dialkyl-methyldihydro-heteropolycycle

Short-term toxicity to fish

Administrative data

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2020-03-27 to 2020-06-10

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: OECD. OECD series on testing and assessment number 23 (Second Edition), Guidance Document on Aqueous-Phase Aquatic Toxicity Testing of Difficult Test Chemicals. Paris: OECD, Adopted on February 8, 2019.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

The actual concentration of test substance in the 100 mg/L WAF test group were measured at 0 h and 72 h in the new solutions and measured at 24 h and 96 h in the old solutions by GC. The blank control was measured at 0 h in the new solution and 24 h in the old solution.

100 mL test solution was transfened into a separating funnel and be extracted three times with 20 mL, 15 mL and 10 mL of n-hexane, respectively. The extract solution was collected into 50 mL volume flask and diluted to 50 mL with n-hexane, the extract was filtered through 0.45 µm aqueous phase nylon filter membranes (the first 5 mL - 10 mL filtrate was discarded) before analysis. The samples was analyzed immediately, otherwise the samples were stored at 2 °C - 8 °C and protected from light after pretreatment, and the measurement was carried out within 96 h.

Test solutions

Vehicle:

no

Details on test solutions:

1.000 g of test substance was weighed on a piece of watch glass, then it was slowly put into a 10 L aspirator bottle which contained 10000 mL dechlorinated tap water, and the nominal loading rate of 100 mg/L test suspension was obtained. The suspension was continuously stirred with a magnetic stirrer for 48 h, and the stirring intensity was sufficient to maintain a vortex height of about 10% of liquid depth.
After the completion of stirring, the suspension was allowed to stand for 2 hour. Then the middle solution was collected through the outfall at the bottom of aspirator bottle (the first 100 - 200 mL solution was discarded), and the nominal loading rate of 100 mg/L WAF solution was obtained and used as test solution.
The preparation of test solution is in according with the OECD guidance document NO.23 (2019).

Test organisms

Test organisms (species):

other: Rare Minnow (Gobiocypris rarus)

Details on test organisms:

Rare Minnow (Gobiocypris rarus) with the batch number was FGr20191106-1115.
Before the start of the test, Rare Minnow (Gobiocypris rarus) were acclimated for 55 days under the same conditions of the test (water quality: dechlorinated tap water, temperature: 23 °C ± 2 °C, photoperiod: 14 h light / 10 h darkness). The dissolved oxygen concentration during acclimation was kept above 80% of the air saturation value. The fish were fed one time on each workday until 24 hours before the test was started.
The mortality was 0% during 7 days prior to the start of the test, which met the requirement of mortalities being less than 5% of the population.

Study design

Test type:

semi-static

Water media type:

other: dechlorinated tap water

Limit test:

yes

Total exposure duration:

96 h

Test conditions

Hardness:

110 mg/L (expressed as CaCO3)

Test temperature:

21.1 °C to 23.5 °C

pH:

7.80 to 8.34

Dissolved oxygen:

83% to 102%

Nominal and measured concentrations:

nominal: 100 mg/L WAF
measured: lower than LOD of 0.125 mg/L

Details on test conditions:

Photoperiod: 14 h light / 10 h darkness
Feeding: No feedding
Aeration: no aeration

Reference substance (positive control):

yes

Remarks:

K2Cr2O7

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: WAF (water accommodated fraction)

Basis for effect:

mortality (fish)

Effect concentrations 2

Duration:

96 h

Dose descriptor:

LL100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: WAF (water accommodated fraction)

Basis for effect:

mortality (fish)

Effect concentrations 3

Duration:

96 h

Dose descriptor:

LL0

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: WAF (water accomodated fraction)

Basis for effect:

mortality (fish)

Results with reference substance (positive control):

The sensitivity test of reference substance K2Cr2O7 showed that the 96 h-LC50 of K2Cr2O7 to Rare Minnow (Gobiocypris rarus) was 215 mg/L and the 95% confidence limits ranged from 171 mg/L to 270 mg/L.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

At the end of the test, the cumulative mortality of the blank control was 0%, which met the validity criterion that the mortality should not exceed 10%.

Conclusions:

The acute toxicity of test substance to Rare Minnow (Gobiocypris rarus) was determined in a limit test under semi-static conditions (24 h intervals). At the end of the test, the cumulative mortality in the 100 mg/L WAF test group was 0%. Hence, the 96 h - LL50 of test substance for Rare Minnow (Gobiocypris rarus) was greater than 100 mg/L (Based on the nominal loading rate WAF).

Executive summary:

The purpose of the study is to evaluate the possible toxicity of the test substance to Rare Minnow (Gobiocypris rarus) for a period of 96 h.

According to the results of preliminary tests, a nominal loading rate of 100 mg/L of test substance water accommodated fraction (WAF) test group and a blank control were selected.

The preparation of test solution is in according with the OECD guidance document NO.23 (2019).

The actual concentrations of test substance in the 100 mg/L WAF test group were measured at 0 h and 72 h in the new solutions and measured at 24 h and 96 h in the old solutions by Gas Chromatography (GC). The measured concentrations of test substance in blank control were both lower than LOD of 0.125 mg/L at 0h (new solution) and 24 h ( old solution).

At 0h, 72 h (new solutions) and 24 h, 96 h (old solutions), the measured concentrations of test substance in 100 mg/L WAF test group were all lower than LOD of 0.125 mg/L. The measured concentration lower than the LOD of the analytical method, which indicated that the test substance is poorly soluble in test water, but this did not necessarily mean that there was no test item present in the test solution.

The acute toxicity of test substance to Rare Minnow (Gobiocypris rarus) was detennined in a limit test under semi-static conditions (24 h intervals). At the end of the test, the cumulative mortality in the 100 mg/L WAF test group was 0%. Hence, the results for the 96 h median lethal loading rate (LL50), the lowest loading rate causing 100% mortality (LL100) , and the highest loading rate causing 0% mortality (LL0) were described based on the nominal loading rate of the test substance.

LL50 > 100 mg/L (Based on the nominal loading rate WAF)

LL100 > 100 mg/L (Based on the nominal loading rate WAF)

LL0 = 100 mg/L (Based on the nominal loading rate WAF)