Tritiated stainless steel (nano)particle release following a nuclear dismantling incident scenario: Significant exposure of freshwater ecosystem benthic zone.

Nuclear facilities continue to be developed to help meet global energy demands while reducing fossil fuel use. However, an incident during the dismantling of these facilities could accidentally release tritiated particles (e.g. stainless steel) into the environment. Herein, we investigated the environmental dosimetry, fate, and impact of tritiated stainless steel (nano)particles (1 mg.L-1 particles and 1 MBq.L-1 tritium) using indoor freshwater aquatic mesocosms to mimic a pond ecosystem. The tritium (bio)distribution and particle fate and (bio)transformation were monitored in the different environmental compartments over 4 weeks using beta counting and chemical analysis. Impacts on picoplanktonic and picobenthic communities, and the benthic freshwater snail, Anisus vortex, were assessed as indicators of environmental health. Following contamination, some tritium (∼16%) desorbed into the water column while the particles rapidly settled onto the sediment. After 4 weeks, the particles and the majority of the tritium (>80%) had accumulated in the sediment, indicating a high exposure of the benthic ecological niche. Indeed, the benthic grazers presented significant behavioral changes despite low steel uptake (<0.01%). These results provide knowledge on the potential environmental impacts of incidental tritiated (nano)particles, which will allow for improved hazard and risk management.

One-Step Extraction of Olive Phenols from Aqueous Solution Using ß-Cyclodextrin in the Solid State, a Simple Eco-Friendly Method Providing Photochemical Stability to the Extracts.

The extraction of phenolic compounds from olive mill wastes is important, not only to avoid environmental damages, but also because of the intrinsic value of those biophenols, well-known for their high antioxidant potential and health benefits. This study focuses on tyrosol (Tyr) and hydroxytyrosol (HT), two of the main phenolic compounds found in olive mill wastes. A new, simple, and eco-friendly extraction process for the removal of phenolic compounds from aqueous solutions using native ß-cyclodextrin (ß-CD) in the solid state has been developed. Several ß-CD/biophenol molar ratios and biophenol concentrations were investigated, in order to maintain ß-CD mostly in the solid state while optimizing the extraction yield and the loading capacity of the sorbent. The extraction efficiencies of Tyr and HT were up to 61%, with a total solid recovery higher than 90% using an initial concentration of 100 mM biophenol and 10 molar equivalents of ß-CD. The photochemical stability of the complexes thus obtained was estimated from ∆E*ab curve vs. illumination time. The results obtained showed that the phenols encapsulated into solid ß-CD are protected against photodegradation. The powder obtained could be directly developed as a safe-grade food supplement. This simple eco-friendly process could be used for extracting valuable biophenols from olive mill wastewater.

An exploratory study of energy reserves and biometry as potential tools for assessing the effects of pest management strategies on the earwig, Forficula auricularia L.

Apple orchards are heavily treated crops and some sprayed insecticides are recognized to have toxic effects on non-target arthropods. Earwigs are important natural enemies in pip-fruit orchards and contribute to the biological control of aphids. In addition, due to their ease of capture and identification, they are an interesting potential bioindicator of the possible detrimental effects of different orchard management strategies. In this study, we measured the energy reserves and some morphological traits of Forficula auricularia L. sampled in apple orchards under management strategies (organic versus integrated pest management (IPM)). We observed a significant decrease in mass (22 to 27%), inter-eye width (3%), and prothorax width (2 to 5%) in earwigs from IPM compared to organic orchards. Energy body reserves also confirmed these results with a significant decrease of 48% in glycogen and 25 to 42% in lipid content in earwigs from IPM compared to organic orchards. However, the protein content was approximately 70% higher in earwigs from IPM than in organic orchards. Earwigs sampled in IPM orchards may adapt to minimize the adverse toxic effects of pesticide treatments using a large number of strategies, which are reflected in changes to their energy reserves. These strategies could, in turn, influence the population dynamics of natural enemies and impair their role in the biological control of pests in apple orchards.

