N,N-dimethyldecylamine N-oxide

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
Both the target and source substances contain identical functional groups and differ only by the C-chain length. The ecotoxicological properties of these substances will be similar or predictable.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source: Dodecyl(dimethyl)amine oxide (EC 216-700-6; CAS 1643-20-5; C12 AO)
Source: Dimethyl(tetradecyl)amine oxide (EC 222-059-3; CAS 3332-27-2; C14 AO)
Source: Amines, C12-14 (even numbered) -alkyldimethyl, N-oxides (EC 931-292-6; C12-14 AO)
Target: N,N-dimethyldecylamine N-oxide (EC 220-020-5; CAS 2605-79-0; C10 AO)

3. ANALOGUE APPROACH JUSTIFICATION
The target and source substances contain identical functional groups. The only difference between the substances is the alkyl chain length (C10 in the target and C12 or C14 or C12/14 in the source). No acute daphnia studies have been performed using C10 AO. However, studies are available for C12 AO, C14 AO and C12-14 AO. The results of these studies show a small trend for toxicity to daphnia magna to increase as chainlength increases from C12 AO to C14 AO with C12-14 AO having intermediate toxicity between the two monoconstituents. On this basis, taking a geometric mean of the available data for C12 AO, C14 AO and C12-14 AO gives a worse case estimate of the likely toxicity of C10 AO.

4. DATA MATRIX
Target: No data
Source (C12 AO): 48-h EC50 = 3.9 mg AO/L; 48-h EC50 = 4.24 mg AO/L
Source (C14 AO): 48-h EC50 = 2.63 mg AO/L
Source (C12-14 AO): 48-h EC50 = 3.1 mg AO/L; 48-h EC50 = 2.9 mg AO/L; 48-h EC50 = 4.2 mg AO/L

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

3.43 mg/L

Conc. based on:

act. ingr.

Basis for effect:

mobility

Remarks on result:

other: Geometric mean of available data for C12, C14 and C12-14 AO

Executive summary:

No acute daphnia studies have been performed using C10 AO. However, studies are available for C12 AO, C14 AO and C12-14 AO. The results of these studies show a small trend for toxicity to daphnia magna to increase as chainlength increases from C12 AO to C14 AO with C12-14 AO having intermediate toxicity between the two monoconstituents.  On this basis, taking a geometric mean of the available data for C12 AO, C14 AO and C12-14 AO gives a worse case estimate of the likely toxicity of C10 AO. The estimated 48-h EC50 = 3.43 mg AO/L.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1990-02-19 to 1990-03-23

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

no analysis of test concentrations during the study.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

no

Details on sampling:

No data

Vehicle:

no

Details on test solutions:

The diluting water used for preparation of the test concentrations was a synthetic water (Dutch Standard Water) having a pH of approximately 8.2 and a hardness of 13 degrees dH. Composition per litre of dionized water was 100 mg/L NaHCO3, 20 mg/L KHCO3, 200 mg/L CaCl2.2H2O and 180 mg/L MgSO4.7H2O.

The deionized water used had a conductivity of less than 5 uS/cm, a TOC constant of less than 2 mg/L and contained not more than 10 ug copper/L.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water fleas
- Source: Continuous culture maintained at Akzo Research Laboratories, Arnhem
- Age at study initiation (mean and range, SD): Less than 24 hours (obtained from parent animals having an age of about 3 weeks)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

No data

Hardness:

No data

Test temperature:

The air temperature during the test ranged from 18.9 to 19.3 degrees Centigrade

pH:

The pH ranged from 8.1 to 8.2 at the beginning of the definitive test and was 8.1 at the end of the test (see Table V, attached)

Dissolved oxygen:

The dissolved oxygen concentrations varied from 9.0 to 9.2 mg/L throughout the definitive test (see Table IV, attached)

Salinity:

No data

Nominal and measured concentrations:

Nominal concentrations used during preliminary test: 1.0, 10, 100 mg/L
Nominal concentrations used during definitive test: 1.0, 2.1, 4.6, 10, 21 mg/L

Details on test conditions:

The test vessels were 400 mL glass beakers containing 250 mL of test medium and were partially covered with a glass plate. Each beaker contained five animals. A minimum of 20 animals were tested per concentration and associated control.

