Toxicity testing basis

As of the end of 1980, two-thirds of PMNs submitted contained no toxicity information whatsoever. Preliminary statistics from 1981 indicate that a greater percentage of PMNs during the past year contained more toxicity testing information. Still, there were few chronic toxicity data. The lack of such information has meant that EPA s evaluations have had to be conducted on the basis of structure-activity relationships. Such analyses involve comparing the PMN chemicals to existing ones with similar structures whose toxicities are known. 

While not officially required, the FDA does have the authority to request, on a case-by-case basis, specific tests it feels may be necessary to address a point of concern. A genetic toxicity test could be part of such a request. In general, therefore, companies deal with genetic toxicity (after screening ) on a case-by-case basis, dictated by good science. If more than a single administration is intended, common practice is to perform the tests prior to submitting an IND. 

According to wastewater requirements, the water quality of effluents should not be toxic on the basis of results of two acute toxicity tests. The following tests can be applied toxicity to fish, toxicity to daphnia, toxicity to luminescent bacteria, toxicity to green algae [205]. 

Dutton, R.J. Bitton, G. Koopman, B. Enzyme biosynthesis versus enzyme activity as a basis for microbial toxicity testing. Toxic. Assess. 1988, 3, 245 -253. 

In this section, the sample information was the raw toxicity test data for each species and test. Prior information was not available outside the data set, so vague prior information was used as a basis for implementing the procedures. 

The reader is also referred to the OECD Guidance Document No. 43 on Reproductive Toxicity Testing and Assessment (13), which will form the basis for the methodological points discussed below. More information can also be found in the IPGS paper on principles for evaluating health risks to reproduction associated with exposure to chemicals (14) as well as in an overview paper by Buschmann (15). 

It is important to consider both in vitro and in vivo studies for evaluation of altered sexual function and fertility. In vivo studies are the primary basis for such reproductive toxicity testing, but in vitro studies (e.g., detailed studies on receptor interactions) that can provide a mechanistic explanation for the adverse effects observed in vivo are also useful. 

SUFFET You are bringing up two interesting points one that Loper referred to, that is, using treatment techniques as a method to control the contaminants and then testing before and after each treatment to see differences. Maybe the best application of Ames testing and other toxicity testing would be on a difference basis, before and after a process. Is there a difference Is it less Is that an approach that can be used, especially in treatment situations, where industrial wastes are potentially present in drinking water ... 

In a study (Boyle, et al., 1981) conducted by the American Foundrymen s Society (AFS) in conjunction with the University of Wisconsin and the USEPA, leaching tests were conducted on cupola emission control dusts and sludges from 21 different foundries. This study concluded that 9 out of the 21 foundries generated emission control residuals which would be considered as a hazardous waste on the basis of EP Toxicity for lead. Two other foundries generated emission control residuals which would be classified as hazardous on the basis of EP Toxicity for cadmium. Concentrations in the EP Toxicity Test for the 21 foundries ranged from less than 0.6 mg/1 to 130 mg/1. The mean lead... 

Ecobichon, D. J.. The Basis of Toxicity Testing. Boca Raton, FL CRC Press, 1992. 

For both the Saint-Lawrence River Action Plan (Costan et al., 1993) and the Toyama Bay Japanese (Kusui and Blaise, 1999) studies, the two suites of bioassays employed represented three trophic levels (decomposers, primary producers and primary or secondary consumers), and sought to measure both acute and chronic toxicity. Toxicity tests were selected on the basis of practical and scientific criteria including low sample volume requirement, sensitivity, simplicity of undertaking the assay, ease in maintaining laboratory cultures, cost-effectiveness, procedural reliability and/or frequency of use internationally. 

Rating the relationship between ZPE andfield measurements The relationship between sublethal toxicity tests and field measurements can be rated on the basis of zones of potential effect (Environment Canada, 1999). The following points describe the criteria used for rating the relationship between zones of potential effect for each sublethal test (lowest IC25) and potential effluent-related effects on fish or the benthic invertebrate community (Moody, 1992). 

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