Current laboratory tests examine only the responses of individuals, which are then averaged to give a mean response for the test species. With given constraints of limited finances and number of personnel, it is not possible to identify the most sensitive species or group of species. . . . The data are too limited in scope for extrapolations to be made from them to responses of other (even closely related) species. (pp. xi-xii)

After more than 15 years, we still do not know whether effluent bioassays sufficiently protect species in the field from direct toxic effects, and we do not have well-established methods for extrapolating from single-species toxicity measurements to community- and ecosystem-level effects of effluents. Although this is perhaps not surprising given the complexity of ecosystems and the number of variables involved, it must be recognized that this limitation in our understanding severely limits our ability to reliably extrapolate from the results of single-species bioassays to effects on receiving ecosystems.

Summary

It is important to define the proper role of single-species bioassays. Single-species bioassays are suitable for developing water-quality criteria for particular chemicals, based on the assumption that these criteria protect individuals and that no synergistic effects occur with other chemicals in the environment. They are also useful as an initial screen to detect effluent toxicity. However, bioassays alone cannot ensure that effluents will not harm the ecosystems into which they are released.

References

Baird, D. J., I. Barber, M. Bradley, P. Calow, and R. Soares. 1989. The Daphnia bioassay: A critique. Hydrobiologia 188/189:403-406.

Bliss, C. I. 1934a. The method of probits. Science 79:38-39.

Bliss, C. I. 1934b. The method of probits—A correction. Science 79:409-410.


Finney, D. J. 1952a. Statistical Method in Biological Assay. New York: Hafner Publishing.

Finney, D. J. 1952b. Probit Analysis, 2nd ed. Cambridge, England: Cambridge University Press.

Forbes, T. L., and V. E. Forbes. 1993. A critique of the use of distribution-based extrapolation models in ecotoxicology. Functional Ecology 7:249-254.


Gaddum, J. H. 1933. Reports on Biological Standards. III. Methods of Biological Assay Depending on Quantal Response. Special Report Series of the Medical Research Council, No. 183. London: Her Majesty's Stationery Office.

Golley, F. 1994. A History of the Ecosystem Concept in Ecology. New Haven, Conn.: Yale University Press.


Horning, W. B., and C. I. Weber, eds. 1985. Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms. EPA/600/4-85/014. Environmental Monitoring and Support Laboratory. Cincinnati, Ohio: U.S. Environmental Protection Agency.



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