary marine aerosols.

Disentangling complex genomic signals to understand population structure of an exploited, estuarine-dependent flatfish.

Interpreting contemporary patterns of population structure requires an understanding of the interactions among microevolutionary forces and past demographic events. Here, 4,122 SNP‐containing loci were used to assess structure in southern flounder (Paralichthys lethostigma) sampled across its range in the US Atlantic Ocean (Atlantic) and Gulf of Mexico (Gulf) and relationships among components of genomic variation and spatial and environmental variables were assessed across estuarine population samples in the Gulf. While hierarchical amova revealed significant heterogeneity within and between the Atlantic and Gulf, pairwise comparisons between samples within ocean basins demonstrated that all significant heterogeneity occurred within the Gulf. The distribution of Tajima's D estimated at a genome‐wide scale differed significantly from equilibrium in all estuaries, with more negative values occurring in the Gulf. Components of genomic variation were significantly associated with environmental variables describing individual estuaries, and environment explained a larger component of variation than spatial proximity. Overall, results suggest that there is genetic spatial autocorrelation caused by shared larval sources for proximal nurseries (migration/drift), but that it is modified by environmentally driven differentiation (selection). This leads to conflicting signals in different parts of the genome and creates patterns of divergence that do not correspond to paradigms of strong local directional selection.

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.