2-amino-2-methylpropanol

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OCSPP 850.4500 (Algal Toxicity) (January 2012)

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Samples of the test solutions were collected at approximately 0 and 96 hours to measure concentrations of the test substance. At test initiation, samples were collected from each test concentration and control solution prior to distribution into the test chambers. At test termination, the biological replicates from each respective test concentration and blank control solution were pooled and then sampled. All samples were collected in glass scintillations vials and were processed immediately for analysis.

Vehicle:

yes

Details on test solutions:

A primary stock solution was prepared by mixing 0.1199 g of 2-amino-2-methyl-1-propanol in 1000 mL of saltwater algal medium, to achieve a nominal concentration of 120 mg/L (107 mg a.i./L). The primary stock was inverted at least twenty times and stirred with a magnetic stirplate and Tefloncoated stirbar to mix. The primary stock continued stirring while all subsequent dilutions were made and while pH adjustments were made. The pH of the primary stock was adjusted to 7.9 with 10% hydrochloric acid. The primary stock appeared clear and colorless and otherwise unremarkable at the time of preparation. The primary stock was then proportionally diluted with saltwater algal medium to prepare five additional test solutions at nominal concentrations of 1.2, 3.1, 7.7, 19 and 48 mg/L (equivalent to 1.1, 2.8, 6.9, 17 and 43 mg a.i./L, respectively). Test solutions were inverted to mix and appeared clear and colorless.

Test organisms (species):

Skeletonema costatum

Details on test organisms:

Original algal cultures were obtained from the Provasoli-Guillard Nation Center for Culture of Marine Phytoplankton (CCMP), and cultures had been maintained in culture medium at Wildlife International, Easton, Maryland since September 2008. Cultures were maintained at similar environmental parameters as used in the definitive test. Algal cells used in this test were obtained from Wildlife International cultures that had been actively growing in culture medium for at least two weeks prior to test initiation. Diatoms for this study were taken from a culture that had been transferred to fresh medium three days prior to test initiation.

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

103 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 103 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks on result:

other: in absence of effect at any concentration, no estimation was possible

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 103 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks on result:

other: in absence of effect at any concentration, no estimation was possible

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

> 103 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Validity criteria fulfilled:

yes

Conclusions:

In Skeletonema costatum, 72h ErC50 and ErC10 were both >103 mg/L (in absence of effect at any concentration, no estimation of the value was possible). NOECr was 103 mg/L too. All values are measured concentrations expressed as mg active substance/L.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Not applicable

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

no analytical follow-up

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

yes

Remarks:

close vessels

Principles of method if other than guideline:

Not applicable

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

The chemical was added at increasing concentrations from a test solution prepared from a continuously illuminated algae stock culture, prepared with nutrient solution, and was placed in front of a light wall. A single vessel was tested per concentration.

Test organisms (species):

Scenedesmus sp.

Details on test organisms:

No data

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Details on test conditions:

The investigations according to the guideline give false results in the case of volatile substances due to the decreasing concentration. Closing of the test vessel led to growth inhibition or death in the absence of the test material. By previous passage of CO2-enriched air and variation of the air space in the test vessel, the conditions could be optimized for the growth of the algae in the closed vessel during the 96 hour test so that the growth rate was comparable to that in an open vessel.

The chemical was added at increasing concentrations from a test solution prepared from a continuously illuminated algae stock culture, prepared with nutrient solution, and was placed in front of a light wall. The test vessels were shaken slightly from time to time in order to prevent sedimentation of the algae.

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

519 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: Probit analysis of consolidated dose-response curve (4 assays, 28 points + controls)

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

220 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: Probit analysis of consolidated dose-response curve (4 assays, 28 points + controls)

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

402 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: assay 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

540 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: assay 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

609 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: assay 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

522 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: assay 4

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: assay 1

Details on results:

Four tests were performed. NOEC was not determined. The endpoint followed is not clearly specified, but the methods cite "The determination of the algae concentrations was carried out", suggesting it may be cell number.

