Aluminium triisopropanolate

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to microorganisms, other

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:

according to guideline

Guideline:

ISO 10712 (Water quality – Pseudomonas putida growth inhibition test (Pseudomonas cell multiplication inhibition test

Version / remarks:

ISO 107122-1994 Water quality – Pseudomonas putida growth inhibition test
(Pseudomonas cell multiplication test).

GLP compliance:

not specified

Remarks:

data published

Specific details on test material used for the study:

purity > 98%

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

test solutions were prepared in water and sonicated for 30 minutes to prevent aggregation. Further dilutions were prepared in according to ISO 107122-1994

Test organisms (species):

Pseudomonas putida

Details on inoculum:

- Laboratory culture: laboratory activated sludge (Department of Biology, Faculty of Building Services, Hydro and Environmental Engineering, Warsaw University of Technology)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

16 h

Test temperature:

26°C

Nominal and measured concentrations:

0.17 to 200 mg/L (serial dilution with factor 2)

Details on test conditions:

TEST SYSTEM: no details provided according to guidline

TEST MEDIUM / WATER PARAMETERS accoding to the guideline

Duration:

16 h

Dose descriptor:

EC50

Effect conc.:

295.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: 156.5 mg/L as Al

Duration:

16 h

Dose descriptor:

NOEC

Effect conc.:

1.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: 1.0 mg/L as Al

Details on results:

the results of the nano material indicated an increased toxicity with an EC50 of 0.5 mg/L and a NOEC of 0.19 mg/L

Reported statistics and error estimates:

Effective concentrations (EC50) were calculated using probit analysis with 95% confidence intervals [25]. No observed effect concentrations (NOEC) were determined using ANOVA and Tukey’s test

Validity criteria fulfilled:

not specified

Conclusions:

The EC50 of aluminium oxide in pseudonomas putida is 295 mg/L (165.5 mg/L as Al)

Executive summary:

In a standard test in pseudonomas putida, the bacteria were exposed to concentrations of alumium hydroxide between 0.17 and 200 mg/L for 16 hours. Effects on bacterial growth became apparent above 1.9 mg/L. The EC50 is 295 mg/L (165.5 mg/L as Al)

Reference 2

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1980

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study without detailed documentation.

Qualifier:

equivalent or similar to guideline

Guideline:

DIN 38412-8 (Pseudomonas Zellvermehrungshemmtest)

Deviations:

not specified

Principles of method if other than guideline:

The concentration of the bacterial suspension is measured turbidimetrically; it is expressed by the extinction of the primary light of the monochromatic radiation at 436 nm for a layer of 10 mm thickness. The concentration at which the inhibitory action of a pollutant starts will be present in that step of a dilution series of the pollutant having an extinction value at the end of the test period that is ≥ 3% below the mean value of extinction for non-toxic dilutions of the test cultures.

GLP compliance:

no

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Aluminium tri-isopropylate reacts instantaneously with water to form 2-propanol 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 tri-isopropylate is abiotically degradable and forms 2-propanol being readily biodegradable as shown in the registration dossier of 2-propanol submitted by the same lead registrant. Thus, 2-propanol is the ideal surrogate for testing toxicity effects on sludge microorganisms posed by the organic moiety of the reference substance.

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

Before preparing the test cultures neutralize the pollutant solution having a known content in sterile double-distilled water to be tested by using the minimum volume of acid or alkaline solution. The initial concentration of the pollutant solution was not reported.

From this pollutant solution, prepare four parallel dilution series in 300 ml Erlenmeyer flasks, stoppered with cotton-lined plastic caps. Each of the dilutions contains 1 part v/v of polutant solution in 2E0 to 2E14 parts v/v mixture. Prepare the dilution series as follows: the first flask of each series contains 160 ml of pollutant solution at the start. Starting from this flask prepare the subsequent dilution steps at a constant dilution ratio by consistently mixing 80 ml of preliminary pollutant dilution and 80 ml double distilled water. Consequently, each flask contains 80 ml of culture liquid at the start. Make up each flask of the three dilution series to be inoculated to 100 ml by adding 5 ml each of stock solution I, 5 ml of stock solution II and 10 ml each of the prepared bacterial suspension from the preliminary culture having a known adjusted extinction value.

Test organisms (species):

Pseudomonas putida

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

16 h

Hardness:

not reported

Test temperature:

25 ºC

pH:

not reported

Dissolved oxygen:

not reported

Salinity:

freshwater

Nominal and measured concentrations:

2 E0 to 2 E14 parts v/v mixture

Details on test conditions:

Following inoculation, the extinction value of the monochromatic radiation at 436 nm for a 10-mm layer of the bacterial suspension of the test cultures will correspond to the extinction value of the Formazin standard suspension TE/F/436 nm = 10.

Leave both inoculated and non-inoculated dilution series at 25ºC for 16 hours. After termination of the test period measure the extinction of the monochromatic radiation at 436 nm in a 10-mm layer in the inoculated dilution series.