The light regime was 16 hours of ambient light per day (supplied by fluorescent tubes) and the air temperature was continuously registered.

Measurements of pH and oxygen concentration were carried out at the beginning and the end of the test using one random beaker per test concentration and associated control.

No chemical analyses of the concentrations of the test substance dissolved in the test media were performed. Therefore, all concentrations reported were nominal.

One preliminary test was performed using 5 Daphnids per test concentration and 11 Daphnids in the control vessel.

For the definitive test a stock solution of 0.5 g/L was used to prepare the test concentrations. Twenty animals were divided between 4 test vessels at each concentration level whilst 30 animlas were divided between 6 control vessels.

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

9.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% confidence limits 7.8 to 11.5 mg/L

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

4.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

21 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

2.9 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

1.4 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

6.3 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mobility

Details on results:

Preliminary test

The highest concentration causing no immobilisation amounted to 1 mg/L, whilst 100 % immobilisation was observed at a concentration of 10 mg/L within 48 hours and 100 mg/L within 24 hours. The results of the preliminary test are summarised in Table I (attached).

Definitive test

The results of the definitive test are summarised in Tables II and III (attached). A slight effect (< 10 % immobilisation) was observed at concentrations of 1.0 mg/L and 2.1 mg/L but this was considered to be allowed by the quality criteria of the test.

Results with reference substance (positive control):

No data

Reported statistics and error estimates:

The EC50 was determined with an LC50 program of Griffioen (RIZA) based on a model of Kooyman (1991)

The quality criteria were fulfilled:

- Immobilisation in the control was < 10 % at the end of the test

- No Daphnids of the control group were trapped on the surface of the water during the test

- The dissolved oxygen concentration did not drop below 2 mg/L throughout the test

- In view of the results of a published biodegradability study it is likely that the concentration of the test substance remained constant during the test.

Validity criteria fulfilled:

yes

Conclusions:

The EC50 (48 h) was calculated to be 9.5 mg/L (equivalent to 2.9 mg AO/L) with 95% confidence limits of 7.8 and 11.5 mg/L. A slight effect (< 10% immobilisation) seen at concentrations of 1.0 mg/L and 2.1 mg/L as well as in the control was attributed to allowable variation. The NOEC after 48 hours was therefore reported as 4.6 mg/L (equivalent to 1.4 mg AO/L) whereas 21 mg/L (equivalent to 6.3 mg AO/L) produced 100 % immobilisation within 48 hours.

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

no analysis of test concentrations during the study.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

GLP compliance:

no

Analytical monitoring:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Stock solution of test material prepared in deionised water (1 g/L)

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water fleas
- Source: Continuous culture maintained at the Akzo Nobel Central Research, Arnhem, Dept. CRL Netherlands
- Age at study initiation (mean and range, SD): less than 24 hours

ACCLIMATION
- Acclimation period: None

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

None

Hardness:

12°dH

Test temperature:

Not recorded - room temperature controlled.

pH:

8.0 - 8.1

Dissolved oxygen:

8.6 - 9.1 mg/L

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal: 0, 5, 9, 16.2, 29.2, 52.5 mg/L (equivalent to 0, 1.19, 2.13, 3.84, 6.92 or 12.44 mg AO/L).

Details on test conditions:

TEST SYSTEM
- Test vessel: 400 mL glass beakers
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 250 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
- Source/preparation of dilution water: Synthetic Dutch Standard water:
100 mg NaHCO3
20 mg KHCO3
200 mg CaCl2.2H2O
180 mg MgSO4.7H2O
- Total organic carbon: < 2 m/L
- Particulate matter: Not specified
- Metals: < 0.01 mg copper/L


OTHER TEST CONDITIONS
- Adjustment of pH: None
- Photoperiod: 16 hours light
- Light intensity: ambient (fluorescent tubes)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :

TEST CONCENTRATIONS
- Range finding study: Yes
- Test concentrations: 0, 0.1, 1, 10, 32, 100 mg/L
- Results used to determine the conditions for the definitive study: Yes

