for the measurement of effects on the central nervous system and the hema- 

 topoietic system; and histological changes in the liver, kidney, and male 

 and female reproductive systems. 



Registration or re-registration of a pesticide may be questioned if the 

 proposed use could result in an average concentration, in water 6 inches 

 deep, greater than 0.5 of the LC50 for representative aquatic organisms. 

 Pesticides giving an average concentration in 6-inch-deep water of between 

 0.1 and 0.5 of the LC50 would most likely be classified for restricted use 

 by certified applicators. These criteria also apply to metabolites or de- 

 gradation products of the pesticide. In addition, a determination of un- 

 reasonable adverse effects on the environment must include an analysis of 

 the chronic effects of exposures to pesticides. 



REGISTRATION GUIDELINES 



The various test methods by which pesticide registration requirements 

 can be satisfied are included as an appendix to "Guidelines for Registering 

 Pesticides in United States" (Environmental Protection Agency, 1975b). In 

 general, methods are organized along the lines of the pesticide registra- 

 tion requirements - i.e., methods are given for the assessment of (1) pesti- 

 cide efficacy, (2) environmental chemistry, and (3) hazards to humans, 

 domestic animals, fish, and wildlife. The presentation of methods is not 

 intended to imply that they are necessarily standard, inflexible, or the 

 only methods that can be used. However, they are now considered acceptable 

 for developing data to support registration and for planning research and 

 are an excellent source of information. Literature citations are given 

 only for references that are readily available and that describe methods 

 that are acceptable as presented. Modifications of methods are presented 

 as annotated bibliographic citations, and unpublished methods are included 

 as full tests. Applicants for pesticide registrations are encouraged to 

 discuss with EPA the research methods they intend to use. 



The aquatic toxicology methods include acute toxicity testing with 

 various marine and freshwater fish and invertebrates, chronic (complete 

 life cycle) and partial chronic studies (includes reproductive phase of 

 life cycle), accumulation tests, and field appraisal studies. The methods 

 classed as "routine" have been used by numerous investigators for many 

 years to investigate a wide variety of toxicants. Those methods classed as 

 "tentative" have been used by two or more toxicologists for several years, 

 but there is no consensus concerning detailed application of the methods, 

 and there are no interlaboratory test comparisons to show consistency of 

 results. "Developmental" methods are those used or proposed by one or a 

 few investigators, and the techniques involved may not be well known and 

 may require that investigators have considerable experience to achieve 

 consistent results. 



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