Uranium contamination of bivalve Mytilus galloprovincialis, speciation and localization.

Uranium is a natural radioelement (also a model for heavier actinides), but may be released through anthropogenic activities. In order to assess its environmental impact in a given ecosystem, such as the marine system, it is essential to understand its distribution and speciation, and also to quantify its bioaccumulation. Our objective was to improve our understanding of the transfer and accumulation of uranium in marine biota with mussels taken here as sentinel species because of their sedentary nature and ability to filter seawater. We report here on the investigation of uranium accumulation, speciation, and localization in Mytilus galloprovincialis using a combination of several analytical (Inductively Coupled Plasma Mass Spectrometry, ICP-MS), spectroscopic (X ray Absorption Spectroscopy, XAS, Time Resolved Laser Induced Fluorescence Spectroscopy, TRLIFS), and imaging (Transmission Electron Microscopy, TEM, µ-XAS, Secondary Ion Mass Spectrometry, SIMS) techniques. Two cohorts of mussels from the Toulon Naval Base and the Villefranche-sur-Mer location were studied. The measurement of uranium Concentration Factor (CF) values show a clear trend in the organs of M. galloprovincialis: hepatopancreas â‰« gill > body ≥ mantle > foot. Although CF values for the entire mussel are comparable for TNB and VFM, hepatopancreas values show a significant increase in those from Toulon versus Villefranche-sur-Mer. Two organs of interest were selected for further spectroscopic investigations: the byssus and the hepatopancreas. In both cases, U(VI) (uranyl) is accumulated in a diffuse pattern, most probably linked to protein complexing functions, with the absence of a condensed phase. While such speciation studies on marine organisms can be challenging, they are an essential step for deciphering the impact of metallic radionuclides on the marine biota in the case of accidental release. Following our assumptions on uranyl speciation in both byssus and hepatopancreas, further steps will include the inventory and identification of the proteins or metabolites involved.

Validation of a carbon monoxide sampling method using polypropylene syringes: a reliable alternative method, easy to implement in the field or emergency situations.

Carbon monoxide (CO) is a lethal gas, present during incomplete combustion of carbonaceous materials. CO may be present in certain occupational atmospheres or during accidental events such as fires. Colorless and odorless, its presence can only be detected analytically. Nevertheless, the measurement methods available today may either be lacking (not available, for example, for military people deployed in the field) or not completely adapted (interference for electrochemical detectors, cost for infrared detectors). Another solution is to take samples on the field and then analyze them in a laboratory. Tedlar® bags or canisters can be used for this purpose but are relatively cumbersome. An alternative, not well described in the literature and not metrologically validated, consists in using plastic syringes. In order to generalize the use of this system and to characterize it in terms of performance and stability over time, we conducted a validation study. This method was validated using a 50-cc polypropylene syringe, over a concentration range of 2 to 40 ppm. The sampling system is efficient (sample yields between 101 and 102%) and repeatable (relative standard deviations under 2%). Storage tests were conducted on syringes containing 2 and 20 ppm carbon monoxide, indicating that the syringes can be stored for up to 2 weeks in the dark at room temperature. Coupled with a laboratory infrared analysis, this technique allows a high sensitivity and specificity. Easy to implement, rugged, inexpensive, and energy self-sufficient, this sampling system is attractive and offers a new solution for field or accidental situations.

Cd transfers during marine sediment resuspension over short and long-term period: Associated risk for coastal water quality.

Cadmium (Cd) is a highly toxic metal, regularly monitored uniformly for water quality across Europe, but scarcely for sediments. This study was designed to compare the kinetics of Cd remobilization and the amplitude of its transfers with different marine sediments. The results showed a highly reproducible transfer kinetics. Dissolved Cd was strongly and quickly removed from the dissolved phase (from 5 min up to 7 h). Then, the dissolved Cd concentration increased progressively to reach a maximal value after two weeks of mixing. The influence of the resuspension intensity representing light wind-induced resuspension up to dredging operations was observed after 2 weeks. The intensity of the sediment resuspension clearly impacted the amplitude of Cd remobilization, dissolved Cd ranging from a few ngL-1 to few hundreds of ngL-1, exceeding the maximal dissolved Cd concentration accepted by the European Union Water Framework Directive (WFD-2008/105 32/EC).

