The current socio-economic, environmental and public health challenges that countries are facing clearly need common-defined strategies to inform and support our transition to a sustainable economy. ...Here, the technology-critical elements (which includes Ga, Ge, In, Te, Nb, Ta, Tl, the Platinum Group Elements and most of the rare-earth elements) are of great relevance in the development of emerging key technologies—including renewable energy, energy efficiency, electronics or the aerospace industry. In this context, the increasing use of technology-critical elements (TCEs) and associated environmental impacts (from mining to end-of-life waste products) is not restricted to a national level but covers most likely a global scale. Accordingly, the European COST Action TD1407: Network on Technology-Critical Elements (NOTICE)—from environmental processes to human health threats, has an overall objective for creating a network of scientists and practitioners interested in TCEs, from the evaluation of their environmental processes to understanding potential human health threats, with the aim of defining the current state of knowledge and gaps, proposing priority research lines/activities and acting as a platform for new collaborations and joint research projects. The Action is focused on three major scientific areas: (i) analytical chemistry, (ii) environmental biogeochemistry and (iii) human exposure and (eco)-toxicology.
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•High trace metals concentration confined within the Gulf of Cadiz inner shelf.•Southeastward currents transport Cd, Co, Cu, Ni, and Pb onto the Mediterranean Sea.•Countercurrents ...advect Cd, Co, Cu, Fe, Ni, and Zn towards the Portuguese shelf.•Variable currents accumulate Ag, Cd, Co, Cu, Fe, Pb, and Zn near their source.•The Guadalquivir River supply of trace metals is related to the winter NAO.
The GoC shelf waters present much higher concentrations of dissolved Cu, Cd, and Zn than other coastal areas, constituting an important source of these elements onto its neighbouring basins, i.e., the Atlantic Ocean and the Mediterranean Sea. In this study we assessed the role of the GoC surface currents in the trace metals transport. For this purpose, ten dissolved (<0.22 µm) trace metals were sampled (Ag, Cd, Co, Cu, Fe, Mo, Ni, Pb, Zn, V) along the GoC continental shelf, and their spatial and temporal distribution was interpreted according to the surface circulation. Results show that the complex surface circulation over the shelf confines the metals concentration mainly along the inner shelf and determines their transport patterns: under southeastward currents, Cd, Co, Cu, Ni, and Pb are transported toward the Mediterranean Sea; under northwestward countercurrents, Cd, Co, Cu, Fe, Ni, and Zn are transported toward the southern and, occasionally, the western Portuguese shelf; under variable currents, Ag, Cd, Co, Cu, Fe, Pb, and Zn tend to accumulate near their source. Considering that some of these metals have not been analysed before in this region (Ag, Mo, V), or that the spatial distribution of certain metals (Ag, Fe, Mo, Pb, V) has not been interpreted in terms of the ocean circulation, this work could be considered as a baseline study for future comparisons.
Rhodium (Rh) is present at the Earth's surface at ultra-trace concentrations (0.06ngg−1); however, its use in catalytic converters has increased its deposition nearby traffic pressure and therefore ...the interest in analytical techniques for Rh determination has raised in the recent years. In this study we propose an improvement of Rh measurement by adsorptive voltammetry applying second-derivative signal transformation.
The optimization of experimental parameters affecting the voltammetric analysis were carried out using sediment samples; these include the amount of sample digest used, the hydrochloric acid and formaldehyde concentrations, deposition potential and equilibration time. The use of the second derivative transformation provided well-defined peaks due to the minimization of background interferences, leading to a significant decrease in the detection limits. Accordingly, a detection limit of 200fM Rh in the cell was obtained, which corresponds to 14pgg−1 of Rh for 200mg of sediments.
The optimized methodology was applied to the analysis of Rh in a sediment core collected close to a motorway bridge from Tagus Estuary (Lisbon, Portugal). Here, Rh concentrations ranged from 0.06 to 0.47ngg−1, showing a surface Rh-enrichment linked to traffic, which was consistent with a Pt superficial peak. Reference materials were also analyzed, including road dust (BCR-723) and river sediment (JSD-2), and values obtained were in agreement with certified concentrations and previously values reported in the literature.
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•Second derivative transformation improves Rh determination by adsorptive voltammetry.•Lower detection limits are obtained compared to the methods proposed before.•Rh concentration in non-contaminated sediments has been reported for the first time.•Traffic pressure causes a superficial Pt and Rh-enrichment in sediments.