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

11.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL = 10.0 - 12.4 mg/L

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

2.64 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mobility

Remarks on result:

other: 95% CL = 2.37 - 2.94 mg/L

Table 1: Immobilisation in definitive test

mg of test substance/L	Number of test vessel	Number of mobile animals
		0 hours	24 hours	48 hours
Control	I	5	5	5
	II	5	5	5
	III	5	5	5
	IV	5	5	5
	total	20	20	20
5	I	5	5	5
	II	5	5	5
	III	5	5	4
	IV	5	5	5
	total	20	20	19
9	I	5	5	3
	II	5	5	5
	III	5	5	5
	IV	5	5	4
	total	20	20	17
16.2	I	5	5	0
	II	5	5	0
	III	5	4	0
	IV	5	2	0
	total	20	14	0
29.2	I	5	2	0
	II	5	2	0
	III	5	1	0
	IV	5	2	0
	total	20	7	0
52.5	I	5	2	0
	II	5	2	0
	III	5	3	0
	IV	5	2	0
	total	20	9	0

Validity criteria fulfilled:

yes

Conclusions:

The EC50 (48h) was calculated to be 11.1 mg/L with 95% confidence limits of 10.0 and 12.4 mg/L. The observed no effect concentration (NOEC) after 48 hours amounted to 5.0 mg/L. 16.2 mg/L produced 100% imobilisation after 48 hours.
The test material had an active ingredient content of 23.7%. Assuming a 100% active ingredient content, the EC50 (48h) would be 2.64 mg/L (95% CL = 2.37 - 2.94 mg/L) and the NOEC to 1.19 mg/L

Executive summary:

In a 48-hour acute toxicity study performed according to OECD TG 202, groups of 5 Daphnia magna per concentration were exposed to C14 AO under static conditions at nominal test concentrations of 0, 5, 9, 16.2, 29.2 or 52.5 mg/L (equivalent to 0, 1.19, 2.13, 3.84, 6.92 or 12.44 mg AO/L). The 48-h EC50 based on nominal concentrations was 2.63 mg AO/L.

Reference 4

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

no analysis of test concentrations during the study.

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

no

Analytical monitoring:

no

Details on sampling:

not applicable

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: Akzo Nobel Central Research, Arnhem, Dept CRL
- Age at study initiation: < 24 hrs

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

not applicable

Hardness:

Dilution water hardness was approximately 12 dH

Test temperature:

19.4-19.5 deg C

pH:

8.2 at the beginning of the test and 8.0 at the end of the test

Dissolved oxygen:

8.3-9.1 mg/L

Salinity:

not measured

Nominal and measured concentrations:

Nominal test concentrations:
Preliminary test: 0.1, 1, 10, 32 or 100 mg/l (equivalent to 0.237, 0.237, 2.37, 7.58 or 23.7 mg AO/L
Main test: 5, 9, 16.2, 29.2 or 52.5 mg/L (equivalent to 1.19, 2.13, 3.84, 6.92 or 12.44 mg AO/L)

Details on test conditions:

TEST SYSTEM
- Test vessel: beaker
- Type: covered with a glass plate
- Material: glass, 400 mL volume, filled to 250 mL
- 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
- Source/preparation of dilution water: Dutch Standard Water
- Total organic carbon: < 2 mg/L
- Metals: < 0.01 mg Cu/L
- Conductivity: < 5 uS/cm

OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod: 16 hrs ambient light per day, supplied by fluorescent tubes

EFFECT PARAMETERS MEASURED: Immobilization

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8
- Range finding study
- Test concentrations: 0.1, 1, 10, 32 or 100 mg/L
- Results used to determine the conditions for the definitive study: The highest concentration causing no immobilization within 48 hrs was 1 mg/L, while 100 % immobilization was observed at 100 mg?L after 24 hrs.

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

17.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

4.24 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mobility

Details on results:

- Mortality of control: no control animals died during the study

Results with reference substance (positive control):

not applicable

Reported statistics and error estimates:

The EC50 was calculated with a programme (Akzo Nobel programme SKBT, version 1.0) using both the binomial test method (5.3) and the trimmed Spearman-Karber method (5.4)