Trace Metal Contamination Impacts Predicted Functions More Than Structure of Marine Prokaryotic Biofilm Communities in an Anthropized Coastal Area.

Trace metal (TM) contamination in marine coastal areas is a worldwide threat for aquatic communities. However, little is known about the influence of a multi-chemical contamination on both marine biofilm communities' structure and functioning. To determine how TM contamination potentially impacted microbial biofilms' structure and their functions, polycarbonate (PC) plates were immerged in both surface and bottom of the seawater column, at five sites, along strong TM contamination gradients, in Toulon Bay. The PC plates were incubated during 4 weeks to enable colonization by biofilm-forming microorganisms on artificial surfaces. Biofilms from the PC plates, as well as surrounding seawaters, were collected and analyzed by 16S rRNA amplicon gene sequencing to describe prokaryotic community diversity, structure and functions, and to determine the relationships between bacterioplankton and biofilm communities. Our results showed that prokaryotic biofilm structure was not significantly affected by the measured environmental variables, while the functional profiles of biofilms were significantly impacted by Cu, Mn, Zn, and salinity. Biofilms from the contaminated sites were dominated by tolerant taxa to contaminants and specialized hydrocarbon-degrading microorganisms. Functions related to major xenobiotics biodegradation and metabolism, such as methane metabolism, degradation of aromatic compounds, and benzoate degradation, as well as functions involved in quorum sensing signaling, extracellular polymeric substances (EPS) matrix, and biofilm formation were significantly over-represented in the contaminated site relative to the uncontaminated one. Taken together, our results suggest that biofilms may be able to survive to strong multi-chemical contamination because of the presence of tolerant taxa in biofilms, as well as the functional responses of biofilm communities. Moreover, biofilm communities exhibited significant variations of structure and functional profiles along the seawater column, potentially explained by the contribution of taxa from surrounding sediments. Finally, we found that both structure and functions were significantly distinct between the biofilm and bacterioplankton, highlighting major differences between the both lifestyles, and the divergence of their responses facing to a multi-chemical contamination.

Long-term monitoring emphasizes impacts of the dredging on dissolved Cu and Pb contamination along with ultraplankton distribution and structure in Toulon Bay (NW Mediterranean Sea, France).

A long-term monitoring during dredging and non-dredging periods was performed. Total and dissolved Cu and Pb concentrations, DGT-labile Pb, ultraphytoplankton abundance and structure were monitored at four sites: dredging site, dumping site (inside/outside of a geotextile bag) and reference site. During the reference period (non-dredging), an increasing contamination in Pb, Cu and a progressive shift from Synechococcus to photosynthetic picoeukaryotes dominance was observed from reference to dumping site. Pb concentrations were significantly higher during dredging period, pointing out sediment resuspension as Pb major source of contamination. Unlike Pb, Cu concentrations were not statistically different during the two periods. Dredging period did not impact on ultraphytoplankton abundance and structure but influence heterotrophic prokaryotes abundance. Sediment resuspension is therefore a major driver of chemical and biological qualities in Toulon Bay. Furthermore, although the geotextile bag reduces particulate transport of the dredged sediment, the transport in the dissolved phase remains a major problem.

Kinetic processes of copper and lead remobilization during sediment resuspension of marine polluted sediments.

