PAHs and trace metals in marine surficial sediments from the Porcupine Bank (NE Atlantic): A contribution to establishing background concentrations.

Little is known about pollutant concentrations in marine remote areas such as the Porcupine Bank in the NE Atlantic Ocean. Remote locations are much less studied than the more readily accessible coastal areas, nevertheless, are of great importance both to unveil how far human influence has reached and, are more challenging, to infer background concentrations (BCs) of naturally occurring and/or anthropogenic pollutants. Knowledge of contaminant background levels are critical for establishing remediation and management strategies; in addition, background assessment is heavily emphasised in legislative monitoring requirements. Obtaining suitable sampling locations to assess background concentrations can be challenging, as samples should match characteristics to the target area and not be impacted by historical or current inputs of the chemical substances of study. Anthropogenic impacts generally deem local-based sampling to be unsuitable to infer background pollution values. Sampling in remote areas such as the Porcupine Bank better fulfils low impact and pressure requirements making them more suitable for the derivation of background concentration estimates for organic compounds and metals. The total concentrations of polycyclic aromatic hydrocarbons (PAHs) and metal(loid)s in deep sea sediments were evaluated and both an environmental status and a set of concentration data were adequate to derive BCs concentrations is presented. Concentration data indicated, in comparison with previous published data, trace level presence of PAHs and metal(loids) in sediments from the Porcupine Bank. These values will provide a valuable tool to identify the natural presence of organic and inorganic compounds and be the basis to perform a sound environmental assessment.

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) occurrence in Sparus aurata exposed to microplastic enriched diets in aquaculture facilities.

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) are highly stable and bioaccumulative, and microplastics (MPs; plastics <5 mm) are ubiquitous in the marine environment. In this study we report the levels of a selection of pollutants in liver and muscle of juvenile gilthead seabream (Sparus aurata) exposed to virgin and weathered MP enriched diets during three months and followed by one month of MP depuration. In general, a major concentration of pollutants in liver was observed. According to OCPs, total DDTs was two or three times higher in liver. Levels in muscle suffer higher variability between treatments and sampling periods. The MP index was negatively correlated to HCB and positively to p,p'DDT in liver. Levels of pollutants are correlated to biological parameters such as total size and total weight. Our results suggest that the bioaccumulation is subjected to the molecular structure of the pollutants and that MPs are correlated with the detoxification system.

Yellow-legged gull eggs (Larus michahellis) as persistent organic pollutants and trace metal bioindicator for two nearby areas with different human impact.

The concentration of different persistent organic pollutants (POPs including chlorinated and brominated compounds) and trace metals and metalloids (As, Cd, Cu, Cr, Pb, Hg, Ni, and Zn) was examined in eggs from two colonies of yellow-legged gulls. The two colonies are established in Ría de Vigo, Northwest Spain, with a distance between them of only 10 km, one in Vigo town (industrial and harbour activities) and the other in the Cíes Islands in a Natural Park and Marine Protected Area -MPA- (with no known anthropogenic inputs). Statistically significant differences for the two colonies were observed for Hg, the sum of 7 CBs, the sum of DDTs y and the sum of 9 PBDEs, with values that could be causing some toxic effects in the area of the most anthropogenically influenced colony. The estimated isotopic niche was also calculated, based on δ15N and δ13C, for the two colonies, pointing to a wider diet in the Cíes colony when compared to the diet in the Vigo colony. The study supports the use of the yellow-legged seagull eggs as a bioindicator of pollution capable of differentiating pollution level even in geographically close areas.

A new perspective on marine assessment of metals and organic pollutants: A case study from Bay of Santander.

Pollution assessment is worldwide generally performed based on 'Trend assessment' or 'Status assessment´, and usually requires monitoring programs that should be designed in terms of pollutants to be studied, frequency and locations. Five groups of pollutants: polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs) and trace metals, were selected to evaluate how actual monitoring programs are coping with the evaluation of anthropogenic activities affect the environment and whether use restrictions and laws that ban certain pollutants are being effective. Santander Bay, in Northern Spain, is an industrial area with 250,000 inhabitants and with several rivers discharging into the Bay; those characteristics made the area an adequate location to perform the study. Marine sediment was selected as the study matrix since it gives comprehensive information regarding the human activities in coastal areas. The study clearly shows that there can be some potential biological impacts on the marine environment due to PAHs (mainly BghiP), PCBs (mainly congener CB118) and metals. On the other hand all analysed OCPs and PBDEs presented values below the applicable guidelines and will therefore, in principle, not give rise to environmental problems. Consequently, even after decades of banning and use restrictions, the studied pollutants are still a main issue in coastal areas. Moreover, the present study helps in the definition of future monitoring programs providing a complete description about the current situation of the listed pollutants.

Limpet (Patella sp) as a biomonitor for organic pollutants. A proxy for mussel?

The scarcity of the most widely used species for assessing marine pollution (mussels) in some areas brings out the need to test the use of a different organism. In this study, 11 sampling sites along the Atlantic Spanish coast were selected and both mussels (Mytilus galloprovincialis) and limpets (Patella sp.) were analysed for PAHs, PBDEs and PCBs. The concentrations of the different pollutants in both species followed the same general distribution allowing us to differentiate polluted and unpolluted sites using any of them. Although the concentrations found in limpets were generally lower than those measured in mussels, a good correlation was observed for most of the groups of pollutants and also for every individual congener. A conversion factor was proposed for most of the individual PAH and PCB congeners, allowing the conversion of limpet concentration into mussel concentration that can be directly applied in assessments using environmental criteria derived for mussels.

