EFFECTS OF CADMIUM AND ZINC ON OXYGEN UPTAKE IN THE WHELK BULLIA DIGITALIS (DILLWYN)

SUMMARY

Solutions of both cadmium chloride and zinc chloride affect the oxygen intake of Bullia digitalis at 15 °C, the sensitivity to cadmium being about ten times greater than to zinc. Zinc concentrations above 1 ppm result in a lowering of oxygen consumption, uptake being reduced by some 40% at 2 ppm. Cadmium, on the other hand, increases respiration at levels between 0,1 and 0,7 ppm, there being an increase of 30% at 0,5 ppm. Above 0,6 ppm cadmium, oxygen uptake decreases rapidly and is 20% below normal at 0,75, 38% down at 1 ppm. Altering the temperature within the range 10–20 °C has little effect on these responses, while the length of the exposure period has a greater effect. Low concentrations of zinc do not alter the responses to cadmium but at higher concentrations of zinc the effect is additive.