TA8 Field-Based Effects Measures
A105 & A106
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() Sublethal in situ sediment and sediment-overlying water assays with microalgae, polychaetes and crabs for estuaries.

Moreira, S1, 2, Moreira-Santos, M3, Guilhermino, L1, 2, Ribeiro, R3, 1 CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Porto, Portugal2 ICBAS - Instituto de Ciências Biomédicas de Abel Salazar, Porto, Portugal3 IAV - Instituto do Ambiente e Vida, Coimbra, Portugal

ABSTRACT- There is a clear requirement for the development of ecotoxicological tools for ecological risk assessments in estuaries, particularly in what concerns sediment contamination. In opposition to laboratory toxicity testing, in situ assays allow a more realistic exposure, generating more ecologically relevant information for the area under study. Given that the vast majority of environmental decisions concerning estuarine systems are still based on laboratory toxicity estimates, the main goal of this study was to develop an integrated approach for the improvement of ecological relevance, together with cost-effectiveness, in both sediment and sediment-overlying water toxicity assessments in estuaries. Short-term sublethal in situ assays were developed and evaluated using three species with different functions at the ecosystem level: the microalga Phaeodactylum tricornutum as primary producer, the polychaete Hediste diversicolor as detritivore, and the crab Carcinus maenas as consumer. Assay organisms were deployed at reference and contaminated Portuguese estuaries. The results obtained confirmed the suitability of the deployment and retrieval procedures. Moreover, they allowed discriminating moderately and highly impacted sites from reference sites, rendering the proposed in situ assays a potential useful test battery to assess sediment and sediment-overlying water toxicity in estuarine systems.

Key words: sediment toxicity, in situ assay, sediment-overlying water toxicity, estuaries

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