The geochemical behaviour of dissolved trace elements in sediment interstitial waters from the Vigo Ria (Galicia, Spain) has been determined. Dissolved concentrations in the pore waters ranged ...between 1.7–23.2 nM for Co, 1.5–131 nM for Cu, 19.5–159 nM for Ni, 0.02–19.3 nM for Pb, 5.4–260 nM for V and 0.2–241 nM for Zn. Values for Cu, Pb and Zn were highest along the axis of the ria, whereas Co, Ni, V and Zn were more abundant in the area of the industrialised shipyards. The metal profiles were affected by sedimentary redox processes, which were monitored by means of Mn and Fe concentrations and pore water pH. Dissolved Cu and V had relatively high concentrations in the oxic surface layer and their concentrations decreased with depth, although in deeper layers concentrations of V increased in association with the presence of dissolved organic ligands. Cobalt and Ni followed the behaviour of Mn, although they were depleted in surface oxic layers their concentrations increased in the Mn reduction zone. Lead and Zn had highly irregular profiles because of their lower redox-sensitivity and their complexation with organic material is not as pronounced as that for Cu. Dissolved metal concentrations in overlying waters oscillated between 0.7–2.1 nM for Co, 5.5–50.5 nM for Cu, 4.6–10.0 nM for Ni, 1.4–9.1 for Pb, 5.7–28.5 nM for V and 14.6–66.5 nM for Zn. Using Fick's first law of diffusion, the benthic fluxes of the elements varied between 0.03–0.24 nmol cm
−
2
y
−
1
for Co, (−
0.02)–1.11 nmol cm
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2
y
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1
for Cu, 0.16–1.70 nmol cm
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2
y
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1
for Ni, (−0.14)–0.03 nmol cm
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2
y
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1
for Pb, 1.52–4.35 nmol cm
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2
y
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1
for V and (−
0.37)–0.90 nmol cm
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2
y
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1
for Zn. Fluxes were higher in the ria axis for Cu, Ni, V and Zn and in the shipyard area for Co, while Pb fluxes were negligible at all the stations. This work has demonstrated that the redox geochemistry and diagenetic processes of the sediments and pore waters control the benthic fluxes in the Vigo Ria. When the upper layer of the sediment is oxic a high exportation of Cu and V to the overlying waters occurs and during less oxidizing conditions of this layer, Ni and Co exportation from the pore water increases. Dissolved trace metal benthic fluxes to the Vigo Ria were significant for most of the metals (Cu, Ni and V) and were of the same order of magnitude to the riverine inputs.
All information published on metals in this region up to the year 2000 is reviewed from a biogeochemical viewpoint.
The 18 Galician Rias, comprising 25% of the Iberian Peninsula coastline, form a ...unique system within the European continental Atlantic coast and provide a useful reference area for studies of metals. These rias are sensitive to anthropogenic influence due to the socioeconomic importance generated in these areas by industry, aquaculture, port activities, fishing, tourism and, accordingly, several islands lying within close proximity to the rias have recently been declared natural parks. Aquaculture in the Galician Rias is a growth industry and in 2000 the rias supported 3386 mussel rafts producing 2.5×10
8 kg year
−1, i.e. 40% of European Union total seafood production. The Galician Rias are partially stratified estuaries with positive residual circulation with fresh (runoff lower than 100 m
3 s
−1) and salt water mixing inside the basins. This behaviour has direct consequences on metal fluxes whereby the rias behave as a barrier and accumulate metals in the sediments. Metals tend to deposit close to point sources and remobilization occurs inside the ria, leading to a seaward decrease in metal concentration. With the exception of the Ulla (Arosa Ria) and Eume (Ares-Betanzos Ria) head rivers and the Lagares river (Vigo Ria) the available data suggest that riverine freshwater inputs are not the main source of contamination.
Metal studies reported in the literature mainly relate to Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn, and to a lesser extent Hg and Sn. Studies of other harmful metals such as Ag, Se and As are notably lacking. In addition, the studies have been localized and mainly restricted to the surface sediment. Data of heavy metals in the dissolved phase, suspended particulate matter and biota is scarce in the mainstream literature and should be considered in the future research. From the entire Galician coast, data from seven rias of socio-economic importance form the bulk of the published work. There is an urgent need to standardize procedures, employ ‘clean’ procedures to avoid contamination of samples and regular assessment of analytical accuracy with CRMs in order that results can be compared among the scientific community and produce reliable results. The continuation of coastal environmental studies requires an enlargement of the sampling locations as well as systematic and periodic analysis of known pollution sources in order to decide whether coastal regeneration action is needed. Studies dedicated to metals in the water column are lacking and need more attention in future research. The majority of the available data correspond to the fluvial front (30%) at ria head and, to a lesser extent, to the oceanic front (3%), under summer upwelling events.
