Reaction mass of dodecyl (S)-2-(((S)-2-hydroxypropanoyl)oxy)propanoate and dodecyl (S)-2-hydroxypropanoate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Not yet reported

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

>= 32 - <= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

loading rate WAF

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

< 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

loading rate WAF

Basis for effect:

growth rate

Details on results:

- Biologically relevant growth rate and yield inhibition (i.e. > 10 %) was recorded at all test concentrations, except for the WAF prepared at a loading rate of 1.0 mg/L.
- A dose-related increase of growth rate and yield inhibition was measured at the loading rate of 3.2 and higher, reaching 85 % growth rate inhibition and 100 % yield inhibition at the WAF prepared at a loading rate of 100 mg/L.
- Based on these results, the NOEC for both growth rate and yield inhibition is expected to lie below a loading rate of 1.0 mg/L.

PERCENTAGE INHIBITION OF GROWTH RATE DURING THE FINAL TEST

Test item loading rate WAF (mg/L)	Mean	Standard deviation	n	% inhibition
Control	1.856	0.0091	6	-
1.0	1.603	0.0533	3	14
3.2	1.832	0.0108	3	1.3
10	1.170	0.0674	3	37
32	1.147	0.0288	3	38
100	0.276	0.0133	3	85

 

PERCENTAGE INHIBITION OF YIELD DURING THE FINAL TEST

Test item loading rate WAF (mg/L)	Mean	Standard deviation	n	% inhibition
Control	260.8	7.09	6	-
1.0	122.8	20.42	3	53
3.2	242.5	7.83	3	7.0
10	32.9	7.18	3	87
32	30.3	2.67	3	88
100	1.3	0.09	3	100

ANALYTICAL RESULTS

Sampling time (hours)	Date of sampling	Date of analysis	Loading rate (mg/L)	Concentration analysed (mg/L)	Relative to initial (%)	Note
0	14 May 2018	23 May 2018	0	0.0020	Not applicable	1
0	14 May 2018	23 May 2018	1.0	0.0841	Not applicable	-
0	14 May 2018	23 May 2018	3.2	0.0050	Not applicable	1
0	14 May 2018	23 May 2018	10	0.132	Not applicable	-
0	14 May 2018	23 May 2018	10	0.134	Not applicable	ZA
0	14 May 2018	23 May 2018	32	0.126	Not applicable	-
0	15 May 2018	23 May 2018	100	0.520	Not applicable	-
24	15 May 2018	23 May 2018	0	0.0017	84	1
24	15 May 2018	23 May 2018	1.0	0.0016	1.9	1
24	15 May 2018	23 May 2018	3.2	< 0.000057	< 1.1	2
24	15 May 2018	23 May 2018	10	0.0025	1.9	1
24	15 May 2018	23 May 2018	10	0.0037	2.8	1 + ZA
24	15 May 2018	23 May 2018	32	0.0020	1.6	1
24	15 May 2018	23 May 2018	100	0.0436	8.4	-
72	17 May 2018	23 May 2018	0	0.0016	78	1
72	17 May 2018	23 May 2018	1.0	< 0.000057	< 0.07	2
72	17 May 2018	23 May 2018	3.2	0.0014	29	1
72	17 May 2018	23 May 2018	10	0.0015	1.2	1
72	17 May 2018	23 May 2018	10	< 0.000057	< 0.04	ZA + 2
72	17 May 2018	23 May 2018	32	0.0016	1.2	1
72	17 May 2018	23 May 2018	100	0.0019	0.4	1

ZA = Without Algae

1 = Estimated value, calculated by extrapolation of the calibration curve.

2 = Not detected. The limit of detection of the method was determined to be 0.057 µg/L taking a dilution factor of 2 into account.

Validity criteria fulfilled:

yes

Conclusions:

The 72-hour EC50 values are expressed in terms of loading rates. Based on growth rate, the EC50 (72 h) value is considered to lie between 32 and 100 mg/L loading rate WAF. Based on yield, the EC50 (72 h) value is considered to lie between 3.2 and 10 mg/L loading rate WAF. The NOEC for both growth rate and yield inhibition is predicted to be < 1.0 mg/L.

