|
1J - Bioaccumulation (WEP/68) Uptake of cadmium and zinc by Carp under hypoxia. Hattink, J.1, De Boeck, G.1, Blust, R.1, 1 University of Antwerp, Dept of Biology, Ecophysiology and Biochemistry, Antwerp, Belgium ABSTRACT- A side effect of pollution of natural waters with for example heavy metals, is the occurrence of hypoxia. Hypoxia may alter the ventilation rate of aquatic organisms and often also their physiology, which may alter the ecotoxicology of the micropollutant in question. Here we studied the effect of hypoxia on the toxicokinetics of cadmium and zinc in carp. In some aquatic ecosystems cadmium and zinc are still present in such concentrations that they affect the local ecological structure with hypoxia as side effect. Carp was acclimated at three oxygen concentrations (25%, 50%, and 100% saturation) at 25°C. Subsequently, a standard radiotracer accumulation and elimination experiment was performed with the acclimated fish at the corresponding oxygen level for 21 d accumulation and 28 d elimination period. Total zinc and cadmium concentrations were 100 nmol/l and 5 nmol/l, respectively. Differences in metal assimilation due to a possible higher ventilation rate or an altered physiology as a result of hypoxia could not be detected. Uptake of both metals was linear for the 21 d accumulation period. Zinc was retained in the fish, while 40% of the cadmium taken up was excreted after 28 d elimination. Additional short-term experiments (12 h) were performed to test when the ventilation rate for carp was affected by the oxygen level. Furthermore possible physiological changes in carp as a result of the oxygen levels applied were followed by monitoring some biochemical processes during the acclimatisation period and the tracer experiment. Key words: hypoxia, heavy metals, carp |
