Tar acids, xylenol fraction

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to microorganisms, other

Remarks:

Tetrahymena pyriformis

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

Test procedure according to T.W. Schultz (1993) Aquatic toxicology of nitrogen heterocyclic molecules: Quantitative structure-activity relationship, in J.O. Nriagu, (Ed.) Aquatic Toxicology, Wiley, New York, 1983, 579-612.

GLP compliance:

no

Specific details on test material used for the study:

purchased from commercial sources (Aldrich Chemical Co., Milwaukee, WI, U.S.A. or Pfaltz and Bauer Inc., Sanford, CT, U.S.A.) and not repurified.

Analytical monitoring:

no

Vehicle:

yes

Remarks:

dimethylsulfoxide (DMSO)

Details on test solutions:

Due to solubility and toxicity differences, stock solutions of the individual test compounds were prepared in dimethylsulfoxide (DMSO) at a number of concentrations: 5000,
10000, 25000, or 50000 mg/L. In all cases the amount of stock solution added to the cultures was less than 0.75%. Such levels have no effect on Tetrahymena growth.

Test organisms (species):

Tetrahymena pyriformis

Details on inoculum:

Axenic cultures used.

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

60 h

Nominal and measured concentrations:

5 concentrations tested and a control

Details on test conditions:

- Cell-population levels were estimated spectrophotometrically
- Assayed in duplicate for a minimum of 3 replicates.

Reference substance (positive control):

not specified

Duration:

60 h

Dose descriptor:

IC50

Effect conc.:

130.51 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: 95% CL: 109.45 - 152.29

Reported statistics and error estimates:

Biological response was determined using probit analysis in the Statistical Analysis System software. In this analysis, Y equaled the % control absorbance and X equaled the concentration of toxicant in mg/L.

Validity criteria fulfilled:

not applicable

Reference 2

Endpoint:

toxicity to microorganisms, other

Remarks:

Tetrahymena pyriformis

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

Test procedure according to T.W. Schultz (1993) Aquatic toxicology of nitrogen heterocyclic molecules: Quantitative structure-activity relationship, in J.O. Nriagu, (Ed.) Aquatic Toxicology, Wiley, New York, 1983, 579-612.

GLP compliance:

no

Specific details on test material used for the study:

purchased from commercial sources (Aldrich Chemical Co., Milwaukee, WI, U.S.A. or Pfaltz and Bauer Inc., Sanford, CT, U.S.A.) and not repurified.

Analytical monitoring:

no

Vehicle:

yes

Remarks:

dimethylsulfoxide (DMSO)

Details on test solutions:

Due to solubility and toxicity differences, stock solutions of the individual test compounds were prepared in dimethylsulfoxide (DMSO) at a number of concentrations: 5000,
10000, 25000, or 50000 mg/L. In all cases the amount of stock solution added to the cultures was less than 0.75%. Such levels have no effect on Tetrahymena growth.

Test organisms (species):

Tetrahymena pyriformis

Details on inoculum:

Axenic cultures used.

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

60 h

Nominal and measured concentrations:

5 concentrations tested and a control

Details on test conditions:

- Cell-population levels were estimated spectrophotometrically
- Assayed in duplicate for a minimum of 3 replicates.

Reference substance (positive control):

not specified

Duration:

60 h

Dose descriptor:

IC50

Effect conc.:

168.25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: 95% CL: 140.084 - 224.53

Reported statistics and error estimates:

Biological response was determined using probit analysis in the Statistical Analysis System software. In this analysis, Y equaled the % control absorbance and X equaled the concentration of toxicant in mg/L.

Validity criteria fulfilled:

not applicable

Reference 3

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Reason / purpose for cross-reference:

reference to same study

Principles of method if other than guideline:

methanogens: CH4 release from acetate in the presence of chemical additives
aerobic heterotrophs: inhibition of respiration according to Owen WF (1979) Bioassay for monitoring biochemical methane potential and anaerobic toxicity. Water Res. 13, 485 (prolonged incubation compared with ISO 8192)

GLP compliance:

no

Analytical monitoring:

no

Test organisms (species):

other: mixed liquor of activated sludge treatment plant

Details on inoculum:

Nitrosomonas: seed bacteria were obtained from mixed liquor of activated sludge treatment plant
methanogens: anaerobic toxicity test cultue reared in the laboratory for 10 years
aerobic heterotrophs: seed bacteria were obtained from mixed liquor of activated sludge treatment plant

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

24 h

Remarks on exposure duration:

Mehtnaogens 1,2,3, or 4 d, aerobic heterotrphs 15, 27,38, and 49 h

Test temperature:

25 °C (methanogens 35°C; aerobic heterotrophs 25 and 35°C)

pH:

6.5-8 (methanogens and aerobic heterotrophs 7)

Dissolved oxygen:

not measured but atmospheric composition (by volumes):
Nitrosomonas: N2:O2 = 1.6
methanogens: N2:CO2 = 2
aerobic heterotrophs: N2:O2 = 1

Duration:

96 h

Dose descriptor:

IC50

Effect conc.:

890 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: methane production

Duration:

49 h

Dose descriptor:

IC50

Effect conc.:

440 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Test with Nitrosomas sp.: In principal the test is comparable to standard methods, but the authors state that the compounds with log IC50 <1.5 µmol/l had questionable results. The result is considered invalid by the authors.

