Adsorption of anti-inflammatory and analgesic drugs traces in water on clay minerals

The aim of this study was to assess the adsorption of four non-steroidal anti-inflammatory drugs (NSAIDs), namely Paracetamol (PRC), Diclofenac (DIC), Ibuprofen (IBU), and Ketoprofen (KET), using both batch and continuous experiments with clay. Various analytical techniques, including XRD, FTIR, SEM coupled to EDX, and Zeta potential, were employed to characterize both raw and calcined clay. XRD and FTIR analyses confirmed the kaolinite nature of the clay. SEM data revealed a lamellar structure formed in the clay after calcination at 550 °C. Adsorption tests were conducted to determine the optimal adsorption conditions. Batch kinetics of adsorption demonstrated rapid adsorption of all four NSAIDs, with the highest adsorption occurring at pH 4 (DIC, IBU, and KET) and pH 6 for PRC, using a concentration of 20 mg L-1 of calcined clay. Additionally, the pseudo-second-order model provided the best fit for all NSAIDs adsorption processes. Maximum adsorption capacities, as determined by the Langmuir model, were 80 mg g-1 for PRC, 238 mg -1g for DIC, 138 mg g-1 for IBU, and 245 mg g-1 for KET. In fixed bed column studies, three dynamic models (Thomas, Adams-Bohart, and Yoon-Nelson) were utilized to describe the breakthrough curves, with linear regression used to identify key characteristics for process design. The fixed bed column adsorption study revealed that DIC exhibited the highest removal efficiency at 98%, while KET, IBU, and PRC were more persistent, with removal efficiencies of 77.1%, 76.7%, and 67.1%, respectively. The Thomas model was deemed appropriate for describing the breakthrough curve. These findings offer valuable insights into the interactions between clay and pharmaceuticals with varying physicochemical properties. They also provide information on the adsorption models, saturation, and adsorption capacities of various pharmaceuticals on natural clays, which can be crucial for further research and environmental remediation efforts.

Water implications in dialysis therapy, threats and opportunities to reduce water consumption: a call for the planet

Water is a dwindling natural resource, and potable water is wrongly considered an unlimited resource. Dialysis, particularly hemodialysis, is a water-hungry treatment that impacts the environment. The global annual water use of hemodialysis is approximately 265 million m3/yr. In this reference estimate, two-thirds of this water is represented by reverse osmosis reject water discharged into the drain. In this review, we would like to draw attention to the complexity and importance of water saving in hemodialysis. We propose that circular water management may comply with the "3R" concept: reduce (reduce dialysis need, reduce dialysate flow, and optimize reverse osmosis performance), reuse (reuse wastewater as potable water), and recycle (dialysis effluents for agriculture and aquaponic use). Awareness and sustainability should be integrated to create positive behaviors. Effective communication is crucial for water savings because local perspectives may lead to global opportunities. Besides the positive environmental impacts, planet-friendly alternatives may have significant financial returns. Innovative policies based on the transition from linear to circular water management may lead to a paradigm shift and establish a sustainable water management model. This review seeks to support policymakers in making informed decisions about water use, avoiding wasting, and finding solutions that may be planet friendly and patient friendly in dialysis, especially in hemodialysis treatments.

Hazard and health risk assessment of exposure to pharmaceutical active compounds via toxicological evaluation by zebrafish

The uncontrolled or continuous release of effluents from wastewater treatment plants leads to the omnipresence of pharmaceutical active compounds (PhACs) in the aquatic media. Today, this is a confirmed problem becoming a main subject of twin public and scientific concerns. However, still little information is available about the long-term impacts of these PhACs on aquatic organisms. In this review, efforts were made to reveal correlation between the occurrence in the environment, ecotoxicological and health risks of different PhACs via toxicological evaluation by zebrafish (Danio rerio). This animal model served as a bioindicator for any health impacts after the exposure to these contaminants and to better understand the responses in relation to human diseases. This review paper focused on the calculation of Risk Quotients (RQs) of 34 PhACs based on environmental and ecotoxicological data available in the literature and prediction from the ECOSAR V2.2 software. To the best of the authors' knowledge, this is the first report on the risk assessment of PhACs by the two different methods as mentioned above. RQs showed greater difference in potential environmental risks of the PhACs. These differences in risk values underline the importance of environmental and experimental factors in exposure conditions and the interpretation of RQ values. While the results showed high risk to Danio rerio of the majority of PhACs, risk qualification of the others varied between moderate to insignifiant. Further research is needed to assess pharmaceutical hazards when present in wastewater before discharge and monitor the effectiveness of treatment processes. The recent new advances in the morphological assessment of toxicant-exposed zebrafish larvae for the determination of test compounds effects on the developmental endpoints were also discussed. This review emphasizes the need for strict regulations on the release of PhACs into environmental media in order to minimize their toxicity to aquatic organisms.

