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There is a current interest in the study of the geochemical behavior of the rare earth elements (REE) in aquatic systems since their identification as potential microcontaminants in natural waters. In this context, here we report the concentrations and patterns of dissolved REE (dREE) in the waters of the Gulf of Cádiz (GoC) and its major estuaries (Guadiana, Tinto-Odiel and Guadalquivir). Contamination in this area by metals has been extensively reported, linked to acid-mine inputs resulting from the mineralization of the Iberian Pyrite Belt, discharged mainly to the Tinto-Odiel river. However, the impact of these inputs on the concentrations and distribution of the dREE in the coastal waters of the GoC has not been addressed yet. Accordingly, elevated concentrations of dREE were obtained in the Tinto-Odiel estuary compared to the Guadiana and Guadalquivir, reflecting the impact of acid-mine drainage on this system. Only a significant fraction of anthropogenic gadolium (Gd) was observed in the Guadalquivir estuary, as a result of the input from major urban areas, where anthropogenic Gd fractions higher than 70% over the total dissolved pool were obtained for the freshwater end-member. Regarding the surface waters of the GoC, typical NE Atlantic distribution patterns of dREEs were obtained, but modified by two different end-members within this region. Accordingly, and despite the low water discharge of the Tinto-Odiel river, its elevated concentrations lead to an increase in the concentrations of dREEs in the nearshore waters of the GoC and producing a distinctive signature as observed for the MREE anomalies and HREE/LREE ratios. At the easternmost stations, close to the Strait of Gibraltar, these signals are also impacted by the inflow of Mediterranean waters and also by the discharge of the Guadalquivir river.

There is a current interest in the study of the geochemical behavior of the rare earth elements (REE) in aquatic systems since their identification as potential microcontaminants in natural waters. In this context, here we report the concentrations and patterns of dissolved REE (dREE) in the waters of the Gulf of Cádiz (GoC) and its major estuaries (Guadiana, Tinto-Odiel and Guadalquivir). Contamination in this area by metals has been extensively reported, linked to acid-mine inputs resulting from the mineralization of the Iberian Pyrite Belt, discharged mainly to the Tinto-Odiel river. However, the impact of these inputs on the concentrations and distribution of the dREE in the coastal waters of the GoC has not been addressed yet. Accordingly, elevated concentrations of dREE were obtained in the Tinto-Odiel estuary compared to the Guadiana and Guadalquivir, reflecting the impact of acid-mine drainage on this system. Only a significant fraction of anthropogenic gadolium (Gd) was observed in the Guadalquivir estuary, as a result of the input from major urban areas, where anthropogenic Gd fractions higher than 70% over the total dissolved pool were obtained for the freshwater end-member. Regarding the surface waters of the GoC, typical NE Atlantic distribution patterns of dREEs were obtained, but modified by two different end-members within this region. Accordingly, and despite the low water discharge of the Tinto-Odiel river, its elevated concentrations lead to an increase in the concentrations of dREEs in the nearshore waters of the GoC and producing a distinctive signature as observed for the MREE anomalies and HREE/LREE ratios. At the easternmost stations, close to the Strait of Gibraltar, these signals are also impacted by the inflow of Mediterranean waters and also by the discharge of the Guadalquivir river

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.

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 mm) 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.

The Mediterranean region is, by far, the leading tourism destination in the world, receiving more than 330 million tourists in 2016. This tourism is undertaken mostly for seaside holidays, and during the summer season concentrates between 46% and 69% of the total international arrivals; this is equivalent to a density of 2.9 tourists per meter of Mediterranean coast, or double this number taking into account the local/permanent population in addition. Previous studies have reported not only the presence of sunscreen in the various environmental compartments (water, sediments and biota) of the Mediterranean Sea (MS) and other regions, but also show that sunscreen products are toxic for marine biota and are accumulated and biomagnificated. Here, we highlight that the environmental risk of these chemicals is likely to be exacerbated in the MS due to the massive influx of tourists and its densely populated coasts, the basin's limited exchanges with the ocean, the high residence time of surface waters, and its oligotrophic waters.