Redox Reactivity of Cerium Oxide Nanoparticles Induces the Formation of Disulfide Bridges in Thiol-Containing Biomolecules.

The redox state of disulfide bonds is implicated in many redox control systems, such as the cysteine-cystine couple. Among proteins, ubiquitous cysteine-rich metallothioneins possess thiolate metal binding groups susceptible to metal exchange in detoxification processes. CeO2 NPs are commonly used in various industrial applications due to their redox properties. These redox properties that enable dual oxidation states (Ce(IV)/Ce(III)) to exist at their surface may act as oxidants for biomolecules. The interaction among metallothioneins, cysteine, and CeO2 NPs was investigated through various biophysical approaches to shed light on the potential effects of the Ce(4+)/Ce(3+) redox system on the thiol groups of these biomolecules. The possible reaction mechanisms include the formation of a disulfide bridge/Ce(III) complex resulting from the interaction between Ce(IV) and the thiol groups, leading to metal unloading from the MTs, depending on their metal content and cluster type. The formation of stable Ce(3+) disulfide complexes has been demonstrated via their fluorescence properties. This work provides the first evidence of thiol concentration-dependent catalytic oxidation mechanisms between pristine CeO2 NPs and thiol-containing biomolecules.

Accumulation of nanoparticles in "jellyfish" mucus: a bio-inspired route to decontamination of nano-waste.

The economic and societal impacts of nano-materials are enormous. However, releasing such materials in the environment could be detrimental to human health and the ecological biosphere. Here we demonstrate that gold and quantum dots nanoparticles bio-accumulate into mucus materials coming from natural species such as jellyfish. One strategy that emerges from this finding would be to take advantage of these trapping properties to remove nanoparticles from contaminated water.

Decontamination of nanoparticles from aqueous samples using supramolecular gels.

The growing use of nanomaterials and their associated risks necessitate the emergence of efficient decontamination systems. The main objective of this study is to develop a new prototype based on artificial supramolecular hydrogel capable of removing nanoparticle (NP) waste and nanomaterial by-products from aqueous suspensions. We demonstrate the high trapping efficacy of the low-molecular-weight gelators (LMWG) for very small particles (quantum dots (QDs), gold nanoparticles (AuNPs), TiO2 nanoparticles (TiO2-NPs), below 50 nm in diameter) from aqueous suspensions. The performance levels of removing nanoparticles from contaminated effluents could lead to a competitive alternative to filtration and dialysis devices.

An adaptable mesocosm platform for performing integrated assessments of nanomaterial risk in complex environmental systems.

Physical-chemists, (micro)biologists, and ecologists need to conduct meaningful experiments to study the environmental risk of engineered nanomaterials with access to relevant mechanistic data across several spatial and temporal scales. Indoor aquatic mesocosms (60L) that can be tailored to virtually mimic any ecosystem appear as a particularly well-suited device. Here, this concept is illustrated by a pilot study aimed at assessing the distribution of a CeO2-based nanomaterial within our system at low concentration (1.5 mg/L). Physico-chemical as well as microbiological parameters took two weeks to equilibrate. These parameters were found to be reproducible across the 9-mesocosm setup over a 45-day period of time. Recovery mass balances of 115 ± 18% and 60 ± 30% of the Ce were obtained for the pulse dosing and the chronic dosing, respectively. This demonstrated the relevance of our experimental approach that allows for adequately monitoring the fate and impact of a given nanomaterial.

Exposure to cerium dioxide nanoparticles differently affect swimming performance and survival in two daphnid species.

