FIFRA Microcosm

One of the interesting aspects of the FIFRA microcosm system is the variety of methods used to ensure a uniform temperature among the experimental... 

FIFRA microcosm experimental unit. An example of a microcosm experimental unit designed to test the effects of a herbicide on an aquatic environment. This particular setup does not include fish since the predatory effects would tend to hide lower trophic level effects upon the invertebrate populations. Typically, a FIFRA microcosm experiment includes fish species, especially when acetylcholinesterase inhibitors or other toxicants particularly effective against animal species are tested. 

Although the FIFRA microcosm has a number of advantages, there are also compromises. The few experiments that have been conducted and the variance in methodologies have not provided an accurate representation of the repeatability or replicability of the experiments. In addition, the method is somewhat local specific since the temperature, diurnal cycle, and to some extent the experimental organisms are controlled by the local environmental conditions. On the other hand, the sensitivity to local conditions can also act as a more accurate model of local fate and effects of the test material. 

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