Table 1: Immobilization in the definitive test

 

mg of test substance/L (mg AO/L)	Test vessel No.	Number of mobile animals
		0 hrs	24 hrs	48 hrs
control	i	5	5	5
	ii	5	5	5
	iii	5	5	5
	iv	5	5	5
	Total	20	20	20
5 (1.19)	i	5	5	5
	ii	5	5	5
	iii	5	5	5
	iv	5	5	5
	Total	20	20	20
9 (2.13)	i	5	5	5
	ii	5	4	4
	iii	5	5	5
	iv	5	5	5
	Total	20	19	19
16.2 (3.84)	i	5	1	0
	ii	5	5	5
	iii	5	3	3
	iv	5	2	1
	Total	20	11	9
29.2 (6.92)	i	5	1	0
	ii	5	2	1
	iii	5	2	2
	iv	5	5	2
	Total	20	10	5
52.5 (12.44)	i	5	1	0
	ii	5	2	0
	iii	5	4	1
	iv	5	2	0
	Total	20	9	1

Validity criteria fulfilled:

yes

Executive summary:

The acute immobilisation (EC50) of C12 AO to Daphnia magna was determined according to OECD guideline 202 and EC method C.2 under static conditions over a duration of 48 h. Daphnia magna were exposed to the substance at nominal concentrations of 0, 1.19, 2.13, 3.84, 6.92 or 12.44 mg AO/L. The 48 h EC50 value, based on nominal test concentrations, was 4.24 mg AO/L

Reference 5

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

22-11-2000 to 24-11-2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

Recovery rates of the test item could not be determined because neither DOC of the test item was clearly specified nor molecular weight of the test item was specified by the sponsor.

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

not specified

GLP compliance:

yes

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
No data

Analytical monitoring:

yes

Details on sampling:

The test item concentrations were analytically verified via DOC analysis according to DIN 38409 part 3 at nominal concentrations of 20, 40 and 80 mg/L and control after 0 h (new media) and 48 h (old media).

Vehicle:

not specified

Details on test solutions:

No data

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Strain: Straus, clone 5.
- Source: Institut fur Wasser-, Boden- und Lufthygiene des Bundesgesundheitsamtes, Berlin.
- Age at study initiation: 2 - 24 h
- Method of breeding: The mother animals were removed twice within 22 h.
- Feeding frequency: 5 x weekly ad libitum mix of Scenedesmus subspicatus and Chlorella vulgaris, with an alge density of > 10E06 cells/mL.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

No data

Hardness:

Total hardness (CaCO3) of the dilution water was 262 mg/L.

Test temperature:

21 ± 1 ºC

pH:

pH at the beginning of the test (new media): 7.46 - 7.55; measured in one replicate per concentration and control.
pH at the end of the test (old media); measured in all replicates:
Replicate1: 7.44 - 7.53
Replicate2: 7.49 - 7.52
Replicate3: 7.49 - 7.55
Replicate4: 7.48 - 7.54

Dissolved oxygen:

Oxygen concentration at the beginning of the test (new media): 8.22 - 8.38 mg/L; measured in one replicate per concentration and control.
Oxygen concentration at the end of the test (old media); measured in all replicates:
Replicate1: 7.59 - 7.77
Replicate2: 4.55 - 7.71
Replicate3: 7.59 - 7.66
Replicate4: 7.52 - 7.69

Salinity:

No data

Nominal and measured concentrations:

Nominal: 5, 10, 20, 40 and 80 mg/L, equivalent to 1.5, 3, 6, 12 and 24 mg AO/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: 2 - 3 L glass vessels
- Fill volume: 20 mL
- Renewal rate of test solution: Once in 48 h
- No. of organisms per vessel: 5; 10 in the control.
- No. of vessels per concentration: 4
- No. of vessels per control: 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: According to EEC 92/69 L383A C.2.
- Conductivity: In the dilution water: 658 μS/cm
- Intervals of water quality measurement: The dissolved oxygen concentration and pH value of the test and control groups at the beginning of the test were measured in one replicate per concentration and in the control. After 48 h the water parameters of all the old media were measured. pH value, oxygen concentration, temperature, conductivity and total hardness of the dilution water were measured prior to the test start. DOC was measured in the nominal concentrations 20, 40 and 80 mg/L and control after 0 h (new media) and 48 h (old media).

OTHER TEST CONDITIONS
- Photoperiod: 16/8 light/dark cycle.
- Light intensity: Diffuse light, illumination range 1.5 to 5 μmol/m2/s.