Contaminated sediments could act as a source of contamination to the surrounding environments by several processes (e.g., diffusive flux, sediment resuspension). This study aimed at highlighting the mechanisms of copper and lead mobilization from resuspended particles to the aqueous phase using laboratory experiments and a kinetic model. Three sediments, differed by their compositions and metal partition from Toulon Bay (SE France) were used. In addition, three solid/liquid ratios (0.1, 1 and 10 g L-1) allowed simulating at best natural and anthropogenic scenarios (e.g., storm, nautical traffic, dredging). We monitored metal concentrations, physicochemical parameters (pH, Eh, [O2]) and organic matter concentration along with their optical properties. Experimental results showed successive reactions over short and long terms (hour and day scale, respectively) that controlled Cu and Pb exchanges between particles and the aqueous phase over 4 weeks. The quick Cu removal was attributed to the implications of newly formed oxides while the long-term Cu release in the dissolved fraction from the more refractory solid pool is more likely related to organic complexation. In fact, we observed a transformation of the dissolved organic matter: an increase in molecular weight and in humic fluorescence properties. However, the Pb removal toward the end of the experiment could be explained by a migration toward the exchangeable sites of higher energy, which could correspond to the particulate organic matter or a combination with organic-coating carrier phases. Both kinetic rate and system response times (τi) were coherent despite the variability of parameters intrinsic to sediments (e.g., sediment composition and initial metal repartition) but also extrinsic parameters (solid/liquid ratios). Such a coherence would imply the universality of the obtained constants to be used in a more predictive approach to assess the potential of metal mobility using metal repartition in contaminated sediments when combined with hydrological and sedimentological models.

Changes in Bacterioplankton Communities Resulting From Direct and Indirect Interactions With Trace Metal Gradients in an Urbanized Marine Coastal Area.

Unraveling the relative importance of both environmental conditions and ecological processes regulating bacterioplankton communities is a central goal in microbial ecology. Marine coastal environments are among the most urbanized areas and as a consequence experience environmental pressures. The highly anthropized Toulon Bay (France) was considered as a model system to investigate shifts in bacterioplankton communities along natural and anthropogenic physicochemical gradients during a 1-month survey. In depth geochemical characterization mainly revealed strong and progressive Cd, Zn, Cu, and Pb contamination gradients between the entrance of the Bay and the north-western anthropized area. On the other hand, low-amplitude natural gradients were observed for other environmental variables. Using 16S rRNA gene sequencing, we observed strong spatial patterns in bacterioplankton taxonomic and predicted function structure along the chemical contamination gradient. Variation partitioning analysis demonstrated that multiple metallic contamination explained the largest part of the spatial biological variations observed, but DOC and salinity were also significant contributors. Network analysis revealed that biotic interactions were far more numerous than direct interactions between microbial groups and environmental variables. This suggests indirect effects of the environment, and especially trace metals, on the community through a few taxonomic groups. These spatial patterns were also partially found for predicted bacterioplankton functions, thus indicating a limited functional redundancy. All these results highlight both potential direct influences of trace metals contamination on coastal bacterioplankton and indirect forcing through biotic interactions and cascading.

Quantitative model of carbon and nitrogen isotope composition to highlight phosphorus cycling and sources in coastal sediments (Toulon Bay, France).

Nutrient loadings from either point or non-point sources to the environment are related to the growing global population. Subsequent negative impacts of nutrient loading to aquatic environments requires a better understanding of the biogeochemical cycling and better tools to track their sources. This study examines the carbon (C), nitrogen (N) and phosphorus (P) discharge and cycling in a Mediterranean coastal area from rivers to marine sediments and assesses the anthropogenic contributions. Carbon and N concentrations and isotope compositions in rivers particles, surface sediments, and sediment cores were investigated to build up a quantitative multiple-end-member mixing model for C and N isotopes. This model predicts the contribution of four natural and one anthropogenic sources to the sediments and highlighted the anthropogenic fraction of P based on the relationship with anthropogenic δ15N. Although P is a monoisotopic element and total P concentration has been the sole index to study P loading, this study suggests an alternative approach to differentiate anthropogenic and non-anthropogenic (diagenetic) P, revealed point and non-point sources of P, and the corresponding P loading. Also, the diagenetic P background has been calculated for the 50-cm sediment layer of the whole Bay.

Remobilization of polycyclic aromatic hydrocarbons and organic matter in seawater during sediment resuspension experiments from a polluted coastal environment: Insights from Toulon Bay (France).

