The SeKT joint research project: Definition of Reference Conditions, Control Sediments and Toxicity Thresholds for Limnic Sediment Contact Tests
While the water quality has improved considerably in the last years due to water protection, in many European catchment basins highly polluted sediments still represent a legacy of the industrial era, strongly influencing the water quality in the future. Sediment bound contaminants can be remobilized by bioturbation, floods, or dumping of dredged material. Therefore, monitoring and assessment of sediment quality plays an important role not only for national legislation, but also for the implementation of the EU water framework directive.
The EU water framework directive (EWFD) aims to achieve a good ecological and chemical state for surface waters in European catchment basins till 2015. The reduction of anthropogenic water pollution from diffuse and point sources should be reached by a combination of specifications of emission limit values and immision orientated quality objectives.
Against this background, there is a demand for the application of sediment contact tests: While the commonly used bioassays reflect only insufficiently contaminant bioavailability, sediment contact tests (whole sediment tests) have a higher ecological relevance. Sediment contact tests are biological tests that determine the effect of whole sediment on organisms, considering all possible contaminant uptake routes for the test organism (particle contact, food, pore water). The complexity of the matrix sediment (particles and water) make high methodological demands on the test systems. The bioassays must be able to differentiate between anthropgenic disturbances (e.g. pollution) and the influence of natural factors (e.g. grain size), to enable a risk assessment.
The aim of the investigations of the joint research project SeKT (Sediment Kontakt Tests) was to evaluate the applicability of the sediment contact tests for a possibly wide range of different types of sediments. The definition of reference conditions and standardized control sediments were a prerequisite for: 1. the determination of toxicity thresholds
2. the comparability of sediment contact tests with in a test battery
3. the application of sediment dilution series.
Therefore, the first step was the investigation of uncontaminated natural and artificial sediments with a test battery, to determine the response of the test systems to important sediment properties, such as TOC and grain size. The results should explain the variability of the different tests with the investigates sediment properties. Information on the variability helps to define more reliable toxicity thresholds for the various tests. Additionally, artificial and natural control sediments were defined for the whole test battery.
Uptake route: The bioavailability and thus the potential effect of a contaminant were determined by the partitioning equilibrium between particles and pore water, as well as by the way of moving and feeding of test organism.
Trophic Level: Various contaminants affect organisms of different trophic levels (bacteria; fungi; primary producers; consumers) in different ways.
Effect mechanisms: Various test systems or test parameters are able to detect different modes of action of chemicals (e.g. endocrine disruption; mutagenicity) or effects on different ecological levels (organisms, population) and thus to provide indication of different potential risks.
Degree of standardization: The tests should not be in the state of development. Their application was approved in sediments.
Step I: Natural and artificial sediments were investigated with all sediment contact tests (SeKTs) and sychronously analyzed in terms of their physico-chemical properties. By this means, the natural variation can be determined for each SeKT in respect to the sediment properties and toxicity thresholds can be defined. Moreover, it will be possible to define common control sediments.
Steps II-IV: Evaluation of the test system (SeKT-battery + control sediment) by the ecotoxicological and physico-chemical analysis of
Step II: contaminant enriched control sediments
Step III: contaminated environmental sediment samples
Step IV: sediment dilution series
This joint research project was funded by the German Federal Ministry of Education and Research (BMBF; 02WU 0598) and was for a period of 3 years: July 2005 till Mai 2008. Within the SeKT project, ibn worked under the supervsion of Dr. Sebastian Höss for 30 month (October 2005 till March 2008) on the subproject TV3: Sediment contact test with Caenorhabditis elegans (Nematoda).
Bundesanstalt für Gewässerkunde (BfG) (Coordination; Dr. Ute Feiler)
Am Mainzer Tor 1, D-56068 Koblenz
Fon ++49 261 13065356, Fax ++49 261 13065363
e-mail: feiler@bafg.de
ECT Oekotoxikologie GmbH (Dr. Michael Meller)
Böttgerstr. 2 - 14, D-65439 Flörsheim/Main
Fon ++49 6145 956450, Fax ++49 6145 956499
e-mail: m-meller@ect.de
Dr. Fintelmann und Dr. Meyer (Dr. Neumann-Hensel; Kerstin Melby)
Handels- und Umweltschutzlaboratorien GmbH
Mendelssohnstr. 15D, D-22761 Hamburg
Fon ++49 40 89966425, Fax ++49 40 89966450
e-mail: hensel@inlabco.com
Nordum - Institut fur Umwelt und Analytik GmbH & Co. KG (Dr. Jürgen Weber)
Am Weidenbruch 22, D-18196 Kessin
Fon ++49 38208 637-0, Fax ++49 38208 637-28
e-mail: weber@nordum.de
Technische Universitat Hamburg-Harburg (TUHH) (PD Dr. Wolfgang Ahlf)
Arbeitsbereich Umweltschutztechnik Eisendorferstr. 40, D-21073 Hamburg
Fon ++49 40 428782862, Fax ++49 40 428782315
e-mail: ahlf@tuhh.de
Universitat Heidelberg Institut fur Zoologie (Dr. Henner Hollert)
Im Neuenheimer Feld 230, D-69120 Heidelberg
Fon ++49 6221 54-5650, Fax ++49 6221 54-6162
e-mail: henner.hollert@urz.uni-heidelberg.de
SeKT project website
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