Comprehensive Assessment and Potential Ecological Risk of Trace Element Pollution (As, Ni, Co and Cr) in Aquatic Environmental Samples from an Industrialized Area

A global assessment of arsenic (As), nickel (Ni), cobalt (Co) and chromium (Cr) was performed in environmental samples from an important industrial bay. Different fractions of water, sediments and tissues from four species of fish were analysed. Samples were collected from selected sampling sites during four consecutive samplings in spring and autumn seasons, in order to evaluate concentrations and their possible correlations among the aquatic compartments. While a higher availability of Cr and Ni was found in water, Co and As were the most available elements in sediments. In fish, the liver was the tissue with the highest proportion of As and Co, and gills showed the highest concentrations of Ni and Cr. Significance differences were observed among sites showing the pollution sources. In sediments, high correlations were found between total Co content and the most available fractions. Total Ni content highly correlated with the oxidisable fraction, while Cr total content tightly correlated with the least available fractions. Quality guideline values for sediments were frequently exceeded. In sediments and biota, concentrations were slightly higher than in other ecosystems, indicating that maritime, industrial and urban activities are affecting this type of ecosystem with great anthropogenic influence.This research was funded by "Consejeria de Economia, Conocimiento, Empresas y Universidad", Junta de Andalucia (Spain) (PAI-EXCEL-06-FQM-02075) and by "Fomento e Impulso de la Investigacion y de la Transferencia" Programme, Universidad de Cadiz (Spain) (PR2020-013)

Solid phase extraction of copper traces using poly (styrene-divinylbenzene) membrane disks modified with pyridoxal salicyloylhydrazone in water samples

A simple technique for the isolation, concentration and matrix simplification of Cu(II) ion in natural waters is proposed. This method has been developed using poly(styrene-divinylbenzene) membrane disks modified with the synthesized ligand pyridoxal salicyloylhydrazone (PSH). The retained ions on the disks were eluted with 10mL 1mol L 1 HNO3 and measured by flame atomic absorption spectrometry at 324.8nm. The influence of pH, amount of ligand, type and amount of eluent for the stripping of copper ion from the membrane over extraction efficiency were evaluated. Extraction efficiencies 499% were obtained by elution of the disks with minimal amount of solvent with a preconcentration factor up to 100. The precision of the method for 10 replicate measurements of aqueous solutions containing 40 mg L 1 Cu(II) was 1.5% at significance level of 95%. The breakthrough volume for 5 mg of Cu(II) was found to be 1000mL and the detection limit of the method was 4ngL 1 of metalion. The present method was successfully applied to the extraction and determination of copper in lake and sea waters

Sherry wine industry by-product as potential biosorbent for the removal of Cr(VI) from aqueous medium

A low-cost biosorbent obtained from the Palomino Fino grape seed, a Sherry wine industry by-product, has been proposed as a way of valorising this material. The biomass was characterised obtaining values of 0.68 +/- 0.05 g mL(-1) for bulk density, 1.02 +/- 0.09 g mL(-1) for apparent density and 33.3% for porosity. The pH(pzc) was 5.2 and the surface negative charge value was 2.4 +/- 0.2 mmol g(-1). The analysis of surface morphology showed differences due to the sorption. The results showed a promising potential for chromium(VI) removal from aqueous solutions. The studies were carried out in batch scale and a 2(3) factorial design was applied for the optimisation of the process. A percentage of 91.7 +/- 0.6% was achieved for the biosorption of Cr(VI) under optimal conditions using pH 5.5, 15 g/L of biosorbent and 8 h of contact time. The biosorption capacity showed a remarkable linearity from 0 to 2 mmol L-1 Cr(VI) and a precision of 0.64% for the removal of 1 mmol L-1 of metal. Langmuir, Freundlich and Temkin isotherm equations and the parameters of six kinetic models were used in the equilibrium modelling and identifying the mechanism of the biosorption. The combination of physical and chemical sorption mechanisms was proposed for the chromium removal with a high maximum sorption capacity (q(max) = 208.3 mg g(-1)). Thermodynamic parameters indicated the spontaneous and endothermic nature of the chromium removal. The successful biosorption was based on the special grape seed components with a relevant content in antioxidant and lignocellulosic compounds.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work has been supported by "Consejeria de Economia, Conocimiento, Empresas y Universidad", Andalusian Government (Spain) (support for RNM-236 Research group) and the Programme of "Fomento e Impulso de la Investigacion y de la Transferencia" from the University of Cadiz (Spain) (Project PR2020-013)

Sensing Cd(II) Using a Disposable Optical Sensor Based on a Schiff Base Immobilisation on a Polymer-Inclusion Membrane. Applications in Water and Art Paint Samples