The CeO2 NPs are increasingly used in industry but the environmental release of these NPs and their subsequent behavior and biological effects are currently unclear. This study evaluates for the first time the effects of CeO2 NPs on the survival and the swimming performance of two cladoceran species, Daphnia similis and Daphnia pulex after 1, 10 and 100 mg.L⁻¹ CeO2 exposures for 48 h. Acute toxicity bioassays were performed to determine EC50 of exposed daphnids. Video-recorded swimming behavior of both daphnids was used to measure swimming speeds after various exposures to aggregated CeO2 NPs. The acute ecotoxicity showed that D. similis is 350 times more sensitive to CeO2 NPs than D. pulex, showing 48-h EC50 of 0.26 mg.L⁻¹ and 91.79 mg.L⁻¹, respectively. Both species interacted with CeO2 NPs (adsorption), but much more strongly in the case of D. similis. Swimming velocities (SV) were differently and significantly affected by CeO2 NPs for both species. A 48-h exposure to 1 mg.L⁻¹ induced a decrease of 30% and 40% of the SV in D. pulex and D. similis, respectively. However at higher concentrations, the SV of D. similis was more impacted (60% off for 10 mg.L⁻¹ and 100 mg.L⁻¹) than the one of D. pulex. These interspecific toxic effects of CeO2 NPs are explained by morphological variations such as the presence of reliefs on the cuticle and a longer distal spine in D. similis acting as traps for the CeO2 aggregates. In addition, D. similis has a mean SV double that of D. pulex and thus initially collides with twice more NPs aggregates. The ecotoxicological consequences on the behavior and physiology of a CeO2 NPs exposure in daphnids are discussed.

Role of molting on the biodistribution of CeO2 nanoparticles within Daphnia pulex.

As all arthropods, microcrustaceans shed their chitinous exoskeleton (cuticule, peritrophic membrane) to develop and grow. While the molting is the most crucial stage in their life cycle, it remains poorly investigated in term of pollutant biodistribution within the organisms. In this paper, we used optical, electronic, and X ray-based microscopies to study the uptake and release of CeO2 nanoparticles by/from Daphnia pulex over a molting stage. We measured that D. pulex molts every 59 ± 21 h (confidence interval) with growth rates about 1.1 or 1.8 µm per stage as a function of the pieces measured. Ingestion via food chain was the main route of CeO2 nanoparticles uptake by D. pulex. The presence of algae during the exposure to nanoparticles (sub-lethal doses) enhanced by a factor of 3 the dry weight concentration of Ce on the whole D. pulex. Nanoparticles were localized in the gut content, in direct contact with the peritrophic membrane, and on the cuticle. Interestingly, the depuration (24 h with Chlorella pseudomonas) was not efficient to remove the nanoparticles from the organisms. From 40% to 100% (depending on the feeding regime during exposure) of the CeO2 taken up by D. pulex is not release after the depuration process. However, we demonstrated for the first time that the shedding of the chitinous exoskeleton was the crucial mechanism governing the released of CeO2 nanoparticles regardless of the feeding regime during exposure.

Lipid oligonucleotide conjugates as responsive nanomaterials for drug delivery.

We report Lipid OligoNucleotide conjugates (LONs) bearing either two or three hydrophobic chains. LONs self-assemble into micellar aggregates, which provide a suitable reservoir for hydrophobic drugs such as paclitaxel. Our results demonstrate that the composition of the LONs both in terms of the lipid and the oligonucleotide sequence impacts their ability to host lipophilic molecules. Interestingly, binding of the complementary oligonucleotide selectively induces the release of part of the drug payload of the aggregates. These LON based micelles, which efficiently host hydrophobic drugs, represent an original stimuli-responsive drug delivery system.

Larvicidal activity of extracts from Artemisia species against Culex pipiens L. mosquito: comparing endemic versus ubiquist species for effectiveness.

The larvicidal activity of ethanolic leaf extracts from two Artemisia species, Artemisia campestris var. glutinosa and A. molinieri, on mosquito Culex pipiens Linnaeus (Diptera, Culicidae) larvae was investigated. Since A. molinieri is a rare and protected species confined to temporary ponds of Southern France, its toxic activity may help to value this species and to finance its conservation. A. molinieri extracts showed a higher larvicidal activity (from 50 ppm (K=9.488, DDL=4, P<0.001)) than those from A. campestris var glutinosa (from 500 ppm (K=9.488, DDL=4, P<0.01)) after 48 h of exposure. Calculated lethal concentrations, after 48 h of exposure, (LC(50)) were low, 9091 and 9898 ppm for A. molinieri and A. campestris var. glutinosa extracts, respectively, but using a non-pollutant solvent (ethanol). However, A. molinieri may be valued as an environmentally friendly biocide and developing its culture may be of interest for both pesticide activity and conservation purpose.

