Boron removal from aqueous solutions by using a novel alginate-based sorbent: Comparison with Al2O3 particles

Boron removal was evaluated in the present work by using calcium alginate beads (CA) and a novel composite based on alginate–alumina (CAAl) as sorbents in a batch system. The effects of different parameters such as pH, temperature, contact time, and composition of alginate (at different concentrations of guluronic and mannuronic acids) on boron sorption were investigated. The results confirm that calcium alginate beads (CA) exhibited a better adsorption capacity in a slightly basic medium, and the composite alginate–alumina (CAAl) exhibited improved boron removal at neutral pH. Sorption isotherm studies were performed and the Langmuir isotherm model was found to fit the experimental data. The maximum sorption capacities were 4.5 mmol g-1 and 5.2 mmol g-1, using CA and CAAl, respectively. Thermodynamic parameters such as change in free energy (¿G0), enthalpy (¿H0), and entropy (¿S0) were also determined. The pseudo-first-order and pseudo-second-order rate equations (PFORE and PSORE, respectively) were tested to fit the kinetic data; the experimental results can be better described with PSORE. The regeneration of the loaded sorbents was demonstrated by using dilute HCl solution (distilled water at pH 3) as eluent for metal recovery.Peer ReviewedPostprint (published version

Persistent Organic Pollutants in the Bizerte Lagoon Ecosystem: Occurrence, Distribution, and Ecotoxicological Assessment Using Marine Organism

Marine ecosystem represents an ecologically and economically important water bodies for human and animal living. Their increasing pollution by persistent organic pollutants has represented a major environmental alarm during the last years. In the current study, we examined the occurrence, local distribution and ecotoxicological menace of organic pollutants, comprising brominated flame retardants (BFR), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides (OCPs) in different matrices from the Northern Tunisian Coastal Ecosystem (Bizerte lagoon). The pollutant existence in this biome is related with a negative impact on the biocenosis health. Many approach including (i) chemical analyses; (ii) taxonomic structure and ecological indices analyses; (iii) and biochemical experimental studies, were investigated to determine the ecosystem quality and the contaminant effects. Our chapter introduces the baseline information on the organic contaminations extent and toxicological impact, as well as, it contribute to evaluate the ecological quality of this marine coastal ecosystem

Geochemistry and oxidative potential of the respirable fraction of powdered mined Chinese coals

This study evaluates geochemical and oxidative potential (OP) properties of the respirable (finer than 4 μm) fractions of 22 powdered coal samples from channel profiles (CP4) in Chinese mined coals. The CP4 fractions extracted from milled samples of 22 different coals were mineralogically and geochemically analysed and the relationships with the OP evaluated. The evaluation between CP4/CP demonstrated that CP4 increased concentrations of anatase, Cs, W, Zn and Zr, whereas sulphates, Fe, S, Mo, Mn, Hf and Ge decreased their CP4 concentrations. OP results from ascorbic acid (AA), glutathione (GSH) and dithiothreitol (DTT) tests evidenced a clear link between specific inorganic components of CP4 with OPAA and the organic fraction of OPGSH and OPDTT. Correlation analyses were performed for OP indicators and the geochemical patterns of CP4. These were compared with respirable dust samples from prior studies. They indicate that Fe (r = 0.83), pyrite (r = 0.66) and sulphate minerals (r = 0.42) (tracing acidic species from pyrite oxidation), followed by S (r = 0.50) and ash yield (r = 0.46), and, to a much lesser extent, Ti, anatase, U, Mo, V and Pb, are clearly linked with OPAA. Moreover, OPGSH correlation was identified by organic matter, as moisture (r = 0.73), Na (r = 0.56) and B (r = 0.51), and to a lesser extent by the coarse particle size, Ca and carbonate minerals. In addition, Mg (r = 0.70), B (r = 0.47), Na (r = 0.59), Mn, Ba, quartz, particle size and Sr regulate OPDTT correlations. These became more noticeable when the analysis was done for samples of the same type of coal rank, in this case, bituminous.This study was supported by Generalitat de Catalunya (AGAUR 2017 SGR41), Spain; by the National Science Foundation of China (grant 41972180); the Program of Introducing Talents of Discipline to Universities (grant B14031) and Overseas Top Scholars Program for the Recruitment of Global Experts, China; and by the Spanish Ministry of Science and Innovation (Excelencia Severo Ochoa, Project CEX2018-000794-S). Malvern Mastersizer Scirocco 2000 extension measurements were performed at the ICTS NANBIOSIS by the Nanostructured Liquids Unit (U12) of the CIBER in Bioengineering, Biomaterials & Nanomedicine (CIBER-BBN), located at the IQAC-CSIC (Barcelona, Spain). Pedro Trechera is contracted by the ROCD (Reducing risks from Occupational exposure to Coal Dust) project supported by the European Commission Research Fund for Coal and Steel; Grant Agreement Number 754205.Peer reviewe

