1,4-Benzenediol, 2-(6-oxido-6H-dibenz[c,e][1,2]oxaphosphorin-6-yl)-

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:

June-October 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Remarks:

A HPLC-Method

Details on sampling:

The samples were diluted with an equal amount of methanol (dilution factor 2) and acidified immediately after sampling with 1 % 2 M hydrochloric acid (final content).

Vehicle:

yes

Remarks:

Acetone The concentration of the solvent was 5000-fold higher than the nominal concentration in the treatment. For the solvent control, only acetone in a concentration of 0.2 mL/L was used.

Details on test solutions:

a stock solution containing 3 g/L in acetone was prepared. 1.4 mL of this stock solution was mixed with 7 L drinking water for preparation of the test solution.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

sexually immature young fish of the same age,
length 1 – 2 cm

Test type:

static

Water media type:

freshwater

Remarks:

Tap water was used in the test.

Limit test:

yes

Total exposure duration:

96 h

Post exposure observation period:

4 days

Hardness:

124.6 mg CaCO3/L

Test temperature:

24.1-23.6 oC

pH:

8.4-7.9

Dissolved oxygen:

100-94%

Conductivity:

233 μS/cm

Nominal and measured concentrations:

nominal 0.6 mg/L
measured 0.27 mg/L

Details on test conditions:

Date: 28. Jun – 02. Jul. 2020
Treatment: 0.6 mg/L nominal concentration Test Design: static
Medium renewal: none
Duration: 96 hours
Loading: 1 fish/L
Aeration: accomplished with glass tubes
Feeding: none
Photo period: 12/12 hours using LED’s
Light intensity: 540 lux
Temperature: 23.5 – 24.5 °C
within one test, temperature did not vary more than 2 °C
between test vessels and between successive days
Test vessels: Glass aquaria total volume 12 L
Replicate (Treatment): 1 vessel, each containing 7 L test solution and 7 fish
Replicate (Solvent control): one test vessel containing 7 L test medium, 0.2 mL/L ace-tone and 7 fish

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.11 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Remarks:

At the start and at the end of the test, the content of the test item in the test solutions was determined using HPLC-UV-determination. The concentration determined at the start of the test was 44 % of the nominal concentration. At the end of the test (af

Basis for effect:

mortality (fish)

Details on results:

At the start and at the end of the test, the content of the test item in the test solutions was determined using HPLC-UV-determination. The concentration determined at the start of the test was 44 % of the nominal concentration. At the end of the test (after 96 h), the measured concentration was 7 % of the nominal concentration. The low measured concentration was caused by the poor solubility in test medium and instability of the test item in aqueous me-dium, which was already shown during the validation of the analytical method (LAUS study 20011702G926). However, a low test item concentration was still detectable at the end of the test.

Validity criteria fulfilled:

yes

Remarks:

The mortality in the blank control may not exceed 1 fish at the end of the test. No mortality occurred in the blank control. The dissolved oxygen concentration must be at least 60% throughout the test.

Conclusions:

96h LC50
> 0.11 mg/L

Executive summary:

96h LC50
> 0.11 mg/L

Description of key information

The concentration determined at the start of the test was 44 % of the nominal concentration. At the end of the test (after 96 h), the measured concentration was 7 % of the nominal concentration. The low measured concentration was caused by the poor solubility in test medium and instability of the test item in aqueous me-dium, which was already shown during the validation of the analytical method (LAUS study 20011702G926). However, a low test item concentration was still detectable at the end of the test.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

0.11 mg/L