PARENT SESSION
4F Alternatives for risk assessment in terrestrial ecosystems
9:00 AM to 7:00 PM, Monday, 07 May 2001

(M/MF156) Relationship between hepatopancreas cell damage and mass change resulting from cadmium exposure in Porcellio laevis.

Odendaal, James¹, Reinecke, Adriaan¹, ¹

ABSTRACT- Cadmium is a widely used metal in industry. It has no biological function and can be accumulated in terrestrial ecosystems. Woodlice are known to accumulate cadmium in their bodies, especially in the hepatopancreas. The hepatopancreas has two cell types. The smaller S-cells have a storage function and the larger B-cells secrete digestive enzymes. Detrimental effects of cadmium on this organ may impact negatively on growth of these animals. The aim of this study was to investigate the influence of cadmium contamination on the hepatopancreas cells and to determine the relationship between possible damage to hepatopancreas cells and mass change. Woodlice were experimentally exposed to different concentrations of cadmium sulphate (0, 20, 80, 160 mg.kg^-1) for a period of 6 weeks. There was a statistically significant increase in the accumulation of cadmium in the hepatopancreas as the exposure concentrations increased (P<0.05). After 6 weeks differently exposed woodlice exhibited statistically significant lower mass changes than control woodlice (P<0.05). Histological investigation revealed a degeneration of B-cells in the exposed woodlice. This negative effect on the B-cells could influence the ability of these cells to perform their digestive related function adequately, which in turn can influence mass change. To determine the relationship between damage to the hepatopancreas and mass change, the histological data of the hepatopancreas were quantified. The cell area in hepatopancreas transverse sections correlated positively with mass change (r=0.99). The lower mass change of woodlice exposed to cadmium sulphate relative to those in the control can thus be causally linked to the degeneration of B-cells, expressed as cell area. A number of reasons are presented to explain this phenomenon.

Key words: hepatopancreas, mass change, cadmium, woodlouse