Platinum (Pt) is a Technology Critical Element (TCE) which, since the 1990s, has been mainly used in the industry in catalytic converters for automobile emission control. Previous studies have shown ...Pt contamination of road-side sediments and surface sediments in urban rivers and lakes but few of them have addressed temporal variations. The present work presents historical Pt concentration trends in 137Cs-dated sediment cores from floodplains or secondary channels at the outlets of three major French watersheds (Loire, Rhone, and Seine Rivers) covering the past ∼110 years, i.e., from the 1910s to 2021. Platinum baseline levels in the sediment were estimated for the Loire River (0.76 ± 0.22 μg kg−1 for the period ∼1910-∼1955) and the Rhone River (1.64 ± 0.41 μg kg−1), and historical Pt variations seem to reflect variations in hydrodynamics and grain size composition. Since the early 2000s, Pt concentrations in the Loire and the Rhone River sediments tend to increase (>2.5 μg kg−1) and were attributed to the use of car catalytic converters, an emerging technology since the 1990s using >50 % of European Pt demand. High and variable historical Pt concentrations (up to 14.6 μg kg−1) in the Seine River sediments may reflect legacy Pt sources due to former anthropogenic activities in this watershed, such as the use of Pt-based catalysts for petroleum refinery since the end of the 1940s, coal handling and precious metals refining, probably concealing the likely presence of an emerging traffic-related Pt signal. This first comparison of historical Pt concentration trends in sediments from contrasting watersheds allows to distinguish signals originating from different natural and anthropogenic sources (background level, historical sources, road traffic).
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•Few studies on Pt level in sediment for reconstructing the past geochemical quality•Ad-CSV analysis on selected sediments collected in dated cores in 3 French rivers•Temporal evolution of Pt concentrations (trajectory) between 1910 and 2021•Signals originating from different natural (baseline) and anthropogenic sources•Highest Pt concentrations in the Seine R. to past/historical and emerging sources
Platinum (Pt) is considered an emerging environmental micro-contaminant due to its increasing use in anthropogenic activities during the past decades. However, there are still important gaps in the ...understanding of its biogeochemical behavior in the aquatic environment – e.g. its speciation, reactivity and fate – mainly as a result of the analytical challenge of the determination of its typical ultra-trace environmental concentrations. Also, Pt is a kinetically-hindered metal displaying slow reaction kinetics, which has important implications regarding eco-toxicological studies. That is, investigation of its toxicity under laboratory-controlled conditions may therefore require ensuring that equilibrium speciation conditions are reached before starting the experiments. In order to shed further light on this issue, in this study we have monitored the speciation changes during aging of the Pt(IV) spikes in controlled media (seawater) using an UV-Vis spectrophotometry. Platinum toxicity to the green microalgae Dunaliella salina was then compared, using standardized tests, with fresh and aged Pt(IV) spikes at the mg L−1 concentration range. Following 96-hour exposure, ecotoxicological assays consisting in spectrometric measurements of chlorophyll-a concentrations and Effective Concentrations (EC) of Pt resulting in the inhibition of 10% and 50% of algae growth rate were calculated (EC10 and EC50, respectively). Daily monitoring of Pt speciation reflected the transition from PtCl62- (spike) to hydrolyzed species, probably in the form PtCl3−n(OH)3+n2-, n = 0–3. Exposure experiments showed that after a short period of aging (10 days), Pt(IV) toxicity increased one order of magnitude compared to freshly spiked media. These results confirm the relevance of considering spike aging to ensure that speciation equilibrium conditions are attained in order to produce environmental realistic eco-toxicological data.
•Platinum is a kinetically-hindered metal displaying extremely low reaction kinetics.•Platinum spike aging has a significant impact on its toxicity towards D. salina.•Speciation equilibrium conditions are essential for realistic ecotox data.
Platinum (Pt) is considered a Technology Critical Element (TCE) and an emerging metallic contaminant with increasing release into the environment. Gaps in knowledge and understanding of environmental ...levels, fate and effects of Pt still exist, especially in the marine environment. This work presents Pt concentrations in the northwestern Mediterranean coast including: (i) temporal variability from sediment cores and farmed mussels in the Toulon Bay (historically affected by intense human activities) and (ii) spatial distribution from recent wild mussels collected along ∼ 700 km coastline with contrasting ecosystems (including natural reserves), quantified using voltammetry and inductively coupled plasma-mass spectrometry. The historical (>100 years) record of Pt in sediments from the Toulon Bay suggests the existence of non-negligible Pt sources older than those related to vehicle emission devices, such as petrol industry and coal-fired activities. A strong Pt increase in more recent sediments (from ∼12 to 16 ng g−1) and mussels (8-fold increase from ∼0.12 to 0.80 ng g−1) covering the past 25 years reflect the overall evolution of Pt demand in Europe (∼20-fold increase for vehicle catalysts in 20 years). Spatial biomonitoring of Pt in mussels along the northwestern Mediterranean coast is assumed to reflect inter-site differences of Pt exposure (0.09–0.66 ng g−1) despite seasonal effect on tissue development. This study highlights the need for thorough and regular monitoring of Pt levels in sediments and biota from urbanized coastal areas in order to better assess the environmental impact of this TCE, including potential risks for marine organisms.