Mining impacts on coastal environments have been extensively studied around the world. However, the role of Submarine Groundwater Discharge (SGD) and Porewater Exchange (PEX) as pathways for pollutants from mining waste deposits into seawater has been largely overlooked. Portmán Bay is located in the Cartagena-La Unión Pb-Zn sulphur mining district in Murcia, SE of Spain. The disposal of about 60 million tons of metal-rich mine tailings from 1957 to 1990 led to the infill of most of the bay. Although the effects of metals on indicator organisms have been shown previously, there is a major lack of knowledge on the release of dissolved metals from the emerged tailing deposit into the sea, more than 25 years after the closure of the mining activities. Samples for Ra isotopes (Ra, Ra, Ra and Ra) and dissolved metals (Ag, Cd, Co, Pb, Zn) were analyzed in porewaters and seawater in order to separately estimate SGD and PEX driven dissolved metal fluxes. Our results show a continuous release of dissolved metals into the sea driven by both PEX and SGD. Most of dissolved metals are remobilized and released into the water column by PEX, which is a ubiquitous mechanism acting along the shoreline. Although SGD only represents 13% of the water flow, it drives large fluxes of dissolved Fe into the sea, mainly restricted to the west side of the bay. Large inputs of dissolved Fe from the anoxic tailings deposit trigger a massive precipitation of iron hydroxides that enables the removal of most dissolved metals from the water column. This study highlights the role of PEX and SGD as significant mechanisms for the land to ocean transfer of dissolved metals from coastal mine tailings deposits.

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)

Given the large numbers of sunbathers on beaches, sunscreen compounds are being released into the coastal aquatic environment in significant amounts. Until now the effect of these potential pollutants on microbiota has been not well-known. Phytoplankton is a key component of the microbiota community. It forms the basis of the aquatic trophic networks, and any change in the natural population of phytoplankton can affect the structure of aquatic biota. This paper describes an experiment performed outdoors (in natural sunlight conditions including ultraviolet radiation (UVR) and with UVR blocked) on mixed microalgae populations (four species from different key marine taxonomic groups, Nannochloropsis gaditana, Chaetoceros gracilis, Pleurochrysis roscoffensis and Amphidinium carterae), for three days, exposed to a range of concentrations of three commercial sunscreens (with variable TiO2 concentrations: highest concentration for sunscreen C, followed by sunscreen A; and sunscreen B did not contain TiO2 in its composition). With regard to UVR effect, in the absence of sunscreens, the most sensitive species is the centric diatom, Chaetoceros gracilis, and the least is Nannochloropsis gaditana; this last species presented the same behavior in the absence of UVR and with high sunscreen concentrations. The toxicity gradient obtained for sunscreens and nanoparticles under UVR is: TiO2 NPs > Sunscreen C > Sunscreen A > Sunscreen B. The differential sensitivity of microalgae to sunscreens and TiO2 NPs can produce a change in the dynamics of phytoplankton populations and provoke undesirable ecological effects (such as giving dinoflagellates more prominence). The effects of UVR, commonly neglected in bioassays, could alter the results in important ways and should be considered when performing environmentally-relevant bioassays. The toxicity mediated by hydrogen peroxide production associated with the concentration of TiO2 NPs cannot be considered the only factor responsible for t

This study quantifies the concentration of trace metals in coastal marine macrophytes (seagrasses, Chlorophytae, Phaeophytae and Rhodophytae). We do so by compiling, from 155 peer review research articles, almost 23,000 estimates of trace metals (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn) contents in natural populations of marine macroalgae and seagrasses distributed worldwide. The objective was to explore the global distribution of concentrations of these metals in marine macrophytes, provide an estimate of their average and range in its tissues and to identify hotspots of coastal pollution. Our results reveal Phaeophytae as the group with the largest accumulation capacity and tolerance to elevated concentrations of metals regardless the species and the location. The mapping of geographic distribution of metal accumulation in marine macrophytes identifies some coastal areas as hotspots of trace metal contamination, where concentrations could reach levels up to 600 times higher than the mean.

Maó (Minorca) is a narrow and semi-enclosed harbour impacted by historic urban and industrial metal pollution. We analyse and compare surficial and long-term sediment records along the Harbour to assess the sources and historical trends in pollution. Trace metal concentrations (Al, Ca, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sr and Zn) measured in sediments of Maó were of the same order of magnitude than those reported in other anthropogenically impacted areas of the Mediterranean Sea. Mercury was the only element that presented significantly higher concentrations in the harbour than other sites (up to 2 orders of magnitude higher). Although surficial concentrations of some metals (e.g. Hg, Pb, Cu and Zn) showed levels lower than those presented in the oldest sedimentary record, they showed concentrations above those recommended for acceptable sediment quality. Enrichment factors (EF) calculations support the anthropogenic origin of these metals in the Maó harbour; however, some variations can be attributed to natural fluctuations in the sediment deposition in the harbour.

