title: Bioaccumulation and retention kinetics of cadmium in the freshwater decapod Macrobrachium australiense.
abstract: The potential sources and mechanisms of cadmium bioaccumulation by the native freshwater decapods Macrobrachium species in the waters of the highly turbid Strickland River in Papua New Guinea were examined using (109)Cd-labelled water and food sources and the Australian species Macrobrachium australiense as a surrogate. Synthetic river water was spiked with environmentally relevant concentrations of cadmium and animals were exposed for 7 days with daily renewal of test solutions. Dietary assimilation of cadmium was assessed through pulse-chase experiments where prawns were fed separately (109)Cd-labelled fine sediment, filamentous algae and carrion (represented by cephalothorax tissue of water-exposed prawns). M. australiense readily accumulated cadmium from the dissolved phase and the uptake rate increased linearly with increasing exposure concentration. A cadmium uptake rate constant of 0.10 ± 0.05 L/g/d was determined in synthetic river water. During depuration following exposure to dissolved cadmium, efflux rates were low (0.9 ± 5%/d) and were not dependent on exposure concentration. Assimilation efficiencies of dietary sources were comparable for sediment and algae (48-51%), but lower for carrion (28 ± 5%) and efflux rates were low (0.2-2.6%/d) demonstrating that cadmium was well retained by M. australiense. A biokinetic model of cadmium accumulation by M. australiense predicted that for exposures to environmentally relevant cadmium concentrations in the Strickland River, uptake from ingestion of fine sediment and carrion would be the predominant sources of cadmium to the organism. The model predicted the total dietary route would represent 70-80% of bioaccumulated cadmium.
authors: Centre for Environmental Contaminants Research, CSIRO Land and Water, Locked Bag 2007, Kirrawee, NSW 2232, Australia; School of Applied Sciences, RMIT University, Plenty Road, Bundoora, VIC 3083, Australia. Electronic address: tom.cresswell@ansto.gov.au.
authors: Tom
authors: T
authors: Cresswell
authors: School of Applied Sciences, RMIT University, Plenty Road, Bundoora, VIC 3083, Australia.
authors: Stuart L
authors: SL
authors: Simpson
authors: Hydrobiology, Lang Parade, Auchenflower, QLD 4066, Australia.
authors: Ross E W
authors: RE
authors: Smith
authors: School of Applied Sciences, RMIT University, Plenty Road, Bundoora, VIC 3083, Australia.
authors: Dayanthi
authors: D
authors: Nugegoda
authors: Institute for Environmental Research, ANSTO, Locked Bag 2001, Kirrawee, NSW 2232, Australia.
authors: Debashish
authors: D
authors: Mazumder
authors: Austral Radioecology, Oyster Bay, NSW, 2225, Australia.
authors: John
authors: J
authors: Twining
mesh_terms: D000818:Animals; D002104:Cadmium / Q000378:metabolism*; D004032:Diet; D005618:Fresh Water; D019015:Geologic Sediments / Q000737:chemistry; D007700:Kinetics; D033541:Palaemonidae / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D014874:Water Pollutants, Chemical; D002104:Cadmium
keywords: (109)Cd; Biokinetic model; Diet; Metal; Radioisotope tracer