Effects of chronic exposure to sediments from the Zarzis area, Gulf of Gabes, measured in the mussel (Mytilus spp.): a multi-biomarker approach involving oxidative stress and neurotoxicity

Abstract

ABSTRACT The hereby study was conducted to assess the chronic biological effects of potentially contaminated sediments collected at the Zarzis area, Tunisia, on the marine mussel species (Mytilus spp.). Useful information can be provided through the analysis of biomarkers that allow inferring about the presence of pollutants and their adverse effects, contributing for a better assessment of ecosystems' quality and functions. Three sampling sites were chosen taking into account the putative impact of different human activities at several sites located in Zarzis area, compared to an unpolluted reference site, located in Afurada, Vila Nova de Gaia, Portugal. Physical-chemical characterization involved the survey of metals (Cd, Cu, Cr, Hg, Zn and Pb) and polycyclic aromatic hydrocarbons (PAHs), whose toxic effects are involved in the onset of oxidative stress. Biomarkers involving oxidative stress and neurotoxicity were quantified in hemolymph, gills, and digestive gland tissues of Mytilus spp. following the chronic exposure to the distinct sediments. Organisms exposed to sediments collected at the Zarzis area presented the highest values of the tested oxidative stress biomarkers and a significant inhibition of AChE activity in comparison with the unpolluted reference site. This set of results suggests that biomarker responses representing different biological endpoints in Mytilus spp. are useful for the assessment of environmental pollution effects, namely by PAHs and metals. Our results suggest the presence of these chemicals in specific sampling sites whose sediment caused evident biological responses in mussels.