Occurrence and toxicological assessment of polycyclic aromatic hydrocarbons (PAHs) in marine sediments under mussel farming influence.

The use of marine resources for mussel culture has become increasingly important, particularly on the European Atlantic coast and notably in the Galician Rías in the northwest of Spain. Despite its importance, there is a lack of research and analysis in this area and of the potential problems that it could cause to the environment. This paper details the findings of a study that aimed to find the probable environmental impact of mussel culture activities and to evaluate the polycyclic aromatic hydrocarbon (PAH) content derived from this activity. The Ría de Arousa, where you can find over 70% of all installed rafts in Galicia, was selected for the present study, and nearly 40 marine sediment samples were collected there. The sediments were extracted by ASE (accelerated solvent extraction) procedure, and the quantification of PAHs was performed using gas chromatography coupled to mass spectrometry (GC-MS), with the aid of deuterated PAH internal standards. The total concentration of parental PAHs ranged from 11.66 to 30,272-ng g-1 dry weight (d.w.), with a mean value of 3907-ng g-1 d.w.; the concentration of alkyl PAHs varied from 3.72 to 1187-ng g-1 d.w., with a mean value of 205.1-ng g-1 d.w. Compositional patterns, principal component analysis (PCA) and hieratical cluster association (HCA) yielded a sediment classification where the mussel raft impact is pointed out. PAH ratios indicated a predominance of combustion sources, except in two samples, located in small harbors. Only one station showed total potential carcinogenic PAH values in the range that would frequently cause negative biological effects, and the toxic equivalent concentrations based on BaP equivalents identified another ten positions where biological effects would occur occasionally.

Historical Profiles of Polycyclic Aromatic Hydrocarbons (PAHs) in Marine Sediment Cores from Northwest Spain.

The northwest coast of Spain is characterized by an irregular coastline rich in marine life and with the highest mussel production in Europe. Taking this into account, the characterization of the pollution levels and the sources involved appear necessary. Not only were parent Polycyclic Aromatic Hydrocarbons (PAHs) analysed but also their alkylated homologues. In total, 35 compounds were analyzed in 5 sediment cores. Sediments were collected using a box core dredge and extracted by (Pressurized Liquid Extraction) whilst the quantification of PAHs was performed using gas chromatography coupled to mass spectrometry (GC-MS). The total concentration detected varied from 49.6 to 2489 ng g-1 dry weight (d.w.) of which parent PAHs ranged from 44.5 to 2254 ng g-1 d.w. and alkylated PAHs varied from 5.04 to 317 ng g-1 d.w. Temporal and spatial evolution were outlined and pollution sources were identified along with a possible correlation between this pollution and local history and industry. Most of the PAHs from the superficial samples have a biomass and coal combustion profile, and some specific, localized events are reflected in the total PAH concentration evolution. Moreover, the study of the deepest layers of the sampled cores provides a baseline to develop background concentration values that will help in future sediment quality assessment.

PAHs in the Ría de Arousa (NW Spain): A consideration of PAHs sources and abundance.

Analysis of 35 parental and alkylated homologues of PAHs (Polycyclic Aromatic Hydrocarbons) was carried out in eleven marine sediment samples collected along a central transect in the biggest Galician ría. The samples were collected using a box-core dredge and, after freeze-drying, were kept frozen until analysis. The sediments were extracted by PLE (Pressurized Liquid Extraction) procedure and the quantification of PAHs was performed using gas chromatography coupled to mass spectrometry (GC-MS) with the aid of deuterated PAH internal standards. The total concentration of studied PAHs (Σ35PAHs) ranged from 44.8 to 7901ngg(-1) dry weight (d.w.). The highest PAH concentrations were found in sediments collected near the harbour (7901ngg(-1)) and the cleanest positions were located in the outer zone of the ría. To date, these results are the first data presented in the area so they could be used for regular monitoring and control of future pollution episodes.

Temporal and spatial changes of PAH concentrations in Mytilus galloprovincialis from Ria de Vigo (NW Spain).

The aim of this study was to establish the temporal trends and spatial distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in Ria de Vigo by means of studying the PAH burden in wild mussels. The samples were collected in eight sites along the margins of the Ria de Vigo during November from 1998 to 2008 and Polycyclic Aromatic Hydrocarbon contents were determined using high performance liquid chromatography-fluorescence derivatization (HPLC-FLD). Quality of chemical analysis was guaranteed by participation in QUASIMEME intercalibration exercises carried out during the period of analysis. The concentrations for the sum of 13 PAHs were in the range 24-480 µg/kg dw, typical of an urban and industrialized area (50-500 µg/kg dw) except for a punctual input in La Guía in 1998 that led to a concentration above 1,000 µg/kg dw. In general, the sites in the outermost section of the estuary (ría) showed the lowest values, with an increasing gradient in the medium and inner parts of the ría. Temporal patterns show, in general, a downward trend. The relative proportion of 3 and 4 ring PAHs also varies with the site, the former being predominant in the outermost area and the latter in the medium and inner parts of the ría. This is consistently related with the sources and processes taking place in different areas of the estuary.