Toxicity tests standardized aquatic microcosm

The Standardized Aquatic Microcosm (SAM) was developed by Frieda Taub and colleagues (Taub et al. 1987, Conquest and Taub 1989) to examine the effects of toxicants on multispecies systems in the laboratory. Figure 4.1 illustrates the course of events over the 63 d of the experiment and Table 4.13 provides a tabular overview. The microcosms are prepared by the introduction of ten algal, four invertebrate, and one bacterial species into 3 1 of sterile defined medium. Test containers are 4-1 glass jars. An autoclaved sediment consisting of 200 g silica sand and 0.5 g ground chitin are autoclaved separately and added to the already autoclaved jar and media. 

Timeline for the standardized aquatic microcosm. The 63-d toxicity test is specific in its sampling requirements, acclimation times, and dosing. 

The multivariate methods described above have been used to examine a series of multispecies toxicity tests. Described below are the data analyses from two published tests using methodology derived from the Standardized Aquatic Microcosm (SAM) (ASTM E1366-91). The method is described in some detail in Chapter 4. 

Community conditioning has been tested in a series of standardized aquatic microcosms using the turbine fuel JP-8 in a series of two back-to-back replicated experiments (Landis et al. 2000). The first experiment was for the typical 63-d duration of the protocol, but the second was extended to 126 d. As far as possible, the experiments were replicated with organisms taken from the same cultures, conducted in the same rooms, with the same lot of toxicant and with the same basic staff. As in previous microcosm experiments, the organisms were counted, the toxicant quantified, and the oxygen content and pH measured. Graphical methods and three multivariate clustering methods were used to follow the patterns within both experiments. 

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