Living membrane bioreactor for highly effective and eco-friendly treatment of textile wastewater

The treatability of synthetic textile wastewater containing model dyes, such as reactive black and direct black dye (25.0 ± 2.6 mg_dye/L), with chemical oxygen demand (COD, 1000 ± 113 mg/L), ammonia‑nitrogen (NH₃-N, 140 ± 97 mg/L) and sulphate ions (SO₄^2-, 1357 ± 10.86 mg/L) was investigated in this study using an innovative living membrane bioreactor (LMBR) using an encapsulated self-forming dynamic membrane (ESFDM). The key advantage of ESFDMBR is the self-forming of the biological filtering layer protected between two meshes of inert robust and inexpensive material. A laboratory scale bioreactor (BR) equipped with a filtering unit mounting polyester meshes with a pore size of 30 μm, operated at an influent flux of 30 LMH was thus used. After the formation of the biological living membrane (LM), the treatment significantly reduced COD and DOC concentrations to the average values of 34 ± 10 mg/L and 32 ± 7 mg/L, corresponding to reduction efficiencies of 96.0 ± 1.1 % and 94 ± 1.05 %, respectively. Throughout the LMBR operation, the colours were successfully removed from synthetic textile wastewater with an overall removal efficiency of about 85.0 ± 1.8 and 86.0 ± 1.9 % for direct and reactive dyes, respectively. In addition, the proposed system was also found effective in affording removal efficiency of ammonia (NH₃) of 97 ± 0.5 %. Finally, this treatment afforded circa 40.7 ± 5.8 % sulphate removal, with a final concentration value of 805 ± 78.61 mg/L. The innovative living membrane, based on an encapsulated self-forming dynamic membrane allows a prolonged containment of the membrane fouling, confirmed by investigating the concentration of membrane fouling precursors and the time-course variations of turbidity and transmembrane pressure (TMP). Those final concentrations of wastewater pollutants were found to be below the limits for admission of the effluents in public sanitation networks in Italy and Tunisia, as representative countries for the regulation in force in Europe and North Africa. In conclusion, due to the low costs of plant and maintenance, the simple applicability, the rapid online implementation, the application of LMBR results in a promising method for the treatment of textile wastewater.

Soil contamination by microplastics in relation to local agricultural development as revealed by FTIR, ICP-MS and pyrolysis-GC/MS

Plastic film mulching and use of wastewaters for irrigation have been common agricultural practices for over half a century in Tunisia, especially in arid regions, resulting in the undesired creation of a pathway for microplastics (MPs) to enter farmland soil. In order to assess the extent and characteristics of soil contamination by MPs in the Moknine province, an area of intensive agricultural practices, 16 farmland soil samples were collected and characterized. The total concentration of targeted MPs was 50-880 items/kg; among them, the most common MPs type being polypropylene (PP), mainly occurring as white/transparent fibers with small size (cross section <0.3 mm). SEM images of MPs surfaces revealed multiple features related to environmental exposure and degradation. ATR-FTIR spectroscopy and pyrolysis-GC/MS analyses enabled the accurate identification of MPs separated from the embedding soil micro- and macro-aggregates. Finally, contamination of the polymeric microparticles with a broad range of metals was found by ICP-MS analysis, suggesting that MPs can be vectors for transporting heavy metals in the soil and indicators of soil contamination as a result of mismanagement of industrial wastewaters.

Storage facilities reclamation using dredged sediments from waterways: Growing media formulation for plants according to the EU Ecolabel requirements

Dredged sediments display a great potential for growing media applications; however, there are few studies about their beneficial reuse for the waste storage reclamation. This research study aims at checking the agronomic values and environmental impacts of three growing media based on waterways sediments (WSs) and green waste (GW) according ecolabel requirements. For this purpose, three growing media named GW0, GW25, and GW50 were prepared at field pilot scale by co-composting WS and GWs during 12 months. Samples were submitted to ecolabel analyses package. Following to the ecolabel requirements, the growing media comply with criteria like pH, electrical conductivity, trace elements and polycyclic aromatic hydrocarbon contents, chlorides, and pathogens, whereas they are not in compliance with the EU Ecolabel guidelines for propagules, organic matter, and zinc contents. Results of laboratory leaching tests performed according to NF EN 12457-2 for GW0, GW25, and GW50 have shown that sulfates, soluble fraction exceed limit for inert waste storage. Lysimeter tests at pilot scale were performed during 6 months to check the leaching potential of pollutants from growing media under real field conditions, including a European ecolabel product. Results demonstrate that Ba, Mo, Sb, Zn, Se, and Sb are higher in GW0, GW25, and GW50 than in the European ecolabel. As, Cd, Cr, Ni, and F^- are more soluble in the commercial product compared to other growing media. This study allowed to demonstrate that main characteristics are fulfilling for reusing these growing media in the specific field of waste storage reclamation.

Types, occurrence, and distribution of microplastics and metals contamination in sediments from south west of Kerkennah archipelago, Tunisia

Microplastics (MPs) are one of the most significant solid waste pollutants in the marine environment and accumulate in sediments around worldwide. In this study, the pollution level, the type, occurrence, and distribution of MPs in sediments from the southwestern Kerkennah archipelago, Tunisia, were investigated. Sediment samples were collected from 20 adjacent sites through three "lines L1, L2, and L3." MPs were separated from sediment by density flotation (NaCl, 1.2 g cm^-3) and characterized in terms of shape, size, and color using microscope. The accumulation of toxic chemicals such as trace metals on microplastics was measured by atomic absorption microwave-assisted acid extraction. Polymer types were identified using FTIR-ATR spectroscopy. This study showed that microplastics were found in all samples, which emphasized that their extensive distribution throughout three lines by an average abundance of "MPs" was 611 items/m². Among the shape categories of plastic particles, fiber and fragment were the most dominant frequent shapes (94%). The more frequent colors found were white (52.7%) and transparent (35.1%). Regarding the sizes, the microplastics below 1 mm were the most common accounting for 97% of all plastics. Results of trace metals Zn, Cu, Pb, Cr, and Ni in sediments with concentrations were reported as 3.48 μg/g, 0.41 μg/g, 0.38 μg/g, 0.33 μg/g, and 0.12 μg/g, respectively. Graphical abstract.

