Multiple biomarker comparison in Mytilus galloprovincialis from the Greece coast:: Lysosomal membrane stability, neutral red retention, micronucleus frequency and stress on stress

The lysosomal membrane stability test applied on the digestive cells (LMS) and the neutral red lysosomal retention assay (NRR) performed on hemocytes have been evaluated on mussels Mytilus galloprovincialis collected from Thermaikos and Strymonikos gulfs (Nothern Greece) in June and December 2000. The correlation analysis indicated that there was a strong positive relationship between the above mentioned biomarkers in both sampling seasons, supporting the validity of their application in water quality assessment. The evaluation of micronucleus frequency (MN) has been also performed in hemocytes of the same mussels and, according to the results, it requires additional validation before using it as a stress index. The results obtained in parallel by the stress on stress (SOS) technique do not support the application of this biomarker in biomonitoring, showing, however, negative correlation with LMS and NRR in one sampling season. Finally, morphological observations were performed on cryosections stained for the enzyme N-acetyl-beta-hexosaminidase, revealing differences in the epithelial cell-layer thickness, as well as changes in the digestive lysosomal system of mussels, obtained from different sampling sites in the two sampling seasons.