1-(2,2,4-trimethyl-3,4-dihydroquinolin-l (2H)-yl)ethanone

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29.10.2020 - 03.02.2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2021

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

adopted April 13, 2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1-(2,2,4-trimethyl-3,4-dihydroquinolin-l (2H)-yl)ethanone

EC Number:

855-228-0

Cas Number:

4497-59-0

Molecular formula:

C14 H19 N O

IUPAC Name:

1-(2,2,4-trimethyl-3,4-dihydroquinolin-l (2H)-yl)ethanone

Test material form:

solid

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Sampling: Duplicate samples from the freshly prepared test media of all test concentrationsand the control were taken at the start of the test.For the determination of the stability of the test item under the test conditions and of the maintenance of the test item concentrations during the test period, duplicate samples from the test media of all test concentrations and the control were collected at the end of the test (after 48 hours) by pouring together the contents of the test beakers of each treatment. All samples were diluted by a factor of 2 with acetonitrile. Additional samples of the control and the dilution solvent were taken at each sampling test start and test end without any sample treatment.
Storage: All samples were stored in a freezer (≤ - 20 °C), protected from light, until analysis was performed. Afterwards the samples were again stored deep frozen and will be kept stored up to the date of the final report.

Test solutions

Vehicle:

no

Details on test solutions:

The test item is not well soluble in test medium. To avoid physical effects of undissolved test item on the daphnids, no concentrations above the solubility limit of the test item in test water was tested. Therefore, a supersaturated stock solution of nominal 100mg test item/L was prepared by suspending 105.8mg test item in 1058mL test water. The stock suspension was stirred for 24hours at room temperature in the dark to dissolve as much test item as possible. Then, non-dissolved fractions of the test item were separated from the test medium by membrane filtration (0.45 μm cellulose acetate filter). The solution with dissolved test item was used as the test medium of the highest test concentration and to prepare the desired 1:2, 1:4, 1:8 and 1:16 dilutions.The test media were prepared just before introduction of the daphnids (= start of the test)

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Species: Daphnia magna (Straus), clone 5
Age at Test Start: From 0.25 to 22.0 hours old
Origin: The daphnids introduced in the test were taken from ibacon's in-house laboratory culture.
Breeding Conditions:The daphnids were bred in the laboratories of ibacon under similar temperature and light conditions as used in the test. The cultivation of the parental daphnids was performed in Elendt M4 medium. The test organisms were not first brood progeny. The daphnids in the stock culture were fed at least on all working days with green algae (Desmodesmus subspicatus) freshly grown in the laboratories of ibacon.
Acclimatisation: Was not necessary, since the test was performed in the same medium as the culturing.

Study design

Test type:

static

Water media type:

other: Reconstituted Water(Elendt "M4")

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

Water Hardness: 2.5 mmol/L (= 250 mg/L) as CaCO3

Test temperature:

Water Temperature: 20.2 to 20.4 °C at test start
19.4 to 19.9 °C at test end

pH:

pH-Values:
7.7 to 7.8 at test start
7.7 to 7.8 at test end and thus the pH-value did not vary by more than 1.5 units

Dissolved oxygen:

5.5 to 8.5 mg/L at test start
8.8 to 8.9 mg/L at test end

Nominal and measured concentrations:

Due to the low limit of water solubility of the test item a filtrate of 100 mg test item/L and dilutions of 1:2, 1:4, 1:8 and 1:16, corresponding to nominal concentrations of 100, 50, 25, 12.5 and 6.25 mg test item/L, and a control, corresponding to following time weighted average concentrations of the test item: 76.7, 35.8, 18.2, 10.3 and 4.98 mg test item/L, and a control.

Details on test conditions:

TEST SYSTEM
Test vessel: Glass beakers of 100 mL volume containing approximately 60 mL of test medium. The test vessels were covered with a lid to reduce the loss of water due to evaporation and to avoid the entry of dust into the solutions.

No. of organisms per vessel: 20 daphnids per control and test concentration, divided into 4 groups of 5 animals, each group in 60 mL test medium
No. of vessels per concentration (replicates): The test was performed with four replicates per treatment group.

WATER PARAMETERS
Dilution water: Reconstituted Water(Elendt "M4") prepared according to SOP

Photoperiod:
Light Regime: 16 h light : 8 h dark
Light Intensity:The light intensity was 310 to 730 lux (measured once during the test)

EFFECT PARAMETERS MEASURED:
The mobility of the daphnidswas determined by visual observation after 24 and 48 hours. Those animals that are not able to swim within 15 seconds after gentle agitation of the test beaker were considered to be immobile (even if they could still move their antennae).

RANGE-FINDING STUDY
Pre-experiments were performed to determine a suitable concentration range and to establish suitable methods to prepare the test solutions.