•Platinum levels were monitored in contrasting sites of the NW Mediterranean coast.•Historical sediments reflect non-vehicle related, old Pt anthropogenic sources.•Past 25-years sediments and mussels show recent vehicle related Pt contamination.•Biomonitoring mussels reflect the degree of Pt contamination in coastal environment.
Zinc is one of the most important trace elements for life and its deficiency, like its excess, can be fatal. In the bacterial opportunistic pathogen
Pseudomonas aeruginosa
, Zn homeostasis is not ...only required for survival, but also for virulence and antibiotic resistance. Thus, the bacterium possesses multiple Zn import/export/storage systems. In this work, we determine the expression dynamics of the entire
P. aeruginosa
Zn homeostasis network at both transcript and protein levels. Precisely, we followed the switch from a Zn-deficient environment, mimicking the initial immune strategy to counteract bacterial infections, to a Zn-rich environment, representing the phagocyte metal boost used to eliminate an engulfed pathogen. Thanks to the use of the NanoString technology, we timed the global silencing of Zn import systems and the orchestrated induction of Zn export systems. We show that the induction of Zn export systems is hierarchically organized as a function of their impact on Zn homeostasis. Moreover, we identify PA2807 as a novel Zn resistance component in
P. aeruginosa
and highlight new regulatory links among Zn-homeostasis systems. Altogether, this work unveils a sophisticated and adaptive homeostasis network, which complexity is key in determining a pathogen spread in the environment and during host-colonization.
Platinum (Pt) is a technology critical element (TCE) for which biogeochemical cycles are still poorly understood. This lack of knowledge includes Pt effects on marine organisms, which proved to be ...able to bioconcentrate this trace element. Oysters
Crassostrea gigas
were exposed to stable Pt isotope spiked daily in seawater for 35 days. Seawater was renewed daily and spiked (with Pt(IV)) to three nominal Pt concentrations (50, 100, and 10,000 ng L
−1
) for two replicate series. Organotropism study revealed that gills, and to a lesser extent mantle, are the key organs regarding Pt accumulation, although a time- and concentration-dependent linear increase in Pt levels occurred in all the organs investigated (i.e., digestive gland, gonads, gills, mantle, and muscle). In oysters exposed to Pt concentrations of 10,000 ng L
−1
, significant biomarker impairments occurred, especially at cellular levels. They reflect altered lipofuscin and neutral lipid contents, as well as intralysosomal metal accumulation. These observations were attributed to activation of excretion/detoxification mechanisms, including Pt elimination through feces and clearly support the importance of the digestive gland in the response to direct Pt exposure. Despite relatively constant condition index, the integrative biological response (IBR) index suggests a generally decreasing health status of oysters.
In coastal productive zones, phytoplankton activity may influence trace metal speciation and partitioning at short temporal scale. We coupled hourly in situ voltammetry quantification of the lead ...(Pb), cadmium (Cd), and copper (Cu) potentially bioavailable fractions, using an innovative submersible sensing probe (the TracMetal), to surface water sampling for the quantification of the targeted trace metals in the dissolved <0.2 μm and <0.02 μm fractions, suspended particles, and phytoplankton nets in the Gironde Estuary mouth. The in situ TracMetal monitoring reflected real-time dynamic Cd and Cu regeneration related to algal cells under post-bloom conditions as well as Pb remobilization due to photoreduction of colloids. The potentially bioavailable fraction consisted in 30, 30–50 and <10 % of the total dissolved fraction for Pb, Cd, and Cu, respectively, representing crucial ecotoxicological information. Metal bioconcentration factors using the dynamic fraction concentrations showed levels up to 107 for Cu in phytoplankton.