Dynamique des pesticides au sein d’un écosystème lagunaire (lagune de Bizerte, Tunisie) : identification des sources de contaminations et processus de transformation des contaminants

The Bizerte Lagoon watershed is surrounded by intense agricultural activities. The use of phytosanitary products to treat the crops that surround this watershed, causes a deterioration of the lagoon water quality. Monitoring the level of pollution in this ecosystem requires the application of combined approaches. Thus, in this work a survey is carried out to determine the sources of pollution due to agricultural activities and to identify pesticides used by farmers. To verify the presence of the molecules determined during the investigation, a diagnosis of water column pollution is carried out using two sampling techniques: grap sampling and passive sampling (POCIS). Sediments are also threatened by these xenobiotics, thus, a screening was carried out in this matrix. It is relevant to determine the fate of these pollutants once they are present in the aquatic environment. Thus, the study of their photodegradation in the water column was carried out. The degradation of these pollutants can give rise to by-products that are more toxic than the parent molecules. An ecotoxicological approach is developed in this work to determine the toxicity of these products on a model species Ostreococcus tauriLe bassin versant de la lagune de Bizerte est occupé par des activités agricoles importantes. L’utilisation des produits phytosanitaires pour traiter les cultures qui entourent ce bassin versant, engendre une détérioration de la qualité des eaux de cet écosystème lagunaire. La surveillance du niveau de pollution dans ces écosystèmes nécessite l’application des approches combinées. Ainsi, dans ce travail une enquête est réalisée afin de déterminer les sources de pollution à cause des activités agricoles et recenser les pesticides employés par les agriculteurs. Pour vérifier la présence des molécules déterminées pendant l’enquête, un diagnostic de la pollution de la colonne d’eau est concrétisé au moyen de deux techniques d’échantillonnage : un échantillonnage ponctuel et un autre passif au moyen des POCIS. Les sédiments sont aussi menacés par ces xénobiotiques, d’où la réalisation d’un screening au niveau de la fraction sédimentaire. Il est pertinent de déterminer le devenir de ces polluants une fois qu’ils sont présents dans l’environnement aquatique. Ainsi, l’étude de leur photodégradation dans la colonne d’eau est achevée dans cette étude. La dégradation de ces polluants peut donner naissance à des sous- produits qui sont plus toxiques que les molécules mères. Une approche écotoxicologique est élaborée dans ce travail pour déterminer la toxicité de ces produits sur une espèce modèle Ostreococcus taur

Dynamics of pesticides in a lagoon ecosystem (lagoon of Bizerte, Tunisia) : identification of sources of contamination and contaminant transformation process

