In situ‐based effects measures: Considerations for improving methods and approaches

Abstract

In situ‐based effects measures have gained increased acceptance as a means to improve the link between cause and effect in aquatic ecotoxicological studies. These approaches have primarily been employed where more conventional laboratory tests with field collected samples and routine in‐field community surveys have failed to provide reasonable answers with respect to causes of toxicity, primary routes of contaminant exposure, and what constitutes ecotoxicologically relevant contaminant levels, at least at a site‐specific level. One of the main advantages provided by in situ tests compared to more conventional field‐based monitoring approaches is that they provide better control over stressor exposure to a defined population of test animals under natural or near‐natural field conditions. In situ techniques can also be used to avoid artifacts related to sampling, transport and storage of contaminated water and sediment intended for laboratory‐based toxicity assessment. In short, they can reduce the need for laboratory to field extrapolation and, when conducted properly, in situ tests can provide improved diagnostic ability and high ecological relevance. This paper provides suggestions and considerations for designing in situ studies, choosing test species and test endpoints, avoiding or minimizing test artifacts, best addressing some of the limitations of in situ test techniques, and generally improving the overall quality of the in situ approach chosen.

Toxicity to Melita plumulosa from intermittent and continuous exposures to dissolved copper

“…When exposed to single pulses of 100, 200, 300, 400, 600, and 900 mg Cu/L, the 10-d survival of M. plumulosa was not significantly different from that of controls for exposure durations 96, 35,19,10,8, and 4 h, respectively, but significant lethality occurred at durations longer than 160, 62, 29, 18, 12, and 7 h, respectively (Supplemental Data, Figs. S6 A and B for 300 and 400 mg Cu/L pulsed exposure treatments).…”

The impact of sediment bioturbation by secondary organisms on metal bioavailability, bioaccumulation and toxicity to target organisms in benthic bioassays: Implications for sediment quality assessment

“…These conclusions also further emphasise the benefits that may be gained from welldesigned field-based tests (Belzunce-Segarra et al, 2015;Burton et al, 2005;Burton et al, 2012;Liber et al, 2007) which may be deployed in zones where processes such as bioturbation by non-target organisms can naturally influence contaminant bioavailability and exposure. …”

Metal Fluxes from Porewaters and Labile Sediment Phases for Predicting Metal Exposure and Bioaccumulation in Benthic Invertebrates

“…The cages allowed adequate water circulation and prevented predation. 22 The cages were submerged to a depth of 40 cm in an uncontaminated section of the Woronora River estuary (Sydney, Australia). There were two replicates of each test sediment, with all randomly distributed in the laboratory, and one replicate randomly distributed within each of the two field cages.…”