Assessment of sediment ecotoxicological status as a complementary tool for the evaluation of surface water quality: the Ebro river basin case study.

According to the European Water Framework Directive (WFD), assessment of surface water status is based on ecological and chemical status that is not always in coherence. In these situations, ecotoxicity tests could help to obtain a better characterization of the ecosystems. The general aim of this work is to design a methodology to study the ecotoxicological status of freshwater systems. This could be useful and complementary to ecological status, for a better ecological characterization of freshwater systems. For this purpose, sediments from thirteen sampling sites within the Ebro river watershed (NE Spain) were collected for ecotoxicity characterization. The ecotoxicity of pore water has been evaluated employing the test organisms Vibrio fischeri, Pseudokirschneriella subcapitata and Daphnia magna, while whole sediment ecotoxicity was evaluated using Vibrio fischeri, Daphnia magna, Nitzschia palea and Chironomus riparius. An analysis of acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) was performed to evaluate the sediment toxicity associated to bioavailable metals. Moreover, data about priority pollutants defined by the WFD in water, sediment and fish as well as data of surface water status of each sampling point were provided by the Monitoring and Control Program of the Ebro Water bodies. In general terms, whole sediment bioassays have shown more toxicity than pore water tests. Among the different organisms used, P. subcapitata and C. riparius were the most sensitive in pore water and whole sediment, respectively. Our evaluation of the ecotoxicological status showed high coincidences with the ecological status, established according to the WFD, especially when ecosystem disruption due to numerous stressors (presence of metals and organic pollution) was observed. These results allow us to confirm that, when chemical stressors affect the ecosystem functioning negatively, an ecotoxicological approach, provided by suitable bioassays in pore water and whole sediment, could detect these changes with accurate sensitivity.

[1]  D. M. DiToro,et al.  Sediment flux modeling. , 2001 .

[2]  F. Voutsinou-Taliadouri,et al.  Geochemical and sedimentological patterns in the thermaikos gulf, north-west Aegean sea, formed from a multisource of elements , 1995 .

[3]  J. López-Dovál,et al.  Analysis of monitoring programmes and their suitability for ecotoxicological risk assessment in four Spanish basins. , 2012, The Science of the total environment.

[4]  Peter M. Chapman,et al.  General guidelines for using the sediment quality triad , 1997 .

[5]  D. Barceló,et al.  Occurrence and distribution of multi-class pharmaceuticals and their active metabolites and transformation products in the Ebro river basin (NE Spain). , 2012, The Science of the total environment.

[6]  K. Kramer,et al.  Tidal Estuaries: manual of sampling and analytical procedures , 1994 .

[7]  Branislav Vrana,et al.  A "toolbox" for biological and chemical monitoring requirements for the European Union's Water Framework Directive. , 2006, Talanta.

[8]  K. C. Thompson,et al.  Low-cost ecotoxicity testing of environmental samples using microbiotests for potential implementation of the Water Framework Directive , 2007 .

[9]  P. Chapman,et al.  Biological implications of sulfide in sediment—a review focusing on sediment toxicity , 1999 .

[10]  Jacek Namieśnik,et al.  Determination of EC50 toxicity data of selected heavy metals toward Heterocypris incongruens and their comparison to “direct-contact” and microbiotests , 2011, Environmental monitoring and assessment.

[11]  Shallow lakes, the water framework directive and life. What should it all be about? , 2007 .

[12]  M. Ehrhardt,et al.  Methods of Seawater Analysis (3rd Edition) , 1999 .

[13]  Damià Barceló,et al.  Pilot survey of a broad range of priority pollutants in sediment and fish from the Ebro river basin (NE Spain). , 2006, Environmental pollution.

[14]  Hans Blanck,et al.  Induced Community Tolerance in Marine Periphyton established under Arsenate Stress , 1988 .

[15]  C. Emmanouil,et al.  Evaluation of toxic and interactive toxic effects of three agrochemicals and copper using a battery of microbiotests. , 2009, The Science of the total environment.

[16]  Peter M. Chapman,et al.  A Sediment Quality Triad: Measures of sediment contamination, toxicity and infaunal community composition in Puget Sound , 1985 .

[17]  M. Schuhmacher,et al.  Integrated study of metal behavior in Mediterranean stream ecosystems: a case-study. , 2013, Journal of hazardous materials.

[18]  J. C. Greene,et al.  Review of whole-organism bioassays: soil, freshwater sediment, and freshwater assessment in Canada. , 1995, Ecotoxicology and environmental safety.

[19]  Herbert E. Allen,et al.  Analysis of acid‐volatile sulfide (AVS) and simultaneously extracted metals (SEM) for the estimation of potential toxicity in aquatic sediments , 1993 .

[20]  M. Schuhmacher,et al.  Novel approach for assessing heavy metal pollution and ecotoxicological status of rivers by means of passive sampling methods. , 2011, Environment international.

[21]  R. Altenburger,et al.  An ecological perspective in aquatic ecotoxicology: Approaches and challenges , 2008 .

[22]  Wolfgang Ahlf,et al.  A guidance for the assessment and evaluation of sediment quality a German Approach based on ecotoxicological and chemical measurements , 2002 .

[23]  D. Chapman,et al.  Sediment quality triad assessment survey of the Galveston Bay, Texas system , 1996, Ecotoxicology.

[24]  J. Blasco,et al.  Ring test for whole-sediment toxicity assay with -a- benthic marine diatom. , 2010, The Science of the total environment.

[25]  D. H. White,et al.  Effects of Contaminants in Dredge Material from the Lower Savannah River , 2000, Archives of environmental contamination and toxicology.

[26]  Pim E G Leonards,et al.  Responses in sediment bioassays used in the Netherlands: can observed toxicity be explained by routinely monitored priority pollutants? , 2003, Water research.

[27]  Jacek Namieśnik,et al.  Application of ecotoxicological studies in integrated environmental monitoring: Possibilities and problems , 2007 .

[28]  B. Moss,et al.  The Water Framework Directive: total environment or political compromise? , 2008, The Science of the total environment.

[29]  R. Tauler,et al.  Multivariate curve resolution of organic pollution patterns in the Ebro River surface water-groundwater-sediment-soil system. , 2010, Analytica chimica acta.

[30]  Tomislav Hengl,et al.  Heavy metals in European soils: A geostatistical analysis of the FOREGS geochemical database , 2008 .

[31]  Á. Borja,et al.  The European Water Framework Directive at the age of 10: a critical review of the achievements with recommendations for the future. , 2010, The Science of the total environment.

[32]  Yolanda Picó,et al.  Prospects for combining chemical and biological methods for integrated environmental assessment , 2009 .