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ASSESSMENT OF THE PRECISION AND ACCURACY OF SAM AND MFC MICROCOSMS EXPOSED TO TOXICANTS
Citation:
Stay, F., T. Flum, L. Shannon, AND J. Yount. ASSESSMENT OF THE PRECISION AND ACCURACY OF SAM AND MFC MICROCOSMS EXPOSED TO TOXICANTS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/D-89/178 (NTIS PB90116112), 1989.
Description:
The results of 30 mixed flank culture (MFC) and four standardized aquatic microcosm (SAM) microcosm experiments were used to describe the precision and accuracy of these two protocols. oefficients of variation (CV) for chemicals measurements (DO,pH) were generally less than 7%, for ecosystem processes (primary productivity, respiration) less than 20%, and for structure (organisms density) between 20 and 200%. icrocosm age had no effects on the CV; however, treatments causing a high magnitude of response resulted in significantly higher CV values. oefficients of variation, statistical power, and minimum detectable differences for several treatment-replicant combinations are presented to aid in designing future MFC experiments. ccuracy was evaluated for the SAM and MFC microcosms by comparison to the results reported for field studies of flourene, atrazine, and chlorpyrifos. omparisons were based primarily on the lowest effect level of short-term direct effects and the relative hazard ranking of these chemicals. he results of comparisons suggests that these microecosystems have properties common to natural systems, and their responses are more than an artifact of the microcosm.