Toxicity ranking of estuarine sediments on the basis of Sparus aurata biomarkers

Abstract

Sparus aurata biomarkers were used to rank sediments from the Sado River estuary (Portugal) according to their toxicity. Initially, the activities of liver ethoxyresorufin-O-deethylase, liver and gill glutathione S-transferases, muscle lactate dehydrogenase, and brain acetylcholinesterase were tested in a laboratory bioassay with the reference compound benzo[a]pyrene. Enzymatic activities were determined in different tissues of fish exposed for 48, 96, or 240 h to three concentrations of benzo[a]pyrene (25, 50, and 100 microg/L). Induction of liver ethoxyresorufin-O-deethylase was observed at all the exposure periods and concentrations, suggesting a continuous response of this system to toxicant exposure. Induction of liver glutathione S-transferases activity was only observed after 240 h of exposure, whereas gill glutathione S-transferases activity was significantly inhibited at all the exposure periods, suggesting a direct or indirect effect of the toxicant on these enzymes. Inhibition of lactate dehydrogenases activity was only observed after 96 h of exposure to 25 microg/L of benzo[a]pyrene. No significant effects were observed on acetylcholinesterase activity, suggesting that cholinergic function of S. aurata is not affected by benzo[a]pyrene. In a second phase, fish were exposed for 240 h to sediments collected at five sites of the Sado River estuary, and the same biomarkers were analyzed. For all the enzymes assayed, significant differences among sites were found. In this study, the battery of biomarkers used allowed to discrimination among sites with different types of contamination, levels of contamination, or both, after multivariate data analysis. Discrimination of sites was similar to the ranking provided by a more complex and parallel study (including chemical analysis of sediments, macrobenthic community analysis, amphipod mortality toxicity tests, and sea urchin abnormality embryo assays), suggesting its suitability to evaluate the toxicity of estuarine sediments.

The versatile, changing, and advancing roles of fish in sediment toxicity assessment—a review

“…Subsequent to anesthetizing in benzocaine (150 ppm, Mondon et al 2001) or tricaine methanesulfonate (MS-222) solution, fish are sacrificed for the evaluation of selected mechanistic-based endpoints. The endpoints cover acute and long-term toxicity, bioaccumulation, endocrine effects, carcinogenicity and mutagenicity, and toxic effects on reproduction (Bucke et al 1989;Roberts et al 1989;Ankley 1991;Almeida et al 2005;Inzunza et al 2006;Jimenez-Tenorio et al 2007; Barbee et al 2008;Cunha et al 2007;Costa et al 2008; Table 1). Over the period of use of these techniques, laboratory studies with bulk sediments have indicated that many samples from numerous locations exhibit acute and/or chronic toxicity to a variety of test species.…”

“…But how are test fish species selected? The primary criteria for fish species selection should be the species' ecological and/or economical importance to the region (e.g., Rhombosolea tapirina in Mondon et al 2001, Oncorhynchus kisutch in Barbee et al 2008; Sparus aurata in Cunha et al 2007) and its relative sensitivity to sediment contamination (e.g., S. maximus in Kilemade et al 2009). Other factors should also be considered including the ease of collection (or purchasing), convenient size, adaptation in laboratory (ease of handling), lifestyle (benthic or pelagic), indigenous to research site or closely related to an indigenous species (Cheung et al 1997;Guy et al 2006).…”

“…It is suspected that dissolved chemicals and chemical suspensions of contaminated sediment are involved. The selection of gilthead seabream (S. aurata) in the study of Cunha et al (2007) was due to its economic significance as well as its distribution in the Atlantic and Mediterranean coastal waters, estuaries, and lagoons, including the Sado River estuary in Portugal. It is intensively cultured in marine and estuarine waters, and it can be found in both pristine and contaminated sites.…”

“…Some have argued (e.g., Ankley 1991;Ingersoll et al 1995;Bat 2005) that fish are typically pelagic making them inappropriate for sediment toxicity as compared to benthic life forms (e.g., invertebrates). However, several studies (e.g., Burton 1991;Cunha et al 2007;Kilemade et al 2009) claimed that many fish species are flat-shaped and are quite adapted to benthic lifestyles, and therefore, can be used for determining sediment pollution. Sediment-feeding (or illiophagous) fish also have the ability to tolerate low concentrations of dissolved oxygen which enables them to inhabit polluted environment (Black 1983).…”

Thirty years of use of multivariate quantitative methods in benthic community ecology of marine and coastal habitats: looking to the past to planning the future

“…There are well reported problems associated with these techniques like strong distortions (called the horseshoe effect) caused by long gradients (Kenkel and Orlóci 1986;Swan 1970) for PCA and redundancy analysis-RDA; the arch effect caused by the erroneous attribution of low Chi square distances to sites with no species in common (Gauch 1982) for CA and CCA; and problems with predefinition of dimensionality, local minima, meaningless axes and confusion of location and dispersion, besides the problem of not, really, use the species' quantitative data for NMDS (Brayard et al 2007;Brehm and Fiedler 2004;Cunha et al 2007;Legendre and Legendre 1998;Warton et al 2012).…”