Aluminium tributanolate

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:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

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

GLP compliance:

not specified

Remarks:

Information on GLP is not reported. Quality of the report implies that GLP conditions were met.

Specific details on test material used for the study:

AlCl3x6H2O, Ajax Finechem, Univar, AR grade)

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

seawater

Details on test solutions:

Bioassay test solutions werde prepared in triplicate using filtered seawater with nutrients added and incubated for 72h at 21°C in 12:12 h light/dark cycle.Cells were harvested from cultures in their exp growth phase (5-6d) and rinsed 3 times in seawter using centrifugation to remove residual culture media. Initial algal coonc were 2x10exp4 cells/mL to 4x10exp4 cells/mL for C. closterium and 2x10exp3 to 4x10exp3 cells/mL for the other species. Flasks were shaken manually twice a day and positioned randomly to account for light and temperature gradients. The algal conc was measured daily using flow cytometry. Growth rate was calculated as the slope of the linear regression of log10 algal cell conc vs time and was used in deriving the chronic effect value for algal growth inhibition. The test was acceptable if the control growth rate was >1 doubling/d and the control growth rate coeefeicient of variation was <10%, and the inhib conc, 50% (IC50) for the copper reference test was within 2SD of the mean.

Test organisms (species):

other: Ceratoneis closterium (formerly Nitzschia closterium), Minutocellus polymorphus, Dunaliella tertiolecta, Tetraselmis sp.

Details on test organisms:

The C. closterium cells were gently homogenized to reduce clumping of cells priot to counting. Inspection of cells under the microscope before and after homogenizing confirmed no damage to cells and reduced clumping. Homogenization was not needed for the other species.

Test type:

static

Water media type:

saltwater

Total exposure duration:

72 h

Test temperature:

21°C

pH:

8.2

Dissolved oxygen:

100 % saturation (±4% SD)

Nominal and measured concentrations:

10-100000µg Al/L nominal

Reference substance (positive control):

yes

Remarks:

CuSO4x5H2O

Duration:

72 h

Dose descriptor:

IC10

Effect conc.:

1 400 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element (total fraction)

Basis for effect:

growth rate

Remarks on result:

other: Dunaliella tertiolecta

Duration:

72 h

Dose descriptor:

IC50

Effect conc.:

1 100 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element (dissolved fraction)

Basis for effect:

growth rate

Remarks on result:

other: Dunaliella tertiolecta

Duration:

72 h

Dose descriptor:

IC10

Effect conc.:

18 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element (total fraction)

Basis for effect:

growth rate

Remarks on result:

other: Ceratoneis closterium

Duration:

72 h

Dose descriptor:

IC10

Effect conc.:

690 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element (total fraction)

Basis for effect:

growth rate

Remarks on result:

other: Minutocellus polymorphus

Duration:

72 h

Dose descriptor:

IC10

Effect conc.:

3 200 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element (total fraction)

Basis for effect:

growth rate

Remarks on result:

other: Tetraselmis sp.

Duration:

72 h

Dose descriptor:

IC10

Effect conc.:

1 300 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element (dissolved fraction)

Basis for effect:

growth rate

Remarks on result:

other: Tetraselmis sp.

Details on results:

The toxicity of Al to the chronic growth rate of marine microalgae as quantified by the IC10 was species specific, with greater effects on diatoms relative to green algae. The microalgal species ranked in sensitivity to Al as follows: C. closterium ) > M. polymorphus > D. teriolecta > Tetraselmis sp.
Toxicity appears to be more strongly related to dossolved Al with potential contributions from particulate Al at total concentations of <100µg/L.
For D tertiolecta, there was a sharp drop in algal growth tae above 890 µg total Al/L. Growth rate reached 50% of the control where dissolved Al reached a max of 1700 µg/L and total Al conc exceeded 4000 µg/L. This region of the the concentration-response curve was dominated by particulate Al and there was little change in dssolved Al conc with increasing total Al concentration. Growth rate eclined further to 30% of control when total Al reached 43000 µg/L. Growth rates showed the best relationship with total Al, suggesting that a combination or particulate and dissolved forms contribute to toxicity.

Reported statistics and error estimates:

Concnentration-response curves were constructed using the biological effect as a funtion of the measure Al conc data from the bioassay. The IC50 for each organisms was determined by nonlinear regression using R package drc (2.3-0). The package uses log-logistic and Weibull models. The 95% confidence limits on the toxicity values were genrated using the delta method of estimating the asmptotic standard error and the approp t-distribution.

