Antonio Cobelo-García

Assessment of coastal marine pollution in Galicia (NW Iberian Peninsula); metal concentrations in seawater, sediments and mussels (Mytilus galloprovincialis) versus embryo-larval bioassays using Paracentrotus lividus and Ciona intestinalis

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.

Heavy metal sedimentary record in a Galician Ria (NW Spain): background values and recent contamination

Two long sediment cores were sampled at the Ferrol Ria (Galicia, NW Spain) and the heavy metal (Co, Cr, Cu, Fe, Ni, Pb and Zn) concentrations measured in order to (i) state accurate background values providing baseline relationships with respect to a reference element and (ii) to investigate the recent metal contamination trends. Background values were found to agree well with the world average values for granite/schists-genisses rocks. However, Cu, Co, Pb and Zn were found to be lower than those previously reported as background values for the Galician Rias. Results emphasize the importance of using baseline relationships with respect to a normalizing element in order to reduce the scattering of data and to allow an accurate statement of background values. The distribution of metals in the cores showed an evident enrichment in the surface layers belonging to the industrial era. Normalized enrichment factors (NEF) for copper and zinc are in the order of 3-5 (certain/severe contamination) in the surface sediments, decreasing with depth. Lead contamination has decreased in the recent years from NEF of 3-7 down to a NEF of 2 (i.e. moderate contamination), probably due to the introduction of unleaded gasolines. Chromium, cobalt and nickel NEFs were always in the <1-2 range indicating null/low contamination by these metals.

COST action TD1407: network on technology-critical elements (NOTICE)—from environmental processes to human health threats

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.

Land inputs, behaviour and contamination levels of copper in a ria estuary (NW Spain).

Copper concentrations were measured in the sediments and dissolved phase of the water column in the Lérez Estuary (Pontevedra Ria, Galicia), NW Spain, and in the freshwater-sewage inputs to the estuary. Dissolved copper fluxes in the estuary were quantified. Results show that the freshwater end-member in the Lérez Estuary has minimal copper contamination ([Cu](Dissolved)=7+/-4 nM, Sediment Enrichment Factor=1) and the source of dissolved copper inputs is localized in the saline end-member ([Cu](Dissolved)=20-55 nM, Sediment Enrichment Factor=6-7). A non-conservative behaviour of dissolved copper showing a net addition during estuarine mixing was observed. The budgetary calculations and the copper sediment distribution suggest that the major copper input to the estuary-ria system is located at the Marín-Placeres transect, playing an important role in the net addition of copper within the estuarine mixing. The importance of upwelling in the renewal of the Galician coastal waters and dilution of continental inputs is discussed.

Improving the voltammetric quantification of ill-defined peaks using second derivative signal transformation: Example of the determination of platinum in water and sediments

The determination of trace elements using stripping voltammetry may be seriously affected by the presence of intensive matrix background or interfering peaks, leading to poorer detection limits and/or inaccurate quantitative results. In this work, we have tested the use of signal transformation (e.g., second derivative) in the analysis of platinum in seawater and sediment digests by means of catalytic adsorptive stripping voltammetry. In natural waters, the limit of detection of Pt is affected by a broad background wave due to the formazone complex used in the sample matrix for its determination, while in sediment digests, the Pt peak may be interfered with due to the presence of elevated concentrations of Zn, affecting the accuracy of the determination. Results applying second derivative signal transformation revealed a significant improvement (2-3-fold) of the detection limit in water due to the minimization of background effects, therefore allowing shorter accumulation times and faster determinations. In the presence of interfering peaks, the inaccuracy resulting from erroneous baseline selection in the original signal is eliminated when the second derivative is used. Signal processing should be considered as a useful tool for other voltammetric methodologies where more accurate or faster determinations are needed.

Evaluation of the contamination of platinum in estuarine and coastal sediments (Tagus Estuary and Prodelta, Portugal).

Platinum contamination in estuarine and coastal sediments has been evaluated in three cores collected from the Tagus Estuary and Prodelta shelf sediments. Elevated concentrations, up to 25-fold enrichment compared to background values, were found in the upper layers of the estuarine sediments. The degree of Pt enrichment in the estuarine sediments varied depending on the proximity to vehicular traffic sources, with a maximum concentration of 9.5 ng g(-1). A considerable decrease of Pt concentrations with depth indicated the absence of significant contamination before the introduction of catalytic converters in automobiles. Platinum distribution in the Tagus Prodelta shelf sediment core showed no surface enrichment; instead a sub-surface maximum at the base of the mixed layer suggested the possibility of post-depositional mobility, thereby blurring the traffic-borne contamination signature in coastal sediments.

