21 C.F.R. § 556.420 – Monensin.

(a) Acceptable daily intake (ADI). The ADI for total residue of monensin is 12.5 µg/kg of body weight per day.
(b) Tolerances. The tolerances for monensin are:
1. (1) Cattle.
  1. (i) Liver: 0.10 ppm.
  2. (ii) Muscle, kidney, and fat: 0.05 ppm.
  3. (iii) Milk: Not required.
2. (2) Chickens and turkeys. Edible tissues (excluding eggs): Not required.
3. (3) Goats. Edible tissues (excluding milk): 0.05 ppm.
4. (4) Quail. Edible tissues (excluding eggs): Not required.
(c) Related conditions of use. See § 558.355 of this chapter.