Assessing and forecasting the impacts of global change on Mediterranean rivers. The SCARCE Consolider project on Iberian basins

Introduction

The Consolider-Ingenio 2010 project SCARCE, with the full title ??Assessing and predicting effects on water quantity and quality in Iberian Rivers caused by global change?? aims to examine and predict the relevance of global change on water availability, water quality, and ecosystem services in Mediterranean river basins of the Iberian Peninsula, as well as their socio-economic impacts. Starting in December 2009, it brought together a multidisciplinary team of 11 partner Spanish institutions, as well as the active involvement of water authorities, river basin managers, and other relevant agents as stakeholders.

Methods

The study areas are the Llobregat, Ebro, Jucar, and Guadalquivir river basins. These basins have been included in previous studies and projects, the majority of whom considered some of the aspects included in SCARCE but individually. Historical data will be used as a starting point of the project but also to obtain longer time series. The main added value of SCARCE project is the inclusion of scientific disciplines ranging from hydrology, geomorphology, ecology, chemistry, and ecotoxicology, to engineering, modeling, and economy, in an unprecedented effort in the Mediterranean area. The project performs data mining, field, and lab research as well as modeling and upscaling of the findings to apply them to the entire river basin.

Results

Scales ranging from the laboratory to river basins are addressed with the potential to help improve river basin management. The project emphasizes, thus, linking basic research and management practices in a single framework. In fact, one of the main objectives of SCARCE is to act as a bridge between the scientific and the management and to transform research results on management keys and tools for improving the River Basin Management Plans. Here, we outline the general structure of the project and the activities conducted within the ten Work Packages of SCARCE.     

Protozoan colonization on artificial substrates in relation to water quality in a tropical Indian harbour

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Development of electrochemical based sandwich enzyme linked immunosensor for Cryptosporidium parvum detection in drinking water

Cryptosporidium parvum is one of the most important biological contaminants in drinking water and generates significant risks to public health. Due to low infectious dose of C. parvum, remarkably sensitive detection methods are required for water and food industry analysis. This present study describes a simple, sensitive, enzyme amplified sandwich form of an electrochemical immunosensor using dual labeled gold nanoparticles (alkaline phosphatase and anti-oocysts monoclonal antibody) in indium tin oxide (ITO) as an electrode to detect C. parvum. The biosensor was fabricated by immobilizing the anti-oocysts McAb on a gold nanoparticle functionalized ITO electrode, followed by the corresponding capture of analytes and dual labeled gold nanoparticle probe to detect the C. parvum target. The outcome shows the sensitivity of electrochemical immune sensor enhanced by gold nanoparticles with a limit of detection of 3 oocysts/mL in a minimal processing period. Our results demonstrated the sensitivity of the new approach compared to the customary method and the immunosensors showed acceptable precision, reproducibility, stability, and could be readily applied to multi analyte determination for environmental monitoring.     

Hg bioavailability and impact on bacterial communities in a long-term polluted soil

Different soil samples characterised by a long-term Hg-pollution were studied for Hg total content, fractionation, phytotoxicity and influence on the bacterial community. Hg pollution ranged from 1 to 50 mg kg(-1) and most of it was speciated in scarcely soluble forms. In agreement with this, the biochemical quality indexes were investigated (biomass, enzyme activities) and the bacterial community (viable heterotrophic (VH) bacteria, functional diversity) apparently was not influenced by the degree of Hg pollution. In particular, the investigated soils exhibited a low percentage of Hg-resistant (Hg(R)) bacteria ranging from less than 0.001% to 0.25% of the VH and the addition of available Hg in the form of HgCl(2) induced an enrichment of resistant Hg(R) populations. The general biodiversity of the bacterial community was evaluated by denaturing gradient gel electrophoresis of DNA of Hg spiked soil microcosms and of control soils. Hg(R) bacteria capable to grow in a minimal medium containing HgCl(2) were also isolated and identified. MerA and merB gene PCR fragments were obtained from different Hg(R) strains and the range of similarities at the DNA level and at the deduced amino acid level showed that they carried mercuric reductase and lyase. Differently from bacteria, some influence of soil Hg content on seeds' germination and root elongation was observed for Lepidium sativum L. and Solanum lycopersicum L. In conclusion, most of the Hg in these long-term polluted soils was scarcely mobile and available and did not significantly influence the soil bacterial community. The risk of potential Hg remobilization over time, that could be naturally favoured by the activity of plant roots or other inorganic processes occurring in soil, can be extenuated since bacterial community was resistant and resilient to subsequent Hg stress.     

Variations of periphytic diatom sensitivity to the herbicide diuron and relation to species distribution in a contamination gradient: implications for biomonitoring

Diatoms are commonly used as bioindicators of trophic and saprobic pollution in rivers. However, more knowledge is needed concerning their sensitivity to toxicants such as agricultural herbicides. In this study, seven species of periphytic diatoms were isolated from the Morcille River (Beaujolais area, France) which presents a streamward contamination gradient by pesticides and particularly diuron. The sensitivity of these species to diuron was assessed through ecotoxicological tests based on short-term growth inhibition of monospecific cultures. After application of an appropriate toxicological model, EC50 were determined and the species were ranked according to their tolerance. EC50 values ranged from 4.5 to 19 μg L(-1). Finally, the results were related to field periphyton samples from an upstream and a downstream site in order to check if variations in specific relative abundance between sites are consistent with differences in tolerance to diuron. Species distribution between sites was only partially in accordance with toxicological results suggesting that other factors (toxic or trophic) have an important influence on diatom communities in the river. Nevertheless, diatoms showed their potential to indicate water contamination by pesticides and toxic indices could be developed in complement to existing trophic indices.     

