4-dimethylaminobenzaldehyde

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:

July 13, 2015 - November 24, 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

4-dimethylaminobenzaldehyde

EC Number:

202-819-0

EC Name:

4-dimethylaminobenzaldehyde

Cas Number:

100-10-7

Molecular formula:

C9H11NO

IUPAC Name:

4-(dimethylamino)benzaldehyde

Test material form:

solid

Specific details on test material used for the study:

Designation: Art. 803057
Synonym: 4-(Dimethylamino)benzaldehyde
CAS-No.: 100-10-7
Batch: S6886257
Assay (GC, area%): 99.6% (a/a)
Appearance: Grey-blue, crystalline powder
Expiry date: May 31, 2019
Storage: Tightly closed, dark at room temperature (15 to 25°C)


Preparation of the Test Item:
The test item was prepared freshly before the exposure. For this purpose, the calibrated flask with test medium (100 mg/L) was stirred for 24 hours.

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Concentrations:
0.3, 0.7, 1.5, 3.2 and 7.0 mg/L

Sampling method:
Samples were taken and analyzed by HPLC from control and test media from both exposure periods, i.e. 0-24 hours and 24-48 hours.

Sample storage conditions before analysis:
Samples were analyzed directly without storage.

Test solutions

Vehicle:

yes

Details on test solutions:

Macro nutrients (mg/L)
CaCI2 •2H20 293.80
MgSO4•7H20 123.30
NaHCO3 64.80
KCI 5.80
Na2SiO3•9H20 10.00
NaNO3 0.27
KH2PO4 0.14
K2HPO4 0.18

Trace elements (mg/L)
B 0.5000
Fe 0.2000
Mn 0.1000
Li, Rb and Sr 0.0500
Mo 0.0250
Br 0.0125
Cu and Zn 0.0063
Co and I 0.0025
Se 0.0010
V 0.0003

Macro nutrients (mg/L)
Na2EDTA • 2H20 2.50

Vitamins (µg/L):
Thiamine 75.00
B12 1.00
Biotin 0.75

- pH: 7.67 - 7.69
- Total hardness: 250 mg CaCO3/L (calculated)

Preparation of the Test Item:
The test item was prepared freshly before the exposure. For this purpose, the calibrated flask with test medium (100 mg/L) was stirred for 24 hours.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Species: Daphnia magna Straus
Origin: Daphnia magna Straus was originally obtained from IBACON GmbH (Roßdorf, Germany).
Culture conditions: The clone is bred in the laboratories of Merck KGaA (room 2068).
Parental daphnids are used for reproduction until they are about 6 weeks old. Thereafter, they are replaced by neonates.
Daphnids are kept individually in 100 mL glass vessels containing approximately 60 mL reconstituted water (ELENDT M4 medium) at a water temperature of 20 ± 2°C and a 16 hour light and 8 hour dark regime to ensure similar conditions as in the experiment. Offspring are removed from the vessels at least twice per week.
Feeding: The parental daphnids are fed ad libitum with unicellular green algae Desmodesmus subspicatus three times per week.
Age: Offspring less than 24 hours old were used for the study.
Acclimation period: same as test

Feeding during test: None

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

250 mg CaCO3/L (calculated)

Test temperature:

19.3 – 19.9°C

pH:

7.67 - 7.73

Dissolved oxygen:

8.04 - 8.24 mg/L

Nominal and measured concentrations:

Nominal concentrations: 0.3, 0.7, 1.5, 3.2 and 7.0 mg/L
Measured concentrations: >80% of nominal concentrations

Details on test conditions:

EXPOSURE:
The study was performed in an air-conditioned room. For the study 20 mL glass test tubes containing at least 20 mL either reconstituted water (control group) or test medium (test item group) were used. Each test vessel contained five daphnids resulting in 4 mL medium per daphnid. They were not fed and the media were not aerated during the exposure.

The test was performed as a semi-static test in open vessels.

The duration of exposure was 48 hours. During the exposure period, the mobility of the daphnids was assessed daily, i.e. after 24 and 48 hours.

NO. OF DAPHNIDS:
Control Group: 20 daphnids
0.3 mg/L: 20 daphnids
0.7 mg/L: 20 daphnids
1.5 mg/L: 20 daphnids
3.2 mg/L: 20 daphnids
7.0 mg/L: 20 daphnids

CONCENTRATION(S)
Stability determination of the test item in the vehicle revealed no difference between an open and closed system. Based on the results of a pretest (non-GLP), the concentration of the test item decreases below recovery rates of 80% during the exposure period of 48 hours (Broschard, 2015).

Therefore, the study was performed as a semi-static test in an open system with the following nominal concentrations: 0.3, 0.7, 1.5, 3.2 and 7.0 mg/L

For the control, reconstituted water without any addition of solvent or test item was used.

VEHICLE
Reconstituted water (ELENDT M4 medium) was used as vehicle.

Macro nutrients (mg/L)
CaCI2 •2H20 293.80
MgSO4•7H20 123.30
NaHCO3 64.80
KCI 5.80
Na2SiO3•9H20 10.00
NaNO3 0.27
KH2PO4 0.14
K2HPO4 0.18

Trace elements (mg/L)
B 0.5000
Fe 0.2000
Mn 0.1000
Li, Rb and Sr 0.0500
Mo 0.0250
Br 0.0125
Cu and Zn 0.0063
Co and I 0.0025
Se 0.0010
V 0.0003

Macro nutrients (mg/L)
Na2EDTA • 2H20 2.50

Vitamins (µg/L):
Thiamine 75.00
B12 1.00
Biotin 0.75

- pH: 7.67 - 7.69
- Total hardness: 250 mg CaCO3/L (calculated)
- O2-Concentration: 8.13 - 8.23 mg/L
- Culture medium different from test medium: no
- Intervals of water quality measurement: 24h (semi-static)


OTHER TEST CONDITIONS
- Photoperiod: 16h light / 8h dark
- Light intensity: The mean light intensities were 614 Lux prior to and at the end of the exposure period.

