4,4'-carbonimidoylbis[N,N-diethylaniline] monohydrochloride

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

02-05-2017 - 04-05-2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Experimental test result performed using standard test guidelines

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

no

Analytical monitoring:

not specified

Vehicle:

yes

Details on test solutions:

The stock solution (10 mg/L) was prepared by dissolving yellow powder in reconstituted water. Test solutions of required concentrationas were prepared by mixing the stock solution of the test sample with reconstituted test water.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Strain: Straus
- Source: Own breeding at University of Chemistry and Technology, Prague
- Age at study initiation (mean and range, SD): The animals used for the test shall be less than 24 h old and should not be first brood progeny
- Feeding during test: No feeding

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

± 1 hr

Test temperature:

20±1°C

pH:

Sample at concentration 0.32 mg/L: pH= 8.0 changed to pH= 7.9 during the test
Control: pH= 8.0 changed to pH= 7.9 during the test

Dissolved oxygen:

higher than 8 mg/L at the end of test

Nominal and measured concentrations:

0, 0.01, 0.02, 0.04, 0.08, 0.16 and 0.32 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 ml glass vessel
- fill volume: 25 ml
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
Natural water (surface or ground water), reconstituted water or dechlorinated tap water are acceptable as culturing and dilution water if D. magna survives in it for the duration of the culturing, acclimation and testing without showing signs of stress. Waters in the range pH 6 to pH 9, with hardness between 140 mg/l and 275 mg/l (as CaCO3) are recommended.
As an example, the preparation of dilution water meeting the requirements is described below.
Dissolve known quantities of reagents in water. The dilution water prepared shall have a pH of 7.8 ± 0.5, a hardness of (225 ± 50) mg/l (expressed as CaCO3), a molar Ca + Mg ratio close to 4 + 1 and a dissolved oxygen concentration above 7 mg/l.

Prepare the solutions specified below:
- Calcium chloride solution: Dissolve 117.6 g of calcium chloride dihydrate (CaCl2.2H2O) in water (4.2) and make up to 1 l with water (4.2).
- Magnesium sulfate solution: Dissolve 49.3 g of magnesium sulfate heptahydrate (MgSO4.7H2O) in water (4.2) and make up to 1 l with water (4.2).
- Sodium bicarbonate solution: Dissolve 25.9 g of sodium bicarbonate (NaHCO3) in water (4.2) and make up to 1 l with water (4.2).
- Potassium chloride solution: Dissolve 2.3 g of potassium chloride (KCI) in water (4.2) and make up to 1 l with water (4.2).

Mixing
Mix 2.5 ml of each of the four solutions and make up to 1 l with water.
The dilution water shall be aerated until the dissolved oxygen concentration has reached saturation and the pH has stabilized. If necessary, adjust the pH to 7.8 ± 0.5 by adding sodium hydroxide (NaOH) solution or hydrochloric acid (HCI). The dilution water prepared in this way shall not be further aerated before use.

- Sodium hydroxide solution, e.g. [NaOH] : 1 mol/l.
- Hydrochloric acid, e.g. [HCl] : 1 mol/l.

Reference substance:
Dissolve 600 mg of potassium dichromate (K2Cr2O7) in water and make up to 1 l with water (4.2).

OTHER TEST CONDITIONS
- Adjustment of pH: no adjustment done
- Photoperiod: No - Darkness
- Light intensity:

CALCULATION:
EC50 was calculated using non linear regression by the software Prism 4.0

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (K2Cr2O7)

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.116 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 0.098 - 0.138 mg/L

Results with reference substance (positive control):

- Results with reference substance valid
- EC50: 0.73 mg/L (24 hours)

Validity criteria fulfilled:

yes

Conclusions:

The median effective concentration (EC50) for the test substance,4,4'-carbonimidoylbis[N,N-diethylaniline] monohydrochloride, in Daphnia magna was determined to be 0.016 mg/L on the basis of mobiity inhibition effects in a 48 hour study.

Executive summary:

Determination of the inhibition of the mobility of daphnids was carried out with the substance 4,4'-carbonimidoylbis[N,N-diethylaniline] monohydrochloride according to OECD Guideline 202.

The test substance was tested at the concentrations 0, 0.01, 0.02, 0.04, 0.08, 0.16 and 0.32 mg/L. Effects on immobilisation were observed for 48 hours.

