Ecotoxicology, bioassays

Here is an overview of ecotoxicological bioassays cited in the above-mentioned legislation ... 

Marsalek, B. Ecotoxicological Bioassays in the Czech Republic, International Workshop FITA 4 Programme, Tallin, Estonia. September 10-11, 1999. 

Some alternative ecotoxicological bioassays are available for environmental monitoring, and amongst these the tests based on invertebrates such us Daphnia magna (ISO, 1996), microalgae, such as Skeletonema costatum (ISO, 1995) and Selenastrum capricornotum (EPA, 1982), the marine bacteria Vibrio fischeri and Photobacterium phosphoreum (ISO, 1998) are well established. These tests use standardized organisms, and are available from a number of commercial companies. 

Matthiessen, P., Sheahan, D., and Harrison, R. et al. (1995). Use of a Gammarus pulex bioassay to measure the effects of transient carbofuran runoff from farmland. Ecotoxicology and Environmental Safety 30, 111-119. 

Continuous culture systems have been widely used to culture microorganisms for industrial and research purposes (Kubitschek 1970 Tempest 1970 Veldkamp 1976 Rhee 1980). In recent years, these culture techniques have found their way into the bioassay methods of ecotoxicology and allelopathy (Rhee 1980). The early development of a continuous culture system can be traced back to the work of Novik and Szilard (1950 a,b) who developed the first chemostat. In a continuous culture system, nutrients are supplied to the cell culture at a constant rate and to maintain a constant volume, an equal volume of cell culture is removed. This allows the cell population to reach a steady state, where the growth rate and the total number of cells/ml of culture remains constant. Two kind of continuous culture systems can be distinguished turbidostat and chemostat. ... 

Cairns, J.,Jr. Myths impeding the utilization of infusoria in ecotoxicological toxicity testing / Infusoria in bioassays, Saint Petersburg, 1998.PP.11-21. 

The use of bioassays as an analytical tool for the assessment of environmental pollution is relatively new in Columbia. Even though the Ministry of Health established in Decree 1594 (1984) that environmental control agencies should propose acceptable LC50 values for 22 substances of ecotoxicological interest in order to protect fauna and flora, none of the entities has carried out this action up to mid-1998. 

Box B) Ecotoxicological risk assessment, using additional bioassays... 

In vitro and in vivo bioassays have been shown to be useful tools in the process of hazard, ecotoxicological risk and impact assessment of dredged harbour sediments, provided they are consciously chosen. Three different purposes for application were distinguished (Fig. 1) for which the considerations differ. 

Bioindicators of effect in the field such as intersex index (ISI) and population decline in gastropods are useful to reveal causal relationships between the exposure to toxic compounds and population effects on local marine organisms. When these effects correspond to the effects predicted based on bioassays in the laboratory, for example expressed as PAF of species, these field effects in gastropods, can be used as a bioindicator for the local ecotoxicological health status. 

Small-scale freshwater toxicity testing is but a modest fraction of a diverse array of scientific activities connected to the field of ecotoxicology. Yet, within this still emerging discipline, few will argue the fact that tools and approaches developed to measure the undesirable effects that countless chemicals (alone or in mixtures) and complex (liquid and solid) media can exert on biota have markedly contributed to aquatic ecosystem preservation. Indeed, the breadth and scope of application of bioassays thus far directed toward obtaining relevant information aimed at problemsolving and prevention of contaminant-based issues has progressed well. 

Ferrari, B., Radetski, C M., Veber, A.-M. and Ferard, J.-F. (1999) Ecotoxicological assessment of solid wastes a combined liquid- and solid-phase testing approach using a battery of bioassays and biomarkers, Environmental Toxicology and Chemistry 18 (6), 1195-1202. 

Martinez-Madrid, M., Rodriguez, P. and Perez-Iglesias, J.I. (1999) Sediment toxicity bioassays for assessment of contaminated sites in the Nervion River (Northern Spain). I. Three-brood sediment chronic bioassay of Daphnia magna Straus, Ecotoxicology 8, 97-109. 

Pereira, A.M.M., Soares, A.M.V.M., Goncalves, F. and Ribeiro, R. (2000) Water-column, sediment, and in situ chronic bioassays with cladocerans, Ecotoxicology and Environmental Safety 47 (1), 27-38. 

As seen further on in this chapter, individual PEEP index values express a condensed portrait of an effluent s hazard potential which takes into account several important ecotoxicological notions (toxic intensity and scope in terms of biotic levels impacted, bioavailability, persistence of toxicity and effluent flow). Unlike wastewater investigations limited to chemical characterization, this bioassay-based scale reflects the integrated responses of several representative toxicity tests to all interaction phenomena (antagonistic, additive and/or synergistic effects) that can be present in effluent samples. 

---