Polycyclic aromatic hydrocarbons (PAHs) and organic matter contents were measured in seawater during resuspension experiments using sediments collected from Toulon Bay (Northwestern Mediterranean Sea, France). The studied sediments were very highly contaminated in PAHs, especially in 4-ring compounds emitted from combustion processes. The sediments used for resuspension experiments were collected at 0-2 cm (diagenetically new organic matter, OM) and 30-32 cm depths (diagenetically transformed OM). They were both mostly composed of fine particles (<63 µm), enriched in organic carbon (8.2 and 6.3%, respectively) and in PAHs (concentration of Σ34 PAHs: 38.2 and 35.7 × 103 ng g-1, respectively). The resuspension of these sediments led to an increase in concentrations of dissolved Σ34 PAHs, dissolved organic carbon (DOC) and dissolved humic- and tryptophan-like fluorophores in seawater up to 10-, 1.3-, 4.4- and 5.7-fold, respectively. The remobilization in seawater was higher for 4-6 ring PAHs, especially benzo(g,h,i)perylene, whose concentration exceeded the threshold values of the European Water Framework Directive. This noted the potential harmful effects of sediment resuspension on marine biota. From these sediment resuspension experiments, we determined OC-normalized partition coefficients of PAHs between sediment and water (Koc) and found that during such events, the transfer of PAHs from sediment particles to seawater was lower than that predicted from octanol-water partition coefficients (Kow) (i.e., measured Koc > Koc predicted from Kow). The results confirmed the sequestration role of sedimentary OC quality and grain size on PAHs; the OM diagenetic state seemed to impact the partition process but in a relatively minor way. Furthermore, differences were observed between 2-4 ring and 5-6 ring PAHs, with the latter displaying a relatively higher mobility towards seawater. These differences may be explained by the distribution of these two PAH pools within different OM moieties, such as humic substances and black carbon.

Human health risks related to the consumption of foodstuffs of plant and animal origin produced on a site polluted by chemical munitions of the First World War.

Shells fired during World War I exhibited different explosive compounds and some of these weapons also contained a wide variety of chemical warfare agents. At the end of the war, for safety purposes, the large quantity of weapons remaining on the former front needed to be dismantled and destroyed. A large amount of the remaining shells was destroyed in specific sites which led to the contamination of the surroundings in Belgium and France. In the 1920s, 1.5 million chemical shells and 30,000 explosive shells were destroyed in a place close to the city of Verdun, in the East of France. In this paper, the risk for human health related to the consumption of foodstuffs produced on this site was assessed. To this end, food products of plant and animal origin were sampled in 2015-2016 and contaminant analyses were conducted. Human exposure was assessed using a specifically built methodology. The contaminants considered in this study were trace elements (TEs - primarily Zn, As, Pb and Cd), nitroaromatic explosives (trinitrotoluene, 2,4-dinitrotoluene, 2,6-dinitrotoluene, 2-amino-4,6-dinitroluene and 4-amino-2,6-dinitrotoluene), phenylarsenic compounds including diphenylarsinic acid and triphenylarsine, perchlorate, tetrabromoethane and vinyl bromide. Depending on the compound, different approaches were used to assess the risk for both adults and children. Exposure to these contaminants through the consumption of foodstuffs produced locally on the considered site was unlikely to be a health concern. However, as for inorganic arsenic, given the presence of highly contaminated zones, it was suggested that cereals should not be grown on certain plots.

Chemical multi-contamination drives benthic prokaryotic diversity in the anthropized Toulon Bay.

