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

Abstract

Sublethal whole-sediment toxicity tests are an important tool for assessing the potential effects of contaminated sediments. However, the longer duration required for evaluating potential chronic effects may increase endpoint variability and test costs compared to survival endpoints. In the present study we compare the performance and sensitivity to contaminants of 10-d sublethal sediment toxicity tests with the amphipod Melita plumulosa and harpacticoid copepod Nitocra spinipes. For both tests, sublethal effects were consistently observed when sediment contaminant concentrations exceeded sediment quality guideline (SQG) concentrations. The response of these bioassays in metal-contaminated sediments was shown to conform ideally with respect to the mean SQG quotient calculated on the basis of the Australian and New Zealand lower SQG trigger value, with toxicity being observed only in those sediments where the mean quotient exceeded one. Better predictions of nontoxicity were obtained when dilute acid-extractable rather than total metal concentrations were used. Using the upper SQG, toxicity frequently occurred at mean quotients below one. The effects were generally consistent with predictions from the acid-volatile sulfide and simultaneously extracted metal model. Effects on reproduction of M. plumulosa were detected for sediments that did not cause effects on survival and highlighted the environmental relevance and importance of using these sublethal endpoints. When using four replicates for M. plumulosa and five replicates for N. spinipes, the endpoint variability (standard error) was less than 10%. Variations in sediment particle size and organic carbon content did not affect endpoint variability. Both species are relatively easily cultured in the laboratory, and the estimated effort and cost of achieving the sublethal endpoints is 1.5 times that of the acute survival test endpoints.

Sediment Contaminants and Infauna Associated with Recreational Boating Structures in a Multi-Use Marine Park

“…In the current study, sediments adjacent to boating structures were more metal contaminated (Cu, Pb, Zn) than reference sites (Table 1a–1c, Fig 3a–3c). However, Cu, Pb and Zn concentrations were mostly below the Australian SQGVs of 65, 50 and 200 mg/kg, respectively [34,35] and therefore it is likely that these sediments present a low risk to the communities living in them [2,42]. Metal concentrations only exceeded SQGVs inside boating structures enclosed by a breakwall (B1 and M, Fig 3a–3c) suggesting potential negative ecological effects.…”

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

“…Analyses of physicochemical properties (pH, organic carbon, particle size, acid-volatile sulfide) and metal contaminants were made on all sediments. Concentrations of total petroleum hydrocarbons were <250 mg/kg and those of polycyclic aromatic hydrocarbons were <1 mg/kg in all sediments [10,25,26].…”

“…These sediments had low or negligible concentrations of metal and organic contaminants and have been demonstrated to not cause toxic effects to the organisms used in the study [24,25]. The surface layers (upper 2-4 cm) of sediments were collected using clean Teflon spatulas and presssieved through a 1.1-mm mesh on-site to remove coarse materials.…”

“…Contaminated sediments were collected from estuarine field sites in New South Wales and Tasmania, Australia. Collected sediments were stored at 48C in the dark, and toxicity testing was undertaken within eight weeks [10,25]. Analyses of physicochemical properties (pH, organic carbon, particle size, acid-volatile sulfide) and metal contaminants were made on all sediments.…”

“…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. However, although dilute acid-extractable metal concentrations (Table 2) are expected to predict the bioavailability of metals better than total metal concentrations [25], the fact that Sediments 5 and 7 were copper-spiked may have resulted in this copper being easier for M. plumulosa to sense than the lead and zinc in the field-collected Sediment 4.…”