A disposable colour-changeable optical sensor based on an interesting polymer inclusion-membrane (PIM) was designed to determine Cd(II) ions in aqueous medium. The Schiff base 2-acetylpyridine benzoylhydrazone (2-APBH) immobilised on the polymer membrane was used as a sensing molecule. The amounts of the PIM components were optimised by a 3(2) fractional factorial design with two central points and two blocks. The best optical sensor composition consisted of 2.5 g of poly(vinylchloride) (PVC) as a base polymer, 3 mL of tributyl phosphate (TBP) as a plasticiser, and 0.02 g of 2-APBH as a reagent. The sensor showed a good linear response in the range from 0.02 mg L-1 (limit of detection) to 1 mg L-1 of Cd(II) under the following experimental conditions: pH 9.5 (adjusted using ammonium chloride buffer solution at 0.337 mol L-1), 60 min of exposure time plus 2 min of sonication (pulses at 2 s intervals), and 10 min of short-term stability. The relative standard deviation of the method was determined to be 4.04% for 0.4 mg L-1 of Cd(II). The optical sensor was successfully applied to the determination of Cd(II) in natural-water and art-paint samples

Comparative Baseline Levels of Heavy Metals and Histopathological Notes in Fish From two Coastal Ecosystems of South-West of Spain

This work reports the comparative study of heavy metal water concentrations from two coastal ecosystems of Cadiz Gulf (SWSpain): Bay of Cadiz and Ria ofHuelva estuary in samples taken on years 1999-2000. Sampling zones showed different heavymetal levels. Statistical analysis of dissolved trace metal concentrations (Cu, Zn, Cd and Pb) showed significant differences between Huelva and Cadiz zones based on the Cu level, with a marked seasonal factor and different metal sources (Industrial, geological, urban,...), observing a higher Cu concentration in Ria de Huelva respect to Bay of Cadiz. On the other hand, to evaluate the pollutant effects on aquatic biota, a histopathological analysis have been conducted in specimens of flat fish, Solea senegalensis from both zones. Lesions weremore severe in fish fromRia ofHuelva, being themost significant alterations: gill hyperplasia, fusion of secondary lamellae, disorganization of the hepatic parenchyma, cellular hypertrophy and vascular congestion in liver and tubular occlusion, loss of interstitial tissue and lipid-like vacuoles in kidney. Obtained results are useful as reference data for future environmental monitoring studies in these zones where to establish a heavy metal concentration temporal trend would be necessary

Oxidative stress biomarkers in Senegal sole, Solea senegalensis, to assess the impact of heavy metal pollution in a Huelva estuary (SW Spain): Seasonal and spatial variation

The responseofwildfishtoheavymetalswasstudiedinsole(Solea senegalensis) collectedin2004, 2005 and 2006 at three sampling sites from Huelva estuary (SWSpain), in the vicinity of a petrochemical and mining industry. Heavy metals As, Cd, Cu, Fe, Pb and Zn were analyzed in samples collected from sediment, water and tissue (liver) to examine their bioconcentration and effects in fish such as lipid peroxidation (LPO), catalase (CAT;EC1.11.1.6), glutathione peroxidase (GPx; EC1.8.1.7), glutathione S-transferase (GST;EC2.5.1.18) and glutathione reductase (GR;EC1.11.1.6) were also analyzed in the fish liver.The results showed different effects in sole from diverse locations with varying degrees of pollution. Significant differences in LPO, CAT and GR activities between control fish and fish from sampling sites were observed as well as seasonal differences for biomarkers. Significant correlations were established between some biomarkers and heavy metals concentrations in liver, sediment and water. This study indicates the usefulness of integrating a set of biomarkers to assess the effects of pollutants in aquatic environments under complex mix of pollutants and chronic pollution situation

Determination of ultra-trace amounts of silver in water by differential pulse anodic stripping voltammetry using a new modified carbon paste electrode