Executive summary:

GUIDELINE

A study was performed to assess the effect of the test item on the growth of the green alga Pseudokirchneriella subcapitata. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (2006) No 201, "Freshwater Alga and Cyanobacteria, Growth Inhibition Test" referenced as Method C.3 of Commission Regulation (EC) 761/2009.

METHODS

For the final test, Water Accommodated Fractions (WAFs) were individually prepared at loading rates of 1.0, 3.2, 10, 32 and 100 mg/L. One hour of gentle magnetic stirring was applied to accelerate dissolution of test item in test medium. The obtained mixtures were allowed to settle for a period of approximately three hours. Thereafter, the WAFs were collected by means of siphoning over glass wool and used as test concentrations. At the end of the preparation procedure, all test solutions were clear and colorless.

RESULTS

Biologically relevant growth rate and yield inhibition (i.e. > 10 %) was recorded at all test concentrations, except for the WAF prepared at a loading rate of 1.0 mg/L. A dose-related increase of growth rate and yield inhibition was measured at the loading rate of 3.2 and higher, reaching 85 % growth rate inhibition and 100 % yield inhibition at the WAF prepared at a loading rate of 100 mg/L. Based on these results, the NOEC for both growth rate and yield inhibition is expected to lie below a loading rate of 1.0 mg/L.

CONCLUSION

The 72-hour EC50 values are expressed in terms of loading rates. Based on growth rate, the EC50 (72 h) value is considered to lie between 32 and 100 mg/L loading rate WAF. Based on yield, the EC50 (72 h) value is considered to lie between 3.2 and 10 mg/L loading rate WAF. The NOEC for both growth rate and yield inhibition is predicted to be < 1.0 mg/L.

Description of key information

The 72-hour EC50 values are expressed in terms of loading rates. Based on growth rate, the EC50 (72 h) value is considered to lie between 32 and 100 mg/L loading rate WAF. Based on yield, the EC50 (72 h) value is considered to lie between 3.2 and 10 mg/L loading rate WAF. The NOEC for both growth rate and yield inhibition is predicted to be < 1.0 mg/L (OECD 201 and EU Method C.3).

Key value for chemical safety assessment

EC50 for freshwater algae:

32 mg/L

EC10 or NOEC for freshwater algae:

1 mg/L

Additional information

GUIDELINE

A study was performed to assess the effect of the test item on the growth of the green alga Pseudokirchneriella subcapitata. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (2006) No 201, "Freshwater Alga and Cyanobacteria, Growth Inhibition Test" referenced as Method C.3 of Commission Regulation (EC) 761/2009.

METHODS

For the final test, Water Accommodated Fractions (WAFs) were individually prepared at loading rates of 1.0, 3.2, 10, 32 and 100 mg/L. One hour of gentle magnetic stirring was applied to accelerate dissolution of test item in test medium. The obtained mixtures were allowed to settle for a period of approximately three hours. Thereafter, the WAFs were collected by means of siphoning over glass wool and used as test concentrations. At the end of the preparation procedure, all test solutions were clear and colorless.

RESULTS

Biologically relevant growth rate and yield inhibition (i.e. > 10 %) was recorded at all test concentrations, except for the WAF prepared at a loading rate of 1.0 mg/L. A dose-related increase of growth rate and yield inhibition was measured at the loading rate of 3.2 and higher, reaching 85 % growth rate inhibition and 100 % yield inhibition at the WAF prepared at a loading rate of 100 mg/L. Based on these results, the NOEC for both growth rate and yield inhibition is expected to lie below a loading rate of 1.0 mg/L.

CONCLUSION

The 72-hour EC50 values are expressed in terms of loading rates. Based on growth rate, the EC50 (72 h) value is considered to lie between 32 and 100 mg/L loading rate WAF. Based on yield, the EC50 (72 h) value is considered to lie between 3.2 and 10 mg/L loading rate WAF. The NOEC for both growth rate and yield inhibition is predicted to be < 1.0 mg/L.