Integrative assessment of ecological responses and chemical contamination of urban wastewater outfalls on soft bottom sediments of an estuarine system

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Contrasting complexing capacity of dissolved organic matter produced during the onset, development and decay of a simulated bloom of the marine diatom Skeletonema costatum

Original research articleThe capacity of natural dissolved organic matter (DOM) produced during the onset, development and decay of a simulated bloom of the marine diatom Skeletonema costatum to complex free copper has been followed for a 2 week period. Copper binding capacity of the culture was measured by anodic stripping voltammetry (ASV) with a hanging mercury drop electrode (HMDE). The concentration of dissolved organic carbon (DOC) and two fluorophores, M (humic-like, Ex/Em: 320 nm/410 nm) and T (protein-like, Ex/Em: 280 nm/350 nm), were followed during the course of the incubation. Models using DOC concentrations alone could not accurately predict the complexing capacity of the culture, especially at the end of the bloom, and better predictions were obtained when fluorescence measurements were considered. They were helpful in characterising two types of copper ligands produced in the culture. The first type, traced by the fluorescence of peak T, was related to labile DOC directly exuded by phytoplankton. The second type, traced by the fluorescence of peak M, was the refractory humic-like material presumably produced in situ as a by-product of the bacterial degradation of phytogenic materials. During the onset and development of the bloom (days 0 to 7), the fluorescence of peak T explains 60–80% of the total complexing capacity of the culture, suggesting that exuded “protein-like” compounds among other exuded complexing agents efficiently complexed free copper. On the contrary, during the decay (days 8 to 13), these ligands were replaced by humic substances as the complexing agent for copper.Financial support for this work came from the Spanish ‘Ministerio de Educación y Ciencia’ (MEC), Grant Nos. REN2000-0880-C02-01 MAR and REN2003-00958 MAR and the ‘Xunta de Galicia’, Grant No. PGIDT01MAR40201PN.Versión del editor2,75

Effect of dissolved organic matter (DOM) of contrasting origins in Cu and Pb speciation and toxicity to Paracentrotus lividus larvae

Original research paperWater samples of contrasting origin, including natural seawater, two sediment elutriates and sewage-influenced seawater, were collected and obtained to examine the effect of the dissolved organic matter(DOM) present on metal bioavailability. The carbon content (DOC) and the optical properties (absorbanceand fluorescence) of the coloured DOM fraction (CDOM) of these materials were determined. Cu and Pbcomplexation properties were measured by anodic stripping voltammetry (ASV) and the effect of DOMon Cu and Pb bioavailability was studied by means of theParacentrotus lividusembryo-larval bioassay.Sediment elutriates and sewage-influenced water (1) were enriched 1.4–1.7 times in DOC; (2) absorbedand reemitted more light; and (3) presented higher Cu complexation capacities (LCu) than the naturalseawater used for their preparation.LCuvaried from 0.08 M in natural seawater to 0.3 and 0.5 Min sediment elutriates and sewage-influenced water, respectively. Differences in DOC, CDOM and Cucomplexation capacities were reflected in Cu toxicity. DOM enriched samples presented a Cu EC50of0.64 M, significantly higher than the Cu EC50of natural and artificial seawater, which was 0.38 M. Theprotecting effect of DOM on Cu toxicity greatly disappeared when the samples were irradiated with highintensity UV-light. Cu toxicity could be successfully predicted considering ASV-labile Cu concentrationsin the samples. Pb complexation by DOM was only detected in the DOM-enriched samples and causedlittle effect on Pb EC50. This effect was contrary for both elutriates: one elutriate reduced Pb toxicity incomparisonwiththecontrolartificialseawater,whiletheotherincreasedit.UVirradiationofthesamplescaused a marked increase in Pb toxicity, which correlated with the remaining DOC concentration. DOMparameterswererelatedtoCuspeciationandtoxicity:goodcorrelationswerefoundbetweenDOCandCuEC50, whileLCucorrelated better with the fluorescence of marine humic substances. The present resultsstress the importance of characterizing not only the amount but also the quality of seawater DOM tobetter predict ecological effects from total metal concentration dataSpanish Ministry of Education and Science (CTM2006-13880-C03-01/MAR), Xunta of Galicia (PGIDIT-05MA40201) and Basque Government (predoctoral grant)Versión del editor3,76

Procedimiento para la criopreservación de embriones de erizo de mar y bioensayo asociado

El procedimiento se basa en el uso de un protocolo de criopreservación para blástulas de 8 horas de erizo de mar para poder almacenar en nitrógeno líquido embriones para su uso fuera de la temporada de reproducción natural de esta especie. Se ha desarrollado además, un bioensayo ecotoxicológico con embriones de erizo de mar criopreservados para la evaluación de la contaminación marina. El procedimiento objeto de esta patente permite el uso durante todo el año de embriones de erizo de mar tanto en bioensayos ecotoxicológicos como con aplicaciones en la industria de la acuicultura

Assessment of hydrocarbon pollution in NW Iberian Peninsula using bioaccumulation and molecular biomarkers in Mytilus galloprovincialis

