Dodecylbenzenesulphonic acid, compound with isopropylamine (1:1)

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Dodecylbenzenesulphonic acid, compound with isopropylamine (1:1)

EC Number:

247-556-2

EC Name:

Dodecylbenzenesulphonic acid, compound with isopropylamine (1:1)

Cas Number:

26264-05-1

Molecular formula:

C18H30O3S.C3H9N

IUPAC Name:

sodium dodecylbenzenesulfonate

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples for possible analysis were taken from all test concentrations and the control as follows:

Frequency: at 0 and 48 hours
Volume: 2.0 mL from the approximate centre of the test vessels
Storage: Samples were stored in a freezer (≤-15°C) until analysis at the analytical laboratory of the Test Facility.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
Preparation of test solutions started with a loading rate of 100 mg/L in the combined limit/range-finding test and 46 mg/L in the final test, applying an overnight-period of magnetic stirring to ensure maximum dissolution of the test item in medium. The obtained mixture was allowed to settle for a period of three hours.

Thereafter, the aqueous Saturated Solution (SS) was collected by means of siphoning through glass wool and used as the highest test concentration. Lower test concentrations were prepared by subsequent dilutions of the SS in test medium. All test solutions were clear and colorless at the end of the preparation procedure, except for the highest test concentration of the combined limit/range-finding test which was slightly hazy and on which a layer of foam was visible. The hazy solution was checked for the presence of the Tyndall effect using a laser pen. No light scattering was observed which indicated that only the dissolved fraction of test item was present in test medium.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain/clone: Straus, 1820
- Source: In-house laboratory culture with a known history.
- Age of parental stock (mean and range, SD): 2nd to 5th brood stock (maximum 4 weeks old)
- Feeding during test No

ACCLIMATION
- Acclimation period: Maximum 4 weeks
- Acclimation conditions (same as test or not): Same as test
- Type and amount of food: Fresh water algae
- Feeding frequency: Daily
- Health during acclimation (any mortality observed): Daphnids showing no signs of stress such as mortality >20% , presence of males, ephippia or discoloured animals and there was no delay in the production of the first brood.

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES: Daphnia, less than 24 hours old, from parental daphnids of more than two weeks old.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

180 mg/L expressed as CaCO3

Test temperature:

Between 19 and 20°C as continuously monitored in a temperature control vessel.

pH:

Between 6 and 9 not varying by more than 1.5 pH units.

Dissolved oxygen:

>/= 3 mg/L at the end of the test.

Salinity:

Not specified

Conductivity:

Not specified

Nominal and measured concentrations:

Combined range-finder/limit test:
Nominal: 1, 10 and 100 mg/L
Measured, 0.53 and 7.9 mg/L (not measured at nominally 100 mg/L).

Main test:
Nominal: 1.0, 2.2, 4.6, 10.1, 22.1 and 46 mg/L.
Measured: 0.82, 1.8, 3.9, 7.7, 15 and 42 mg/L (measured concentrations at the start of the test).

Details on test conditions:

TEST SYSTEM
- Test vessel: All glass beakers
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: 60 mL beakers containing 50 mL test medium
- Aeration: No
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Standard Elendt M7 medium as per OECD guidelines fortified with salts and vitamins.

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 hours light 8 hours darkness
- Light intensity: Not specified

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobility at 24 and 48 hours.

VEHICLE CONTROL PERFORMED: no vehicle used on study.

RANGE-FINDING STUDY
- Test concentrations: 1, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: Yes; 100% immobility at nominally 10 and 100 mg/L with no immobility observed at 1 mg/L.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

6.7 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Analytical:
Samples taken from all test concentrations and the control were analysed. The measured concentrations at the start of the test were respectively 0.82, 1.8, 3.9, 7.7, 15 and 42 mg/L in solutions containing 2.2, 4.8, 10, 22, 48 and 100% of the SS prepared at a loading rate of 46 mg/L (nominally 1.0, 2.2, 4.6, 10.1, 22.1 and 46 mg/L). During the exposure period, the concentrations remained stable, i.e. were at 87-101% of initial at the end of the test. It should be noted that measured concentrations reported were corrected for the relatively high recovery in Quality Control (QC) samples (i.e.118-131%). Additionally, a small response was measured in the control. It was assumed to result from carry-over and therefore, considered not relevant. Based on the obtained results, effect parameters were expressed in terms of initially measured concentrations.

Immobility:
No immobility was observed in the control and at the three lowest test concentrations throughout the exposure period. At the end of the test, 95% immobility was observed at the measured concentration of 7.7 mg/L, while all daphnids were immobilized at the two highest test concentrations.
The responses recorded in this test allowed for reliable determination of an EC50.

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Relevant effect levels: 48 hour EC50 0.59 mg/L (within historical laboratory range of 0.3 and 1.0 mg/L).
- Limit test: No
- Dose-response test: yes

Any other information on results incl. tables

Table 1: Incidences of mobility:

Time (h)	Replicate	Test substance Measured concentration (mg/L)
		Control	0.82	1.8	3.9	7.7	15	42
0	A	5	5	5	5	5	5	5
	B	5	5	5	5	5	5	5
	C	5	5	5	5	5	5	5
	D	5	5	5	5	5	5	5
	Total introduced	20	20	20	20	20	20	20
24	A	0	0	0	0	0	5^1,2	5
	B	0	0	0	0	0	5	5
	C	0	0	0	0	0	5	5
	D	0	0	0	0	0	5	5
	Total immobilised	0	0	0	0	0	20	20
	Effect %	0	0	0	0	0	100	100
48	A	0	0	0	0	5	5	5
	B	0	0	0	0	5	5	5
	C	0	0	0	0	4	5	5
	D	0	0	0	0	5	5	5
	Total immobilised	0	0	0	0	19	20	20
	Effect %	0	0	0	0	95	100	100

¹Microscopic observation revealed no test item attached to the daphnids.

²Dissolved oxygen concentration was measured to be 8.8 mg/L directly measured after observation.

Table 2: Analytical results:

Time of sampling [hours]	Date of sampling	Date of analysis	Percentage of SS [%]	Analyzed concentration [mg/L]	Corrected concentration [mg/L]	Relative to initial [%]
0	09 Jul 2018	01 Aug 2018	0	0.047^1	0.038
			2.2	1.02	0.821
			4.8	2.22	1.78
			10	4.85	3.90
			21.7	9.51	7.66
			47.8	18.2	14.6
			100	52.5	42.2
48	11 Jul 2018	01 Aug 2018	0	0.049	0.039	n.a.
			2.2	0.889	0.716	87
			4.8	2.07	1.67	93
			10	4.58	3.69	95
			21.7	9.43	7.59	99
			47.8	17.9	14.4	98
			100	52.9	42.6	101

¹Estimated value, calculated by extrapolation of the calibration curve. This is probably caused by carry over since a similar response was observed in the analytical blank.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In conclusion, the 48h-EC50 for Daphnia magna exposed to the test substance was 6.7 mg/L based on initially measured concentrations (95% confidence interval between 6.1 and 7.4 mg/L).