Aquatic Toxicology 160 (2015) 22–30 Contents lists available at ScienceDirect Aquatic Toxicology j o ur na l ho me pag e: www.elsevier.com/locate/aquatox Effects of cadmium accumulation from suspended sediments and phytoplankton on the Oyster Saccostrea glomerata Helena A. Schmitz, William A. Maher ∗ , Anne M. Taylor, Frank Krikowa Ecochemistry Laboratory, Institute for Applied Ecology, University of Canberra, Bruce 2601, ACT, Australia a r t i c l e i n f o Article history: Received 17 October 2014 Received in revised form 23 December 2014 Accepted 24 December 2014 Available online 27 December 2014 Keywords: Sydney rock oysters Metal Suspended sediments Phytoplankton Total antioxidant capacity Lipid peroxidation Lysosomal destabilisation a b s t r a c t Metals are accumulated by ﬁlter feeding organisms via water, ingestion of suspended sediments or food. The uptake pathway can affect metal toxicity. Saccostrea glomerata were exposed to cadmium through cadmium-spiked suspended sediments (19 and 93 g/g dry mass) and cadmium-enriched phy- toplankton (1.6–3 g/g dry mass) and cadmium uptake and effects measured. Oysters accumulated appreciable amounts of cadmium from both low and high cadmium spiked suspended sediment treat- ments (5.9 ± 0.4 g/g and 23 ± 2 g/g respectively compared to controls 0.97 ± 0.05 g/g dry mass). Only a small amount of cadmium was accumulated by ingestion of cadmium-enriched phytoplankton (1.9 ± 0.1 g/g compared to controls 1.2 ± 0.1 g/g). In the cadmium spiked suspended sediment exper- iments, most cadmium was desorbed from sediments and cadmium concentrations in S. glomerata were signiﬁcantly related to dissolved cadmium concentrations (4–21 g/L) in the overlying water. In the phytoplankton feeding experiment cadmium concentrations in overlying water were <0.01 g/L. In both exposure experiments, cadmium-exposed oysters showed a signiﬁcant reduction in total antioxidant capacity and signiﬁcantly increased lipid peroxidation and percentage of destabilised lysosomes. Desta- bilised lysosomes in the suspended sediments experiments also resulted from stress of exposure to the suspended sediments. The study demonstrated that exposure to cadmium via suspended sediments and to low concentrations of cadmium through the ingestion of phytoplankton, can cause sublethal stress to S. glomerata. © 2014 Elsevier B.V. All rights reserved. 1. Introduction Urbanised estuaries receive anthropogenic contamination from both land and ocean sources making organisms that inhabit these environments susceptible to contaminants such as metals (Turner et al., 2004). Cadmium concentrations in the environment tend to be naturally low; however, anthropogenic activity such as zinc min- ing and reﬁning activities (Parvau, 2010) increase cadmium inputs. Cadmium entering waterways is adsorbed to sediments and asso- ciated with ferric or manganese oxy-hydroxides, organic matter and sulphides (DiToro et al., 1990; Lion et al., 1982). Cadmium con- centrations in sediments will be several orders of magnitude higher than concentrations of dissolved metals in the water column (Birch and O’Hea, 2007; Meyer et al., 2005). In Australian estuaries, resuspension of sediment adsorbed cad- mium can occur through tidal movements, wind mixing, dredging activities and bioturbation by sediment infauna (Birch and O’Hea, ∗ Corresponding author. Tel.: +61 262012531. E-mail address: bill.maher@canberra.edu.au (W.A. Maher). 2007; Eggleton and Thomas, 2004; Hedge et al., 2009). The phys- ical disturbance of sediments has been shown to rapidly release metals (Atkinson et al., 2007). Resuspension of reduced sedi- ments into oxygenated waters will alter the metal sediment–water partitioning depending on the temperature, salinity and oxygen concentration of the overlying water (Eggleton and Thomas, 2004; Simpson et al., 1998, 2002), primarily by the oxidation of sulﬁdes in sediments and the subsequent release of metals (Simpson et al., 2012). Cadmium is of concern because it is a non-essential metal that can become harmful to aquatic organisms (Parvau, 2010). Cadmium is taken up by ﬁlter feeding organisms through three pathways, suspended sediments, water column, and/or diet (Rand, 1995); although it is generally accepted that uptake from the water col- umn is not as signiﬁcant, as water borne cadmium concentrations are low because of its rapid adsorption onto sediments. Many stud- ies have shown that sediment ingestion and metals associated with particles is a major route of metal accumulation in molluscs (Wu et al., 2012; Wang and Fisher, 1999; Reinfelder et al., 1997; Luoma, 1989). The bioavailability of metals is inﬂuenced by the size and geochemical phase of particles that metals are bound to http://dx.doi.org/10.1016/j.aquatox.2014.12.019 0166-445X/© 2014 Elsevier B.V. All rights reserved.