Current awareness of the rias suggests that they are not contaminated although there is some evidence of important localized anthropogenically induced enrichments at the outflow of the Lagares River (Pb, Zn), the San Simón inlet (Pb) and near to the harbor (Pb, Zn, Cu) in the Vigo Ria, the inner part (Cu, Zn, Hg, Pb) of the Pontevedra Ria, the Ulla River estuary (Cu, Cr, Mn, Ni; Zn) in the Arosa Ria, the inner zone (Cu, Pb, Zn) of the Coruña Ria, the Ferrol Ria (Zn) and the Eume Estuary (Zn, Mn, Ni, Co) in the Ares-Betanzos Ria. In addition, TBT enrichment has been found along the Galician coast, being highest in the industrial bays (Vigo, Coruña and Ferrol). Nevertheless, it is important to point out the lack of information concerning the relationship between metal concentrations in different fractions of sediments and/or water and their bioavailability and toxicity on biota in order to confirm metal contamination dangers.
The present paper reviews all the information published on metals in the rias up to the year 2000 and takes a biogeochemical standpoint, i.e. metal presence in the ria reservoirs: water column, suspended particulate matter, sediments and biota, as well as the fluvial and oceanic frontiers.
A number of trace elements (Mn, Fe, Co, Ni, Cu, Zn, As, Nb, Mo, Ag, Cd, Pb, U and the rare earth elements – REE) were analyzed in the dissolved phase, suspended particulate matter and in different ...organs (gills, hepatopancreas, and the rest of soft tissue) in mussels of the native Mytilus galloprovincialis and invasive Xenostrobus securis species in the Vigo Ria (NW Iberian Peninsula) in order to assess potential differences in their bioaccumulation patterns. Results obtained do not show significant differences in the bioaccumulation of trace elements by M. galloprovincialis and X. securis, except for Zn and Ag. In the case of Zn, a 4-fold enrichment in M. galloprovincialis compared to X. securis was found. The most important differences between species were observed for Ag, with approximately 40-fold higher concentrations in X. securis. Such elevated Ag bioaccumulation by X. securis can be useful for Ag biomonitoring using these invasive species in this area.
•Trace elements analyzed in M. galloprovincialis and X. securis from the Vigo Ria•BFs obtained using the dissolved and particle-leachable concentrations•One order of magnitude higher Ag bioaccumulation in the invasive X. securis•The invasive X. securis can be used as a useful species for Ag biomonitoring.
•Copper and cerium bioavailability may increase under ocean acidification.•Ocean acidification impacts metal accumulation in mussel gills.•Biochemical responses in M. galloprovincialis altered by ...trace metals and OA.•Complex interplay of oxidative stress markers affected by OA and metals.
This study delves into the intricate interplay between ocean acidification (OA), metal bioaccumulation, and cellular responses using mussels (Mytilus galloprovincialis) as bioindicators. For this purpose, environmentally realistic concentrations of isotopically labelled metals (Cd, Cu, Ag, Ce) were added to investigate whether the OA increase would modify metal bioaccumulation and induce adverse effects at the cellular level. The study reveals that while certain elements like Cd and Ag might remain unaffected by OA, the bioavailability of Cu and Ce could potentially escalate, leading to amplified accumulation in marine organisms. The present findings highlight a significant rise in Ce concentrations within different mussel organs under elevated pCO2 conditions, accompanied by an increased isotopic fractionation of Ce (140/142Ce), suggesting a heightened potential for metal accumulation under OA. The results suggested that OA influenced metal accumulation in the gills of mussels. Conversely, metal accumulation in the digestive gland was unaffected by OA. The exposure to both trace metals and OA affects the biochemical responses of M. galloprovincialis, leading to increased metabolic capacity, changes in energy reserves, and alterations in oxidative stress markers, but the specific effects on other biomarkers (e.g., lipid peroxidation, some enzymatic responses or acetylcholinesterase activity) were not uniform, suggesting complex interactions between the stressors and the biochemical pathways in the mussels.