Intra-annual variation and baseline concentrations of dissolved trace metals in the Vigo Ria and adjacent coastal waters (NE Atlantic Coast)

Trace metal analysis in natural waters requires the use of extremely careful procedures to avoid sample contamination. Such techniques include, for example, the use of trace metal-clean sampling and storage devices, high-purity reagents, air-filtered clean lab conditions, and certified reference materials (Howard and Statham, 1993). Accordingly, it has been shown in the decades that most trace metal concentrations reported before the 1980s were subject to a significant overestimation due to contamination (Kremling, 1983). The complexity of trace metal analysis has lead to a limited number of seasonal complete datasets along Atlantic European waters, both in shelf (Auger et al., 1999; Statham et al., 1999; Cottè-Krief et al., 2000; Elbaz-Poulichet et al., 2001) and coastal systems (Martino et al., 2002; Cobelo-García and Prego, 2003; Monbet, 2004, 2006), despite the well-known role of the coastal zone in the transfer of metals from land-based sources (e.g., rivers) to the oceans (Martin and Windom, 1991). Studies on the factors controlling the distribution of trace elements in the Iberian coast and shelf, and in particular the Galician Rias, are still limited (Prego and Cobelo-García, 2003a). Rias are estuarine–coastal systems formed by flooding of river valleys in the Pleistocene–Holocene in regions of high relief during the last interglacial transgression, and are typical of areas such as NE Iberia, SW England or SE Asia (Evans and Prego, 2003; Bianchi, 2007). Several Galician Rias (e.g., Vigo Ria) are under significant anthropogenic influence due to population and industry on their margins (Prego et al., 2008) and/or contamination events (e.g., the Prestige oil tanker shipwreck in 2002; Prego and Cobelo-García, 2003b, Santos-Echeandía et al., 2005, 2008a), which alter to some extent the natural distribution and processes of trace metals. Therefore, studies on the seasonal variability and baseline concentrations of trace elements in these coastal areas are needed. The objectives of this study were: (i) to obtain a complete dataset of dissolved trace metal concentrations in this region of the NE Atlantic Ocean based on a one-year period, providing a baseline for future research in this field; and (ii) to ascertain the anthropogenic influence in the ria waters, comparing their trace metal concentrations with those found in the adjacent coast. In order to achieve the objectives, seawater samples were collected at two stations: station 1 was located inside the Vigo Ria and station 2 at the shelf. Samples were collected on a monthly ba-

Evidence of increased anthropogenic emissions of platinum: time-series analysis of mussels (1991-2011) of an urban beach

The anthropogenic emissions of Pt to the environment have increased significantly over the past decades, especially after the introduction of the catalytic converters in motor vehicles. In order to check whether this is affecting the levels of this trace metal on living organisms, time-series analysis of freeze-dried soft tissue material of wild mussels (Mytilus galloprovincialis) covering the period from 1991 to 2001 and collected at an urban beach in the city of Vigo (NW Iberian Peninsula) was conducted. Concentrations ranged from 0.30 to 0.68 ng g(-1) with an average concentration of 0.47 ± 0.10 ng g(-1) (n=21); these concentrations were higher than those obtained for samples collected at a control location away from anthropogenic pressure (0.31 ± 0.10 ng g(-1); n=5). Platinum concentrations followed a statistically significant temporal trend (at the 0.020 level), and the excess of Pt in mussels over the 1991-2011 period compared to the control location were correlated with the European Pt autocatalyst demand (p=0.0006) and, especially, the car sales in Spain (p=0.0001). A bioaccumulation factor of ~5·10(3) was derived, which is greater than those previously calculated for Pt from exposure experiments, but 1-2 orders of magnitude lower than other trace elements (e.g. Zn, Cu, Pb, Cd).

Improvement of the ultra-trace voltammetric determination of Rh in environmental samples using signal transformation

Rhodium (Rh) is present at the Earths surface at ultra-trace concentrations (0.06 ng g(-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 200 fM Rh in the cell was obtained, which corresponds to 14 pg g(-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 0.47 ng g(-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.

Osmium and Platinum Decoupling in the Environment: Evidences in Intertidal Sediments (Tagus Estuary, SW Europe)

Catalytic converters in automobiles have significantly increased the input of platinum group elements (PGE) to the environment, and their coupled geochemical behavior has been proposed. To check this hypothesis, Pt and Os concentrations and (187)Os/(188)Os ratios were determined in sediment cores and interstitial waters from the Tagus Estuary (SW Europe) affected by different traffic pressure. Platinum concentration in surface sediments nearby the high traffic zone (up to 40 ng g(-1)) indicated severe contamination. Although lower than Pt, Os enrichment was also observed in surface sediments, with lower (187)Os/(188)Os ratios than in deeper layers. Dissolved Pt and Os in interstitial waters, 0.1-0.7 pg g(-1) and 0.03-0.10 pg g(-1), respectively, were higher than in typical uncontaminated waters. Results indicate two sources of Pt and Os into the Tagus Estuary salt marshes: a regional input associated with industrial activities, fossil fuel combustions, and regional traffic and a local source linked to nearby traffic density emissions. Estimations of Os and Pt released by catalytic converters support this two-source model. Differences in geochemical reactivity and range of dispersion from their sources lead to a decoupled behavior of Os and Pt, questioning the use of Os isotopes as proxies of PGE sources to the environment.