Bioassays toxicity

Methods. As discussed in the previous chapter, a number of approaches have been used to assess the presence of potentially toxic trace elements in water. The approaches used in this assessment include comparative media evaluation, a human health and aquatic life guidelines assessment, a mass balance evaluation, probability plots, and toxicity bioassays. Concentrations of trace elements were determined by atomic absorption spectrometry according to standard methods (21,22) by the Oregon State Department of Environmental Quality and the U.S. Geological Survey. 

Toxicity Bioassay. Ninety-six hour acute toxicity tests were conducted on the effluent streams of major industries. A static renewal procedure was used in which waste waters of various dilutions were renewed at 24 hour intervals over a 96 hour period. Rainbow trout was used as the test organism. Tests were conducted at 13°C in 20 liter aquaria according to standard procedures (22), Results are summarized in Table 8. Chemical and toxicity test results indicate that the trace element quantities identified in Table 8 are not acutely toxic under the prevailing conditions and unlikely to pose an acute threat to aquatic life. In this case a chronic toxicity assessment would require additional research. 

Table 8. Industrial Wastewater Toxicity Bioassay Test Results Concentration in Wastewater ...

Warheit, D.B., B.R. Laurence, K.L. Reed, D.H. Roach, G.A. Reynolds, T.R. Webb, Lung toxicity bioassay study in rats with single-wall carbon nanotubes. Proceedings of the ACS Symposium Series, 890 (Nanotechnology and the Environment), 2005, pp. 67-90. 

The toxic effects of pesticides can be diverse and depend on the sensitivity of organisms to these toxicants, and the pesticide concentration or bioavailability. Typically, the short- and long-term effects of pesticides have been evaluated through acute or chronic toxicity bioassays, respectively, using lethality endpoints and sublethal endpoints (e.g., growth and reproduction), particularly these last in chronic bioassays. 

The selection of suitable single species and protocols is not a trivial task and may be dependent on various factors. Some of these include simplicity, low cost, or modest material and equipment demand. However, a higher sensitivity than other species to toxicants may be decisive in this choice in order to serve as warning systems. Table 1 shows the sensitivity in terms of effective concentration (EC50), which is the toxicity endpoint for the organisms (bacteria, crustaceans, algae, and fish) selected for the toxicity bioassays. These toxicity bioassays are usually classified according to the test species involved. 

Episodic pollution events can adequately be addressed by acute toxicity bioassays, however these are not sufficient to investigate the water quality for delayed toxicity effects of chemicals present. Chronic effects of pesticides can include carcinogenicity, teratogenicity, mutagenicity, neurotoxicity, and reproductive effects (endocrine disruption). 

While reported data on the acute and chronic toxicity of many pesticides is plentiful, few studies have been published on toxicity bioassays applied to wastewaters containing pesticides. The application of toxicity bioassays to the quality control of wastewaters offers several advantages in addition to being a... 

Table 2 Combined toxicity effects of pesticides evaluated by three toxicity bioassays... 

Phytoplankton as test organisms in toxicity bioassays with surfactants Microalgae are the basis of the aquatic trophic chain and at least 30% of the organic carbon planetary primary production is attributed to... 

Accordingly, the use of flow cytometry can improve the design of toxicity bioassays, as the detection limit of this apparatus includes cellular concentrations equal to those of microalgal populations found in natural conditions. Comparison of compositions utilised in some known toxicity tests for microalgaes are shown in Table 7.1.1. 

De la Torre, A.I. Fernandez, C. Tarazona, J.V. Munoz, MJ. 1998, Combination of semipermeable membranes and toxicity bioassays for the detection of lipophylic toxic chemicals in environmental samples. Ecotoxicol. Environ. Restoration 1 78-84. 

Snell, T, and Persoone, G. Acute toxicity bioassays using rotifers. I. A test for brackish and marine environments with... 

Biological toxicity tests are widely used for evaluating the toxicants contained in the waste. Most toxicity bioassays have been developed for liquid waste. Applications of bioassays in wastewater treatment plants fall into four categories [19]. The first category involves the use of bioassays to monitor the toxicity of wastewaters at various points in the collection system, the major goal being the protection of biological treatment processes from toxicant action. 

Markwiese, J.T. Ryti, R.T. Hooten, M.M. Michael, D.I. Hlohowskyj, I. Toxicity bioassays for ecological risk assessment in arid and semiarid ecosystems. Rev. Environ. Contam. Toxicol. 2001, 168, 43-98. 

Ribo, J.M. Kaiser, K.L.E. Photobacterium phosphoreum toxicity bioassay. I. Test procedures and application. Toxic. Assess. 1987, 2, 305-323. 

Figure 6. A-Chromatogram of toxic butter clam extract showing the presence of the PSP toxins. B-Chromatogram of extract from non-toxic (bioassay) mussels showing the presence of a trace of GTX II, GTX III, and C. Conditions as in Table I with gradient shown in Figure 4.

ChernoffN, Rogers JM (2004) Supernmnerary ribs in developmental toxicity bioassays and in human populations incidence and biological significance. J Toxicol Environ Health B Crit Rev 7 437-149... 

Bettinetti, R., Giarei, C. and Provini, A. (2003) Chemical analysis and sediment toxicity bioassays to assess the contamination of the River Lambro (Northern Italy), Archives of Environmental Contamination and Toxicology 45 (1), 72-78. 

Femandez-Alba, A.R., Hernando, M.D., Piedra, L. and Chisti, Y. (2002) Toxicity evaluation of single and mixed antifouling biocides measured with acute toxicity bioassays, Analytica Chimica Acta 456 (2), 303-312. 

Kwan, K.K. and Dutka, B.J. (1995) Comparative assessment of two solid-phase toxicity bioassays the direct sediment toxicity testing procedure (DSTTP) and the Microtox solid-phase test (SPT), Bulletin of Environmental Contamination and Toxicology 55 (3), 338-346. 

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. 

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