Biological assessment methods bioassays

The focus of the pilot was on the development of a practical framework for the application of biological test methods in a Triad approach. Consequently, the selection of tools for the assessment was based on scientific and pragmatic arguments, for instance by focusing on readily available techniques for determination of the concentration of contaminants in pore water and readily available biological tests such as simple bioassays and the monitoring of soil organisms. 

Application of bioassays for ecological assessments The evaluation of threats posed to ecological receptors or functions is probably the most significant reason for the application of biological test methods. There exist different approaches for using bioassays to perform risk assessments and to draw conclusions for risk management decisions. 

It is obvious from the provisional risk assessment values for microcystins, and, being of the same order of magnitude of mammalian toxicity, similar values may be calculated for the cyanobacterial neurotoxins, that sensitive detection methods are required to detect these low concentrations of toxins. Of the biological methods of detection discussed earlier, the mouse and invertebrate bioassays are not sensitive enough without concentration of water samples, in that they are only able to detect mg of microcystins per litre. Only the immunoassays (ng-/rg 1 and the protein phosphatase inhibition assays (ng O... 

To be sure, molecular genetics suffers from limitations. Many of its methods cannot be used without the availability of at least one known amino acid sequence. Thus, peptide isolation remains a critical need. Oligonucleotide probes can be too short, leading to useless or "false positive" hybridizations. Also, an appropriate bioassay is required to assess the authenticity of any product of molecular biology. However, the use of molecular genetic techniques will cause an explosion of information on insect neuropeptides and their sequences within the very near future. 

Sprague, J.B. (1973) The ABCs of pollutant bioassay with fish. In Biological Methods for the Assessment of Water Quality, Cairns Jr, J. and Dickson, K.L. (eds), pp. 6-30, STP 528. American Society for Testing and Materials, Philadelphia, PA. 

The proof of activity of a biological pesticide is typically evaluated by a standardized bioassay except in the case of microbial metabolites where the major active ingredient(s) may be measured by analytical methods. Biological activity measurements, besides serving as a parameter for quality control, are an essential tool in the product development and optimization process. It is important to define the assay procedure in order to compare production batches and experimental formulations. These assays are typically used for product release or may be designed to assess specific aspects of product activity such as mobility in soils, colonization on leaf surface, etc. 

---