TEST CONCENTRATIONS
- Spacing factor for test concentrations: Geometric series with a diltion factor of 2
- Range finding study
- Test concentrations: 0, 1, 10 and 100 mg/L.
- Results used to determine the conditions for the definitive study: After 48 h of exposure the total rate of immobilisation of daphnia was 100 % at the concentration of 100 mg/L. No biologically significant effect (≤ 10 %) was seen at the concentration of 1 mg/L.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate p.a.

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

17.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % CL: 15.2 - 20.3 mg/L

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

10.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % CL: 9.8 - 11.2 mg/L

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

5.25 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

3.1 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mobility

Details on results:

The 48 h EC50 of the active ingredient was calculated as 3.1 mg AO/L.

Results with reference substance (positive control):

The percentage immobility of the refrence item was determined after 24 h. The EC100 value was determined directly from the test results. EC10 and EC50 with 95 % confidence interval was determined in a probability network by interpolation according to standard procedures.
EC values after 24 h were as follows:
EC10: 1.3 mg/L
EC50: 2.0 (95% CL 1.8 - 2.0 mg/L)
EC100: 5.8 mg/L

Reported statistics and error estimates:

EC100 values were deduced directly from the dose-reponse relationship after 24 and 48 h. There was no mathematical calculation. The EC10 and EC50 values were calculated via probit analysis, according to Weber (1986). Calculation of the confidence intervals was carried out using standard procedures according to Breitig and Tumpling (1982). Calculations were performed using software SigmaPlot rel. 2000, SPSS Corporation.

Percentage of daphnids incapable of swimming after 24 and 48 h of exposure (n = 20):

Nominal Concentration [mg/L]	Immobilisation (%)
	24 h					48 h
	Replicates					Replicates
	1	2	3	4	Mean	1	2	3	4	Mean
80	100	100	100	100	100	100	100	100	100	100
40	100	80	10	60	85	100	100	100	100	100
20	60	80	60	60	65	100	100	100	100	100
10	0	40	20	0	15	0	40	20	40	25
5	0	0	0	0	0	0	0	0	0	0
Control	0	0	0	0	0	0	0	0	0	0

Validity criteria fulfilled:

yes

Conclusions:

The EC50 value of the test substance at 48 h was 10.5 mg/L (equivalent to 3.1 mg AO/L) with confidence limits of 9.8 - 11.2 mg/L.

Executive summary:

The acute immobilisation (EC50) of the substance to Daphnia magna was determined according to OECD guideline 202 and EC method C.2 under static conditions over a duration of 48 h. Daphnia magna were exposed to the substance at nominal concentrations of 0, 1.5, 3, 6, 12 and 24 mg AO/L. The 48 h EC50 value, based on nominal test concentrations, was 3.1 mg AO/L

Reference 6

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

02-05-2005 to 08-06-2005

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

not specified

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

Daphnia magna

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

14.06 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Validity criteria fulfilled:

not specified

Conclusions:

The test substance was assessed for toxicity to aquatic invertebrates according to OECD guideline 202. The EC50 was reported as 14.06 mg/L.

Reference 7

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

no analysis of test concentrations during the study.

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Details on sampling:

not applicable

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Source: Safepharm laboratories Ltd, Shardlow Business Park, London Road, Sharldow DE72 2GD, UK
- Age at study initiation: < 24 hrs
- Feeding during test: No

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

not applicable

Hardness:

The reconstituted water had an approximate theoretical total hardness of 250 mg/L CaCO3

Test temperature:

20.0-21.0 deg C

pH:

7.9-8.0

Dissolved oxygen:

7.5-8.0 mg/L

Salinity:

not measured

Nominal and measured concentrations:

Nominal concentrations:
Range finding study: 0, 0.1, 1, 110, 100 mg |AO/L
Main study: 0, 1.0, 1.8, 3.2, 5.6, 10, 18, 32, 56, 100 mg AO/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Jar
- Type: covered
- Material, size, headspace, fill volume: glass, 250 mL, 200 mL of test solution used.
- Aeration: No
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Stock solutions of CaCl2.2H2O (11.76 g/L), MgSO4.7H2O (4.93 g/L), NaHCO3 (2.59 g/L and KCl (0.23 g/L) were prepared. An aliquot (25 mL) of each of the solutions was addter to each litre (final volume) of deionised water with a conductivity of < 5 uS/cm. The reconstituted water had a pH of 7.8 +/-0.2 adjusted (if necessary) with NaOH or HCl and was aerated until the dissolved oxygen concentration was approximately air-saturation value.

