The Future of Toxicity Testing

In field-test situations, test chemicals are applied to large areas under natural conditions. The areas are at least several acres and may be either natural or part of some agroecosystem. Because the area is large and in the open, radiolabeled compounds cannot be used, it is not possible to obtain a balance between material applied and material recovered. 

The effects are followed over a long period of time and two types of control may be used first, a comparison with a similar area that is untreated and second, and a comparison with the same area before treatment. In the first case it is difficult, if not impossible, to duplicate exactly a large natural area, and in the second, changes can occur that are unrelated to the test material. 

Because of the public awareness of the potentially harmful effects of chemicals, it is clear that toxicity testing will continue to be an important activity and that it will be 

Subjecting all chemicals to all possible tests is logistically impossible, and the future of toxicity testing must lie in the development of techniques that will narrow the testing process so that highly toxic and relatively nontoxic compounds can be identified early and either banned or permitted unrestricted use without undue waste of time, funds, and human resources. These vital commodities could then be concentrated on compounds whose fate and effects are less predictable. 

Such progress will come from further development and validation of the newer testing procedures and the development of techniques to select, for any given chemical, the most suitable testing methods. Perhaps of most importance is the development of integrated test sequences that permit decisions to be made at each step, thereby either abbreviating the sequence or making the next step more effective and efficient. 

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U.S. Environmental Protection Agency, The Future of Toxicity Testing is Here. Science Matters Newsletter, http //www.epa.gov/sciencematters/ epa-science-matters-newsletter-volume-2-number-4 (accessed Dec 2015). 

Although much useful information on ciguetera toxins has been generated, the presence of these toxins in some seafood remains a serious international health problem. Future research goals should include the development of practical tests for product safety, the development of specific antidotes for the toxins, the introduction of methods to minimize the accidental consumption of toxic seafood, the discovery of the genesis of the toxins and methods to control the problem, and the development and dissemination of an information base on all aspects of this and other seafood toxin problems for the seafood industry, health personnel, researchers, and the public. 

Owing to possible future restrictions that could preclude the testing of samples with all five toxicity tests, we evaluated the index response with a reduced battery of toxicity tests. The basic rule for the selection of tests in a reduced battery was to maintain one primary producer, one primary consumer and a secondary consumer. The test combinations of two selected reduced batteries were Hydra, Daphnia and Lactuca tests (H-D-L) and Hydra, Daphnia and S. capricornutum (H-D-S) tests... 

If the number or quahty of single-exposure toxicity studies found is not deemed to be adequate, multiple exposure studies may be considered but may not achieve a consensus of the NAC/AEGL Committee. If a consensus or two-third majority of the committee cannot agree on the adequacy of the data, the chemical may be placed on the list for future acute toxicity testing. 

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