Where do the metals go? Investigating uptake, retention and spatial distribution of cadmium and zinc using radiotracers within a freshwater decapod crustacean

No Thumbnail Available
Date
2013-10-01
Journal Title
Journal ISSN
Volume Title
Publisher
SETAC Australasia
Abstract
The bioaccumulation of metals by aquatic organisms can be studied in great depth using radiotracers, allowing insights into rates of uptake and fate of the metals once bioaccumulated. This study used the radioisotopes 109Cd and 65Zn to explore the uptake, retention and internal distribution of these non-essential and essential metals in solution by the freshwater decapod crustacean Macrobrachium australiense. Three treatments consisting of cadmium alone, zinc alone and a combination of cadmium and zinc were used to determine the differences in uptake rate of each metal individually and in a mixture over a three week period. The prawns were then allowed to depurate in metal-free water for two weeks to determine rates of efflux. The effects of moulting on the uptake and loss of each metal radionuclide were also identified during the study. Following exposure, prawns were cryosectioned and the spatial distribution of radionuclides visualised using autoradiography for the 3 experimental cohorts. Results showed that a mixture of the two metals did not affect the uptake or efflux rate of each individual metal. Moulting appeared to result in a short-term loss in zinc but an increased cadmium uptake rate. However, metal isotope concentration remained stable within the body during the depuration period. Autoradiography demonstrated that the majority of cadmium uptake was localised within the hepatopancreas, while zinc uptake was distributed between the hepatopancreas and the exoskeleton. The implications of the study are such that M. australiense readily accumulates both cadmium and zinc from solution but does not effectively eliminate either metal while in metal-free water. © 2013, ANSTO and CSIRO.
Description
Keywords
Metals, Aquatic organisms, Radioisotopes, Crustaceans, Zinc, Cadmium
Citation
Cresswell, T., Simpson, S.L., Mazumder, D., Callaghan, P., Nguyen, A. 2013. Where do the metals go? Investigating uptake, retention and spatial distribution of cadmium and zinc usingradiotracers within a freshwater decapod crustacean. Platform presentation at SETAC-AU Melbourne Conference. 1-3 October 2013, Melbourne, Australia.