The Gulf of Cadiz plays a key role in the exchange of biogeochemical fluxes between the Mediterranean Sea and the Atlantic Ocean through the Strait of Gibraltar. Oceanographers have carried out many investigations in the Gulf of Cádiz on water mass circulation and mass balance of nutrients and carbon. However, despite its importance in the global ocean functioning, studies on trace metals in the Gulf of Cádiz and Strait of Gibraltar waters are very scarce. Here we show the concentrations of dissolved trace metal composition (i.e. Ag, Cd, Co, Cu, Fe, Mo, Ni, Pb and Zn) in the Gulf of Cádiz and Mediterranean Sea surface waters as obtained from 5 oceanographic campaigns. Our results indicate that the Gulf of Cádiz surface water mass is receiving large amounts of trace metals transported by the different rivers that flow into the Gulf of Cádiz. Thus, dissolved trace metals in these waters were highly variable with the highest ranges measured for Co (0.06 – 3.1 nM), Fe (0.6 – 392 nM) and Pb (0.04 – 512 nM).

This study compiles, from 155 peer review research articles, almost 23,000 estimates of trace metals (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn) contents in natural populations of marine macrophytes (seagrasses, chlorophytae, phaeophytae and rhodophytae) worldwide. The objective was to explore the distribution of these metals, to examine its trends of accumulation and to identify hotspots of coastal pollution. Our results point out phaeophytae as the group with the maximum accumulation capacity and tolerance to elevated concentrations of metals, and indicate that, despite of the geographic differences and local and regional influences, exist a similar atomic ratio of trace metals accumulation in the four groups of marine macrophytes regardless the species. The mapping of geographic distribution of metal accumulation in marine macrophytes identifies some coastal areas as hotspots of trace metal contamination. This work aims to provide a reference for futures studies.

The environmental conditions of semi-enclosed coastal water-bodies are directly related to the catchment, human activities, and oceanographic setting in which they are located. As a result of low tidal forcing, and generally weak currents, waters in Mediterranean harbours are poorly renewed, leading to quality deterioration. Here, we characterise the seasonal variation of trace metals (i.e. Co, Cd, Cu, Fe, Mo, Ni, Pb, and Zn) in surface waters, and trace metal content in sediments from Maó Harbour, a semi-enclosed coastal ecosystem in the NW Mediterranean Sea. Our results show that most of the dissolved trace metals in the waters of Maó Harbour exhibit a marked inner-outer concentration gradient, suggesting a permanent input into the inner part of the harbour. In general, metal concentrations in the waters of Maó Harbour are higher than those in offshore waters. Concentration of Cu (21 ± 8 nM), Fe (9.2 ± 3.2 nM) and Pb (1.3 ± 0.4 nM) are particularly high when compared with other coastal areas of the Mediterranean Sea. The concentration of some metals such as Cu and Zn increases during summertime, when the human population and boat traffic increase during the tourism season, and when resuspension from the metal enriched sediments is higher. The evaluation of the metal sources in the harbour reveals that, compared with other putative sources such as runoff, aerosol deposition and fresh groundwater discharges, contaminated sediments are the main source of the metals found in the water column, most likely through vessel-driven resuspension events. This study contributes to the understanding of the processes that control the occurrence and distribution of trace metals in Maó Harbour, thus aiding in the effective management of the harbour, and enhancing the overall quality of the seawater ecosystem.