Microplastics on Barra beach sediments in Aveiro, Portugal

Microplastic (MPs) pollution has been recognized as a serious threat to marine environment with the growing use of plastics. There is no sufficient data on the extent and characteristics of MPs pollution in the beach sediments and sand in the Atlantic Ocean. The coastal area is one of the main tourist zones in Aveiro in Portugal, thus, impacted by both tourism and maritime traffic, which are major sources of MPs. Considering this issue, 33 sediment samples were collected from the Praia da Barra beach in Aveiro. This pilot study showed that large quantities of MPs are accumulated on this beach with a median concentration of 100 MP kg-1 (15-320 MP kg-1), that is dominated by polyethylene (30%), polypropylene (27%), polystyrene (18%), nylon (12%), and polyester (6%). Size <1 mm constituted 99.5% of particles, mostly of transparent or black colors, with highest concentrations closest to the water line.

Health risk assessment of heavy metals exposure via consumption of crops grown in phosphogypsum-contaminated soils

The management of phosphogypsum (PG) heap, located south of the Sfax city in Tunisia, has been going on for decades. But dumping this solid waste still poses environmental problems. Even though valorized as amendment to agriculture soils, the sanitary impact of this practice is not seriously considered. To assess the risk of the transference of contaminants from PG to agricultural soil-plants food chain, a wild plant species Salicornia arabica grown in PG-contaminated field and tomato (Lycopersicon esculentum) and oat (Avena sativa) grown in laboratory using different rates (10, 20 and 30%) of PG amendment, were tested. The cadmium, lead, chromium, nickel, copper and zinc concentrations in soils and plants were determined by atomic absorption spectrometry and by inductively coupled plasma-mass spectrometry, respectively. Measurements showed that Ni, Cu and Pb levels in the amended soils were below international standards except for Cd and Cr which exceeded Chinese, FAO/WHO and European allowable standard limits. Gathered results showed that the more the PG rate increases, the more the bioconcentration factors of heavy metals increased in plants, particularly in the roots. This is a prospective study assuming direct or indirect exposure scenario of different human cohorts by consuming varied common food stuffs. The Human Exposure to Soil Pollutants evaluation and United State Environment Protection Agency models were adopted for the hazard quotient calculation to assess the acceptability of sanitary risk related to each metal. The direct and indirect health risk assessments varied in the decreasing order: children, adolescents and then adults. Therefore, the PG amendment must not exceed the rate of 10%.

Potential of Eucalyptus globulus for the phytoremediation of metals in a Moroccan iron mine soil-a case study

The contamination left by abandoned mines demands sustainable mitigation measures. Hence, the aim of this study was to examine the phytoremediator ability of Eucalyptus globulus Labill. to be used for cleaning up metal-contaminated soils from an African abandoned iron (Fe) mine (Ait Ammar, Oued Zem, Morocco). Plantlets of this species were exposed to a control (CTL), a reference (REF), and a mine-contaminated soil (CS). Morphological (growth, leaf area) and physiological stress biomarkers (photosynthetic efficiency, pigments content, leaf relative water, and malondialdehyde (MDA) levels) and metal bioaccumulation were assessed. The growth and leaf area of E. globulus increased overtime in all soils, although at a lower rate in the CS. Its photosynthetic efficiency was not markedly impaired, as well as MDA levels decreased throughout the experiment in CS. In this soil, higher metal contents were detected in E. globulus roots than in leaves, especially Fe (roots: 15.98-213.99 μg g^-1; leaves: 5.97-15.98 μg g^-1) and Zn (roots: 1.64-1.99 μg g^-1; leaves: 0.67-1.19 μg g^-1), indicating their reduced translocation. Additionally, though at low extent, the plants bioaccumulated some metals (Pb > Zn > Cu) from CS. Overall, E. globulus may be potentially used for the phytoremediation of metals in metal-contaminated soils.

Indoor versus outdoor transmission of SARS-COV-2: environmental factors in virus spread and underestimated sources of risk

The first case of Coronavirus Disease 2019 (COVID-19), which is caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), in Europe was officially confirmed in February 2020. On 11 March 2020, after thousands of deaths from this disease had been reported worldwide, the WHO changed their classification of COVID-19 from a public health emergency of international concern to a pandemic. The SARS-CoV-2 virus has been shown to be much more resistant to environmental degradation than other coated viruses. Several studies have shown that environmental conditions can influence its viability and infectivity. This review summarizes current knowledge on the transmission pathways of the novel coronavirus, and directs attention towards potentially underestimated factors that affect its propagation, notably indoor spread and outdoor risk sources. The contributions of significant indoor factors such as ventilation systems to the spread of this virus need to be carefully ascertained. Outdoor risk sources such as aerosolized particles emitted during wastewater treatment and particulate matter (PM), both of which may act as virus carriers, should be examined as well. This study shows the influence of certain underestimated factors on the environmental behavior and survival of the SARS-CoV-2 virus. These aspects of coronavirus propagation need to be accounted for when devising actions to limit not only the current pandemic but also future outbreaks.

Application of a standard risk assessment scheme to a North Africa contaminated site (Sfax, Tunisia) -Tier 1

Phosphorus is a critical element to agriculture, consequently global phosphate rock demand will remain rising to feed a growing world population. The beneficiation of phosphorous ore gives rise to several tons of a waste by-product [phosphogypsum (PG)] which valorisation is limited, within other reasons, by the risks posed to environment and human health. Although threatening, the accumulation in stacks is the only procedure so far practiced by several countries as a means to get rid of this industrial externality. As part of a NATO Science for Peace Project (SfP 983311) this study describes the application of an environmental risk assessment (ERA) framework, to assess the risks posed by a PG stack to the surrounding soils, in Sfax, Republic of Tunisia. The ERA followed a weight of evidence approach, supported by two lines of evidence (LoE): the chemical (ChemLoE) and the ecotoxicological (EcotoxLoE). Integrated risks point for risk values greater than 0.5 in soils collected in PG stack surrounding area. Soil salinization, has likely contributed to the exacerbation of risks, as well as to the lack of consistency between both LoEs. This study highlights the need of rethinking the weight given to each LoE in ERA, in areas where soil salinization is a reality.

