Dibutyl hydrogen phosphate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10/1992

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

Origin: West-Aquarium (Bad Lauterberg)
Body length: 2.5 - 3.5 cm
mortality during cultivation: < 2 %
keeping water: synthetic fresh water in arccordance with ISO

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

10.9 °dH

Test temperature:

20.9 - 21.4°C

pH:

7.2 - 8.2

Dissolved oxygen:

7.8 - 9.1 (90.5 - 104.2%)

Nominal and measured concentrations:

Nominal conc: 100 mg/L (direct weight)

Details on test conditions:

- Test aquarium: 300*135*200 mm
- 5 l Test medium with air circulation
- 16 hour light and 8 hour dark
- Amount of fish per test vessel: 10

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Sublethal observations / clinical signs:

Application of test substance: direct weighing.

Undissolved particles of test substance sedimented on the ground of the vessel, but were dissolved after 15 minutes.

Validity criteria fulfilled:

yes

Remarks:

No mortality in the control was observed. The dissolved oxygen concentration remained above 90% throughout the exposure period.

Conclusions:

The acute toxicity of dibutyl hydrogen phosphate to fish was conducted in a static test according to EU Method C.1 (Acute Toxicity for Fish). After 96 hours of exposure a LC0 value of ≥ 100 mg/L was obtained.

Executive summary:

The acute toxicity of dibutyl hydrogen phosphate to fish was conducted in a static test according to EU Method C.1 (Acute Toxicity for Fish). After 96 hours of exposure a LC0 value of ≥ 100 mg/L was obtained. The reported value related to nominal concentration.

Description of key information

The acute toxicity of dibutyl hydrogen phosphate to fish was conducted in a static test according to EU Method C.1 (Acute Toxicity for Fish). After 96 hours of exposure a LC0 value of ≥ 100 mg/L was obtained.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

EC50

Effect concentration:

> 100 mg/L

Additional information

For dibutyl hydrogen phosphate two reliable studies on acute toxicity to Danio rerio are available, showing no acute effects of dibutyl hydrogen phosphate towards fish.

The acute toxicity of dibutyl hydrogen phosphate to Danio rerio was conducted in a static limit test according to EU Method C.1 (Acute Toxicity for Fish). After 96 hours of exposure a LC0 value of ≥ 100 mg/L was obtained. The reported value related to nominal concentration, as no analytical monitoring was carried out.

In a second experiment, fish were exposed to dibutyl hydrogen phosphate at concentrations of 5000, 7071 and 10000 mg/l under static conditions.

According to the method "Letale Wirkung beim Zebrabaerling (Brachydanio rerio new name: Danio rerio) LC0 / LC50 / LC 100 nach 48 - 96 Stunden" (Umweltbundesamt Berlin, Stand: Mai 1984), a 96h-LC0 of >= 10000 mg/L was received on Brachydanio rerio (new name: Danio rerio). The value is given as nominal concentration as measured concentrations determined via NMR spectroscopy differ less than 5.4 % from nominal concentrations.The substance concentrations were confirmed by analytical monitoring.

Further, a lower value on toxicity of dibutyl hydrogen phosphate to fish was found for the species Oryzias latipes. A 96h-LC50 of 110 mg/l conducted according to OECD TG 204 by the National Institute of Technology and Evaluation, Japan, is reported. The study is not taken into account for assessment, based on the following reason:

Dibutyl hydrogen phosphate was assessed within the scope of the ICCA/HPV-program. Preparing the OECD SIDS-dossiers the studies conducted by the National Institute of Technology and Evaluation, Japan were not available. Information on study design and results are only presented in the OECD-SIDS Report and the OECD-SIDS dossier. In the OECD-SIDS report, the composition of the assessed substance is reported to be a mixture of 64% dibutyl phosphate, 20% tributyl phosphate and 16% monobutyl phosphate. In the context of REACH, the assessed substance/mixture would be regarded as a multi-constituent substance. In the OECD-SIDS dossier, it is reported that dibutyl phosphate with a purity of 97.6% was used as test substance in ecotoxicity tests. It is not really clear, if the degree of purity refers to pure dibutyl hydrogen phosphate or to the assessed substance, which under REACH would be regarded as a multi-constituent substance. Therefore, it is concluded that sameness of both substances, the assessed substance within the OECD-SIDS dossiers and the substance to be registered cannot be proved/demonstrated. The studies conducted by the National Institute of Technology and Evaluation, Japan are considered to be reliable, but they are not taken into account for assessment, based on lack of clarity on substance sameness.