The world coastal-zone population and coastal tourism are expected to grow during this century. Associated with that, there will be an increase in the use of sunscreens and cosmetics with UV-filters in their formulation, which will make coastal regions worldwide susceptible to the impact of these cosmetics. Recent investigations indicate that organic and inorganic UV-filters, as well as many other components that are constituents of the sunscreens, reach the marine environment - directly as a consequence of water recreational activities and/or indirectly from wastewater treatment plants (WWTP) effluents. Toxicity of organic and inorganic UV filters has been demonstrated in aquatic organism. UV-filters inhibit growth in marine phytoplankton and tend to bioaccumulate in the food webs. These findings together with coastal tourism data records highlight the potential risk that the increasing use of these cosmetics would have in coastal marine areas. Nevertheless, future investigations into distribution, residence time, aging, partitioning and speciation of their main components and by-products in the water column, persistence, accumulation and toxicity in the trophic chain, are needed to understand the magnitude and real impact of these emerging pollutants in the marine system. © 2015 Elsevier Ltd.

Sunscreens have been shown to give the most effective protection for human skin from ultraviolet (UV) radiation. Chemicals from sunscreens (i.e., UV filters) accumulate in the sea and have toxic effects on marine organisms. In this report, we demonstrate that photoexcitation of inorganic UV filters (i.e., TiO2 and ZnO nanoparticles) under solar radiation produces significant amounts of hydrogen peroxide (H2O2), a strong oxidizing agent that generates high levels of stress on marine phytoplankton. Our results indicate that the inorganic oxide nanoparticle content in 1 g of commercial sunscreen produces rates of H2O2 in seawater of up to 463 nM/h, directly affecting the growth of phytoplankton. Conservative estimates for a Mediterranean beach reveal that tourism activities during a summer day may release on the order of 4 kg of TiO2 nanoparticles to the water and produce an increment in the concentration of H2O2 of 270 nM/day. Our results, together with the data provided by tourism records in the Mediterranean, point to TiO2 nanoparticles as the major oxidizing agent entering coastal waters, with direct ecological consequences on the ecosystem.

RESUMEN: En este documento se presentan los trabajos científicos realizados por el Instituto Español de Oceanografía, dentro del Plan de Vigilancia Ambiental del dragado del Puerto de Maó (Menorca, Islas Baleares), para la caracterización de los ecosistema marino en el punto de vertido y área adyacente, previa al inicio de las obras. Se incluyen los resultados y las conclusiones de los estudios realizados por diversos grupos de investigación, principalmente en Enero-Marzo 2014, en relación al fondo marino, la hidrodinámica, las praderas de Posidonia oceanica y el molusco bivalvo Pinna nobilis, el macro-bentos de los fondos circalitorales blandos y los contaminantes en agua, sedimentos y biota, así como en especies de interés comercial para el consumo humano. Este informe se contempla en el contrato entre la Autoridad Portuaria de Baleares y el Instituto Español de Oceanografía, suscrito el 5 Febrero 2014, para los trabajos de asistencia técnica para la revisión y control del Plan de Vigilancia Ambiental del dragado del Puerto de Maó., RESUM: En aquest document es presenten els treballs científics realitzats per l’Instituto Español de Oceanografía, dins del Pla de Vigilància Ambiental del dragat del Port de Maó (Menorca, Illes Balears), per a la caracterització dels ecosistemes marins en el punt de vessament i àrea adjacent, prèvia a l’inici de les obres. S’inclouen els resultats i les conclusions del estudis realitzats per diversos grups de recerca, principalment durant Gener-Març 2014, en relació al fons marí, la hidrodinàmica, les praderies de Posidonia oceanica i el mol•lusc bivalve Pinna nobilis, el macro-bentos dels fons circalitorals tous i els contaminants en aigua, sediments i biota, així com en espècies d’interès comercial pel consum humà. Aquest informe es contempla en el contracte entre l’Autoritat Portuària de Balears i el Instituto Español de Oceanografía, subscrit el 5 Febrer 2014, pels treballs d’assistència tècnica per a la revisió i control del Pla de Vigilància Ambiental del dragat de Port de Maó., This document presents the scientific actions developed by the Instituto Español de Oceanografía within the Environmental Monitoring Plan of the works of dredging the Port of Maó (Minorca, Balearic Islands), for the characterization of the marine ecosystems in the point of discharge of dredged material and adjacent area, before the beginning of the dredging. The results and conclusions of the studies developed by several research groups, mainly in January-March 2014, in relation to the bottom, hydrodynamics, Posidonia oceanica meadows, and the bivalve mollusc Pinna nobilis, the macro-benthos of the circalittoral soft bottoms and the contaminants in water, sediments and biota, as well as in commercial species for human consumption, are included. This report is contemplated within the contract between the Autoridad Portuaria de Baleares and the Instituto Español de Oceanografía, signed on 5 February 2014, for the technical assistance activities to review and control the Environmental Monitoring Plan of the works of dredging the Port of Maó.

