Aquatic Toxicology 149 (2014) 83–93 Contents lists available at ScienceDirect Aquatic Toxicology j ourna l ho me pa ge: www.elsevier.com/locate/aquatox Effects of lead-spiked sediments on freshwater bivalve, Hyridella australis: linking organism metal exposure-dose-response Chamani P.M. Marasinghe Wadige ∗ , Anne M. Taylor, William A. Maher, Rodney P. Ubrihien, Frank Krikowa Ecochemistry Laboratory, Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia a r t i c l e i n f o Article history: Received 17 October 2013 Received in revised form 19 January 2014 Accepted 22 January 2014 Keywords: Biologically active lead Biologically detoxified lead Biomarkers Hyridella australis Oxidative stress Sub-cellular partitioning a b s t r a c t Lead entering aquatic ecosystems adsorbs to sediments and has the potential to cause adverse effects on the health of benthic organisms. To evaluate the freshwater bivalve Hyridella australis as a bioindicator for sediment toxicity, their exposure-dose and response to lead contaminated sediments (< 0.01, 205 ± 9 and 419 ± 16 g/g dry mass) was investigated in laboratory microcosms using 28 day exposures. Despite high concentrations of lead in the sediments, organisms accumulated low concentrations of lead in their tis- sues after 28 days of exposure (low treatment: 2.2 ± 0.2 g/g dry mass, high treatment: 4.2 ± 0.1 g/g dry mass), however, accumulated lead concentrations in lead exposed organisms were two fold (low treat- ment) and four fold (high treatment) higher than that of unexposed organisms (1.2 ± 0.3 g/g dry mass). Accumulation of lead by H. australis may have occurred as analogues of calcium and magnesium. Labial palps accumulated significantly more lead than other tissues. Of the lead accumulated in the hepatopan- creas, 83%–91% was detoxified and stored in metal rich granules. The proportions and concentrations of lead in this fraction increased with lead exposure, which suggests that lead detoxification pathway plays an important role in metal tolerance of H. australis. The biologically active lead was mainly present in the mitochondrial fraction which increased with lead exposure. Total antioxidant capacity of H. australis significantly decreased while lipid peroxidation and lysosomal membrane destabilation increased with lead exposure. This study showed a clear lead exposure-dose-response relationship and indicates that H. australis would be a good biomonitor for lead in freshwater ecosystems. © 2014 Published by Elsevier B.V. 1. Introduction Metals are mined in many countries worldwide and significant amounts are deposited into aquatic ecosystems causing adverse effects to biota (Beltman et al., 1999; Besser et al., 2009; Brumbaugh et al., 2005; Farag et al., 1998; Khozhina and Sherriff, 2008). Mine accidents such as collapses of tailings dumps and dam spills may exacerbate metal contamination in aquatic environments (Grimalt et al., 1999; Korte et al., 2000; Pérez-López et al., 2009; Soldán et al., 2001). The Molonglo River, New South Wales, Australia is contam- inated with metals originating from the Captains Flat mining activities, in particular, two separate collapses of tailings dumps in 1939 and 1943 (Weatherley et al., 1967). The inputs of metals to the river and contamination of river biota have been studied on several occasions since the late 1960s (Brooks, 1980; Graham et al., 1986; Nicholas and Thomas, 1978; Norris, 1986; ∗ Corresponding author Tel.: +61 469 786 330. E-mail address: chamani.marasinghe.wadige@canberra.edu.au (C.P.M. Marasinghe Wadige). Weatherley et al., 1967) but none of these studies have inte- grated the uptake of metals with responses of benthic biota. The most recent study conducted in 1996 (Sloane and Norris, 2003) recorded concentrations of cadmium – 11.8 g/g, copper – 748 g/g, lead – 4137 g/g and zinc – 3534 g/g dry mass in Molon- glo River sediments. These values exceed the high trigger value of the ANZECC/ARMCANZ (2000) interim sediment quality guidelines (ISQG) for cadmium – 10 g/g, copper – 270 g/g, lead – 220 g/g and zinc – 410 g/g dry mass. The sediment bound metals have the potential to be released into the water column under suit- able physicochemical conditions, leading to further contamination of aquatic systems (Arakel, 1995; Macklin et al., 1997) thus pos- ing a risk to benthic organisms (Chapman et al., 1998; Lamoureux and Brownawell, 1999; Tessier et al., 1993). In this context, the fate and effects of metals in Molonglo River sediments needs to be investigated. The exposure-dose-response framework provides a means of linking chemical exposure to biological responses to assess the health of organisms and ecosystems (Salazar and Salazar, 1997, 2000; Taylor and Maher, 2012a, b, c). A suitable sentinel organism is required for use within this frame work. Sentinel organisms map the bioavailable metal fraction by 0166-445X/$ – see front matter © 2014 Published by Elsevier B.V. http://dx.doi.org/10.1016/j.aquatox.2014.01.017