A highly sensitive and selective new procedure for the determination of silver in aqueous media was developed using a modified carbon paste electrode (MCPE) by differential pulse anodic stripping voltammetry (DPASV). The modified electrode was based on the incorporation of 2-hydroxybenzaldehyde benzoylhydrazone (2-HBBH) in the carbon paste electrode. Silver ions were preconcentrated on the modified electrode at open-circuit by complexation with the ligand and reduced to zero valent at a potential of 0V, and followed by the reoxidation of adsorbed ions on to the electrode by scanning the potential in a positive direction. The oxidation peak of Ag (I) was observed at 0.2V (versusAg/AgCl). The analysis of Ag (I) was carried out in a cell containing the sample solution (20mL) buffered by 0.1molL 1K2HPO4/NaOH at pH 5.5 in aqueous solution and nitric acid (pH1) in real water samples. The optimum conditions for the analysis of silver include are duction potential of 0V and a pulse amplitude of 100mV, among others. The optimum carbon paste composition was found to be 14.1% (w/w) 2-HBBH, 56.2% (w/w) graphite powder and 29.7%(w/w) paraffin oil. Differential pulse anodic stripping voltammetric response was used as the analytical signal. Under the selected conditions, the voltammetric signal was proportional to the Ag(I) concentration in the range of 0.001–100 μg L 1 with favorable limits of detection and quantification of 1.1ngL 1 and 3.7ngL 1 after 3 min of accumulation time, respectively. By increasing the accumulation time to 10 min, detection and quantification limits can be further improved up to 0.1ngL 1 and 0.34ngL 1, respectively. In addition, the results showed a highly reproducible procedure showing a relative standard deviation of 1.5% for 12 replicate measurements. Many coexisting metal ions were investigated and very few interferences were found on the determination of Ag(I). The proposed method was validated using certified reference estuarine waters (SLEW-3) with a relative error of 1.3% and applied to the determination of silver ions in three river water samples collected from Guadalquivir river (relative errors of þ3.4%, þ1.5% and 0.7%). Moreover,the method was successfully applied to the speciation analysis of total silver, free silver ions and silver nanoparticles in aqueous solutions. The results were in good agreement with those obtained by inductively coupled plasma mass spectrometry (ICP-MS)

EROD activity and cytochrome P4501A induction in liver and gills of Senegal sole Solea senegalensis from a polluted Huelva Estuary (SW Spain).

EROD activity and induction cytochrome P4501A in liver and gills of Senegal sole, Solea senegalensis, from a heavy metal and PAH polluted estuary, was studied. Liver and gill CYP1A catalytic activity was assessed at the enzyme activity level-measured as 7-ethoxyresorufin-O-deethylase and cellular localization of CYP1A in the liver was studied using immunohistochemistry. Liver EROD was correlated with phenanthrene-type metabolites in liver and copper concentrations in water. Strong CYP1A occurrence was observed in acinar pancreatic cells, pancreatic duct epithelium and vascular system endothelium and negative/rare induction were observed in hepatocytes and sinusoidal endothelium. In gills, EROD activity showed a significant correlation with different fractions of heavy metals in sediment but no correlation was observed between EROD activity and PAHs. Strongly positive CYP1A associated staining of the vascular system endothelia and primary filament cells and a moderate staining of pillar cells in gills were observed. The results substantiated the utility of EROD activity and CYP1A induction measurement as biomarkers for use by aquatic toxicologists and indicate that catalytic assays and immunohistochemical assays appear to be sensitive to different kinds of pollutants being the use of both methods recommended for monitoring programs

Biomarkers responses in muscle of Senegal sole (Solea senegalensis) from a heavy metals and PAHs polluted estuary.

The biochemical responses in muscle, such as the enzymatic activities of acetylcholinesterase, lactate dehydrogenase and isocitrate dehydrogenase, were studied in sole (Solea senegalensis) collected in Huelva estuary (SW Spain), in the vicinity of a petrochemical and mining industry. The sampling sites showed different type and degree of pollution. The results demonstrated significant differences in muscle activities of AChE and IDH in Odiel and Tinto Rivers compared to control fish. LDH activity did not show any difference between sampling sites. Significant correlations were established between some biomarkers and heavy metals: AChE was correlated with Pb, Cd and Cu concentrations in water; IDH activity was correlated with Cd and Cu concentrations in water and As, Pb and Cd concentrations in sediments; LDH activity was correlated with As and Zn concentration in water and Cd concentration in sediment. Only one correlation was established between the biomarkers analysed and the concentrations of PAHs: benzo(b)fluoranthene concentration in sediment and IDH

A new use for an old molecule: N-phenyl-2-(2-hydroxynaphthalen-1-ylmethylene)hydrazinecarbothioamide as a ratiometric ‘Off–On’ fluorescent probe for iron

N-Phenyl-2-(2-hydroxynaphthalen-1-ylmethylene)hydrazinecarbothioamide has been investigated as a fluorescent sensor for the determination of Fe(III) in aqueous solutions. The probe was prepared by the facile Schiff base condensation of 2-hydroxy-1-napthaldehyde with N-phenylhydrazinecarbothioamide. The sensor displayed good selectivity for Fe(III) when tested against a range of biologically and environmentally important cations. A concentration dependent increase in the emission of two fluorescent bands at 425 and 495 nm was observed upon increasing Fe(III) addition resulting in a linear ratiometric response in the 17–37 lM range. The binding stoichiometry was confirmed as 1:1 (host/guest) with the binding constant (logb) calculated as 4.56