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Platinum Group Metals (PGM) are modern, technologically relevant elements for which (i) the anthropogenic cycle has outcompeted the natural cycles and (ii) environmental behavior, fate and impact are ...still widely unknown. Stripping voltammetry was used for accurate determinations of platinum (Pt) in historical records of river sediments and estuarine oysters from the Gironde fluvial–estuarine continuum (SW France) comprising the Lot River. Sediment cores from the Lot River, dated from 1952 to 2001, showed past Pt contamination due to former industrial (smelter) activities in the Lot River watershed. These samples revealed the phasing-out of a historical Pt contamination with Pt/Th (Thorium) values of 11×10−5±0.79×10−5 for the deepest part of the core which is clearly greater than the regional geochemical background value (Pt/Th ~2.2×10−5±0.68×10−5). Wild oyster samples from the mouth of the Gironde Estuary collected from 1981 to 2013 showed Pt concentrations ranging from 0.80±0.01pmol.g−1 to 3.10±0.14pmol.g−1. Oyster samples have recorded the phasing-out of the smelter-related historical industrial Pt contamination and empirical modeling suggests the recent rise of a new source of Pt to the system. Temporal variations of Pt in oysters attributed to this recent source reflect the exponential increase of Pt demand for car catalytic converters, pointing towards the increasing importance of this emerging source to the aquatic system. Estuarine oysters prove to be suitable bioindicators for Pt contamination providing sensitive monitoring of emission variations over time. Furthermore, oysters may bioconcentrate Pt (bioconcentration factor, BCF ~103) and transfer this metal contamination to the higher food chain. These findings highlight the need for a deeper understanding of environmental Pt contamination, processes and possible adverse effects to biota.
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•Historical Pt records reflect past and present anthropogenic sources.•Wild oysters are sensitive biomonitors of Pt contamination that bioconcentrate Pt.•Anthropogenic Pt emissions may profoundly affect Pt budget of the watershed.
Sediments from three Galician Rias were tested for toxicity using sea-urchin and ascidian sediment elutriate embryo–larval bioassays. Trace metal contents in seawater, sediments and mussels were also ...determined and subjected to multidimensional scaling methods which grouped stations according to chemical contamination. High metal contents were found in seawater, sediments and mussels from the Ria of Pontevedra, and moderate levels were detected in the Ria of Vigo and Ria of Arousa. The results revealed that samples assessed as toxic, according to the sea-urchin and ascidian embryo–larval bioassays, were among the most polluted by trace metals. A good agreement was reported between ordination plots resulting from applying multidimensional scaling to the chemical data, and the results of the biological endpoints tested.
Metals transported into the coastal zone by the South Iberian rivers are key to understand the biogeochemical cycles and distribution of trace elements in the Gulf of Cadiz (GoC hereinafter) and the ...exchange with the Mediterranean Sea. Previous studies carried out in the 80s have suggested that metal enrichment in the Alboran Sea (Western Mediterranean) is related with fluvial inputs from acid mine drainage from the Tinto and Odiel rivers. The present study evaluates the contribution of dissolved trace metal concentrations (i.e. Cd, Co, Cu, Fe, Mo, Ni, Pb, V, Zn) from the three main rivers discharging into the GoC (i.e. Guadiana, Tinto-Odiel and Guadalquivir rivers). Our results show that the metal composition of water discharged from each river is impacted by the activities developed in the course of the rivers, which clearly influence the GoC coastal surface waters composition. Metal fluxes from the Guadalquivir river are quantitatively higher than those from the Tinto-Odiel (e.g. up to 73% and 19% higher for Ni and Cu, respectively). Although the metal concentrations spatial distributions in the GoC are dominated by the circulation pattern between the Atlantic and the Mediterranean Sea, the concentrations within the GoC continental shelf could be explained by a greater contribution from the Guadalquivir estuary (e.g. 80.5%, 54.6%, 56.5% and 56.6% for Ni, Cu, Mo, and V respectively).
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•High metal concentrations in the Tinto-Odiel estuary by historical mining activities•Metal concentrations in Guadiana and Guadalquivir mostly due to urban-agricultural uses•High fluxes of Ni (73%) and Cu (19%) from the Guadalquivir river to the GoC shelf•Metal pattern over continental shelf largely determined by the Guadalquivir fluxes•Net transport of trace metals from Guadalquivir river to the Mediterranean Sea
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