Conclusions:

In the present study, IC10 and IC50 for Dunaliella tertiolecta are 1400 and 4200 µg Al/L for total Al concentration. For dissolved Al conc, IC10 and IC50 for Dunaliella tertiolecta are 960 and 1100 µg Al/L. The studies showed that dissolved forms of Al dominate below approx 500 µg/L.. Above 1000 µg/L particulate Al hydroxide becomes increasingly dominant. Thus, the authors conclude that Dunaliella tertiolecta was affected by a combination of dissolved and particulate Al species.
In conclusion, the derived IC values are above the water solubility of the relevant Al species in the frame of the experimental conditions.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

no

Specific details on test material used for the study:

no data

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

diluted in distilled water

Test organisms (species):

Stichococcus sp.

Details on test organisms:

TEST ORGANISM: Monoraphidium Monoraphidium dybowskii and Stichococcus sp.
- Source: from slightly acidified Swedish lakes
- Age of inoculum (at test initiation):
- Method of cultivation: grown in erlenmeyer flasks (at 25 °C and continuous light 100 uE/m2s), reinoculated once weekly --> exponentially growing

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

10 d

Remarks on exposure duration:

10-12 days

pH:

tests at pH 5.0, 5.5 and 6.0

Nominal and measured concentrations:

0, 0.10, 0.18, 0.32, 0.56, 1.00 and 1.80 mg/L as Al,

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flask
- Aeration: no data
- Initial cells density: 10E7 cells/L
- Control end cells density: ca 10E9 (taken from figure in the publication)
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

GROWTH MEDIUM
- Standard medium used: no data

TEST MEDIUM / WATER PARAMETERS: similar to growth medium

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: particle counter (Coulter counter)
- Other: cell size of living cells

Duration:

12 d

Dose descriptor:

EC50

Effect conc.:

1.1 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Basis for effect:

growth rate

Remarks on result:

other: for Monoraphidium dybowskii

Duration:

10 d

Dose descriptor:

EC50

Effect conc.:

0.54 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Basis for effect:

growth rate

Remarks on result:

other: for Stichococcus sp

Duration:

12 d

Dose descriptor:

NOEC

Effect conc.:

0.04 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Basis for effect:

growth rate

Remarks on result:

other: for Monoraphidium dybowskii

Duration:

10 d

Dose descriptor:

NOEC

Effect conc.:

0.23 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Basis for effect:

growth rate

Remarks on result:

other: for Stichococcus sp

Duration:

12 d

Dose descriptor:

NOEC

Effect conc.:

0.1 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Basis for effect:

other: cell decomposition

Remarks on result:

other: for both algae species

Conclusions:

The EC50 for growth rate in both algae species tested is 0.54-1.1 mg/L
The NOEC is 0.04-0.23 mg/L

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1978

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study well documented, meets generally accepted scientific principles, acceptable for assessment. However no guideline was followed.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Cell multiplication inhibition test:
The presence of a toxic substance in dissolved water inhibits the cell division of the algae. Therefore, under identical conditions, the increase of the cell count of a test culture containing dissolved toxic substances will be less than the increase of the cell count in a test culture free from toxic substance. The concentration of the algal suspension was measured turbidimetrically (extinction of the primary light of the monochromatic radiation at 578 nm for a layer of 10 mm thickness). The toxicity threshold is defined as the concentration at which the mean extinction value is 3% below the mean value of the extinction value for the control test cultures (non-toxic dilutions) at the end of the test period.

GLP compliance:

no

Remarks:

Study performed before the introduction of GLP

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Microcystis aeruginosa

Details on test organisms:

Stock cultures of the test strain Microcystis aeruginosa were prepared in 100ml flasks containing 20 ml of a nutrient solution 1 (see detailed composition in the section "any information on materials and methods") closed with a metal cap. The cultures were incubated for 10 days with a continuous exposure to artificial light (luminescent worm white tubes kept at a distance of 60 cm from each other) at 27°C and at a relative humidity of 50% for 10 days. The cultures were maintained by inoculating 20 ml of freshly prepared and sterilized nutrient solution 1 with 2 ml of the 10 day-cell suspension.

