Abstract
Most changes in water bodies are result of human activities that have the potential to undermine the environmental integrity of aquatic ecosystems. Changes in genetic material can be evidenced by the frequency of nuclear abnormalities in fish blood cells, in response to genotoxic agents even at low concentrations. Thus, we aimed at comparing the frequencies of nuclear abnormalities of fish kept in acclimation, with fish collected in Timbo river (Santa Cruz do Timbo, Santa Catarina State), under low anthropogenic interference, and fish collected in Iguacu river (Uniao da Vitoria, Parana State), a polluted river. The highest frequency of changes in nuclear morphology of fish erythrocytes was found in the urbanized area around the Iguacu river, while, the fish collected in areas with preserved riparian forest surrounding the Timbo river and acclimated fish showed no morphological changes. Our results suggest that genotoxic compounds in the Iguacu river are acting as stressors to aquatic communities, especially fish. In addition, the absence of nuclear abnormalities in fish from the Timbo river suggests that rivers without significant environmental changes can serve as reference point for comparative studies of genetic modifications for the species studied.
Highlights
Like any aquatic environment, the basin of the Iguaçu river is exposed to pollution processes caused by the huge variety and quantity of chemicals (Livingstone, 1998), and presents pollution evidence from industrial waste from the manufacture of paper, fertilizers and waste from agricultural practice (Bueno-Krawczyk et al, 2015)
We did not observe the occurrence of cell and micronucleus abnormalities in the fish collected in the Timbó river and the fish left in acclimation
When we compared the nuclear abnormalities between the fish collected in the Iguaçu river, Timbó and in acclimation (Table 1), we observed that the fish of the Iguaçu river presented significant differences in the frequency of nuclear abnormalities for Notched, Blebbed and micronucleus when compared with the Timbó river and Acclimation group, whereas for Lobed, no significant differences were detected between these groups (Table 2 and Figure 3)
Summary
The basin of the Iguaçu river is exposed to pollution processes caused by the huge variety and quantity of chemicals (Livingstone, 1998), and presents pollution evidence from industrial waste from the manufacture of paper, fertilizers and waste from agricultural practice (Bueno-Krawczyk et al, 2015) These toxic substances released into the environment may interact with biota, causing changes (Arias et al, 2007) that can have a genotoxic potential and/or mutagenic and clastogenic effects (Zenkner, Soares, Prá, Köhler, & Rieger, 2011), favoring the formation of micronucleus and nuclear abnormalities as they can be absorbed and stored in the animal body (Benites, Doncato, Minho, & Perazzo, 2014). These organisms have genetic structure similar to mammals (Barbazuk et al, 2000; Lieschke & Currie, 2007) responding to environmental contamination
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