Ecological Indicators (Mar 2021)
Intestine of invasive fish Prussian carp as a target organ in metal exposure assessment of the wastewater impacted freshwater ecosystem
Abstract
The application of invasive fish Prussian carp (Carassius gibelio Bloch, 1782) as bioindicator organism, using intestine as bioindicator tissue of anthropogenic influence in the lowland Ilova River was estimated. Intestinal tissue enables the investigation of dietborne metal uptake, so the first record on intestinal metal levels in Prussian carp was presented, as total and cytosolic fraction, which indicates the proportions of potentially toxic and bioavailable metals. Pollution impact was also estimated by analyses of biomarkers of oxidative stress (malondialdehyde), antioxidative capacity (catalase and glutathione) and of metal exposure (metallothioneins). All analyzed parameters were compared in the intestine of fish from the reference site and contaminated site impacted by technological and municipal wastewaters in two seasons. Both total and cytosolic As, Ca, Cd, Cs, Cu, Mg, Na and Rb levels were significantly higher at contaminated than the reference site in at least one season, whereas Mn and V had higher concentrations at the reference site. Despite differences in concentrations, average proportions of total metal levels in cytosolic fraction were comparable at two sites, i.e. over 70% for Na, K, Rb, Se, Cd, Cs, As and Mo, indicating their high possibility of binding to important biomolecules. In addition, higher levels of malondialdehyde in both seasons and enhanced catalase activity in spring, indicated disturbed environmental conditions near the contaminated site and need of continuous monitoring of this region. Finally, our research represents successful application of widely distributed invasive species in ecotoxicological studies, whereas intestine was shown as a suitable bioindicator tissue, clearly reflecting dietary metal uptake.