Le bassin versant de la lagune de Bizerte est occupé par des activités agricoles importantes. L’utilisation des produits phytosanitaires pour traiter les cultures qui entourent ce bassin versant, engendre une détérioration de la qualité des eaux de cet écosystème lagunaire. La surveillance du niveau de pollution dans ces écosystèmes nécessite l’application des approches combinées. Ainsi, dans ce travail une enquête est réalisée afin de déterminer les sources de pollution à cause des activités agricoles et recenser les pesticides employés par les agriculteurs. Pour vérifier la présence des molécules déterminées pendant l’enquête, un diagnostic de la pollution de la colonne d’eau est concrétisé au moyen de deux techniques d’échantillonnage : un échantillonnage ponctuel et un autre passif au moyen des POCIS. Les sédiments sont aussi menacés par ces xénobiotiques, d’où la réalisation d’un screening au niveau de la fraction sédimentaire. Il est pertinent de déterminer le devenir de ces polluants une fois qu’ils sont présents dans l’environnement aquatique. Ainsi, l’étude de leur photodégradation dans la colonne d’eau est achevée dans cette étude. La dégradation de ces polluants peut donner naissance à des sous- produits qui sont plus toxiques que les molécules mères. Une approche écotoxicologique est élaborée dans ce travail pour déterminer la toxicité de ces produits sur une espèce modèle Ostreococcus tauriThe Bizerte Lagoon watershed is surrounded by intense agricultural activities. The use of phytosanitary products to treat the crops that surround this watershed, causes a deterioration of the lagoon water quality. Monitoring the level of pollution in this ecosystem requires the application of combined approaches. Thus, in this work a survey is carried out to determine the sources of pollution due to agricultural activities and to identify pesticides used by farmers. To verify the presence of the molecules determined during the investigation, a diagnosis of water column pollution is carried out using two sampling techniques: grap sampling and passive sampling (POCIS). Sediments are also threatened by these xenobiotics, thus, a screening was carried out in this matrix. It is relevant to determine the fate of these pollutants once they are present in the aquatic environment. Thus, the study of their photodegradation in the water column was carried out. The degradation of these pollutants can give rise to by-products that are more toxic than the parent molecules. An ecotoxicological approach is developed in this work to determine the toxicity of these products on a model species Ostreococcus taur

Evaluating polar pesticide pollution with a combined approach: a survey of agricultural practices and POCIS passive samplers in a Tunisian lagoon watershed

A study of pesticides in the Bizerte lagoon watershed on the Mediterranean coast of Tunisia showed that herbicides and fungicides are the most commonly used compounds. A survey was made of selected farmers. Pesticide contamination was monitored in the water column and sediments at four selected sampling sites (lagoon (A) and in three ouedsChegui (B), Garaa (C), and Tinja (D)). Polar organic chemical integrative samplers (POCIS) were used to assess pesticide contamination. Thirty-two pesticides were investigated; the total concentration of active ingredients ranged from 35.9ngL(-1) in Tinja oued to 1246ngL(-1) in Chegui oued. In the lagoon, the total concentration of pesticides was 67.7ngL(-1). In the sediments, the highest concentration was measured in Chegui oued in the spring (31ngg(-1) dw). The main compounds found in the analyzed sediments were prosulfocarb and tebuconazole molecules

Seasonal changes of chemical contamination in coastal waters during sediment resuspension

International audienceThe potential of remobilization of pollutants is a major problem for anthropogenic ecosystems, because even when the anthropogenic source of pollution is identified and removed, pollutants stored in sediments can be released into the water column and impact pelagic communities during sediment resuspension provoked by dredging, storms or bottom trawling. The objectives of the present study were to assess the changes observed in the chemical composition of the water column following resuspension of a polluted marine sediment and the consequences for the chemical composition of adjacent marine waters according to season. For that purpose, an experimental sediment resuspension protocol was performed on four distinct occasions, spring, summer, fall and winter, and the changes in nutrients, organic contaminants and inorganic contaminants were measured after mixing sediment elutriate with lagoon waters and offshore waters sampled nearby. Significant seasonal variations in the chemical composition of the contaminated sediments were observed, with a strong accumulation of PAHs in fall, whereas minimum PAH concentrations were observed during winter. In all seasons, sediment resuspension provoked a significant enrichment in nutrients, dissolved organic carbon, and trace metal elements like Ni, Cu, and Zn in offshore waters and lagoon waters, with enrichment factors that were season and site dependent. The most pronounced changes were observed for offshore waters, especially in spring and winter, whereas the chemical composition of lagoon waters was weakly impacted by the compounds supplied by sediment resuspension

Boron removal from aqueous solutions by using a novel alginate-based sorbent: Comparison with Al2O3 particles

