Diminished metal accumulation in riverine fishes exposed to acid mine drainage over five decades.

Bony bream (Nematalosa erebi) and black catfish (Neosilurus ater) were sampled from the fresh surface waters of the Finniss River in tropical northern Australia, along a metal pollution gradient draining the Rum Jungle copper/uranium mine, a contaminant source for over five decades. Paradoxically, populations of both fish species exposed to the highest concentrations of mine-related metals (cobalt, copper, lead, manganese, nickel, uranium and zinc) in surface water and sediment had the lowest tissue (bone, liver and muscle) concentrations of these metals. The degree of reduction in tissue concentrations of exposed populations was also specific to each metal and inversely related to its degree of environmental increase above background.

Whole-body to tissue concentration ratios for use in biota dose assessments for animals.

Environmental monitoring programs often measure contaminant concentrations in animal tissues consumed by humans (e.g., muscle).

Comparative accumulation of (109)Cd and (75)Se from water and food by an estuarine fish (Tetractenos glaber).

Few data are available on the comparative accumulation of metal(loid)s from water and food in estuarine/marine fish. Smooth toadfish (Tetractenos glaber), commonly found in estuaries in south-eastern Australia, were separately exposed to radio-labelled seawater (14kBqL(-1) of (109)Cd and 24kBqL(-1) of (75)Se) and food (ghost shrimps; Trypaea australiensis: 875Bqg(-1)(109)Cd and 1130Bqg(-1)(75)Se) for 25 days (uptake phase), followed by exposure to radionuclide-free water or food for 30 days (loss phase). Toadfish accumulated (109)Cd predominantly from water (85%) and (75)Se predominantly from food (62%), although the latter was lower than expected.

Uptake and loss of dissolved 109Cd and 75Se in estuarine macroinvertebrates.

Semaphore crabs (Heloecius cordiformis), soldier crabs (Mictyris platycheles), ghost shrimps (Trypaea australiensis), pygmy mussels (Xenostrobus securis), and polychaetes (Eunice sp.), key benthic prey items of predatory fish commonly found in estuaries throughout southeastern Australia, were exposed to dissolved (109)Cd and (75)Se for 385 h at 30 k Bq/l (uptake phase), followed by exposure to radionuclide-free water for 189 h (loss phase). The whole body uptake rates of (75)Se by pygmy mussels, semaphore crabs and soldier crabs were 1.

Properties of two tropical soils in relation to the transport of radionuclides in the rhizosphere.

The uptake of radionuclides by commercial crops is being studied at two sites, Blain and Tippera, in a research farm in the Northern Territory, Australia. Studies have been performed to characterise the properties of the two soils, particularly the hydraulic properties that are considered to significantly influence the transport and plant uptake of these radionuclides in the soils The Blain soil, a sandy loam, has been categorised as SM according to the Unified Soil Classification System. Quartz is the dominant mineral for the Blain soil.