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A test battery approach for the ecotoxicological evaluation of estuarine sediments

Radiation and Environmental Science Centre, FOCAS Institute, Dublin Institute of Technology, Ireland.
Ecotoxicology (Impact Factor: 2.5). 11/2005; 14(7):741-55. DOI: 10.1007/s10646-005-0022-8
Source: PubMed

ABSTRACT The purpose of this study was to evaluate the overall sensitivity and applicability of a number of bioassays representing multiple trophic levels, for the preliminary ecotoxicological screening (Tier I) of estuarine sediments. Chemical analyses were conducted on sediments from all sampling sites to assist in interpreting results. As sediment is an inherently complex, heterogeneous geological matrix, the toxicity associated with different exposure routes (solid, porewater and elutriate phases) was also assessed. A stimulatory response was detected following exposure of some sediment phases to both the Microtox and algal bioassays. Of the bioassays and endpoints employed in this study, the algal test was the most responsive to both elutriates and porewaters. Salinity controls, which corresponded to the salinity of the neat porewater samples, were found to have significant effects on the growth of the algae. To our knowledge, this is the first report of the inclusion of a salinity control in algal toxicity tests, the results of which emphasise the importance of incorporating appropriate controls in experimental design. While differential responses were observed, the site characterised as the most polluted on the basis of chemical analysis was consistently ranked the most toxic with all test species and all test phases. In terms of identifying appropriate Tier I screening tests for sediments, this study demonstrated both the Microtox and algal bioassays to be more sensitive than the bacterial enzyme assays and the invertebrate lethality assay employing Artemia salina. The findings of this study highlight that salinity effects and geophysical properties need to be taken into account when interpreting the results of the bioassays.

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    • "Many authors have shown that bioassays provide a general indication of metal bioavailability/toxicity in sediments (Latif and Licek 2004; Harikumar and Nasir 2010; Baran and Tarnawski 2013; Besser et al. 2014). Bioassays are a useful tool whose application enables a fuller classification of ecological risk resulting from the presence of chemical substances in sediments, their bioavailability, and interactions (Mankiewicz-Boczek et al. 2008; Nendza 2002; Davoren et al. 2005; Narracci et al. 2009; Buitrago et al. 2013). Many authors emphasize that bioassays are a good complement to chemical analyses in procedures of sediment quality assessment (Wadhia and Thompson 2007; Mamindy-Pajany et al. 2011). "
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    • "In order to estimate the real risk of contaminants, chemical analyses have to be complemented with biological and toxicological assays (Ghirardini et al. 1999; Fent 2003; Tsui and Chu 2003). Although chemical analysis is able to record both source substances and their metabolites, it cannot provide information about the effect upon biota (Champan et al. 1992; Davoren et al. 2005; García-Lorenzo et al. 2009). In addition, chemical contaminants rarely affect organisms as single substances but instead cause adverse effects as diverse mixtures (O' Halloran 2006; Manzo et al. 2008a). "
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    • "Consequently, several sediment samples from the sediment traps and the treatment wetland were assessed. There is a wide range of toxicity methods available for this type of investigation (Keddy et al., 1995; Davoren et al., 2005). In this study test methods and test organisms were selected that cover a range of endpoints and are internationally used and accepted. "
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