Boron removal was evaluated in the present work by using calcium alginate beads (CA) and a novel composite based on alginate–alumina (CAAl) as sorbents in a batch system. The effects of different parameters such as pH, temperature, contact time, and composition of alginate (at different concentrations of guluronic and mannuronic acids) on boron sorption were investigated. The results confirm that calcium alginate beads (CA) exhibited a better adsorption capacity in a slightly basic medium, and the composite alginate–alumina (CAAl) exhibited improved boron removal at neutral pH. Sorption isotherm studies were performed and the Langmuir isotherm model was found to fit the experimental data. The maximum sorption capacities were 4.5 mmol g-1 and 5.2 mmol g-1, using CA and CAAl, respectively. Thermodynamic parameters such as change in free energy (¿G0), enthalpy (¿H0), and entropy (¿S0) were also determined. The pseudo-first-order and pseudo-second-order rate equations (PFORE and PSORE, respectively) were tested to fit the kinetic data; the experimental results can be better described with PSORE. The regeneration of the loaded sorbents was demonstrated by using dilute HCl solution (distilled water at pH 3) as eluent for metal recovery.Peer Reviewe

Legacy and Emerging Brominated Flame Retardants in Bizerte Lagoon Murex (Hexaplex Trunculus): Levels and Human Health Risk Assessment

Occurrence of traditional (PBDEs) and novel (HBB, PBEB, DBDPE) brominated flame retardants, as well as the natural compounds of MeO-PBDEs, were studied in a shellfish species (Hexaplex trunculus) sampled from Bizerte Lagoon. PBDE and MeO-PBDE mean concentrations in murex soft tissues were 187 and 264 ng g−1 lw respectively. The alternative flame retardants were not identified. The sum of PBDE and MeO-PBDE levels recorded in murex from the investigated aquatic ecosystem were comparable or a relatively lower than those reported for other organisms from other regions across the world. The amount of PBDE and MeO-PBDE concentrations from the Bizerte Lagoon recorded in murex were comparable or a relatively lower than those recorded from other areas across the world for other species. There is not a danger to the population health with regard to PBDE intakes associated with the consumption of murex in Bizerte city. We believe that this is the first study of the analysis of these pollutants in marine gastropod mollusks from Tunisian aquatic areas. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.The Spanish Ministry of Science and Innovation (CEMAGUA-CGL2007-64551/HID) and the Tunisian Ministry of Higher Education and Scientific Research supported this study. The authors are thankful to R. Chaler, D. Fangul, and M. Comesaña for their help at the mass spectrometry work.Peer reviewe

Biomarkers responses and polybrominated diphenyl ethers and their methoxylated analogs measured in Sparus aurata from the Lagoon of Bizerte, Tunisia

This study aimed to the examination of the levels and effects of organobromine compounds (polybrominated diphenyl ethers: PBDEs and methoxylated brominated diphenyl ethers: MeO-PBDEs), in Sparus aurata native to the Lagoon of Bizerte. For that, different biomarkers of exposure (somatic indices, superoxide dismutase, and catalase activities) and effect (malondialdehyde level, histopathologic alterations, and DNA damage) as well as pollutant levels were measured in specimens collected from this impacted ecosystem and the Mediterranean Sea as a reference site. Bizerte Lagoon PBDE fish levels were higher than the Mediterranean Sea, whereas MeO-PBDEs were higher in the reference site. Fish from Bizerte Lagoon presented a higher hepatosomatic index, lower catalase and superoxide dismutase activity, higher level of malondialdehyde, and higher percentage of DNA tail in comparison to fish from the reference area. The histological study of the liver indicated substantial lesions in fish from the polluted site. The results showed strong positive correlations between the concentrations of the PBDE or MeO-PBDE and the MDA and DNA tail % levels and negative correlations for the activities of enzymes of SOD and CAT. Consequently, these findings could suggest a potential link between exposure to these pollutants and the observed biomarker responses in the Bizerte Lagoon seabream. Taken together, these results highlight the importance of biomarker selection and the selected sentinel fish species as useful tools for biomonitoring of aquatic pollution.The Spanish Ministry of Science and Innovation (CEMAGUA-CGL2007-64551/HID) and the Tunisian Ministry of Higher Education and Scientifc Research supported this study. The authors are thankful to R. Chaler, D. Fangul, and M. Comesaña for their help at the mass spectrometry work. We gratefully acknowledge the technical assistance of Joan Serret, David Ramos-López, Javier Gonzalez-Linares, Lydia Camps, Natàlia Brull Barco, and Constança Porredon Guarch in biomarker analysis. The authors would like to express their gratitude to the Deanship of Scientific Research, Saudi Electronic University, Riyadh, Kingdom of Saudi Arabia.Peer reviewe