Organic pollution and genotoxicity of sediments of the Palun marshes (Berre lagoon, France).

The impact of industrial, rural, and urban activities on two runnels (B1, B2, and B3 from Beausset runnel and V1 and V2 from Vallat du Ceinturon runnel) located in the Palun marshes (Berre lagoon, France) was evaluated by analyzing 16 polycyclic aromatic hydrocarbons (PAHs), 1-nitropyrene (1-NP), 1-aminopyrene (1-AP), and six pesticides in sediment samples. The mutagenicity was assessed with the Salmonella mutagenicity test using tester strains TA98+S9 Mix and YG1041 +/- S9 Mix. The clastogenicity was evaluated with the micronucleus assay on Chinese Ovarian cells +/- S9 Mix. A gradient of PAHs concentrations was observed from B1 (3359 microg kg(-1) dry weight [dw]), close to industrial zones, to V2 (497 microg kg(-1) dw), away from the source of pollution. Similar gradient was noted for 1-AP (from B1: 11.8 microg kg(-1) dw to V2: 0.6 microg kg(-1) dw). However, this trend was not observed in 1-NP concentrations (concentrations ranged from 1.2 microg kg(-1) dw [V1] to 0.4 microg kg(-1) dw [B1]). Pesticides were detected in all samples. Diazinon and dieldrin were found in high concentrations in B1 extracts (74.5 and 39.9 microg.kg(-1) dw, respectively). All the sediments except V2 were mutagenic with strain TA98+S9 Mix. The mutagenicity was linked to the presence of PAHs (V1), nitroarenes (B1 and B3) and aromatic amines (B2). All sediments were clastogenic with and without S9 Mix except V1 extract, which was negative without S9 Mix. Overall, the two runnels in the Palun marshes were found to be polluted by many organic compounds that originate from direct human activities and pose a significant genotoxic risk.

Molecular characterization of the invasive Asian tiger mosquito, Aedes (Stegomyia) albopictus (Diptera: Culicidae) in Corsica.

The Asian tiger mosquito Aedes albopictus, vector of various human viruses and parasites, has recently spread and established in many temperate regions including European countries. In the present study, we developed a simple PCR-based assay (the amplification of the internal transcribed spacer ITS2 within nuclear ribosomal rDNA) for molecular identification of A. albopictus and confirmed its presence in Corsica island. This assay may (i) facilitate future large scale studies and avoid misidentifications, especially because of the presence of co-occurring close species in this island and (ii) contribute to the monitoring of A. albopictus populations required for targeted control programs.

Amphiphilic copolymer for delivery of xenobiotics: in vivo studies in a freshwater invertebrate, a Mesostominae flatworm.

The synthesis of an amphiphilic polymethacrylate copolymer containing cholesterol hydrophobic moieties and rhodamine as a fluorescent probe, the formation of microspheres, and the uptake of these microspheres in an invertebrate are reported. The cholesterol-derived methacryloyl monomer, which was prepared via a one-step synthesis, was copolymerized with methacrylic acid and methacryloxyethyl thiocarbamoyl rhodamine B in the presence of AIBN as initiator. The obtained dye-labeled copolymer was characterized by (1)H NMR and UV-vis spectroscopy. Fluorescence and TEM microscopies studies show that this amphiphilic copolymer aggregates to give microspheres with diameters ranging from approximately 3 to 11 microm. The in vivo study in a freshwater invertebrate, a Mesostominae flatworm (Rhabdocoela, Thyphloplanidae), indicates that the microspheres enter the cells by endocytosis. The data collected demonstrate that the rhodamine B covalently attached to the amphiphilic copolymers is bioaccumulated without being translocated out of the cell by the multixenobiotic resistance (MXR) transporters. As the MXR system is similar to the multidrug resistance (MDR) first observed in tumor cell lines resistant to anticancer drugs, the present data confirm the significant role that amphiphilic copolymers can play in the ongoing development of drug delivery strategies to overcome multidrug resistance. These investigations illustrate a promising approach for the development of new medical and ecotoxicological tools that can deliver specific molecules within cells.