An eco-friendly epoxy polymer binder for the treatment of Tunisian harbor sediments: Laboratory investigations for beneficial reuse

The management of dredged sediments poses serious environmental and economic problems because of their geochemical properties and in particular their pollutant content. In this research, marine sediments from Tunisian harbors were collected to study their beneficial reuse as construction materials using an eco-friendly polymer binder. Experimental investigations include the determination of physicochemical, mineralogical, and environmental parameters of sediments from the Sidi Mansour and Sidi Youssef areas in Tunisia. Prismatic mortar samples (4 × 4 × 16 cm) were prepared at laboratory scale using normalized sand and epoxy resin. Then their composition was modified by including a sediment fraction in the substitution of sand at rates ranging from 10 to 50% in dry mass. After a 7-day curing period, mortar samples were submitted to mechanical, physicochemical, and environmental analyses. Mortar samples including sediment fractions displayed lower strength than sand mortar used as control. This result is explained by the increase of porosity values in the mortar samples when sediment samples were incorporated. A positive relationship between porosity and compressive strength values was evidenced, suggesting that the compactness of granular skeleton could play an important role in the preparation of materials. From an environmental point of view, the mortar samples containing sediment fractions showed relatively low leaching levels, which confirms their suitability for the manufacturing of construction materials.

Microplastic pollution in the sediments of Sidi Mansour Harbor in Southeast Tunisia

Despite the increasing interest in microplastic (MP) research, the accurate prevalence, distribution and fate of these materials in the environment is yet poorly known and, consequently, a focus of debate. Hence, to better ascertain the presence of microplastics in specific environments, samples from 35 random sites distributed across a 4200-meter long section from the area of Sidi Mansour, Sfax-Tunisia, were collected and analyzed. MPs were extracted, digested with potassium hydroxide and dyed with Eosin B, for visual microscopy counting and sorting. Polymer composition and surface morphology were identified by FTIR-ATR spectroscopy and SEM microscopy. Total abundances ranged from 252 to-5332 particles per m² where fragments and granules were the most frequent types of microplastics. These findings highlight the considerable presence of these materials in the studied harbor region and underscore the density dependence on the distribution and occurrence of MPs and how these tend to accumulate in the sandy sediments.

Interregional traceability of Tunisian olive oils to the provenance soil by multielemental fingerprinting and chemometrics

The aim of this study was to prove the usefulness of multielements as provenance markers of olive oils by evaluating their link with soil composition and their discriminatory power. Eleven elements in twenty-one olive oils and their paired soils from four Tunisian regions were characterized. Chemometrics have been implemented for ICP-MS data processing. Principal component analysis identified the predominant geochemical source of the elements in the oils based on their associations according to Goldschmidt's rule. Although a clear correlation was not proven, correspondence was identified between the discriminating elements for both the soils and olive oils, which included Fe, Rb, Mg, and Pb. Linear discriminant analysis achieved classification and prediction rates of 92.1% and 87.3%, respectively. Our study substantiates the validity of multielements as markers of the olive oils' provenance, and that an elemental fingerprinting approach can be successfully applied in the construction of a database of Tunisian olive oils.

Decision tree for mapping of halophyte cover around Ghannouch, Tunisia

Environment of Ghannouch in the south-east of Tunisia is characterized by the wide-spread hypersaline soils, typically colonized by halophytes. The study of their distribution is required in order to reveal the extent of salinization and its dynamic. Mapping and monitoring with a remote sensing approach are foreseen as the ways to trace the spatial and temporal dimensions of the phenomenon. The identification of halophyte vegetation can take advantage by analyzing optical remote sensing data. Here, we propose using a decision tree approach applied to European Space Agency Sentinel-2 imagery, for an accurate land cover mapping of Ghannouch district in Gabès governorate. Data pre-processing was carried out using the European Space Agency's Sentinel Application Platform and the SEN2COR toolboxes. The mapping approach combines the spectral information in several channels of the visible-near-infrared spectrum. The land cover identification was performed following a spectral classification approach, exploiting several optical indices, normalized difference water index, normalized difference vegetation index, and several soil salinity index, in order to elaborate a decision tree algorithm. As a result, for an area of interest of 50 × 50 km², at least 68% was classified as halophyte land cover. This mapping exercise represents an important step toward improved halophytes mapping in Tunisia and could be used to monitor the status of other salinity prone regions in the world.