References:

ELENDT, B.-P. Selenium deficiency in Crustacea. An ultrastructural approach to antennal damage in Daphnia magna Straus.
Protoplasma 154, 25-33, 1990

Reference substance (positive control):

no

Remarks:

No positive control used in this study. The accuracy and reliability of the test method is demonstrated periodically as recommended by guidelines with potassium dichromate.

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

4.352 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: EC50 based on nominal concentrations

Effect concentrations 2

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

1.58 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: EC50 based on nominal concentrations

Details on results:

Art. 803057 (4-(Dimethylamino)benzaldehyde), dissolved in reconstituted water, was tested in an open semi-static system. Under the conditions of the present study the test item revealed a 48h EC50 of 1.580 mg/L.

Results with reference substance (positive control):

Potassium dichromate:
24h EC50 1.059 mg/L (0.950 – 1.183 mg/L)
48h EC50 0.685 mg/L (0.596 – 0.787 mg/L)

The test item Art. 104864 (Potassium dichromate) showed a 24h EC50 value which was within the range of the published data of 0.6 to 1.7 mg/L (Council Regulation (EC) No. 440/2008) and 0.6 to 2.1 mg/L (OECD Guideline No. 202).

Any other information on results incl. tables

Objective

The objective of this study was to determine the effect of the test item Art. 803057 (4-(Dimethylamino)benzaldehyde) on the immobilization of Daphnia magna.

Study Design

Juvenile daphnids were exposed to 5 different concentrations (0.3, 0.7, 1.5, 3.2 and 7.0 mg/L) of the test item over 48 hours, in an open semi-static system. The daphnids were observed for immobilization 24 and 48 hours after placing in the aqueous test item solution. Based on results of a stability determination before start of study, a semi-static test system was chosen and the test media were renewed after 24 hours. The concentrations of the test item Art. 803057 (4-(Dimethylamino)benzaldehyde) in the test media were analyzed via HPLC with UV detection directly after preparation and after 24 hours. The study comprised of four test vessels per test item group containing five daphnids each, i.e. 20 daphnids in total per test item group. Additionally, one control group (20 daphnids) was used.

Results

The measured concentrations of the test item in the test medium are given in the following table:

	Analytical results
	0h Fresh preparation		24h Old preparation		24h Fresh preparation		48h Old preparation
Nominal	[mg/L]	%	[mg/L]	%	[mg/L]	%	[mg/L]	%
0.0 mg/L	<LOD	-	<LOD	-	<LOD	-	<LOD	-
0.3 mg/L	0.285	95.0	0.248	82.7	0.290	96.7	0.268	89.3
0.7 mg/L	0.689	98.4	0.639	91.3	0.697	99.6	0.675	96.4
1.5 mg/L	1.482	98.8	1.423	94.9	1.491	99.4	1.453	96.9
3.2 mg/L	3.126	97.7	3.132	97.9	3.170	99.1	3.188	99.6
7.0 mg/L	7.074	101.1	6.990	99.9	7.026	100.4	7.045	100.6

As the recovery of the test item in the aqueous solution was >80% during the study, the EC50 values were calculated with the nominal concentrations.

After exposure of daphnids to nominal concentrations of 0.3, 0.7, 1.5, 3.2 and 7.0 mg/L for 48 hours, the following results were obtained:

	Number of daphnids immobilized / exposed		% of daphnids immobilized
Nominal	24 hours	48 hours	24 hours	48 hours
0.0 mg/L	0/20	0/20	0%	0%
0.3 mg/L	0/20	0/20	0%	0%
0.7 mg/L	0/20	1/20	0%	5%
1.5 mg/L	3/20	12/20	15%	60%
3.2 mg/L	10/20	16/20	50%	80%
7.0 mg/L	12/20	20/20	60%	100%

The lowest concentration of 0.3 mg/L revealed no effect. A concentration dependent immobilization of the daphnia was observed at concentrations of 0.7 to 7.0 mg/L.

For the test item, Art. 803057 (4-(Dimethylamino)benzaldehyde), the following EC50 values for daphnids were determined:

24h EC50       4.352 mg/L (3.158 – 7.020 mg/L)

48h EC50       1.580 mg/L (1.245 – 2.003 mg/L)

Conclusion

Art. 803057 (4-(Dimethylamino)benzaldehyde), dissolved in reconstituted water, was tested in an open semi-static system. Under the conditions of the present study the test item revealed a 48h EC50 of 1.580 mg/L.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Art. 803057 (4-(Dimethylamino)benzaldehyde), dissolved in reconstituted water, was tested in an open semi-static system. Under the conditions of the present study the test item revealed a 48h EC50 of 1.580 mg/L.

Executive summary:

This study was performed according to GLP and the methods applied are fully compliant with OECD TG 202. Art. 803057 (4-(Dimethylamino)benzaldehyde), dissolved in reconstituted water, was tested in an open semi-static system. Under the conditions of the present study the test item revealed a 48h EC50 of 1.580 mg/L.