Evaluation of the genotoxicity of river sediments from industrialized and unaffected areas using a battery of short-term bioassays.

The present investigation evaluated the capacity of the Salmonella mutagenicity test, the comet assay, and the micronucleus assay to detect and characterize the genotoxic profile of river sediments. Three stations were selected on an urban river (Bouches du Rhône, France) exposed to various sources of industrial and urban pollution (StA, StB, and StC) and one station on its tributary (StD). One station in a nonurban river was included (REF). The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were determined by HPLC, and the genotoxicity of the sediments was monitored by the Salmonella mutagenicity test (TA98 + S9, YG1041 +/- S9), the comet assay, and the micronucleus assay on CHO cells. Chemical analysis showed that the total PAH concentrations ranged from 23 microg kg(-1) dw (REF) to 1285 microg kg(-1) dw (StD). All the sediments were mutagenic in the Salmonella mutagenicity test. The mutagenicity was probably induced by the presence of nitroarenes (StA, StB, StC, and StD) and aromatic amines (REF) as deduced from the mutagenicity profiles of strains YG1041 +/- S9 and TA98 + S9. The comet assay revealed direct DNA lesions in REF, StA, and StB sediments and metabolization-dependent DNA damage in StC and StD. The micronucleus assay showed an absence of clastogenicity for StA +/- S9 and StC-S9, and a significant clastogenicity +/- S9 for the three other stations. The genotoxicity ranking determined by the comet assay + S9 matched the ranking of total and carcinogenic PAH concentrations, and this assay was found to be the most sensitive.

Expression of the heat shock protein Hsp70 in chloride target cells of mayfly larvae from motorway retention pond: a biomarker of osmotic shock.

The aim of this work was to study, by an in toto immunohistochemical technique, the expression pattern of the heat shock protein, Hsp70, in the widely used bioindicator species Cloeon dipterum (Linnaeus 1761) (Ephemeroptera, Baetidae), living in a motorway retention pond. All sampling and measurements have been performed from March 2002 to March 2003. The water physicochemical analyses have revealed a large increase in Na(+) and Cl(-) concentrations after the de-icing road surface in winter related to motorway maintenance that correspond to an osmotic shock (from 3.1 to 105.7 mg L(-1) for Na(+) and from 3.5 to 193.9 mg L(-1) for Cl(-)). An expression of Hsp70 was observed in the chloride cells only during the osmotic shock. In contrast, the gill insertions were Hsp70 immunoreactive in specimens collected all along the year. For comparison, the expression of Hsp70 was investigated in specimens collected in a temporary pond. C. dipterum larvae living in this pond, not submitted to such osmotic shock, do not express Hsp70 neither in chloride cells nor in gill insertions. Likewise, the expression of Hsp70 was not detected in these structures during the drying period when the abiotic conditions become progressively stressful (elevation of temperature and anoxia). As chloride cells play a key role in osmoregulation, their functional integrity is crucial for the survival of the mayfly larvae in occasionally salty freshwaters. According to the well known protective role of the Hsp70 stress proteins, it is likely that the induction of Hsp70 may protect the chloride cells from osmotic shock injuries resulting from the increase in salinity. So, the Hsp70 induction in chloride cells is designed as a useful biomarker of osmotic shock. The in toto immunohistochemical detection of Hsp70 allows to characterize both the exposure situation and biological effects in target cells induced by stresses. This method could be used as a complementary qualitative approach in the biomarker actual concept. Finally, this investigation that combines this osmotic shock biomarker and this kind of bioindicator species would be a helpful tool for the monitoring of freshwater ecological systems.