Summary of the Public Health Goal for Endothall
A Public Health Goal (PHG) of 580 ppb for endothall in drinking water is developed based on gastric toxicity observed in dogs. The U.S. Environmental Protection Agency’s (U.S. EPA’s) Maximum Contaminant Level (MCL) is 0.1 mg/L (100 ppb). Endothall, a dibasic acid, is used primarily as a herbicide and defoliant for cotton crops. It is not volatile and has a limited life in water. Due to its acidic properties, endothall has poor gastrointestinal and dermal absorption and is primarily an irritant. Endothall primarily damages the gastrointestinal tract leading to nausea, vomiting and hemorrhaging and death. Endothall was reported to be very irritating and damaging to the skin and eyes as well. Evidence of some tumor formation in the digestive tract was noted in animals severely affected by high doses of endothall in their diet. As a result, estimation of hazard focused on determining the lowest dose at which the digestive organs or body weight are affected. A PHG for endothall of 0.586 mg/L was calculated by using the level at which no effects on the gastric tract were observed in a chronic dog study and applying uncertainty factors to account for inter-species variation and human sensitivity and exposure. As a result, a drinking water concentration at or below 0.58 mg/L (580 ppb) should present no appreciable adverse health effects to the public.
- Endothall