Reference substance (positive control):

yes

Remarks:

The reference item potassium dichromate is tested at least twice a year to demonstrate satisfactory test conditions

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

13.3 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Effect concentrations 2

Key result

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

10.3 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Effect concentrations 3

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

10.3 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Effect concentrations 4

Key result

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

18.2 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Effect concentrations 5

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

25.8 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Effect concentrations 6

Key result

Duration:

24 h

Dose descriptor:

EC10

Effect conc.:

15.1 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Effect concentrations 7

Key result

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

10.3 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Effect concentrations 8

Key result

Duration:

24 h

Dose descriptor:

LOEC

Effect conc.:

18.2 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Details on results:

Signs of Intoxication after 48 Hours:
After 48 hours of exposure no immobilisation of the test animals was observed in the control and up to and including the test item concentration of 4.98 mg test item/L. At the concentration of 10.3 mg test item/L, one animal was immobile and all animals were immobile at the concentrations of 18.2, 35.8 and 76.7 mg test item/L.

Results with reference substance (positive control):

Results of the most recent Test with the Reference Item Potassium dichromate
EC50 24 h: 1.163 mg test item/L
EC50 48 h: 0.986 mg test item/L
The results indicate that the sensitivity of the daphnidswas consistent with the level proposed by the OECD 202 guideline (EC50-24 h between 0.6 and 2.1 mg potassium dichromate/L)

Reported statistics and error estimates:

The 24-hour and 48-hour EC50, EC20 and EC10 and the 95%confidence limits were calculated by probit analysis.The NOEC and LOEC after 24 and 48 hours were determined directly from the raw data. The software used to perform the statistical analysis was ToxRat Professional, Version 3.3.0, ToxRat Solutions GmbH

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Control Immobilisation Rate:Was 0 % and furthermore no daphnid showed signs of disease or stress Dissolved Oxygen Concentration:Was ≥ 8.8 mg O2/L in in all treatment groups at the end of the test;

Conclusions:

The toxic effect of the test item [trade name] to Daphnia magna was assessed in a static concentration-response test. The 48-hour NOEC was determined to be 10.3 mg test item/L. The 48-hour LOEC was determined to be 18.2 mg test item/L and the 48-hour EC50 value was calculated to be 13.3 mg test item/L. The initial concentrations and the maintenance of the exposure concentrations during the test were determined in the analytical part. All reported results refer to the measured time weighted average concentrations of the test item.

Executive summary:

Title: [trade name]: Acute Toxicity to Daphnia magnain a Static 48-hour Immobilisation Test

Purpose: The purpose of this study was to determine the influence of the test item [trade name] on the mobility of Daphnia magna. For this purpose, young daphnids (< 24 hours old) were exposed in a static test to various concentrations under defined conditions for 48 hours. The recorded effects were the mobility of the daphnids after 24 and 48 hours.The test method of application and the test system are recommended by the test guidelines and Daphnia magna is the recommended test species.The purpose of the analytical part of this study was to verify the concentrations of the test item in the test medium.

Test Species: Daphnia magna, clone 5; 0.25 to 22.0 hours old

Source: The daphnids introduced in the test were taken from ibacon's in-house laboratory culture.

Test Design: This study encompassed 6 treatment groups (5 dose rates of the test item and a control) each containing 20 individuals. The mobility of thedaphnids was determined in a static 48-hour test by visual observation after 24 and 48 hours.

Endpoints: Number of immobile organisms after 24 and 48 hours

Test Concentrations: Due to the low limit of water solubility of the test item a Filtrate of 100 mg test item/L and dilutions of 1:2, 1:4, 1:8 and 1:16, corresponding to nominal concentrations of 100, 50, 25, 12.5 and 6.25 mg test item/L, and a control, corresponding to following time weighted average concentrations of the test item: 76.7, 35.8, 18.2, 10.3 and 4.98 mg test item/L, and a control.

Test Conditions:Water temperature: 19.4 to 20.4 °C; pH value: 7.7 to 7.8; dissolved oxygen concentration: 5.5 to 8.9 mg/L; photoperiod: 16 h light - 8 h dark; light intensity: 310 to 730 lux; and thus were within the ranges requested by guideline OECD 202

Biological test results: After 48 hours of exposure no immobilisation of the test animals was observed in the control and up to and including the test item concentration of 4.98 mg test item/L. At the concentration of 10.3 mg test item/L, one animal was immobile and allanimals were immobile at the concentrations of 18.2, 35.8 and 76.7 mg test item/L.

EC50 24 h: 25.8 mg test item/; EC50 48h: 13.3 mg test item/L

Analytical test results: The quantification of the test item [trade name] in the test samples was performed using liquid chromatography with UV detection. At the start of the test 83 % of the nominal test concentrations were found (average of all test concentrations). After 48 hours test duration, 71 % of the nominal value was determined (average of all test concentrations). During the test the daphnids were exposed to a mean of 77 % of nominal.