Freshwater Bivalve Shells as Archival Indicators of Metal Pollution from a Copper−Uranium Mine in Tropical Northern Australia

• Published in: Environmental science & technology 2002-03, Vol.36 (5), p.821-832
• Main Authors: Markich, Scott J, Jeffree, Ross A, Burke, Patrick T
• Format: Article
• Language: English
• Subjects: Analysis methods; Animal, plant and microbial ecology; Animals; Applied ecology; Applied sciences; Australia, Finniss R; Biological and medical sciences; Bivalvia; Copper; Earth sciences; Earth, ocean, space; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on protozoa and invertebrates; Engineering and environment geology. Geothermics; Environmental Monitoring - methods; Exact sciences and technology; Freshwater; Fundamental and applied biological sciences. Psychology; Geography; Metals; Metals, Heavy - analysis; Metals, Heavy - pharmacokinetics; Mining; Mollusca; Mollusks; Natural water pollution; Pollution; Pollution, environment geology; Tissue Distribution; Uranium; Velesunio angasi; Water Pollutants - analysis; Water Pollutants - pharmacokinetics; Water pollution; Water treatment and pollution
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es011066c

Freshwater bivalves (Velesunio angasi) were sampled in 1996 from the Finniss River in tropical northern Australia at 10 sites a priori exposed and nonexposed to acid rock drainage (ARD), containing elevated metal concentrations, from the rehabilitated Rum Jungle copper−uranium mine. Secondary ion mass spectrometry (SIMS) was used to measure Cu, Mn, Zn, U, Ni, Co, Pb, and Fe/Ca ratios across the annual shell laminations of the longest-lived bivalves found at each site, with the aim of evaluating the ability of the shells to archive measured annual metal inputs and their temporal patterns. At sites not contaminated by ARD, relatively constant and similar (baseline) SIMS signals were found for all metals in the shell laminations of V. angasi, dating as far back as 1965. At sites contaminated by ARD, relatively constant, but variably elevated, SIMS signals were evident for Cu, Mn, Zn, Ni, and Co in the shell, which extended back to the end of rehabilitation (1986) only. Since rehabilitation, the temporal patterns of Cu, Zn, and Mn observed in the shells at the most contaminated sites reflected those of the measured annual dissolved loads in the surface waters. The average concentrations of Cu, Mn, Zn, Ni, and Co in the shells decreased (3−13-fold) with increasing distance downstream of the mine site, until concentrations characteristic of the noncontaminated sites were reached. This geographic pattern of decline in pollution signal in the shell with increasing distance downstream of the pollution input is consistent with the pattern established for water and sediment chemistry. Overall, the SIMS results support the proposition that the shells of V. angasi can be used as archival indicators of metal pollution in surface waters of the Finniss River over their lifetime.