Acute reference dose , definition

The term acceptable is used widely to describe safe levels of intake and is apphed for chemicals to be used in food production such as, e.g., food additives, pesticides, and veterinary dmgs. The term tolerable is applied for chemicals unavoidably present in a media such as contaminants in, e.g., drinking water and food. The term PTWI (Provisional Tolerable Weekly Intake) is generally used for contaminants that may accumulate in the body, and the weekly designation is used to stress the importance of limiting intake over a period of time for such substances. The tolerable intake is similar in definition and intent to terms such as Reference Dose and Reference Concentration (RfD/RfC), which are widely used by, e.g., the US-EPA. For some substances, notably pesticides, the ARID (Acute Reference Dose), is also established, often from shorter-term studies than those that would support the ADI. The ARfD is defined as the amount of a substance in food that can be consumed in the course of a day or at a single meal with no adverse effects. 

According to the definitions provided in the OECD test guidelines (TG 420 and 423), acute oral toxicity refers to those adverse effects that occur following oral administration of a single dose of a substance or multiple doses given within 24 h. 

Dose In the context of chemicals, the temi dose means the amount, quantity, or portion of the chemical exposed to or applied to the target (e.g., a human being). It may also refer to a consistent measure used in toxicological testing to determine acute and chronic toxicities. An alternate definition is die amount of ionizing radiation energy absorbed per unit mass of irradiated material at a specific location, such as a part of die human body, measured in REMS, or an inanimate body, measured in rads. 

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