#609 Short-term toxicity – 90-day oral (rodent)
Objective of the study
The 90-day study provides information on the possible health hazards likely to arise from repeated exposure over a prolonged period of time, covering post-weaning maturation and growth well into adulthood. The study will provide information on the major toxic effects, indicate target organs and the possibility of accumulation.
The study can provide an estimate of a no-observed-adverse-effect level (NOAEL), which can be used for establishing safety criteria for human exposure. Short-term toxicity studies will thus provide useful data on the risks for operators who are handling and using the pesticide, as well as for other persons who may be exposed sub-chronically.
In addition, the outcome of the 90-day study can be used in selecting dose levels for chronic toxicity studies.
Circumstances under which the study is recommended to be required
The 90-day oral toxicity study (rodent) is always required, both if the pesticide is to be applied for food or for non-food uses.
Test organism
The study is normally conducted with rats. If other rodent species are used, a justification should be provided by the applicant.
The test in mice is not recommended, but the responsible authority may wish to strongly encourage the applicant to conduct a 90-day range-finding study for the purposes of dose selection for the mouse carcinogenicity study.
Test substance
- Technical grade active ingredient
Typical endpoints of the study
The principle of the test is that the test substance is orally administered daily in graduated doses to several groups of experimental animals, one dose level per group for a period of 90 days. During the period of administration the animals are observed closely for signs of toxicity. Animals which die or are killed during the test are necropsied and, at the conclusion of the test, surviving animals are also killed and necropsied.
Typical endpoints are mortality, signs of toxicity, including time of onset, duration, and severity of any toxic effects, lesions and pathological changes, target organs.
Where possible, the No Observed Adverse Effect Level (NOAEL) will be reported.
Test guidelines
The following test guidelines may be used for the 90-day oral short-term toxicity study with rodents:
• OECD Guidelines for the Testing of Chemicals. Test No. 408: Repeated dose 90-day oral toxicity study in rodents.
• US EPA Health Effects Test Guidelines. OPPTS 870.3100. 90-day oral toxicity in rodents