Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Stability (Hydrolysis)

Hydrolysis of dibutyl hydrogen phosphate was investigated at pH 4, 7 and 9, and a temperature of 50°C. The test was performed according to OECD Guideline 111 (Hydrolysis as a Function of pH). After 5 days the recoveries of dibutyl hydrogen phosphate were in the range of 97.5 % to 104.4%. Therefore, dibutyl hydrogen phosphate is regarded as hydrolytically stable, and no degradation due to hydrolysis is expected under environmental conditions.

Biodegradation (screening tests)

According to EU method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test) a degradation of 12 % after 28 days was observed. In conclusion dibutyl hydrogen phosphate is not readily biodegradable.

The inherent biodegradability of dibutyl hydrogen phosphate was determined according to the EU Method C.9 (Biodegradation: Zahn-Wellens Test).

Within 28 days a degradation of > 98 % was determined. Therefore dibutyl hydrogen phosphate is considered as inherently biodegradable.

Biodegradation (water/sediment, soil)

Dibutyl hydrogen phosphate is considered as not readily biodegradable, but inherently biodegradable. The performance of simulation tests covering the aquatic, sediment and soil compartment is scientifically not necessary as it would not provide additional information for the hazard, risk and persistency assessment.

Bioaccumulation

Following the OECD Guideline 305C with Cyprinus carpio as test organism the obtained BCF values were in the range of <0.7 - <7. Determinations were conducted at concentrations of 0.2 and 2 mg/L. The received BCF values indicate that dibutyl hydrogen phosphate is not bioaccumulative. These results are in accordance with the calculated log Kow of -0.90 for the dissociated form of dibutyl hydrogen phosphate.

Adsorption/desorption

Based upon its pKa, dibutyl hydrogen phosphate exits predominantly in its dissociated form under relevant environmental pH 5 - 9.

Following the OECD Guideline 121 (HPLC method) a log Koc value of 0.5 was received for the dissociated form of dibutyl hydrogen phosphate. This value indicates that dibutyl hydrogen phosphate has a negligible sorption potential to soil and sediment. QSAR determinations revealed log Koc values of 0.53 for the dissociated form and 2.3 for the non-dissociated form. Both values also indicate a low potential for adsorption.

Henry's Law Constant

The QSAR determination of the Henry's Law Constant for dibutyl hydrogen phosphate using the Estimation Program Interface (EPI) Suite v4.11 revealed a value of 0.000432 Pa*m³/mol at 25°C. This value indicates that dibutyl hydrogen phosphate is essentially non-volatile from water, and a long-range transport via the atmosphere is not expected.