Investigating the impact of human activities on marine coastal ecosystems remains difficult because of the co-occurrence of numerous natural and human-induced gradients. Our aims were (i) to evaluate the links between the chemical environment as a whole and microbial diversity in the benthic compartment, and (ii) to compare the contributions of anthropogenic and natural chemical gradients to microbial diversity shifts. We studied surface sediments from 54 sampling sites in the semi-enclosed Toulon Bay (NW Mediterranean) exposed to high anthropogenic pressure. Previously published chemical data were completed by new measurements, resulting in an in depth geochemical characterization by 29 representative environmental variables. Bacterial and archaeal diversity was assessed by terminal restriction fragment length polymorphism profiling on a selection of samples distributed along chemical gradients. Multivariate statistical analyses explained from 45% to 80% of the spatial variation in microbial diversity, considering only the chemical variables. A selection of trace metals of anthropogenic origin appeared to be strong structural factors for both bacterial and archaeal communities. Bacterial terminal restriction fragment (T-RF) richness correlated strongly with both anthropogenic and natural chemical gradients, whereas archaeal T-RF richness demonstrated fewer links with chemical variables. No significant decrease in diversity was evidenced in relation to chemical contamination, suggesting a high adaptive potential of benthic microbial communities in Toulon Bay.

Evidencing the Impact of Coastal Contaminated Sediments on Mussels Through Pb Stable Isotopes Composition.

Heavily contaminated sediments are a serious concern for ecosystem quality, especially in coastal areas, where vulnerability is high due to intense anthropogenic pressure. Surface sediments (54 stations), 50 cm interface cores (five specific stations), river particles, coal and bulk Pb plate from past French Navy activities, seawater and mussels were collected in Toulon Bay (NW Mediterranean Sea). Lead content and Pb stable isotope composition have evidenced the direct impact of sediment pollution stock on both the water column quality and the living organisms, through the specific Pb isotopic signature in these considered compartments. The history of pollution events including past and present contaminant dispersion in Toulon Bay were also demonstrated by historical records of Pb content and Pb isotope ratios in sediment profiles. The sediment resuspension events, as simulated by batch experiments, could be a major factor contributing to the high Pb mobility in the considered ecosystem. A survey of Pb concentrations in surface seawater at 40 stations has revealed poor seawater quality, affecting both the dissolved fraction and suspended particles and points to marina/harbors as additional diffuse sources of dissolved Pb.

Seasonal variations of coastal sedimentary trace metals cycling: insight on the effect of manganese and iron (oxy)hydroxides, sulphide and organic matter.

The combination of analysis, multivariate treatment (PCA) and chemical speciation calculation confirmed the control of Fe, Mn, sulphide and organic matter on metals dynamics in coastal sediments (0-5 cm surface sediments and sediments cores) of Toulon Bay (NW Mediterranean). The temporal monitoring of the physic-chemical parameters as well as the dissolved/particulate minor (Fe/Mn) and trace elements (i.e. Ag, Cd, Co, Cu, Ni, Pb, Zn, …) concentrations in porewaters and sediments were assessed. Multivariate treatment revealed different behaviours for marine elements, terrestrial ones and contaminants. Seasonal variations of metals mobilization in porewater were observed, related to diagenesis activity. Element mobility was studied by selective extractions (ascorbate, acid and alkaline) on sediments. Thermodynamic simulation (PHREEQC) was performed to calculate the elemental dissolved speciation, the mineral saturation index and then to simulate the solid/liquid interaction through precipitation processes, studying the contrasted influence of dissolved organic matter and sulphide.

Sources and historical record of tin and butyl-tin species in a Mediterranean bay (Toulon Bay, France).