Soil contamination with olive mill wastes negatively affects microbial communities, invertebrates and plants

The aim of the present study was to evaluate the ecotoxicological effects of olive mill waste (OMW) on soil habitat function. To this end, soil samples from OMW evaporating ponds (S1-S5) located at Agareb (Sfax, Tunisia) and a reference soil (R) were collected. The effects of OMW on the springtails Folsomia candida (F.c.), the earthworm species Eisenia fetida (E.f.), Enchytraeus crypticus (E.c.) reproduction and on the soil living microbial communities were investigated. E.f. reproduction and tomato growth assays were performed in the reference soil amended with 0.43 to 7.60 % (w_OMW/w_ref-soil) mass ratios of dried OMW. Changes in microbial function diversity were explored using sole-carbon-source utilization profiles (BiologEcoPlates^®). E.f. absolutely avoided (100 %) the most polluted soil (S4) while the F.c. moderately avoided (37.5 ± 7.5 %) the same soil. E.c. reproduction in S4 was significantly lower than in S1, S2, S3 and S5, and was the highest in R soil. Estimated effect concentration EC₅₀ for juveniles' production by E.f., and for tomato fresh weight and chlorophyll content were 0.138, 0.6 and 1.13 %, respectively. Community level physiological profiles (CLPPs) were remarkably different in R and S4 and a higher similarity was observed between soils S1, S2, S3 and S5. Principal component analysis (PCA) revealed that differences between soil microbial functional diversity were mainly due to high polyphenol concentrations, while the salinity negatively affected E.c. reproduction in OMW contaminated soils. These results clearly reflect the high toxicity of dried OMW when added to agricultural soils, causing severe threats to terrestrial ecosystem functions and services provided by invertebrates and microbial communities.

Comparison between several techniques of olive tree bark extraction (Tunisian Chemlali variety)

In order to better understand the chemical composition of the olive tree bark of Tunisian chemlali variety (Olea europaea cv. 'Chemlali'), this material was extracted by different ways. Compositions of extracts were used at best-selected conditions for each technique, and characterised using HPLC, LC/MS and GC-MS techniques. Analyses are conducted to an important variety of high carbon number compounds such as aliphatic compounds as nanocosane and heptacosane, and molecules with high value added tax (VAT) which can be classified as follows: diterpenes as phytol, triterpenes as squalene and also esters as Benzyl cinnamate. Hydrodistillation at high pressure seems to be a very common method to get a wide variety of compounds, the results are better than the ones obtained using supercritical fluid extraction and solvent extraction.

Ecotoxicity of titanium silicon oxide (TiSiO4) nanomaterial for terrestrial plants and soil invertebrate species

The huge evolution of nanotechnology and the commercialization of nanomaterials (NMs) positively contributed for innovation in several industrial sectors. Facing this rapid development and the emergence of NMs in the market, the release of this nanometric sized materials in the environment and the possible impact on different ecosystem components attracted the attention of researchers in the last few years. In our study we aimed to assess the impact of titanium silicon oxide nanomaterial (nano-TiSiO4) on soil biota to estimate a risk limit for this material. In the present research a battery of standardized ecotoxicological assays aimed at evaluating a wide range of endpoints (avoidance and reproduction of earthworms and collembolans, emergence/growth of four selected terrestrial plants) were carried out, using OECD artificial soil as test substrate spiked with aqueous suspension of different concentrations of nano-TiSiO4. The results showed a maximum avoidance percentage of 40% for earthworms (Esenia andrei) at the highest concentration tested (1000mgkg(-1) soildw of nano-TiSiO4). No significant effect on the reproductive function of both invertebrate species was recorded. Nevertheless, significant phytotoxic data was registered at least for the growth of dicotyledonous plant species (Lactuca sativa and Lycopersicon lycopersicum) with EC20 values ranging between 236 and 414 mg kg(-1) soildw of nano-TiSiO4 for L. sativa dry mass and fresh mass, respectively. Further, the characterization of nano-TiSiO4 in suspensions used to spike the soil, performed by Dynamic Light Scattering, showed the formation of aggregates with important average size diameter, thus demonstrating that the toxic effects observed were likely not size dependent. A deterministic PNEC (predicted no effect concentration) for this NM of 10.02mg kg(-1) soildw of nano-TiSiO4, is suggested, while no more ecotoxicological information exists.

UV and solar photo-degradation of naproxen: TiO₂ catalyst effect, reaction kinetics, products identification and toxicity assessment

Direct photolysis and TiO2-photocatalytic degradation of naproxen (NPX) in aqueous solution were studied using a UV lamp and solar irradiation. The degradation of NPX was found to be in accordance with pseudo-first order kinetics, the photocatalytic process being more efficient than photolysis. The NPX removal by photolysis (pHinitial 6.5) was 83% after 3h, with 11% of chemical oxygen demand (COD) reduction, whereas the TiO2-UV process led to higher removals of both NPX (98%) and COD (25%). The apparent pseudo-first-order rate constant (kapp) for NPX degradation by photolysis ranged from 0.0050 min(-1) at pH 3.5 to 0.0095 min(-1) at pH 6.5, while it was estimated to be 0.0063 min(-1) under acidic conditions in photocatalysis, increasing by 4-fold at pH 6.5. Ultra High Performance Liquid chromatography (UHPLC) coupled with a triple quadrupole detector and also a hybrid mass spectrometer which combines the linear ion trap triple quadrupole (LTQ) and OrbiTrap mass analyser, were used to identify NPX degradation products. The main intermediates detected were 1-(6-methoxynaphtalene-2-yl) ethylhydroperoxide, 2-ethyl-6-methoxynaphthalene, 1-(6-methoxynaphtalen-2-yl) ethanol, 1-(6-methoxynaphtalen-2-yl) ethanone and malic acid. Solar photocatalysis of NPX showed COD removals of 33% and 65% after 3 and 4h of treatment, respectively, and some reduction of acute toxicity, evaluated by the exposure of Eisenia andrei to OECD soils spiked with NPX-treated solutions.

