Ames test basis

The inhalation toxicity of NF on animals has been studied extensively (37—40). These studies provide the basis of emergency exposure limits (EEL) that have been proposed for NE. The NAS—NRC Committee on Toxicology recommends that the EEL for NE be 10 min at 2250 ppm, 30 min at 750 ppm, and 60 min at 375 ppm. Gaseous NE is considered to be innocuous to the skin and a minor irritant to the eyes and mucous membranes. NE does give a weakly positive metabotically activated Ames test but only at concentrations greater than 2% or 10 times the 10 minute EEL. 

Ecoflex (powder) was tested for its mutagenic potential on the basis of its ability to induce point mutations in several bacterial strains Salmonella typhimurium and Escherichia coll) in a reverse mutation assay (Ames test), according to OECD guideline 471. Results revealed that the polyester is not mutagenic to bacteria. 

Bacterial Toxicity. A variety of criteria are used by testing laboratories to determine toxicity during the Ames test and when additional sample preparation (i.e., fractionation) is required to separate toxic components from potential mutagenic components of a complex mixture. However, no uniform criteria are available or accepted. The following criteria were proposed and accepted by panel meeting participants as the appropriate conceptual basis for determining lack of... 

I think those would be the logical mutagens to pursue on a name-by-name basis. Then go to Ames testing for toxicological assessment, setting limits, whether they are industrial outfalls or whatever then, having removed them from the problem, you can look at the other category that I described, for example, the question of chlorination byproducts in the absence of those industrial compounds. 

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 ... 

Mutagenesis tests as an indicator of carcinogenic potential (such as the Ames test) have clearly come into their own in the past few years. It is expected that they will continue to play an important role in setting priorities for conducting more definitive studies in the areas of mutagenesis and carcinogenesis on a more selective basis and thereby permit us to use our resources more wisely. 

Many plant metabolites marketed as natural pesticides are in fact more toxic than their synthesized competitors for example, rotenone (extracted from the roots of certain members of the bean plant family) has been used as a crop insecticide since the mid-19th century to control leafeating caterpillars, but is six times more toxic to mammals on a strictly comparable basis than carbaryl, a synthetic chemical also effective for caterpillar control. Nicotine sulfate is extracted from tobacco by steam distillation or solvent extraction and has been used as a pesticide since the early 20th century it is six times more toxic than diazinon, a widely available synthetic insecticide sold for control of many of the same pests. The best known work in this area (Ames 1990, 1990a, 1997) used the Ames test (Ames 1973, 1973a) to compare potencies of natural and synthetic pesticide compounds with respect to mutagenicity in special bacterial strains. While some of the conclusions of this work are controversial (Tomatis 2001), it does at least emphasize the importance of development of analytical methods for natural as well as synthetic compounds in foodstuffs. In this section an example of each is considered. 

It was the consensus of the panel participants that the methods summarized here represent the best available technology to prepare environmental samples for the Ames assay. These methods were chosen, after group discussion, on the basis of the collective laboratory experience of the participants and a thorough review of the literature. However, these are interim protocols subject to laboratory validation. This validation effort has been initiated, and workers in the field of environmental mutagenesis are urged to test these interim protocols in their own laboratories. 

Because of very complex terrain the application of simple dispersion models is very limited in Slovenia. Traffic pollution and the high level of surface ozone are the main current air pollution problems in the country. No official standard model for regulatory purposes has been accepted in Slovenia up to present. The US EPA model ISC3 is used for routine dispersion calculations from point sources. Some other imported models were tested in Slovenia but only on research basis. A neural network forecasting model was developed for the Sostanj thermal power plant. No urban air pollution studies are reported from Slovenia. Air pollution modelling is performed at the Jozef Stefan Institute, Dept, of Environmental Sciences, Ljubljana, Slovenia (US, 2005), AMES d.o.o. and the Hydrometeorological service. 

A reagent stick manufactured by Ames for the estimation of blood urea. The basis of the test is the hydrolysis of urea by urease to give carbon dioxide and ammonium ions. The latter causes a change in colour of a pH sensitive dye. 

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