Preliminary cultures were prepared under identical conditions and kept for 10 days. The algae were isolated from the culture solutions by membrane filtration, rinsed and rediluted with 100 ml of sterile double-distilled water. The algal suspension were diluted once more with sterile double-distilled water to obtain final suspensions presenting a turbidity value (extinction of the monochromatic radiation at 578 nm) equal to the Formazin standard suspension TE/F/578 nm=20.

Test type:

static

Limit test:

no

Total exposure duration:

8 d

Test temperature:

27°C

pH:

7.0

Details on test conditions:

Stock cultures of the test strain were prepared in 100ml flasks containing 20 ml of a nutrient solution 1 (see detailed composition in the section "any information on materials and methods") closed with a metal cap. The cultures were incubated for 10 days with a continuous exposition to artificial light (luminescent worm white tubes kept at a distance of 60 cm from each other) at 27°C and at a relative humidity of 50% for 10 days. The cultures were maintained by inoculating 20 ml of freshly prepared and sterilized nutrient solution 1 with 2 ml of the 10 day-cell suspension.

Preliminary cultures were prepared under identical conditions and kept for 10 days. The algae were isolated from the culture solutions by membrane filtration, rinsed and rediluted with 100 ml of sterile double-distilled water. The algal suspension were diluted once more with sterile double-distilled water to obtain final suspensions presenting a turbidity value (extinction of the monochromatic radiation at 578 nm) equal to the Formazin standard suspension TE/F/578 nm=20.

An initial solution of Äthylamylketon was prepared, neutralised if required and two parallel dilution series were prepared in 300 ml flasks. The first flask contained 80 ml of the initial solution containing the test substance. Subsequent dilutions were prepared from this first flask using a constant dilution ratio of 40 ml preliminary n-butanol dilution with 40ml of double-distilled water. Each flask contained 40ml of liquid and were completed with 5 ml of the stock solution 1 and inoculated with 5 ml of the algal suspension having a given turbidity. Blank solutions (controls) were prepared by adding 5 ml of the stock solution 2 and 5 ml of double-distilled water to 40 ml of the liquid containing the different concentrations of the test substance.

The experiments were conducted in triplicates: 10ml of the suspension (or control) were transferred in 3 Kapsenberg culture tubes (18x180mm) and stoppered with metal caps. The cultures and controls were incubated under the same experimental conditions as for stock cultures and shaked once a day. After 7 days of incubation, the test tubes were shaked intensively before measurement of the extinction of the monochromatic radiation at 578nm in a 10mm layer of the cell suspension using controls as blank.

Duration:

8 d

Dose descriptor:

other: TT

Effect conc.:

ca. 100 mg/L

Nominal / measured:

nominal

Basis for effect:

biomass

Details on results:

Toxicity threshold (TT) obtained in a cell multiplication inhibition test for Microcystis aeruginosa. In the publication the ratio of TT for green algae (scenedesmu quadricauda) vs Microcystis aeruginosa was provided as 9/1

For the graphic evalutation of the results, the mean value (A) of the extinction for the test cultures free from both toxic influence and stimulation of growth (with the exception of those having extinction values outside a standard deviation of < 3%) and the mean value (B) for the extinction for the test cultures having the lowest toxic pollutant concentration within the dilution series were calculated at the end of the test period.

For mathematical evaluation, the highest non-toxic poIlutant concentration (a) was plotted against (A) and the lowest toxic pollutant concentration (b) was plotted against (B) as coordinates in a semi-logarithmic coordinate system. With the assumption that a negative deviation of the mean extinction by a 3% difference against the mean extinction value for all test cultures having a non toxic and non-stimulating pollutant concentration may be used as an indicator of the beginning of inhibitory action, the pollutant concentration at which the inhibitory effect was beginning (c) was deduced from the regression line between (a; A) and (b;B) using the extinction value (A-3%) as ordinate.

Validity criteria fulfilled:

not specified

Conclusions:

The following results was determined for 1-butanol (species: Microcystis aeruginosa): TT(8d)= 312 mg/L.

Executive summary:

Toxicity threshold of the test substance 1-butanol was determined for Microcystis aeruginosa (blue algea) by a cell multiplication inhibition test. The toxicity threshold concentration (greater or equal 3% lower measured light extinction in cell suspension in comparison to control) can therefore be interpreted as an EC03 value which represents a worst-case for a EC10 value. The following result was determined for 1-butanol (species: Microcystis aeruginosa): TT(8d)= 100 mg/L.