Results with reference substance (positive control):

Not applicable

Not applicable

Validity criteria fulfilled:

not specified

Conclusions:

In Scenedesmus, 72h EC50 ranged 402-609 mg/L across 4 assays, with overall EC50 and EC10 values of 519 and 220 mg/L, resp., expressed in test material with 10% water. The NOEC wasn't determined. The endpoint followed is not clearly specified but is probably cell number.
When expressed in active substance, this corresponds to EC10 and EC50 of 198 and 467 mg/L, resp.
All values are nominal (no analytical follow-up).

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.5400 (Algal Toxicity, Tiers I and II) (January 2012)

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Samples of the test solutions were collected at approximately 0 and 96 hours to measure concentrations of the test substance. At test initiation, samples were collected from each test
concentration and control solution prior to distribution into the test chambers. At test termination, the biological replicates from each respective test concentration and blank control solution were pooled and then sampled. All samples were collected in glass scintillations vials and were processed immediately for analysis.

Vehicle:

yes

Details on test solutions:

A primary stock solution was prepared by mixing 0.1200 g of 2-amino-2-methyl-1-propanol in
1000 mL of freshwater AAP medium, to achieve a nominal concentration of 120 mg/L (107 mg a.i./L). The primary stock was inverted at least twenty times and stirred with a magnetic stirplate and Teflon-coated stirbar to mix. The primary stock continued stirring while all subsequent dilutions were made and while pH adjustments were made. The pH of the primary stock was adjusted to 7.6 with 10% hydrochloric acid and 0.1 N sodium hydroxide. The primary stock appeared clear and colorless and otherwise unremarkable at the time of preparation. The primary stock was then proportionally diluted with freshwater AAP medium to prepare five additional test solutions at nominal concentrations of 1.2, 3.1, 7.7, 19 and 48 mg/L (equivalent to 1.1, 2.8, 6.9, 17 and 43 mg a.i./L, respectively). Test solutions were inverted to mix and appeared clear and colorless.

Test organisms (species):

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

Details on test organisms:

Original algal cultures were obtained from the University of Toronto Culture Collection (UTCC#37), and cultures had been maintained in culture medium at Wildlife International, Easton, Maryland. The cultures were maintained at similar environmental parameters as used in the definitive test. Algal cells used in this test were obtained from Wildlife International cultures that had been actively growing in culture medium for at least two weeks prior to test initiation. Algal cells for this study were taken from a culture that had been transferred to fresh medium three days prior to test initiation.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

6.6 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 103 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks on result:

other: estimated as 789 mg/L by probit analysis

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

68.8 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks on result:

other: estimated by probit analysis

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

> 103 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Validity criteria fulfilled:

yes

Conclusions:

In Pseudokirchneriella subcapitata, 72h ErC50 was >103 mg/L (indicatively calculated as 789 mg/L using probit). NOECr and ErC10 values were 6.6 and 68.8 mg/L, resp. All values are measured concentrations expressed as mg active substance/L.

Description of key information

All available studies evidence negligible acute toxicity to algae. 72h NOEC, EC10 and EC50 values were:

• not determined, 198 and 467 mg/L in freshwater species Scenedesmus (endpoint not specified but probably cell number; values are nominal).


• 6.6, 68.8 and >103 mg/L (the latter estimated as 789 mg/L) in freshwater species Pseudokirchneriella subcapitata (growth rate; measured concentrations).


• 103, >103 and >103 (in absence of effect at any concentration, no estimation possible) in marine species Skeletonema costatum (growth rate; measured concentrations).

All values are expressed as mg active substance/L. In the two studies with analytical follow-up, measured concentrations at 0h and 96h were all >= 81% of nominal values, demonstrating the stability in both fresh- and saltwater media. In the 1989 study on Scenedesmus, reported nominal EC10/NOECs were converted into active substance equivalents taking into account the water content of the test item.

The data evidence similar sensitivity of freshwater and marine species.

Key value for chemical safety assessment

EC50 for freshwater algae:

467 mg/L

EC10 or NOEC for freshwater algae:

68.8 mg/L

EC10 or NOEC for marine water algae:

103 mg/L