Reaction mass of Ammonium dihydrogenorthophosphate and diammonium hydrogenorthophosphate.

Endpoint summary

Description of key information

Based on reliable studies with ammonium dihydrogenorthophosphate and diammonium hydrogenorthophosphate for acute oral and dermal 
exposure to rats, the oral LD50 is >2000 mg/kg bw and the dermal LD50 is >5000 mg/kg bw. 
For liquid form of the reaction mass, since the vapour pressure is low, inhalation exposure is not expected.
For solid form of the reaction mass, since the aerodynamic diameter is high, inhalation exposure to this solid form is not expected. Moreover, a 
reliable acute toxicity inhalation study with diammonium hydrogenorthophosphate shows an LC50 is > 5 mg/L. 

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Dose descriptor:

LC50

Value:

5 000 mg/m³ air

Acute toxicity: via dermal route

Endpoint conclusion

Dose descriptor:

LD50

Value:

5 000 mg/kg bw

Additional information

Oral

For acute oral toxicity, ammonium dihydrogenorthophosphate showed in an OECD 425 guideline study no mortality and no toxicity to rats up to 2000 mg/kg bw. Therefore the LD50 was determined to be >2000 mg/kg bw. For acute oral toxicity, diammonium hydrogenorthophosphate showed in an OECD 425 guideline study no mortality and no toxicity to rats up to 2000 mg/kg bw. Therefore the LD50 was determined to be >2000 mg/kg bw.

Dermal

For acute dermal toxicity, ammonium dihydrogenorthophosphate showed in an OECD 402 guideline study no mortality and no toxicity to rats up to 5000 mg/kg bw. Therefore the LD50 was determined to be >5000 mg/kg bw. For acute dermal toxicity, diammonium hydrogenorthophosphate showed in an OECD 402 guideline study no mortality and no toxicity to rats up to 5000 mg/kg bw. Therefore the LD50 was determined to be >5000 mg/kg bw.

Inhalation

Liquid form: since exposure by inhalation is not expected (low vapour pressure, assimilated to vapour pressure of water), an acute toxicity data by inhalation is not mandatory.

Solid form: the aerodynamic diameter of the solid form of the reaction mass is high. Therefore, inhalation exposure to this type of reaction mass is not expected. Moreover, a reliable study with diammonium hydrogenorthophosphate particles was available, showing in an OECD 403, EC B.2 and EPA guideline study no mortality and no toxicity to rats up to 5 mg/L. Therefore, the LC50 was determined to be >5 mg/L for diammonium hydrogenorthophosphate particles.

Justification for classification or non-classification

Based on the data available for the two components, the reaction mass of ammonium dihydrogenorthophosphate and diammonium hydrogenorthophosphate does not have to be classified according to the Directive 67/548/EC and the CLP Regulation for acute oral and dermal toxicity.

For inhalation, based on the available study performed on diammonium hydrogenorthophosphate particles in which a LC50 >5 mg/L was calculated, the solid form of the reaction mass is not classified for inhalation toxicity according to the Directive 67/548/EC and the CLP Regulation. Moreover, since the aerodynamic diameter of the solid form of the reaction mass is high, inhalation exposure to this type of reaction mass is not expected.

For liquid form, since the vapour pressure is low, inhalation exposure is not expected.