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•Pb, Cd, Cu concentrations in dissolved, particulate, and phytoplankton fractions•In situ quantification of dynamic (dissolved bioavailable) metal species•Simultaneous monitoring of phytoplankton sorption and photo-redox processes•Metal bioconcentration factors applying dynamic metal concentrations
Platinum Group Elements (PGEs) are contaminants of emerging environmental concern considering their continuous increasing use and subsequent release in the environment. While recent field studies ...provided PGE levels in seawater, scarce knowledge still exists regarding PGE contamination in marine organisms, especially for rhodium (Rh). Water, macroalgae and mussels were sampled along two representative urbanized estuarine systems and adjacent coastal areas (Douro and Ave estuaries, Portugal). Rhodium and platinum (Pt) concentrations were quantified through both stripping voltammetry and mass spectrometry in collected samples. Spatial mapping of PGE contamination was, to a certain extent, correlated with proxies of urban effluents. The use of Pt/Rh ratios reflected the dominant influence of PGE traffic emissions along the Douro and inputs from various sources (including industries) on the Ave Estuary. Macroalgae and mussels PGE concentrations reflected urban pressure, amplifying environmental signals, and supporting their relevant use as bioindicators of PGE contamination in estuarine/coastal systems.
•Rhodium concentrations in wild marine organisms•Rhodium and platinum can trace urban estuarine contamination.•Macroalgae and bivalves are suitable PGE bioindicators.
•Renewable nanostructured gold-plated gel-integrated microelectrode arrays.•Selectivity to potentially bioavailable arsenite fraction.•Integrated antifouling membrane.•Direct arsenite measurements in ...fresh and marine aquatic systems.•Accurate remote in situ high-resolution measurements.
This work presents the development, characterization and field validation of newly designed gel-integrated nanostructured gold-basedmicroelectrode arrays (Au-GIMEs) enabling the direct detection of inorganic arsenite (As(III)) in fresh and marine aquatic systems. They consist of renewable Au nanoparticles (AuNP) or Au nanofilaments (AuNF) electroplated on 100- to 500- interconnected iridium (Ir)-based microdisk arrays and covered with a gel. The gel protects the sensor surface from fouling and ensures that mass transport of analytes toward the sensor surface is by diffusion only, and therefore independent of the ill-controlled hydrodynamic conditions of the media. The responses of these sensors to direct Square Wave Anodic Stripping Voltammetry (SWASV) quantification of As(III) at pH 7.6 were investigated first in 0.1 M NaNO3, then in fresh and marine water samples. The analytical responses were found to be correlated to the number of interconnected microelectrodes and the morphology of the nanostructured Au deposits but independent of the media composition. The new interconnected AuNF-GIME have sub-nanomolar detection and quantification limits fulfilling the requirement for direct monitoring of As(III) in fresh and marine aquatic systems. The AuNF-GIME were incorporated in a submersible multi-channel trace metal sensing probe for remote high-resolution monitoring. Field evaluation and validation was performed during a one-week field study in the Elbe Estuary (North Germany), from which environmental data are presented.
The water column of harbors contains significant amounts of (priority) hazardous trace metals that may be released into coastal areas of high societal and economic interests where they may disturb ...their fragile equilibria. To deepen our understanding of the processes that influence the transport of the various metal fractions and allow for a more rigorous environmental risk assessment, it is important to spatially monitor the relevant chemical speciation of these metals. It is of particular interest to assess their so-called dynamic fraction, which comprises the dissolved chemical forms that are potentially bioavailable to living organisms. In this study this was achieved in the Genoa Harbor (NW Italy) for copper (Cu), lead (Pb), cadmium (Cd) and zinc (Zn) by applying a multi-method approach. For the first time in this system the dynamic fractions of the target metals (CuDyn, CdDyn, PbDyn, ZnDyn) were observed in real-time on-board by voltammetry using innovative electrochemical sensing devices. Trace metals in the operationally defined dissolved <0.2 μm and <0.02 μm fractions were equally quantified through sampling/laboratory-based techniques. The obtained results showed a clear spatial trend for all studied metals from the enclosed contaminated part of the harbor towards the open part. The highest CuDyn and CdDyn fractions were found in the inner part of the harbor while the highest PbDyn fraction was found in the open part. The proportion of ZnDyn was negligible in the sampled area. Small and coarse colloids were involved in Cu, Cd and Zn partitioning while only coarse colloids played an important role in Pb partitioning. The determined concentrations were compared to the Environmental Quality Standards (EQS) established by the EU and those determined by the Australia and New Zealand to trigger for 99 and 95% species protection values. The results of this work allow us to highlight gaps in the EQS for which metal concentration thresholds are excessively high or non-existent and should urgently be revised. They also reflect the need to quantify the potentially bioavailable fraction of hazardous trace metals instead of just their total dissolved concentrations. The data support the establishment of environmental quality standards and guidelines based on realistic risk assessment to protect aquatic life and resources and ultimately human health.
•On-board simultaneous detection of the bioavailable fraction of Cu, Cd, Pb and Zn.•The proportion of bioavailable metal depends on the studied metals.•Spatial variation of the bioavailable target metal species is site dependent.•Coarse and small colloids influence Cu, Cd, Pb and Zn speciation.•Bioavailable and dissolved Cu concentrations surpassed ANZECC 99% trigger value.
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