The median effective concentration (EC50) for the test substance, 4,4'-carbonimidoylbis[N,N-diethylaniline] monohydrochloride, in Daphnia magna was determined to be 0.016 mg/L for immobilisation effects.

This value indicates that the substance is likely to be hazardous to aquatic invertebrates and can be classified as Aquatic acute category 1 as per the CLP criteria.

Description of key information

The median effective concentration (EC50) for the test substance,4,4'-carbonimidoylbis[N,N-diethylaniline] monohydrochloride, in Daphnia magna was determined to be 0.016 mg/L on the basis of mobiity inhibition effects in a 48 hour study.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.016 mg/L

Additional information

Experimental key and supporting Short term toxicity to aquatic invertebrates endpoint was reviewed for the substance 4,4'-carbonimidoylbis(N,N-diethylaniline) monohydrochloride (CAS no 6358-36-7) and structurally related substance (CAS 548 -62 -9) which are as follows:

In key study, Determination of the inhibition of the mobility of daphnids was carried out with the substance 4,4'-carbonimidoylbis(N,N-diethylaniline) monohydrochloride according to OECD Guideline 202. The test substance was tested at the concentrations0, 0.01, 0.02, 0.04, 0.08, 0.16 and 0.32 mg/L. Effects on immobilisation were observed for 48 hours. The median effective concentration (EC50) for the test substance,4,4'-carbonimidoylbis[N,N-diethylaniline] monohydrochloride, in Daphnia magna was determined to be 0.016 mg/L for immobilisation effects. This value indicates that the substance is likely to be hazardous to aquatic invertebrates and can be classified as Aquatic acute category 1 as per the CLP criteria.

In supporting study, Acute Immobilisation test in Daphnia magna was performed in compliance with the OECD Guidelines for Testing of Chemicals, Section 2, No. 202, "Daphnia Sp., Acute Immobilisation Test" . The structurally related substance

N-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloride was tested for acute toxic effects on the swimming capabilities of Daphnia magna employing a static test procedure. In the main study, six groups of daphnids, each comprising 5 daphnids per replicate, were exposed to the test article at concentration levels of 0.025 mg, 0.05 mg, 0.1 mg, 0.2 mg, 0.4 mg and 0.8 mg/L. Observations were made for immobilisation at 24 hours and 48 hours of treatment. A concurrent blank control was also run simultaneously.Potassium Dichromatewas employed as a positive control and tested at the concentration of   0.4 mg, 0.63 mg and 1 mg/L. The animals were observed for immobility after 24 hours and 48 hours of exposure. Those daphnids which were unable to swim within 15 seconds after gentle agitation of the test container were considered to be immobile. The rates of immobilisation observed at 24 hours were 0%, 0%, 0%, 10%, 25% and 75% at the test concentrations of 0.025 mg, 0.05 mg, 0.1 mg, 0.2 mg, 0.4 mg and 0.8 mg/L respectively. The rates of immobilisation observed at 48 hours were 0%, 0%, 10%, 25%, 55% and 85% at the test concentrations of 0.025 mg, 0.05 mg, 0.1 mg, 0.2 mg, 0.4 mg and 0.8 mg/L respectively. The Positive control, Potassium Dichromate induced immobilisation in 20%, 50% and 80% of the exposed daphnids at 24 hours and 25%, 65% and 100% immobilization at 48 hours at the concentrations of 0.4 mg, 0.63 mg and 1 mg/L respectively. No immobilisation was observed in blank control group.The acute immobilisation EC50 value of N-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloridetoDaphniamagnaat 24 hour exposure period was found to be 0.53 mg/L with fiducial limits between 0.41 to 0.69 mg/L at 95% confidence level. The acute immobilisation EC50 value of N-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloride to Daphnia magna at 48 hour exposure period was found to be 0.35 mg/L with fiducial limits between 0.24 to 0.50 mg/L at 95% confidence level. On the basis of EC50 value obtained it can be concluded that the substance N-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloride is toxic to the aquatic environment and can be considered as "Aquatic Acute 1" as per CLP regulation.

Thus considering the key study value, it can be concluded that 4,4'-carbonimidoylbis[N,Ndiethylaniline] monohydrochloride exhibits toxicity to aquatic invertebrate (Daphni magna) in the acute 1 classification category. Also since long term toxicity data is not available and the substance is inherently biodegradable (near to not readily biodegradable), the final classification for aquatic invertebrate is considered to be Aquatic Acute 1 as well as Chronic category 1 as per CLP criteria.