© 2014 American Chemical Society. Submarine groundwater discharge (SGD) and derived nutrient (NO2 -, NO3 -, NH4 +, PO4 3-, and SiO2) and trace element (Cd, Co, Cu, Fe, Mo, Ni, Pb, V and Zn) loadings to the coastal sea were systematically assessed along the coast of Majorca Island, Spain, in a general survey around the island and in three representative coves during 2010. We estimated that brackish water discharges through the shoreline are important contributors to the DIN, SiO2, Fe, and Zn budgets of the nearshore waters. Furthermore, our results showed that SGD-derived elements are conditioned by the hydrogeological formations of the aquifer and discharge type. Thus, while rapid discharges through karstic conduits are enriched in SiO2 and Zn, the large detrital aquifers of the island typically present enhanced concentrations of Fe. The estimated total annual inputs of chemicals constituents discharged by SGD to the coastal waters were as follows: DIN: 610 × 103 kg yr-1, SiO2: 1400 × 103 kg yr-1, Fe: 3.2 × 103 kg yr-1, and Zn: 2.0 × 103 kg yr-1. Our results provide evidence that SGD is a major contributor to the dissolved pool of inorganic nutrients and trace metals in the nearshore waters of Majorca.

Sunscreens have been shown to give the most effective protection for human skin from ultraviolet (UV) radiation. Chemicals from sunscreens (i.e., UV filters) accumulate in the sea and have toxic effects on marine organisms. In this report, we demonstrate that photoexcitation of inorganic UV filters (i.e., TiO2 and ZnO nanoparticles) under solar radiation produces significant amounts of hydrogen peroxide (H2O2), a strong oxidizing agent that generates high levels of stress on marine phytoplankton. Our results indicate that the inorganic oxide nanoparticle content in 1 g of commercial sunscreen produces rates of H2O2 in seawater of up to 463 nM/h, directly affecting the growth of phytoplankton. Conservative estimates for a Mediterranean beach reveal that tourism activities during a summer day may release on the order of 4 kg of TiO2 nanoparticles to the water and produce an increment in the concentration of H2O 2 of 270 nM/day. Our results, together with the data provided by tourism records in the Mediterranean, point to TiO2 nanoparticles as the major oxidizing agent entering coastal waters, with direct ecological consequences on the ecosystem. © 2014 American Chemical Society.

An analytical method to determine the total content (i.e., not only in the soluble fraction but also in the particulate one) of eight commonly used UV filters in seawater samples is presented for the first time. Dispersive liquid-liquid microextraction (DLLME) is used as microextraction technique to pre-concentrate the target analytes before their determination by gas chromatography-mass spectrometry (GC-MS). In order to release the UV filters from the suspended particles an ultrasound treatment is performed before DLLME. The ultrasound treatment time was studied in order to achieve a quantitative lixiviation of the target analytes. The type and volume of both disperser and extraction solvent, the sample volume, the pH and the ionic strength involved in the DLLME have been optimized to provide the best enrichment factors. Under the optimized conditions, the method was successfully validated showing good linearity, enrichment factors between 112 and 263 depending on the analyte, limits of detection and quantification in the low ngL-1 range (10-30ngL-1 and 33-99ngL-1, respectively) and good intra- and inter-day repeatability (RSD <15%). No significant matrix effects were found. Finally, the method was satisfactorily applied to the analysis of three seawater samples from different origin. Results showed significant amounts of UV filters in the particulate fraction that would have been ignored if only the soluble fraction had been considered. This fact shows that the UV filters are also accumulated in the suspended particles contained in water, what should be taken into account from an environmental standpoint. © 2013 Elsevier B.V.

Tovar-Sanchez A., Basterretxea G., Rodellas V., Sanchez-Quiles D., Garcia-Orellana J., Masque P., Jordi A., Lopez J.M., & Garcia-Solsona E. (2014). Contribution of groundwater discharge to the coastal dissolved nutrients and trace metal concentrations in Majorca Island: Karstic vs detrital systems. Environmental Science and Technology, 48(20), 11819-11827. Available here