Label-free disposable immunosensor for detection of atrazine

This work reports the construction of a fast, disposable, and label-free immunosensor for the determination of atrazine. The immunosensor is based on a field effect transistor (FET) where a network of single-walled carbon nanotubes (SWCNTs) acts as the conductor channel, constituting carbon nanotubes field effect transistors (CNTFETs). Anti-atrazine antibodies were adsorbed onto the SWCNTs and subsequently the SWCNTs were protected with Tween 20 to prevent the non-specific binding of bacteria or proteins. The principle of the immunoreaction consists in the direct adsorption of atrazine specific antibodies (anti-atrazine) to SWCNTs networks. After exposed to increasing concentrations of atrazine, the CNTFETs could be used as useful label-free platforms to detect atrazine. Under the optimal conditions, a limit of detection as low as 0.001 ng mL(-1) was obtained, which is lower than that of other methods for the atrazine detection, and in a working range between 0.001 and 10 ng mL(-1). The average recoveries obtained for real water samples spiked with atrazine varied from 87.3% to 108.0%. The results show that the constructed sensors display a high sensitivity and could be useful tools for detecting pesticides like atrazine at low concentrations. They could be also applied to the determination of atrazine in environmental aqueous samples, such as seawater and riverine water.

Effects of contaminated soils from a former iron mine (Ait Amar, Morocco) on enchytraeids (Enchytraeus bigeminus) and predatory mites (Hypoaspis aculeifer) in standard laboratory tests

Mining activity is an important economic activity in several North Atlantic Treaty Organization (NATO) and North African countries. Within their territory derelict or active mining explorations represent risks to surrounding ecosystems, but engineered-based remediation processes are usually too expensive to be an option for the reclamation of these areas. A project funded by NATO was performed, with the aim of finding a more eco-friendly solution for reclamation of these areas. As part of an overall risk assessment, the risk of contaminated soils to selected soil organisms was evaluated. The main question addressed was: Does the metal-contaminated soils from a former iron mine located at Ait Amar (Morocco),which was abandoned in the mid-Sixties, affect the reproduction of enchytraeids (Enchytraeus bigeminus) and predatory mites (Hypoaspis aculeifer)? Soil samples were taken at 20 plots along four transects covering the mine area and at a reference site about 15km away from the mine. The soils were characterized pedologically and chemically, which showed a heterogeneous pattern of metal contamination (mainly cadmium, copper, and chromium, sometimes at concentrations higher than European soil trigger values). The reproduction of enchytraeids (Enchytraeus bigeminus) and predatory mites (Hypoaspis aculeifer) was studied using standard laboratory tests according to OECD guidelines 220 (2004) and 226 (2008). The number of juveniles of E. bigeminus was reduced at several plots with high concentrations of Cd or Cu (the latter in combination with low pH values). There was nearly no effect of the metal contaminated soils on the reproduction of H. aculeifer. The overall lack of toxicity at the majority of the studied plots is probably caused by the low availability of the metals in these soils unless soil pH was very low. Different exposure pathways are likely responsible for the different reaction of mites and enchytraeids (hard-bodied versus soft-bodied organisms). The results of this study can be used not only for assessing the risk of contaminated soils but also could play a role for the identification of soil remediation programs.

Effects of metal pollution on sediments in a highly saline aquatic ecosystem: case of the Moknine continental Sebkha (eastern Tunisia)

Potential contamination of the sediments in the Sebkha of Moknine (Tunisia) ecosystem was assessed by means of enrichment factors (EFs) estimated against reference sediment located ≈70 km away from the Sebkha. The use of EFs is recommended as a reliable method for heavy metal contamination assessment, provided that (1) element contents are corrected following a careful normalization procedure, and (2) the reference sediment is unaffected by anthropogenic alterations. The degree of contamination was assessed by the modified contamination degree approach. The obtained results indicated that surface sediments were enriched up to 22.9, 13.2, 5.46 and 3.19 times with Pb, Cu, Cr and Zn, respectively. Lower enrichment factors for Ni and Co suggested that anthropogenic sources were less important for these metals. The modified degree of contamination showed that the sediments in the Sebkha of Moknine have suffered significant systematic heavy metal contamination following catchment urbanization and industrialization .

Effects of long-term irrigation with treated wastewater on soil quality, soil-borne pathogens, and living organisms: case study of the vicinity of El Hajeb (Tunisia)

Medium (i.e. 15 years) and long-term (i.e. 20 years) impact of irrigation using secondary-treated municipal wastewater (TWW) was assessed on two agricultural soil samples, denoted by E and G, respectively, in the vicinity of El Hajeb region (Southern Tunisia). Soil pH, electrical conductivity particle size grading, potential risk of salinity, water holding capacity and chemical composition, as well as organic matter content, pathogenic microorganisms and heavy metal concentrations in the TWW-irrigated (E and G) and rainwater-irrigated (T) soils at various depths, were monitored and compared during a 5-year experiment. Our study showed that bacterial abundance is higher in sandy-clayey soil, which has an enhanced ability to retain moisture and nutrients. The high level of bacterial flora in TWW-irrigated soils was significantly (p < 0.05) correlated (r = ~0.5) with the high level of OM. Avoidance assays have been used to assess toxic effects generated by hazards in soils. The earthworms gradually avoided the soils from the surface (20 cm) to the depth (60 cm) of the G transect and then the E transect, preferring the T transect. The same behaviour was observed for springtails, but they seem to be less sensitive to the living conditions in transects G and E than the earthworms. The avoidance response test of Eisenia andrei was statistically correlated with soil layers at the sampling sites. However, the avoidance response test of Folsomia candida was positively correlated with silt-clay content (+0.744*) and was negatively correlated with sand content (-0.744*).

