Reaction mass of Ammonium dihydrogenorthophosphate and diammonium hydrogenorthophosphate.

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Effect on fertility: via oral route

Dose descriptor:

NOAEL

1 500 mg/kg bw/day

Additional information

No reliable studies with ammonium dihydrogenorthophosphate are present. In an OECD 422 study rats (10/sex/dose) were dosed with 250, 750 and 1500 mg/kg bw/day diammonium hydrogenorthophosphate orally via gavage. Males were treated until termination during week 6 of treatment. Doses were administered to the females for two weeks prior to pairing, throughout pairing and gestation until Day 3 of lactation. No effects on reproduction parameters were observed up to the highest dose tested. Therefore, the NOAEL is considered to be =1500 mg/kg bw/day.

In accordance with REACH Annex XI section 1, no further studies are considered necessary. Ammonium dihydrogenorthophosphate dissociates into NH4+ and phophate ions. Phosphate is a normal body and nutritional component and is regulated within the body. NH4+ serves a major role in the maintenance of the acid-base balance. The available data from the OECD422 study show no effects on reproduction and developmental parameters in the presence of maternal toxic effects. The lack of effects at dose levels well in excess of the NOAEL based on general toxicity suggests that ammonium dihydrogenorthophosphate is not a significant risk to the reproductive process and further studies are unlikely to show any significant effects. In addition, the World Health Organisation reports that the maximum tolerable daily intake (MTDI) of phosphates is 70 mg/kg bw (WHO TR series 683), and this value is considered to be well below that observed for reproduction/developmental toxicity. Overall, an additional study is unlikely to result in providing further evidence of reproductive/developmental toxicity as the existing data have demonstrated a lack of effect at dose levels well in excess of general toxicity and expected human exposure. Therefore, such a study is not considered necessary.

Short description of key information:
No data on ammonium dihydrogenorthophosphate is present. However, reliable data available on diammonium hydrogenorthophosphate shows a
NOAEL for reproduction toxicity after oral exposure of rats of =1500 mg/kg bw/day. Based on the toxicity profile, the properties of the NH4+ and
phosphate ions and the tolerable intake of phosphorus, the overall conclusion is that no additional studies are considered necessary.

Effects on developmental toxicity

Description of key information

No data on ammonium dihydrogenorthophosphate is present. Reliable data available on diammonium hydrogenorthophosphate shows a NOAEL for 
developmental toxicity after oral exposure of rats of =1500 mg/kg bw/day.  Based on the toxicity profile, the properties of the NH4+ and phosphate ions and 
the tolerable intake of phosphorus, the overall conclusion is that no additional studies are considered necessary.

Effect on developmental toxicity: via oral route

Dose descriptor:

NOAEL

1 500 mg/kg bw/day

Additional information

No reliable studies with ammonium dihydrogenorthophosphate are present.

In an OECD 422 study rats (10/sex/dose) were dosed with 250, 750 and 1500 mg/kg bw/day ammonium dihydrogenorthophosphate orally via gavage. Males were treated until termination during week 6 of treatment. Doses were administered to the females for two weeks prior to pairing, throughout pairing and gestation until Day 3 of lactation. No effects on developmental parameters were observed up to the highest dose tested. Therefore, the NOAEL is considered to be =1500 mg/kg bw/day.

In accordance with REACH Annex XI section 1, no further studies are considered necessary. Ammonium dihydrogenorthophosphate dissociates into NH4+ and phophate ions. Phosphate is a normal body and nutritional component and is regulated within the body. NH4+ serves a major role in the maintenance of the acid-base balance. The available data from the OECD422 study show no effects on reproduction and developmental parameters in the presence of maternal toxic effects. The lack of effects at dose levels well in excess of the NOAEL based on general toxicity suggests that ammonium dihydrogenorthophosphate is not a significant risk to the reproductive process and further studies are unlikely to show any significant effects. In addition, the World Health Organisation reports that the maximum tolerable daily intake (MTDI) of phosphates is 70 mg/kg bw (WHO TR series 683), and this value is considered to be well below that observed for reproduction/developmental toxicity. Overall, an additional study is unlikely to result in providing further evidence of reproductive/developmental toxicityas the existing data have demonstrated a lack of effect at dose levels well in excess of general toxicity and expected human exposure. Therefore, such a study is not considered necessary.

Justification for classification or non-classification

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