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 hours light/ 8 hours dark with 20 minutes dawn and dusk transition periods.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mobility

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8
- Range finding study
- Test concentrations: 0, 0.1, 1, 10, 100 mg AO/L
- Results used to determine the conditions for the definitive study: No immobilisation was observed at the test concentrations of 0.1 and 1 mg AO/L. However immobilisation was observed at 10 and 100 mg AO/L

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

3.9 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mobility

Details on results:

- Mortality of control: no control animals were immobilised during the study

Results with reference substance (positive control):

not applicable

Reported statistics and error estimates:

The EC50 values and associated confidence limits at 24 hrs were calcualted by the maximum-likelihood probit method of Finney (1971) and at 48 hrs y the trimmed Spearman-Karber method of Hamilton et al (1977) using the ToxCalc computer software package. Probit analysis is used where two or more partial responses to expisure are shown. When only one artial response is shown the trimmed Spearman-Karber method is appropriate.

Table 1: Immobilization in the definitive test

Nominal concentration (mg AO/L)	Cumulative immobilized Daphnia (Initial population: 10 per Replicate)
	24 hrs				48 hrs
	R1	R2	Total	%	R1	R2	Total	%
0	0	0	0	0	0	0	0	0
1.0	0	0	0	0	0	0	0	0
1.8	0	0	0	0	0	0	0	0
3.2	0	0	0	0	1	2	3	15
5.6	0	0	0	0	10	10	20	100
10	5	4	9	45	10	10	20	100
18	8	9	17	85	10	10	20	100
32	10	10	20	100	10	10	20	100
56	10	10	20	100	10	10	20	100
100	10	10	20	100	10	10	20	100

Executive summary:

The acute immobilisation (EC50) of C12 AO to Daphnia magna was determined according to OECD guideline 202 and EC method C.2 under static conditions over a duration of 48 h. Daphnia magna were exposed to the substance at nominal concentrations of 0, 1.0, 1.8, 3.2, 5.6, 10, 18, 32, 56 or 100 mg AO/L. The 48 h EC50 value, based on nominal test concentrations, was 3.9 mg AO/L

Description of key information

No acute daphnia studies have been performed using C10 AO. However, studies are available for C12 AO, C14 AO and C12-14 AO. The results of these studies show a small trend for toxicity to daphnia magna to increase as chainlength increases from C12 AO to C14 AO with C12-14 AO having intermediate toxicity between the two monoconstituents.  On this basis, taking a geometric mean of the available data for C12 AO, C14 AO and C12-14 AO gives a worse case estimate of the likely toxicity of C10 AO. The estimated 48-h EC50 = 3.43 mg AO/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

3.43 mg/L

Additional information

No acute daphnia studies have been performed using C10 AO. However, data are available C12 AO, C14 AO and C12-14 AO.

Two reliable studies are available for C12 AO. In both studies, performed according to OECD TG 202, Daphnia magna were exposed to C12 AO under static conditions for 48 hours. The 48-h EC50 based on nominal concentrations were 3.9 mg AO/L [Shacklady LG (2001)] and 4.24 mg AO/L [Mark UE & Garttener-Arends ICM (1994)]. One reliable study is available for C14 AO. In this study, performed according to OECD TG 202, Daphnia magna were exposed to C14 AO under static conditions for 48 hours. The 48-h EC50 based on nominal concentrations was 2.63 mg AO/L [Mark UE (1994)]. Three reliable studies performed using Daphnia magna are available for C12-14 AO. All three studies were performed to OECD TG 202 under static conditions. The EC50 (48h) values (nominal) obtained were 3.1 mg AO/L [Noack M (2001)], 2.9 mg AO/L [Mark U & Meuwsen IJB (1990)] and 4.2 mg AO/L [Beneventi S (2005)]. 

Based on the available studies, it can be seen that there is a slight trend shown for toxicity to daphnia to increase as the alkyl chain length increases going from monoconstituent C12 AO to C14 AO with C12-14 AO having intermediate toxicity compared to C12 AO and C14 AO. On this basis, taking a geometric mean of the available data for C12 AO, C14 AO and C12-14 AO gives a worse case estimate of the likely toxicity of C10 AO. The estimated 48-h EC50 = 3.43 mg AO/L.