Risk assessment of heavy metal toxicity of soil irrigated with treated wastewater using heat shock proteins stress responses: case of El Hajeb, Sfax, Tunisia

Heavy metal contamination of soil resulting from treated wastewater irrigation can cause serious concerns resulting from consuming contaminated crops. Therefore, it is crucial to assess hazard related to wastewater reuse. In the present investigation, we suggest the use of biomarker approach as a new tool for risk assessment of wastewater reuse in irrigation as an improvement to the conventional detection of physicochemical accumulation in irrigated sites. A field study was conducted at two major sites irrigated with treated wastewater and comparisons were made with a control site. Different soil depths were considered to investigate the extent of heavy metal leaching, the estrogenic activity, and the biomarker response. Results have shown that a longer irrigation period (20 years) caused a slight decrease in soil metal levels when compared to the soil irrigated for 12 years. The highest levels of Cr, Co, Ni, Pb, and Zn were detected at 20 and 40 cm horizons in plots irrigated with wastewater for 12 years. The latter finding could be attributed to chemical leaching to deeper plots for longer irrigation period. Furthermore, the treated wastewater sample showed a high estrogenic activity while none of the soil samples could induce any estrogenic activity. Regarding the stress response, it was observed that the highest stress shown by the HSP47 promoter transfected cells was induced by a longer irrigation period. Finally, the treated wastewater and the irrigated soils exhibited an overexpression of HSP60 in comparison with reference soil following 1 h exposure. In conclusion, in vitro techniques can be efficiently used to assess potential hazard related to wastewater reuse.

Evaluation of the efficiency of monopolar and bipolar BDD electrodes for electrochemical oxidation of anthraquinone textile synthetic effluent for reuse

The efficiency of the electrochemical degradation of synthetic wastewater containing an anthraquinone dye has been comparatively studied in two electrolytic cells with a synthetic boron-doped diamond (Si/BDD) as an anode. The first is an individual cell (Cell 1) with monopolar electrode BDD and the second (Cell 2) has two bipolar electrodes BDD self-polarized. The bulk electrolysis was performed at the same initial operating conditions in order to quantify the influence of the initial pH and current density on dye discoloration and global mineralization removal. The current efficiency and the consumption energy were also evaluated. When the same solutions have been comparatively treated with the two cells, a quite good mineralization is found in Cell 2. This result supposed more fraction of the applied current is used for the electrocombustion reaction on Cell 2 if compared to Cell 1 and small amount rest for the side reaction of oxygen evolution. The HPLC analyses confirmed this hypothesis and showed that the concentration trend of intermediates (sulfanilic acid, phthalate acid and salicylic acid) with electrolysis time was different on two cells. Phototoxicity tests show that the electrochemical oxidation with BDD electrodes could be useful as a pretreatment technique for reducing hazardous wastewater toxicity.

Toxicity assessment for petroleum-contaminated soil using terrestrial invertebrates and plant bioassays

The assessment of soil quality after a chemical or oil spill and/or remediation effort may be measured by evaluating the toxicity of soil organisms. To enhance our understanding of the soil quality resulting from laboratory and oil field spill remediation, we assessed toxicity levels by using earthworms and springtails testing and plant growth experiments. Total petroleum hydrocarbons (TPH)-contaminated soil samples were collected from an oilfield in Sfax, Tunisia. Two types of bioassays were performed. The first assessed the toxicity of spiked crude oil (API gravity 32) in Organization for Economic Co-operation and Development artificial soil. The second evaluated the habitat function through the avoidance responses of earthworms and springtails and the ability of Avena sativa to grow in TPH-contaminated soils diluted with farmland soil. The EC50 of petroleum-contaminated soil for earthworms was 644 mg of TPH/kg of soil at 14 days, with 67 % of the earthworms dying after 14 days when the TPH content reached 1,000 mg/kg. The average germination rate, calculated 8 days after sowing, varied between 64 and 74 % in low contaminated soils and less than 50 % in highly contaminated soils.

Photocatalytic degradation of 4-chlorophenol under P-modified TiO2/UV system: kinetics, intermediates, phytotoxicity and acute toxicity

A series of phosphorus-modified titanium dioxide samples with varying P/Ti atomic ratio were conveniently prepared via a conventional solgel route. The effects of phosphorus content and calcination temperature on the crystalline structure, grain growth, surface area, and the photocatalytic activity of P-modified TiO2 were investigated. The XRD results showed that P species slow down the particle growth of anatase and increase the anatase-to-rutile phase transformation temperature to more than 900 degrees C. Kinetic studies on the P-modified TiO2 to degraded 4-chlorophenol had found that the TP5(500) prepared by adopting a P/Ti atomic ratio equal to 0.05 and calcined at 500 degrees C had an apparent rate constant equal to 0.0075 min(-1), which is superior to the performance of a commercial photocatalyst Degussa P25 K(app) = 0.0045 min(-1) and of unmodified TiO2 (TP0(500)) K(app) = 0.0022 min(-1). From HPLC analyses, various hydroxylated intermediates formed during oxidation had been identified, including hydroquinone (HQ), benzoquinone (BQ) and (4CC) 4-chlorocatechol as main products. Phytotoxicity was assessed before and after irradiation against seed germination of tomato (Lycopersicon esculentum) whereas acute toxicity was assessed by using Folsomia candida as the test organism. Intermediates products were all less toxic than 4-chlorophenol and a significant removal of the overall toxicity was accomplished.

Organic matter compounds as source indicators and tracers for marine pollution in a western Mediterranean coastal zone

INTRODUCTION

Complex organic compounds found in oil and sediments linked with a particular source (such as algae, bacteria or vascular plants) are defined as biomarkers and are useful dating indicators in organic geochemistry.

