Carboxylic acids, di-, C4-6

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Qualifier:

according to guideline

Guideline:

ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)

Version / remarks:

, Draft 1984

GLP compliance:

not specified

Analytical monitoring:

no

Test organisms (species):

activated sludge, industrial

Details on inoculum:

Trockensubstanz: 5g/L

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

30 min

Test temperature:

room temperature: 20-25°C

Nominal and measured concentrations:

nominal

Duration:

30 min

Dose descriptor:

other: EC20

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Conclusions:

An EC20 of >100 mg/L was observed.

Executive summary:

A test with activated sludge with a duration of 0.5 hours was performed according to the ISO method 8192. An EC20 of >100 mg/L was observed.

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: test material was adipic acid residue

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

no

Analytical monitoring:

no

Test organisms (species):

activated sludge

Details on inoculum:

- Initial biomass concentration: 6.0 g/L (dry weight)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

pH:

7.3 - 8.0

Nominal and measured concentrations:

nominal concentrations: 1000, 1800, 3200, 5600 and  10000 mg/l

Details on test conditions:

Type: aquatic

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

7 910 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Conclusions:

An EC50 of 7910 mg/L was observed.

Executive summary:

A test with activated sludge with a duration of 3 hours was performed according to the OECD TG 209. An EC50 of 7910 mg/L was observed.

Reference 3

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Read-Across from glutaric acid, which is a structural analogue and serves well as a representative substance for the carboxylic acid mixture.

Principles of method if other than guideline:

Growth Impairment Test
Test was performed according to the method described by Schultz TW (1997) TETRATOX: Tetrahymena pyriformis population growth impairment endpoint. A surrogate for fish lethality. Toxicol. Methods 7, 289-309

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

The solvent DMSO has low toxicity to tetrahymena, low volatility, and high ability to dissolve most organic chemicals. (Concentration : 0.75 % DMSO) This concentration shows no effect on Tetrahymena growth.

Test organisms (species):

Tetrahymena pyriformis

Details on inoculum:

pH 5.0 - 8.6 (optimum: 7.35)

Test type:

static

Water media type:

freshwater

Total exposure duration:

40 h

Test temperature:

27+/- 1°C

pH:

7.4 (Control cultures: pH 5.5)

Nominal and measured concentrations:

A minimum of 5 different concentration with duplicate flasks of each concentration.

Details on test conditions:

- 250 ml Erlenmeyer flask (foam-stoppered)
- containing 50 mL sterile, semidefined proteose-peptone-based medium
- inoculated with an initial density: 1000 - 5000 cells/mL, currently ca. 2500 cells/mL
- duplicate controls
- blank

Duration:

40 h

Dose descriptor:

other: inhibitory growth concentration IGC50

Effect conc.:

591.02 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: Adipic acid

Duration:

40 h

Dose descriptor:

other: inhibitory growth concentration IGC50

Effect conc.:

574.98 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: Glutaric acid

Duration:

40 h

Dose descriptor:

other: inhibitory growth concentration IGC50

Effect conc.:

1 027.32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: Succinic acid

Details on results:

The IGC50 is calculated by probit analysis.
- percent control-normalized absorbance used as dependent variable
- toxicant concentration in mg/L used as the independent variable
- recording of slope and intersept of probit regression equation, Chi-squared value
- normaly Chi-squared value > 0.9

- population density is measured spectrophotometrically

- The 50 % inhibitory growth concentration in mg/L (IGC50) and the 95% fiducial interval are determined for each test compound.

Validity criteria fulfilled:

yes

Conclusions:

Tests on growth inhibition with Tetrahymena pyriformis (Schultz, 1997) show

the following inhibitory growth concentrations (IGC50) after 40 hours:

Adipic acid: IGC50 = 591.02 mg/L

Glutaric acid: IGC50 = 574.98 mg/L

Succinic acid: IGC50 = 1027.32 mg/L

Executive summary:

Tests on growth inhibition with Tetrahymena pyriformis (Schultz, 1997) show

the following inhibitory growth concentrations (IGC50) after 40 hours:

Adipic acid: IGC50 = 591.02 mg/L

Glutaric acid: IGC50 = 574.98 mg/L

Succinic acid: IGC50 = 1027.32 mg/L

Description of key information

An IC50 of 574.98 mg/L was determined for glutaric acid, one of the constituent of the dicarboxylic acids, in a growth inhibition test with Tetrahymena pyriformis (Schultz, 1997).

Key value for chemical safety assessment

EC50 for microorganisms:

574.98 mg/L

Additional information

Concerning the toxicity to microorganisms, there are tests with mixed inoculum and single species avaialbale using the dicarboxylic acids mixture as test substance as well as the single acids.

A test with activated sludge with a duration of 3 hours using a residue from adipic acid manufacturing is available. The test substance contains the following composition: 60 % adipic acid, 14 % glutaric acid, 6 % succinic acid, 10 % carbon, 6.5 % vanadium pentoxide, 3 % copper nitrate and 5 % copper (Bayer, 1988b). The result of EC50 = 7911 mg/l, shows that the compounds other than the dicarboxylic acids did not highly affect the microorganisms.

Another test with activated sludge with a duration of 0.5 hours was performed according to the ISO method 8192 using a dicarboxylic acids mixture without further specification as test substance. An EC20 of >100 mg/L was observed (BASF, 1988).

In a 17 hours test with the dicarboxylic acid mixture towards Pseudomonas putida according to the German standard method DIN-38412 Part 8 (Cell Multiplication Inhibition Test), an EC50 of 91 mg/l was observed (BASF AG 1990). But in this test the pH values in the test solutions ranged from 4.7 (125 mg/l) to 5.5 (3.91 mg/l). As at higher concentrations tested the pH was always <5, it cannot be excluded that the toxicity observed was due to pH effects. Therefore, the study is stated to be reliable, but should not be used for the hazard assessment.

Tests on growth impairment with Tetrahymena pyriformis (Schultz, 1997) using the single acids, adipic-, succinic- and glturaic acid as test substance, results in the following growth inhibitory

concentrations: an IC50 of 591.02 mg/L after 40 hours was found for adipic acid, for glutaric acid an IC50 of 574.98 mg/L was observed and an IC50 of 1027.32 mg/L was determined for succinic acid.