1. Ecotoxicological studies aiming at understanding the effect of the pollutants at population and community level, focusing in nanoparticles, herbicides, heavy metals and UVR.


Linking terrestrial and aquatic ecotoxicology under multiple-stress scenarios provoked by global change and chemicals. As a consequence of global change, organisms are exposed to multiple physical and chemical stressors. As example, ozone depletion and the concomitant increase of ultraviolet radiation (UVR) threaten aquatic communities, representing an urgent research issue. Simultaneously, aquatic communities are exposed to other chemical stressors as pesticides and heavy metals released from nearby terrestrial ecosystems. This research focus on three topics: a) the acclimatization of benthic algae to solar UV radiation (UVR); b) how UVR acclimatization may modify algal sensitivity to chemical stressors from surface runoff; c) how surface runoff of pollutants is controlled by edafic fauna.

Influence of chemical coatings on the short-term toxicity of silver nanoparticles on photosynthesis (in collaboration with R. Behra and B. Wagner, Eawag-Switzerland).We are currently examining the influence of various coatings on the toxicity of silver NP to photosynthesis in the alga Chlamydomonas reinhardtii. Considered coatings include polyvinylpyrrolidone, citrate, lactate, gelatin, chitosan and carbonate. Toxicity data are compared as function of the total silver mass as well as function of the concentration of dissolved silver, which is also present in AgNP suspensions. The results indicate a difference in toxicity among the various AgNP when examined as function of the total Ag mass, though they display similar toxicity when analyzed as function of the dissolved silver concentration. Furthermore, since toxicity of all types of AgNP was abolished in presence of the strong silver ligand cysteine, we conclude that toxicity to photosynthesis is determined by the dissolved silver fraction and that none of the coatings are toxic to algal photosyntesis.

Development of new methods for environmental toxicity of silver nanoparticles incorporated in consumer products (with the collaboration of Argenol SL and NFP Group at the Univ. of Zaragoza). Current standard procedures for environmental risk assessment rely on a set of standardized ecotoxicity tests that may not be adequate for nanomaterials (NM). For example, there are concerns that existing protocols may not account for aspects of dosimetry and dispersion of NM, and that some new biological measurements may be needed in some tests. Hence, an appropriate regulation of NM would require new ecotoxicological tests and/or modifications of existing tests. This project aims at coupling the development of a consumer nanomaterial (based on silver nanoparticles) with the evaluation of its environmental risks.


2. Ecological studies aiming at modeling impacts of human activities at the aquatic ecosystem level, focusing on water quality and impacts of invasive species.


Modelling zebra mussel larvae dynamics at the Ebro River (with the collaboration of ENDESA and M.PeribaƱez at the Univ. of Zaragoza). This research aims at increasing the ecological knowledge about zebra mussel larvae population dynamics (spatial and temporal) at the Ebro River, upon characterization and modeling of the environmental conditions thriving mussel populations. Model will allow water users design better management practices.

Emergence of Antibiotic Resistance in water supply Reservoirs: relevance for public health and ecosystem functioning (in collaboration with R.Marce at ICRA).
The extensive use of antibiotics in humans and animals has promoted the spread of microbes that are resistant to drugs. Chronic exposure of natural bacterial assemblages to sub-lethal doses of antimicrobials is one of the processes that may enhance the emergence of antibiotic resistances. This project will be the first exploring the emergence of resistances in reservoirs devoted to water supply and recreational activities, and assessing the effect of antimicrobials in the composition and functioning of reservoir natural bacterial communities.

Assessing and predicting effects on water quantity and quality in Iberian rivers caused by global change (collaborator of SCARCE). IPCC and EEA define a future scenario of increasing frequency of floods and extended droughts in the Iberian Peninsula. This will extensively affect the available water resources, their quality and the conservation and functioning of associated ecosystems, especially rivers and streams. SCARCE has the aim to describe and predict the relevance of global change impacts on water availability, quality and ecosystem services in Mediterranean river basins of the Iberian Peninsula, as well as their impacts on human society and economy.


3. Studies about urban pollution, caused by airborne nano and micro-sized materials (as PM10) using plants (Nerium oleander) as biomonitoring tools.


Use of urban plants (Nerium oleander) as a biomonitoring tools for assessing heavy metals associated to airborne pollution (in collaboration with Univ. San Jorge). Our goal is assessing the feasability of using heavy metal content in leaves of urban plants as biomonitoring tool for heavy metal pollution immission. Preliminary results shown that leaves from plants located in streets with densier traffic resulted in higher total metal content.


4. Algal biotechnology: use of algae for biodiesel & gas production, and waste water treatment.


Use of algal cultures for the treatment of pig slurry and landfill lixiviates (collaboration with F. Lopez from Univ. of Malaga). This project aims at optimizing growing conditions (upon improved bioreactors) for culturing different algae in order to maximize the photosynthetic production and biomass yield. The goal is to assess the potential of the use of algal biomass production for biodiesel, biogas production and advanced water treatments.


© 2009 E.Navarro