Genotoxicity monitoring of freshwater environments using caged crayfish (Astacus leptodactylus)

Genotoxicity of freshwater pollution was assessed by measuring DNA damage in haemocytes of cagedfreshwater crayfish Astacus leptodactylus by the means of Comet assay and micronucleus test, integratedwith the measurements of physiological (total protein concentration) and immunological (total haemocytecount) haemolymph parameters as biomarkers of undergone stress. Crayfish were collected at thereference site (River Mrezˇnica) and exposed in cages for 1 week at three polluted sites along the SavaRiver (Zagreb, Sisak, Krapje). The long term pollution status of these locations was confirmed by chemicalanalyses of sediments. Statistically significant increase in DNA damage measured by the Comet assay wasobserved at all three polluted sites comparing to the crayfish from reference site. In addition, native crayfishfrom the mildly polluted site (Krapje) cage-exposed on another polluted site (Zagreb) showed lowerDNA damage than crayfish from the reference site exposed at the same location indicating adaptation andacclimatisation of crayfish to lower levels of pollution. Micronuclei induction showed similar gradient ofDNA damage as Comet assay, but did not reach the statistical significance. Observed increase in total haemocytecount and total protein content in crayfish from polluted environments in the Sava River also confirmedstress caused by exposure to pollution. The results of this study have proved the applicability ofcaging exposure of freshwater crayfish A. leptodactylus in environmental genotoxicity monitoring using Comet assay and micronucleus test. 2011 Elsevier Ltd. All rights reserved.