Concentrations of inorganic tin (Sn(inorg)), tributyltin (TBT) and its degradation products dibutyltin (DBT) and monobutyltin (MBT) were measured in surface sediments and in two cores from the Toulon Bay, hosting the major French military harbour. Anticipating planned dredging, the aim of the present work is to map and evaluate for the first time the recent and historic contamination of these sediments by inorganic and organic Sn species derived from antifouling paints used for various naval domains including military, trade, tourism and leisure. Tin and butyl-Sn concentrations in the bay varied strongly (4 orders of magnitude), depending on the site, showing maximum values near the shipyards. The concentrations of total Sn (1.3-112 µg g(-1)), TBT (<0.5-2,700 ng g(-1)), DBT (<0.5-1,800 ng g(-1)) and MBT (0.5-1,000 ng g(-1)) generally decreased towards the open sea, i.e. as a function of both distance from the presumed main source and bottom currents. Progressive degradation state of the butyl-Sn species according to the same spatial scheme and the enrichment factors support the scenario of a strongly polluted bay with exportation of polluted sediment to the open Mediterranean. Low degradation and the historical records of butyl-Sn species in two (210)Pb-dated sediment cores, representative of the Northern Bay, are consistent with the relatively recent use of TBT by military shipyards and confirm maximum pollution during the 1970s, which will persist in the anoxic sediments for several centuries. The results show that (a) degradation kinetics of butyl-Sn species depend on environmental conditions, (b) the final degradation product Sn(inorgBT) is by far the dominant species after 10-12 half-life periods and (c) using recent data to reliably assess former TBT contamination requires the use of a modified butyl-Sn degradation index BDI(mod). Resuspension of extremely contaminated subsurface sediments by the scheduled dredging will probably result in mobilization of important amounts of butyl-Sn species.

Study of the spatial and historical distribution of sediment inorganic contamination in the Toulon bay (France).

This study presents trace elements levels in surface and deep sediments of the Toulon bay (SE France) subjected to anthropogenic inputs (navy base, harbors, etc.). The studied elements (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) are defined as priority contaminants in aquatic systems. Fifty-five points scattered on the entire bay were sampled, allowing the determination of contaminants distribution with a high resolution. Several approaches were used to assess the degree of contamination and the potential toxicity of the Toulon bay sediments: comparison to the French legislation, surface-weighted average metal concentrations, enrichment factors (EF), geoaccumulation indices (Igeo), trace element stock calculation and comparison to sediment quality guidelines. A principal component analysis was performed to reveal common behavior of the studied contaminants. Results demonstrated the very high contamination of the small bay, especially in Hg (EF up to 1500), Cu, Pb and Zn, with export to the large bay further governed by hydrodynamics.

Development and validation of a sensitive and selective method using GC/MS-MS for quantification of 5-fluorouracil in hospital wastewater.

Pollution of the environment by pharmaceuticals is a subject of growing scientific and societal concern. However, few quantitative data have been reported concerning hospital wastewater contamination. Among the different molecules used at hospital, antineoplastic drugs appear to be of special interest, and 5-fluorouracil (5-FU) can be considered as a key compound of this therapeutic class. To monitor this pharmaceutical in hospital wastewater, a highly specific and selective method was developed using gas chromatography tandem mass spectrometry after solid-phase extraction. This sensitive method (limit of quantification = 40 ng L(-1)) was then applied to assess sewage contamination of a middle-size hospital with oncology service located in Paris, France. Native 5-FU was detectable in 12 of the 14 analysed samples. In positive samples, concentration range was measured from 0.09 to 4.0 microg L(-1). Finally, a predicting model for the hospital wastewater concentrations is presented, and results of this model are discussed.

Molecularly imprinted polymers for the clean-up of a basic drug from environmental and biological samples.

A molecularly imprinted polymer (MIP) was synthesized and evaluated to selectively extract an alpha-blocker, i.e. alfuzosin, from human plasma. The synthesis of the MIP was performed in dichloromethane with methacrylic acid as monomer and the target drug as template. A first series of experiments was carried out in dichloromethane to estimate the potential of the MIP in its specific recognition medium, i.e. dichloromethane, by developing a selective procedure and by measuring the capacity of the sorbent. An optimized procedure was developed for the selective extraction of alfuzosin with a recovery close to 100% in this medium and a specific capacity of 1.3 micromol g(-1) of MIP was measured. A study in aqueous media was also carried out by a comprehensive approach of the retention mechanism in order to build a selective procedure of extraction. The effects of the amount and of the charge of cations were studied and an optimal pH value was defined to limit matrix effects. Then, the alfuzosin MIP was then directly used to selectively extract the target drug from human plasma with an extraction recovery of 60%. Lastly, a soil was extracted by a pressurized solvent and the resulting extract was cleaned up on the MIP, showing the possibility to use this selective sorbent for the sample treatment of various complex matrices.