The influence of sediment particle size and organic carbon on toxicity of copper to benthic invertebrates in oxic/suboxic surface sediments

Abstract

The use of sediment quality guidelines to predict the toxicity of metals in sediments is limited by an inadequate understanding of exposure pathways and by poor causal links between exposure and effects. For a 10-d exposure to Cu-spiked sediments, toxicity to the amphipod Melita plumulosa was demonstrated to occur through a combination of dissolved and dietary Cu exposure pathways, but for the bivalves Spisula trigonella and Tellina deltoidalis, toxicity occurred primarily by exposure to dissolved Cu. For relatively oxidized sediments that had moderate amounts of organic carbon (2.6-8.3% OC), silt (20-100% <63-µm particles) but low acid-volatile sulfide (AVS), acute toxicity thresholds for the three species were derived based on the OC-normalized Cu concentration of the less than 63-µm sediment fraction. For all three species, no effects were observed at concentrations below 10 µg/L dissolved Cu (in pore water and overlying water) or below 12 mg Cu/g OC (for <63 µm sediment). For sediments with silt/OC properties of 20/0.5, 50/1, or 70/4%, the particulate Cu-based threshold equated to 60, 120, or 480 mg Cu/kg, respectively. For oxic/suboxic sediments in which AVS is not limiting metal availability, sediment quality guidelines of this form will provide adequate protection against toxicity and improve the prediction of effects for sediments with varying properties.

Performance and sensitivity of rapid sublethal sediment toxicity tests with the amphipod Melita plumulosa and copepod Nitocra spinipes

“…The interpretation of the mean metal SQGQ-response relationships requires the assumption that the individual quotient for each metal (i.e., concentration divided by the respective SQG value) is proportional to the effects that this metal is having on each species. The limitations of these guideline values are well recognized [32,33], as are the influences of sediment properties, particularly AVS, particulate organic carbon, and sediment particle size on the bioavailability of metals [34][35][36]. The interpretation also assumes that the different metals have a similar mode of action, which is also unlikely.…”

Avoidance of contaminated sediments by an amphipod (Melita plumulosa), A harpacticoid copepod (Nitocra spinipes), and a snail (Phallomedusa solida)

“…As it is known that M. plumulosa is sensitive to sediment-bound copper [28,43], avoidance of these sediments was believed to be due to differences in particulate copper or the flux of copper at the sedimentwater interface, rather than differences in dissolved copper in the overlying water. Sediments 5 and 7 were copper-spiked sediments, and although they had been equilibrated and porewater copper concentrations were <5 mg/L (unpublished results), the copper in these sediments was likely to be more bioavailable than if present in field-collected sediments with similar copper concentrations [30]. The greater avoidance of Sediments 5 and 7 compared to Sediment 4, which had high lead and zinc concentrations and greater toxicity, indicates that M. plumulosa may be more sensitive to copper than other metal contaminants.…”

“…Deoxygenated waters were prepared by bubbling solutions with high-purity, oxygen-free nitrogen gas for >8 h to give dissolved oxygen concentrations <0.1 mg/L. Measurements of pH, particle size distribution (wet sieving and gravimetry), organic carbon (high-temperature total organic carbon analyzer), and particulate metals (2:1 concentrated HCl:HNO 3 , heated) were made as described previously [23,30]. Overlying water samples were rapidly filtered through acid-washed 0.45-mm membrane filters (Minisart; Sartorius) immediately following collection and acidified to 2% HNO 3 (v/v) with concentrated HNO 3 (Tracepure; Merck).…”

“…The amphipod M. plumulosa is commonly used in Australia for sediment quality assessment [18,30]. For nine contaminated sediments that caused varying degrees of toxicity to M. plumulosa in 10-d lethality tests (Table 2), the avoidance response after 48 h was determined (Fig.…”

Utilization of Marine Crustaceans as Study Models: A New Approach in Marine Ecotoxicology for European (REACH) Regulation

“…Amphipods are widely used in ecotoxicology, owing to their sensitivity to several contaminants such as metals (Zanders & Rojas, 1992;Liber et al, 2011;Mann et al, 2011;Strom et al, 2011), for the evaluation of sediments in marine and transition environments (Chapman & Wang, 2001) and have been employed to draw up sediment-quality guidelines (Macdonald et al, 2011). ASTM (1999) suggests for testing some amphipods species but unfortunately none of them occurs in the Mediterranean, making problematical their use for the laboratories of this region; on the whole, among the species considered in the guidelines the sole amphipod useful for the Mediterranean is Corophium orientale that is cited in the protocol ISO 16712 (2005).…”