Okadaic acid induces morphological changes, apoptosis and cell cycle alterations in different human cell types

Okadaic acid (OA) is a marine toxin produced by dinoflagellate species which is frequently accumulated in molluscs usual in the human diet. The exact action mechanism of OA has not been described yet and the results of most reported studies are often conflicting. The aim of this work was to evaluate the OA effects on morphology, cell cycle and apoptosis induction by means of light microscopy and flow cytometry, in three different types of human cells (leukocytes, HepG2 cells and SHSY5Y cells). Cells were treated with a range of OA concentrations in the presence and absence of S9 fraction. OA induced morphological changes in all the cell types studied, and cell cycle disruption only in leukocytes and neuronal cells. SHSY5Y cells were the most sensitive to OA assault. Results obtained in the presence and absence of metabolic activation were similar, suggesting that OA acts both directly and indirectly. Furthermore, OA was found to increase the subG(1) region in the flow cytometry cell cycle analysis, suggesting induction of apoptosis. These results were confirmed by the employment of specific methodologies for studying apoptosis such as caspase 3 activation and annexin V staining. Increases in the apoptosis rate were obtained in all the cells treated in the absence of S9 fraction, accompanied by increases in caspase 3 activation, suggesting that apoptosis induced by OA is a caspase 3-dependent process. Nevertheless, in the presence of S9 fraction no apoptosis was detected, indicating a metabolic detoxifying activity, although necrosis was observed in neuroblastoma cells.     

Rapid analysis of neonicotinoid insecticides in guttation drops of corn seedlings obtained from coated seeds

Regarding the hypothesis that neonicotinoid insecticides used for seed coating of agricultural crops - mainly corn, sunflower and seed rape - are related to the extensive death of honey bees, the phenomenon of corn seedling guttation has been recently considered as a possible route of exposure of bees to these systemic insecticides. In the present study, guttation drops of corn plants obtained from commercial seeds coated with thiamethoxam, clothianidin, imidacloprid and fipronil have been analyzed by an optimized fast UHPLC-DAD procedure showing excellent detection limits and accuracy, both adequate for the purpose. The young plants grown both in pots - in greenhouse - and in open field from coated seeds, produced guttation solutions containing high levels of the neonicotinoid insecticides (up to 346 mg L(-1) for imidacloprid, 102 mg L(-1) for clothianidin and 146 mg L(-1) for thiamethoxam). These concentration levels may represent lethal doses for bees that use guttation drops as a source of water. The neonicotinoid concentrations in guttation drops progressively decrease during the first 10-15 days after the emergence of the plant from the soil. Otherwise fipronil, which is a non-systemic phenylpyrazole insecticide, was never detected into guttation drops. Current results confirm that the physiological fluids of the corn plant can effectively transfer neonicotinoid insecticides from the seed onto the surface of the leaves, where guttation drops may expose bees and other insects to elevated doses of neurotoxic insecticides.     

Fractionation of traffic-emitted Ce, La and Zr in road dusts

The introduction of catalytic converters has led to a new environmental problem since catalysts emit platinum group elements (PGEs) which are among the least distributed elements in nature. Along with PGEs the vehicle exhaust catalysts contain also a number of stabilizers, commonly oxides of rare earth elements and alkaline earth elements such as Ce, La and Zr. Since vehicular emission of these elements has received little attention so far this work attempts to offer insight into their distribution and fate in the environment by measuring their speciation in road dust samples collected along several highways in Germany and a city centre (Saarbrücken). Speciation of the elements (fractionation into associated mineralogical phases) was carried out via a conventional sequential extraction protocol and the complexing abilities of humic substances in the organic matter were investigated by selective extraction methods in combination with size segregation. For evaluation purposes soil samples spiked with catalytic converter material were analyzed, showing a much lower fraction of Ce, La and Zr mobilized in comparison to the road dust samples. It was found that the elements were effectively bound to humic substances in road dust with a preference for complexation with low molecular weight compounds (<1600 Da).     

Development of a sampling method for the simultaneous monitoring of straight-chain alkanes, straight-chain saturated carbonyl compounds and monoterpenes in remote areas

Studies have shown that biogenic compounds, long chain secondary compounds and long lifetime anthropogenic compounds are involved in the formation of organic aerosols in both polluted areas and remote places. This work aims at developing an active sampling method to monitor these compounds (i.e. 6 straight-chain saturated aldehydes from C6 to C11; 8 straight-chain alkanes from C9 to C16; 6 monoterpenes: α-pinene, β-pinene, camphene, limonene, α-terpinene, & γ-terpinene; and 5 aromatic compounds: toluene, ethylbenzene, meta-, para- and ortho-xylenes) in remote areas. Samples are collected onto multi-bed sorbent cartridges at 200 mL min(-1) flow rate, using the automatic sampler SyPAC (TERA-Environnement, Crolles, France). No breakthrough was observed for sampling volumes up to 120 L (standard mixture at ambient temperature, with a relative humidity of 75%). As ozone has been shown to alter the samples (losses of 90% of aldehydes and up to 95% of terpenes were observed), the addition of a conditioned manganese dioxide (MnO(2)) scrubber to the system has been validated (full recovery of the affected compounds for a standard mixture at 50% relative humidity--RH). Samples are first thermodesorbed and then analysed by GC/FID/MS. This method allows suitable detection limits (from 2 ppt for camphene to 13 ppt for octanal--36 L sampled), and reproducibility (from 1% for toluene to 22% for heptanal). It has been successfully used to determine the diurnal variation of the target compounds (six 3 h samples a day) during winter and summer measurement campaigns at a remote site in the south of France.     

Gold mining in Siberia and the Far East as a source of mercury contamination of the environment

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