PM15 Biomarkers
Exhibit Hall
8:00 AM - Monday
(PM222) The effect of cadmium on haemocyte viability of the woodlouse Porcellio laevis.
Snyman, R1, Odendaal, J1, 1 Cape Peninsula University of Technology, Cape Town, South Africa, South Africa
ABSTRACT- Cadmium is a major pollutant in the terrestrial environment. Ecotoxicologists are increasingly studying cellular responses to cadmium in soil invertebrates such as woodlice, in order to identify reliable biomarkers of field exposure. The first aim of the present study was to investigate the effect of cadmium on haemocyte viability of the woodlouse Porcellio laevis, using the trypan blue exclusion assay. The ultimate aim is to establish whether changes in haemocyte viability of woodlice can be used as a biomarker of cadmium exposure. Two groups of woodlice (P. laevis) were exposed in the laboratory to sublethal concentrations of cadmium sulphate, namely 10 and 20 
g g-1 respectively, for a period of four weeks. A third group served as control. Each week, six individuals from each group were removed. For each of these woodlice, haemolymph was drawn into a buffer solution and added to an equal volume of trypan blue. The numbers of viable (unstained) and non-viable (blue-stained) cells were counted under a light microscope, using a haemocytometer chamber. Results were expressed as % viable cells. Results showed that, already at the end of the first week of exposure, woodlice from the exposed groups had significantly (p<0.05) lower percentages of viable haemocytes, compared to the control group. The percentage of viable cells did however not decrease significantly in subsequent weeks, suggesting that this response is not time-dependent. The fact that cell viability was affected within the first week of exposure, suggests that this response could possibly be a valuable early warning of cadmium exposure.
Key words: biomarker, woodlouse, cadmium, haemocyte