Reactividad y mecanismos de transporte del alquilbenceno lineal sulfonatos (LAS) y sus intermedios de degradación en sistemas marinos litorales

Se han desarrollado métodos de análisis específicos para el alquilbenceno lineal sulfonato y sus intermedios de degradación en agua y sedimentos marinos. Se ha caracterizado su distribución, reactividad y mecanismos de transporte en sistemas litorales de la península Ibérica.Este trabajo ha sido parcialmente financiado por el proyecto: “Priority surfactants and their toxic metabolites in waste effluents discharges: an integrate study” financiado por la Unión Europea (UE/ENV4-CT97-0494

Presence and distribution of current-use pesticides in surface marine sediments from a Mediterranean coastal lagoon (SE Spain)

Postprin

Integrative assessment of coastal marine pollution in Santander Bay and Galician Rías.

Sediments from Rías of A Coruña, Ferrol, Betanzos and Ares (n = 26) and the Bay of Santander (n = 11) were sampled. The concentration of organic contaminants in sediment elutriates (CBs, PAHs, pesticides and pharmaceutical drugs) and sea urchin (Paracentrotus lividus) embryotoxicity were assessed. The concentration of organic pollutants in the elutriates were relatively low (ΣContaminants < 400 ng/L) and their interpretation in terms of the observed toxicity was not straightforward. A clear gradient of toxicity from the inner part to the outer side of the Santander Bay was observed. Sediment elutriates from two stations situated close to the city of A Coruña showed moderate toxicity values, whereas sediment elutriates from the Rías of Ares and Betanzos showed no marked toxicity. Stations located close to the city of Ferrol showed moderate to high toxicity, which is indicative of a nearby source of contamination. On the contrary, the outer side of the Ría of Ferrol was classified as clean according to the calculated toxic units. These results allowed for an integrative assessment of the environmental quality in the studied areas, which highlights the usefulness of embryo-larval test to monitor the coastal pollution

Occurrence and seasonal distribution of polycyclic aromatic hydrocarbons and legacy and current-use pesticides in air from a Mediterranean coastal lagoon (Mar Menor, SE Spain)

Postprin

SORPTION OF LINEAR ALKYLBENZENE SULFONATES AND SULFOPHENYLCARBOXYLIC ACIDS ON MARINE SEDIMENTS

The sorption of linear alkylbenzene sulfonates (LAS) and of their main biodegradation intermediates, sulfophenylcarboxylic acids (SPC) has been characterized in marine sediments. The required equilibrium time for undecylbenzene sulfonate (C11LAS) sorption is 12 h, and 24 h for sulfophenyl undecanoic acid (C11SPC). C11LAS sorption decreases with temperature due to the exothermic character of this process. C11SPC sorption is less complete and less homogeneous than for C11LAS. The alkylic or carboxylic chain length (C10-C13) is correlated positively with the partition coefficient, and the effect of the carboxylic group is more significant than that of the additional methylene group. Sorption of LAS and SPC homologues (C10-C13) are reversible processes. Desorption of SPC homologues is almost complete, but the desorption percentage of LAS homologue decreases with alkylic chain length. Small fractions of sorbed LAS homologues could take longer to be desorbed than the times covered by this study.This research has been supported by the Environmental and Climate Program of the European Commission PRISTINE (Contract ENV4-CT97-494) from Waste Water Cluster and by the Spanish Inter-Ministerial Science and Technology Commission “BALAS” project (CICYT, REN2001-2980-C02-01/HID)

Seasonal distribution of pharmaceuticals in marine water and sediment from a Mediterranean coastal lagoon (SE Spain)

En prensa3,398

The influence of urban wastes on the interstitial water chemistry in coastal marine sediments of Cadiz Bay

The authors determined, with visual profiles, the concentration of nutrients (i.e. ammonia, nitrate, phosphate and silica), inorganic carbon and sulphate in the interstitial water of Cadiz Bay, as well as organic carbon in sediment, using samples from three stations on Sancti Petri sound. These three stations suffer from different contamination levels due to untreated urban wastewater. Our results show a degradation of the organic matter, principally in the first 30 cm of sediment. These concentration changes are important in the superficial water layer, indicating the efficiency of aerobic oxidation, the organic matter's principal mineralisation mechanism. Two stations, those nearest to the waste point, had the highest organic carbon concentrations in their sediment, as well as the highest vertical gradients of nutrient concentrations in their interstitial water. Sulphate reduction is the principal mechanism involved in the oxidation of organic matter. On the other hand, at the other station studied, with lower organic carbon levels, the gradients were smoother.Se han caracterizado los perfiles verticales en el agua intersticial de las concentraciones de nutrientes (amonio, nitrato, fosfato y silicato), carbono inorgánico y sulfato, así como de carbono orgánico en el sedimento en tres estaciones del caño de Sancti Petri, sujetas a distinto grado de contaminación por vertidos urbanos sin depurar. Analizando globalmente las variaciones con la profundidad de las concentraciones de las distintas especies estudiadas, se puede afirmar que existe una degradación continuada de la materia orgánica, al menos, en los primeros 30 cm del sedimento. Esta hipótesis se encuentra reforzada por la propia disminución de la concentración de carbono orgánico en el sedimento con la profundidad. Estos cambios de concentración son especialmente acusados en la lámina de agua más superficial, poniendo de manifiesto la eficiencia de la oxidación aeróbica como mecanismo de mineralización de la materia orgánica. Las dos estaciones más próximas al vertido, que poseen concentraciones de carbono orgánico más elevadas en el sedimento, presentan también mayores gradientes verticales de concentración de nutrientes en el agua intersticial, y la sulfatorreducción adquiere una mayor importancia relativa como vía de oxidación de la materia orgánica. Por el contrario, en la estación situada en el extremo sur del caño, menos afectada por los aportes de materia orgánica, se observan gradientes más suaves.Instituto Español de Oceanografí

Distribution of anionic and nonionic surfactants in a sewage-impacted Mediterranean coastal lagoon: Inputs and seasonal variations

In this work we have monitored the seasonal inputs, occurrence and distribution of the world’s most widely used surfactants (linear alkylbenzene sulfonates, LAS, nonylphenol polyethoxylates, NPEOs, and alcohol polyethoxylates, AEOs) in Mar Menor lagoon (SE Spain) and its main tributary (El Albujón) for the first time. Concentration of target compounds was determined in both surface waters and sediments after solid phase extraction and pressurized liquid extraction, respectively, followed by liquid chromatography-mass spectrometry (LC-MS). There were significant differences in surfactant fluxes from El Albujón towards Mar Menor depending on the season and the day of the week, with maximum estimated annual inputs being detected for LAS (406 kg) and their metabolites, sulfophenyl carboxylic acids (482 kg). Average concentrations of surfactants in the lagoon were between 44 and 1665 µg/kg in sediment, and between 0.3 and 63 µg/L in water. These levels were significantly higher for samples collected near the shore than for those measured inside the lagoon itself. Overall, the occurrence and distribution of surfactants in the system could be explained due to a combination of different sources (surface and groundwater inputs, treated and untreated wastewater effluents, towns, ports, etc.) and simultaneous in-situ physicochemical and biological processes, with an special emphasis on degradation during warmer months.En prensa3,258