Reference 4

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1978

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study well documented, meets generally accepted scientific principles, acceptable for assessment. However no guideline was followed.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Cell multiplication inhibition test:
The presence of a toxic substance in dissolved water inhibits the cell division of the algae (Scenedesmus quadricauda). Therefore, under identical conditions, the increase of the cell count of a test culture containing dissolved toxic substances will be less than the increase of the cell count in a test culture free from toxic substance. The concentration of the algal suspension was measured turbidimetrically ( extinction of the primary light of the monochromatic radiation at 578 nm for a layer of 10 mm thickness). The toxicity threshold is defined as the concentration at which the mean extinction value is = 3% below the mean value of the extinction value for the control test cultures (non-toxic dilutions) at the end of the test period.

GLP compliance:

no

Remarks:

Study performed before the introduction of GLP

Vehicle:

no

Test organisms (species):

Scenedesmus quadricauda

Details on test organisms:

Scenedesmus quadricauda were grown in 20 ml nutrient solution in 100 ml flasks closed with a metal caps and exposed to constant lighting by luminescent white tubes at 27°C and a relative humidity of 50%. The cultures were maintained by inoculating 2ml of cell supspension in 20 ml of freshly prepared ans sterilised nutrient solution I in 100ml flasks every 10 days.

Stock cultures of the test strain were prepared in 100ml flasks containing 20 ml of a nutrient solution 1 (see detailed composition in any information on materials and methods below) closed with a metal cap. The cultures were incubated for 10 days with a continuous exposition to artificial light (luminescent worm white tubes kept at a distance of 60 cm from each other) at 27°C and at a relative humidity of 50% for 10 days. The cultures were maintained by inoculating 20 ml of freshly prepared and sterilized nutrient solution 1 with 2 ml of the 10 day-cell suspension.

Preliminary cultures were prepared under identical conditions and kept for 10 days. The algae were isolated from the culture solutions by membrane filtration, rinsed and rediluted with 100 ml of sterile double-distilled water. The algal suspension were diluted once more with sterile double-distilled water to obtain final suspensions presenting a turbitdity value (extinction of the monochromatic radiation at 578 nm) equal to the Formazin standard suspension TE/F/578 nm=20.

Test type:

static

Limit test:

no

Total exposure duration:

8 d

Test temperature:

27°C

pH:

7.0

Details on test conditions:

Stock cultures of the test strain were prepared in 100ml flasks containing 20 ml of a nutrient solution 1 (see detailed composition in any information on materials and methods below) closed with a metal cap. The cultures were incubated for 10 days with a continuous exposition to artificial light (luminescent worm white tubes kept at a distance of 60 cm from each other) at 27°C and at a relative humidity of 50% for 10 days. The cultures were maintained by inoculating 20 ml of freshly prepared and sterilized nutrient solution 1 with 2 ml of the 10 day-cell suspension.

Preliminary cultures were prepared under identical conditions and kept for 10 days. The algae were isolated from the culture solutions by membrane filtration, rinsed and rediluted with 100 ml of sterile double-distilled water. The algal suspension were diluted once more with sterile double-distilled water to obtain final suspensions presenting a turbitdity value (extinction of the monochromatic radiation at 578 nm) equal to the Formazin standard suspension TE/F/578 nm=20.

An initial solution of the test substance was prepared, neutralised if required and two parallel dilution series were prepared in 300 ml flasks. The first flask contained 80 ml of the initial solution containing the test substance. Subsequent dilutions were prepared from this first flask using a constant dilution portion of 40 ml preliminary n-butanol dilution with 40ml of double-distilled water. Each flask contained 40ml of liquid and were completed with 5 ml of the stock solution 1 and inoculated with 5 ml of the algal suspension having a given turbidity. Blank solutions (controls) were prepared by adding 5 ml of the stock solution 2 and 5 ml of double-distilled water to 40 ml of the liquid containing the different concentrations of the test substance.

The experiments were conducted in triplicates: 10ml of the suspension (or control) were transferred in 3 Kapsenberg culture tubes (18x180mm) and stoppered with metal caps. The cultures and controls were incubated under the same experimental conditions as for stock cultures and shaken once a day. After 7 days of incubation, the test tubes were shaken intensively before measurement of the extinction of the monochromatic radiation at 578nm in a 10mm layer of the cell suspension using controls as blank.