Society of Environmental Toxicology and Chemistry - SETAC Europe 15th Annual Meeting, Lille, France, May 2005.Polycyclic aromatic hydrocarbons (PAH´s) are ubiquitous contaminants in marine environment as a result of uncontrolled spills, river transport, surface runoff and atmospheric deposition. A significant amount of industrial activity including shipping and oil refining is located along the NW Iberian Peninsula coast. The use of exposure biomarkers holds out promise due to the incipient state of the cost-effective methodologies for diagnosis and monitoring of oil pollution. This work presents the preliminary results concerning the identification of a set of biomarkers for an early warning detection of PAH toxicity. The bivalve Mytillus galloprovincialis was selected due to its ubiquitous distribution along coastline, being used as sentinels in pollution monitoring. This species has also an important value. Four locations in the vicinity of industrial wastewater discharges along the NW Iberian coast were selected and compared with a nearby (reference) site for (i) measurements of PAH body burdens and (ii) levels of enzyme activity: catalase (CAT), superoxide-dismutase (SOD), glutathione peroxidase (GPx), gluthathione S-transferase (GST) and Na+/K+ATPase (ATPase). The results will be discussed on the basis of their potential in providing additional evidence for discriminate between well known polluted and unpolluted sites

Multiple Class I and Class II Haemophilus ducreyi Strains Cause Cutaneous Ulcers in Children on an Endemic Island

Background Together with Treponema pallidum subspecies pertenue, Haemophilus ducreyi is a major cause of exudative cutaneous ulcers (CUs) in children. For H. ducreyi, both class I and class II strains, asymptomatic colonization, and environmental reservoirs have been found in endemic regions, but the epidemiology of this infection is unknown. Methods Based on published whole-genome sequences of H. ducreyi CU strains, a single-locus typing system was developed and applied to H. ducreyi–positive CU samples obtained prior to, 1 year after, and 2 years after the initiation of a mass drug administration campaign to eradicate CU on Lihir Island in Papua New Guinea. DNA from the CU samples was amplified with class I and class II dsrA-specific primers and sequenced; the samples were classified into dsrA types, which were geospatially mapped. Selection pressure analysis was performed on the dsrA sequences. Results Thirty-seven samples contained class I sequences, 27 contained class II sequences, and 13 contained both. There were 5 class I and 4 class II types circulating on the island; 3 types accounted for approximately 87% of the strains. The composition and geospatial distribution of the types varied little over time and there was no evidence of selection pressure. Conclusions Multiple strains of H. ducreyi cause CU on an endemic island and coinfections are common. In contrast to recent findings with T. pallidum pertenue, strain composition is not affected by antibiotic pressure, consistent with environmental reservoirs of H. ducreyi. Such reservoirs must be addressed to achieve eradication of H. ducreyi

Ejercicio interlaboratorio de bioensayos marinos para la evaluación de la calidad ambiental de sedimentos costeros. IV. Ensayo de toxicidad sobre sedimento con crustáceos anfípodos

9 páginas, 2 figuras, 3 tablas.[EN] Interlaboratory variability was studied for the bioassay using crustacean amphipods. Nine series of data were obtained from different laboratories using four different species (Ampelisca brevicornis, Corophium volutator, Corophium multisetosum and Microdeutopus gryllotalpa), all previously used for sediment toxicity assessment in Spain. Results were studied for interlaboratory variability and according to different confounding factors. The coefficients of variation were similar to those previously reported for this bioassay and sample classification was homogeneous among the laboratories that successfully completed the exercise. No significant tendencies related to test species were identified and it seems that the factor most critically affecting test results and the classification of samples is storage time before testing.[ES] Se estudió la precisión interlaboratorio del bioensayo con crustáceos anfípodos. Se recogieron nueve series de datos procedentes de distintos laboratorios europeos y de cuatro especies distintas (Ampelisca brevicornis, Corophium volutator, Corophium multisetosum y Microdeutopus gryllotalpa), todas ellas usadas previamente para la caracterización de la toxicidad de sedimentos en España. Esos resultados se estudiaron para evaluar la variabilidad interlaboratorio de acuerdo a las diferentes especies y los distintos tiempos de almacenamiento de las muestras antes del ensayo. Los resultados mostraron coeficientes de variación similares a los encontrados en estudios previos y permitieron una clasificación homogénea de las muestras entre los laboratorios que completaron el ejercicio con éxito. No se identificaron tendencias significativas debidas al uso de distintas especies y, al parecer, el factor que puede afectar más críticamente la clasificación de las muestras y, por lo tanto, el uso de los resultados para la toma de decisiones, es el tiempo de almacenamiento de los sedimentos previamente al desarrollo del ensayo.This study was carried out under a joint research project between CEDEX and the University of Cádiz. Part of the work was funded by the Spanish Ministry of Science and Technology REN2002_01699/TECNO). The first author was supported by a grant (FPI) from the Spanish Ministry of Education and Science.Peer reviewe