METHODS AND RESULTS

This paper presents the composition of the organic matter (OM) on marine surface sediments from a degraded Tunisian coast analysed by pyrolysis and gas chromatography-mass spectrometry (GC-MS). High total OM contents (0.3-4.2%) were detected with high levels of saturated linear hydrocarbons. The aliphatic lipids had contributed with up to 11.7% of the total OM, and their distribution had consisted of resolved compounds (n-alkanes and fatty acid (FAs)) and an unresolved complex mixture. Hydrocarbons, primarily n-alkanes, were ranged from 368 to 3,886 μg g(-1). The FAs (674-2,568 μg g(-1)) were dominated by derived primary production, and the short chain FAs (C16 and C18) were the most abundant throughout. The ubiquitous presence of petroleum contamination, mainly from offshore oil exploration, discharge of pollutants from rivers, shipping activities and atmospheric deposition was found in all samples. The Gabès littoral seems to be quite to very polluted near the industrial zone of Ghannouch. The C/H ratio (generally around 5.9), the thermal analysis and GC-MS of n-alkanes and FAs showed that the OM in the studied area was composed of anthropogenic/petrogenic, marine and continental sources.

CONCLUSIONS

Our study represents an innovative approach to assessing environmental pollution. The evaluation of organic matter by examination of sterols, alkanes and fatty acids allows the identification of source, both anthropogenic and natural.

Olive mill wastewater degradation by Fenton oxidation with zero-valent iron and hydrogen peroxide

The degradation of olive mill wastewater (OMW) with hydroxyl radicals generated from zero-valent iron and hydrogen peroxide has been investigated by means of chemical oxygen demand (COD) and phenolic compounds analyses. The effects of the H2O2 dose, the pH and the organic matter concentration have been studied. The optimal experimental conditions were found to have continuous presence of iron metal, acid pH (2.0-4.0), and relatively concentrated hydrogen peroxide (9.5M). Coloration of OMW disappeared and phenolic compound decreased to 50% of initial concentration after 3h reaction time. The application of zero-valent Fe/H2O2 procedure permitted high removal efficiencies of pollutants from olive mill wastewater. The results show that zero-valent Fe/H2O2 could be considered as an effective alternative solution for the treatment of OMW or may be combined with a classical biological process to achieve high quality of effluent water.

Discoloration and detoxicification of a Congo red dye solution by means of ozone treatment for a possible water reuse

The objective of this study was to investigate the degradation and mineralization of an azo-dye, the Congo red, in aqueous solutions using ozone. Phytotoxicity and the inhibitory effects on the microbial activity of the raw and the ozonated solutions were also carried out with the aim of water reuse and environment protection. Decolorization of the aqueous solutions, disappearance of the parent compound, chemical oxygen demand (COD) and total organic carbon (TOC) removal were the main parameters monitored in this study. To control the mineralization of the Congo red, pH of the ozonated solution and heteroatoms released from the mother molecule such NH(4)(+), NO(3)(-) and SO(4)(2-) were determined. It was concluded that ozone by itself is strong enough to decolorize these aqueous solutions in the early stage of the oxidation process. Nonetheless, efficient mineralization had not been achieved. Significant drops in COD (54%) were registered. The extent of TOC removal was about 32%. Sulfur heteroatom was totally oxidized to SO(4)(2-) ions while the central -NN- azo ring was partially converted to NH(4)(+) and NO(3)(-). Results of the kinetic studies showed that ozonation of the selected molecule was a pseudo-first-order reaction with respect to dye concentration. The obtained results also demonstrate that ozone process reduced the phytotoxicity of the raw solution and enhanced the biodegradability of the treated azo-dyes-wastewater. Hence, this show that ozone remains one of the effective technologies for the discoloration and the detoxification of organic dyes in wastewater.

A study on removal characteristics of copper from aqueous solution by sewage sludge and pomace ashes

In the present work, the abilities of sewage sludge and pomace ashes to remove copper (Cu(2+)) ions from aqueous solutions are compared. Batch adsorption experiments were performed in order to evaluate the removal efficiency of these materials. Effect of contact time, solution pH, ash concentration and temperature on the removal of Cu(2+) was investigated. The results of batch equilibrium studies showed that the solution pH was the key factor affecting the adsorption characteristics. In general, the amount of Cu removed increased as the solid concentration and pH increased, and then it remained constant over a wide pH region. The adsorption test of applying sewage sludge and pomace ashes into synthetic wastewater revealed that the adsorption data of these materials for copper ions were better fitted to the Langmuir isotherm since the correlation coefficients for the Langmuir isotherm were higher than that for the Freundlich isotherm. The estimated maximum capacities of copper adsorbed by sewage sludge and pomace ashes were 5.71 and 6.98 mg g(-1), respectively. Experimental results indicated that the adsorption was favorable at higher pH and higher temperature. Values of DeltaG degrees ranging from -4.64 to -5.13 kcal mol(-1) for sewage sludge ash and from -4.97 to -5.53 kcal mol(-1) for pomace ash suggest that the adsorption reaction is a physical process enhanced by the electrostatic effect. The values of DeltaH degrees and DeltaS degrees are, respectively, 4.27 kcal mol(-1) and 30.6 cal K(-1)mol(-1) for sewage sludge ash and 4.33 kcal mol(-1) and 31.3 cal K(-1)mol(-1) for pomace ash. The mechanisms of copper removal by these materials included adsorption and precipitation. The sewage sludge and pomace ashes are shown to be effective adsorbents for this metal.