Duration:

8 d

Dose descriptor:

other: TT

Effect conc.:

875 mg/L

Nominal / measured:

nominal

Basis for effect:

biomass

Details on results:

Toxicity threshold (TT) obtained in a cell multiplication inhibition test for Scenedesmus quadricauda

For the graphic evalutation of the results, the mean value (A) of the extinction for the test cultures free from both toxic influence and stimulation of growth (with the exception of those having extinction values outside a standard deviation of < 3%) and the mean value (B) for the extinction for the test cultures having the lowest toxic pollutant concentration within the dilution series were calculated at the end of the test period.

For mathematical evaluation, the highest non-toxic poIlutant concentration (a) was plotted against (A) and the lowest toxic pollutant concentration (b) was plotted against (B) as coordinates in a semi-logarithmic coordinate system. With the assumption that a negative deviation of the mean extinction by a 3% difference against the mean extinction value for all test cultures having a non toxic and non-stimulating pollutant concentraion may be used as an indicator of the beginning of inhibitory action, the pollutant concentration at which the inhibitory effect was beginning (c) was deduced from the regression line between (a; A) and (b;B) using the extinction value (A-3%) as ordinate.

Validity criteria fulfilled:

not specified

Conclusions:

The following result was determined for 1-butanol (species: Scenedesmus quadricauda): TT(8d)= 875 mg/L.

Executive summary:

Toxicity threshold of n-butanol was determined for Scenedesmus quadricauda (green algea) by a cell multiplication inhibition test. The toxicity threshold concentration (greater or equal 3% lower measured light extinction in cell suspension in comparison to control) can therefore be interpreted as an EC03 value which represents a worst-case for a EC10 value. No EC50, that is used for classification, was derived in these tests. The following result was determined for 1-butanol (species: Scenedesmus quadricauda): TT(8d)= 875 mg/L.

Description of key information

Aluminium tributanolate dissociates instantaneously when exposed to water forming butan-1-ol and soluble aluminium(III) species. Therefore the effects of both hydrolysis products are considered most relevant to assess the toxicity of aluminium tributanolate.

For Chlorella sp. the 72 h EC50 values for bulk alumina is 110.2 mg/L. was noted. For Scenedesmus sp. the 72 h EC50 values was 100.4 mg/l. A concentration-dependent decrease in total chlorophyll content was observed in both species (Sadiq 2011).

The EC50 for growth rate in fresh water species Monoraphidium dybowskii and Stichococcus sp. is 0.54-1.1 mg/L. The NOEC is 0.04-0.23 mg/L (Claesson 1988).

The toxicity of Al to the chronic growth rate of marine microalgae was assessed with IC10 values between 18 and 3200 µg Al/L. The microalgal species ranked in sensitivity to Al as follows: C. closterium > M. polymorphus > D. teriolecta > Tetraselmis sp. Toxicity appears to be more strongly related to dissolved Al with potential contributions from particulate Al at total concentrations of <100 µg/L (Golding 2015). 72h IC10 for P. tricornutum (marine species) was 2100 (2000-2000) µg/L and IC50 was >9500 µg/L.  Toxicity to this diatom was due predominantly to precipitated aluminium under the test conditions (Gillmore 2016).

The toxicity threshold of n-butanol was determined as 875 mg/L for Scenedesmus quadricauda (green algea) by a cell multiplication inhibition test during 8 days (Bringmann 1977/1980). For Microcystis aeruginosa(blue algae) a TT(8d) of 100 mg/L was derived (Bringmann 1978).

Key value for chemical safety assessment

EC50 for freshwater algae:

0.54 mg/L

EC10 or NOEC for freshwater algae:

40 µg/L

EC10 or NOEC for marine water algae:

18 µg/L

Additional information

Aluminium tributanolate reacts instantaneously with water to form butan-1-ol and Al3+ species. The resulting pH being weakly alkaline indicates according to Langmuir et al. 2004 that Al3+ species formed are mainly Al(OH)4-, Al(OH)3 and Al(OH)2+ at pH 8.5.

Thus, aluminium tributanolate is abiotically degradable and forms butanol being readily biodegradable as shown in several publications (Bridie 1979, Price 1974).

Hence, both butanol and aluminium species will be present in aqueous media. Based on its toxicity, aluminium species seem to represent a worst case surrogate for assessing toxicity to aquatic species exposed to the substance, aluminium tributanolate.