Nutrient medium (for stock and preliminary cultures)
Dissolve in 1000 ml double -distilled water:
1.060 g sodium nitrate, NaNO3
0.600 g dipotassium hydrogen phosphate, K2HPO4, anhydrous
0.300 g potassium dihydrogen phosphate, KH2PO4
0.200 g magnesium sulphate, MgSO4.7 H2O
10.000 g D(+) glucose
18.00 g Difco Bacto agar
0.010 g ferrous sulphate, FeSO4.7 H2O
1.5 ml trace elements solution.

Sterilize the solution in a steam sterilizer for 1.5 hours, after which add 3 ml of vitamin solution.

Trace elements solution (in grams per liter of double-distilled water)
0.055 Al2(SO4)3.18 H2O
0.028 KI
0.028 KBr
0.055 TiO2
0.028 SnCl2.2 H2O
0.028 LiCl
0.389 MnCl2.4 H2O
0.614 H3BO3
0.055 ZnSO4.7 H2O
0.055 CuSO4.5 H2O
0.059 NiSO4.6 H2O
0.055 Co(NO3)2.6 H2O

Vitamin solution
0.2 mg biotin (as D+ biotin)
2.0 mg nicotinic acid
1.0 mg thiamine (as thiamine HCl)
1.0 mg p-aminobenzoic acid
0.5 mg panthothenic acid (as D-panthothenic acid, Na-salt)
5 mg pyridoxamine (as pyridoxamine dihydrochloride)
2.0 mg cyanocobalamin (vitamin B12)
100 ml double distilled water

Fill 6 ml each of the nutrient medium into culture tubes, sterilize the latter in a steam sterilizer by fractionated sterilization (three times) for 30 min. Let solidify in slant position.

Stock solution I
20.000 g D(+) glucose
4.240 g sodium nitrate, NaNO3
2.400 g dipotassium hydrogen phosphate, K2HPO4 anhydrous
1.200 g potassium dihydrogen phosphate, KH2PO4
30 ml trace elements solution.

Dissolve glucose and nutrient salts separately in 500 ml double-distilled water each, sterilize in a steam sterilizer for 30 min and unite solutions when cooled.

Stock solution II
Dissolve:
0.200 g ferrous sulphate, FeSO4.7 H2O
4.000 g magnesium sulphate MgSO4.7 H2O

in 1000 ml sterile double distilled water.

Saline
Dissolve:
0.500 g sodium chloride, NaCl

in 1000 ml double-distilled water. Sterilize solution in a steam sterilizer for 30 min.

Reference substance (positive control):

no

Duration:

16 h

Dose descriptor:

other: Toxicity threshold

Effect conc.:

1 050 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

other: mean extinction value

Details on results:

For evalution of the toxicological findings at the end of the test period, the mean value (A) of the extinction is calculated for all test cultures that are free from both toxic influence and stimulation of growth except for those having extinction values outside a standard deviation of <3% and also, the mean value (B) of the extinction for those test cultures having the lowest toxic pollutant concentration within the dilution series.

For mathematical evaluation, (a) (highest non-toxic pollutant concentration) is plotted against (A) and (b) (lowest toxic pollutant concentration) against (B) as coordinates. After having entered (A - 3%), the pollutant concentration at which the inhibitory action (c) begins may be obtained from the regression line between (a;A) and (b;B) if a negative deviation of the mean extinction by a 3% difference against the mean extinction value of all test cultures having a non-toxic and non-stimulating pollutant concentration is used as an indicator of the beginning of inhibitory action.

Validity criteria fulfilled:

not applicable

Conclusions:

The toxicity threshold (EC3) for 2-propanol is 1050 mg/l following 16 hours exposure.

Executive summary:

According to the ECHA Guidance on information requirements and chemical safety assessment, Chapter R.7b: Endpoint specific guidance section R.7.8.17.1 Laboratory data on toxicity on STP microorganisms, results of the cell multiplication inhibition test with P. putida (Bringmann and Kühn 1980) can be used for calculation of the PNECmicro-organisms.

Description of key information

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

In a standard test in pseudonomas putida, the bacteria were exposed to concentrations of aluminium hydroxide between 0.17 and 200 mg/L for 16 hours. Effects on bacterial growth became apparent above 1.9 mg/L. The EC50 is 295 mg/L (165.5 mg/L as Al) (Doskocz 2017).

The toxicity threshold (EC3) for 2-propanol for the bacterial strain Pseudomonas putida by a cell multiplication inhibition test during 16 hours to be 1050 mg/L (Bringmann 1980)

Key value for chemical safety assessment

EC50 for microorganisms:

165 mg/L

Additional information

Aluminium tri-isopropanolate reacts instantaneously with water to form isopropanol 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.

Aluminium tri-isopropanolate is abiotically degradable and forms isopropanol being rapidly biodegradable as shown in a publication by Bridie (1979).

Hence, both isopropanol 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 tri-isopropanolate.