Executive summary:

The effect of m-cresol on activated sludge was determined by a respiration inhibition test. An 49 h-IC50 of 440 mg/L was obtained (Blum and Speece 1991).

Reference 4

Endpoint:

toxicity to microorganisms

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

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

DIN 38412-27 (Pseudomonas putida Zellvermehrungshemmtest)

Principles of method if other than guideline:

Method: other: Cell multiplication inhibition test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

A stock solution was prepared; to achive the test concentrations a defined amount of the stock solution was dissolved

Test organisms (species):

Pseudomonas putida

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

16 h

Test temperature:

25 °C

Duration:

16 h

Dose descriptor:

other: TT

Effect conc.:

53 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

TT = Toxicity threshold; determined at 3% effect compared to control

Validity criteria fulfilled:

not specified

Executive summary:

For Pseudomonas putida a NOEC of 53 mg/l was obtained in a cell multiplication inhibition test during 16 hours of exposure (Bringmann, 1976).

Reference 5

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

DIN 38412-27 (Pseudomonas putida Zellvermehrungshemmtest)

Principles of method if other than guideline:

cell multiplication inhibition test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

A stock solution was prepared; to achive the test concentrations an defined amount of the stock solution was dissolved

Test organisms (species):

Entosiphon sulcatum

Details on inoculum:

holozoic bacteriovorous flagellate

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

25 °C

pH:

initial pH 6.9

Duration:

72 h

Dose descriptor:

other: TT

Effect conc.:

31 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

TT = Toxicity threshold; determined at 5% effect compared to control

Validity criteria fulfilled:

not specified

Executive summary:

In a cell multiplication inhibition test conducted with Entosiphon sulcatum a 72h-NOEC of 31 mg/L is determined (Bringmann, 1978).

Reference 6

Endpoint:

toxicity to microorganisms

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:

DIN 38412-27 (Pseudomonas putida Zellvermehrungshemmtest)

Principles of method if other than guideline:

cell multiplication inhibition test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

A stock solution was prepared; to achive the test concentrations a defined amount of the stock solution was dissolved

Test organisms (species):

Uronema parduzci

Details on inoculum:

holozoic bacteriovorous ciliate

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

20 h

Test temperature:

25 °C

pH:

initial pH 6.9

Duration:

20 h

Dose descriptor:

other: TT

Effect conc.:

62 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

TT = Toxicity threshold; determined at 5 % effect compared to control

Validity criteria fulfilled:

not specified

Reference 7

Endpoint:

toxicity to microorganisms

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

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

DIN 38412-27 (Pseudomonas putida Zellvermehrungshemmtest)

Principles of method if other than guideline:

cell multiplication inhibition test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

A stock solution was prepared; to achieve the test concentration a defined amount of the stock solution was dissolved

Test organisms (species):

Chilomonas paramaecium

Details on inoculum:

saprozoic flagellates

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

20 °C

pH:

initial pH 6.9

Duration:

48 h

Dose descriptor:

other: TT

Effect conc.:

114 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

TT = toxicity threshold; determined at 5% effect compared to control

Validity criteria fulfilled:

not specified

Reference 8

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

yes

Remarks:

Incresed buffer capacity (K2HPO4)

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge, domestic

Details on inoculum:

Activated sludge obtained from local municipal wastewater treatment plant, settled and liquor dicarded. Solids detremined by gravimetry. Sediment wahsed three times. Resuspended and sludge adjusted to 4000 +/- 400 mg dw/L. Aerated at 0.5 L/min per 9 L of suspension. Daily resupplied with synthetic sewage stock solution according to OECD guideline with the exception of K2HPO4 which was incresed to 28 g/L in the stock solution

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3.08 h

Post exposure observation period:

5 min to determine respiration rate

Test temperature:

21 °C

pH:

7.0 adjusted with H3PO4 in sludge, and 7.5 during incubations

Dissolved oxygen:

not known, but aerated at 0.1 to 1 L/min to ensure mixing

Details on test conditions:

Type: aquatic

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

461.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Results with reference substance (positive control):

3,5-Dichorophenol

synthetic sewage stock solution slightly different from OECD guideline

Validity criteria fulfilled:

yes

Executive summary:

The sensitivity of activated sludge to m-cresol was determined by a respiration inhibition test according to OECD Guideline 209. The 3h IC50 for respiration inhibion of microorganisms is 462 mg/L.

Reference 9

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Principles of method if other than guideline:

Toxicity test towards different bacteria

GLP compliance:

no

Analytical monitoring:

no

Test organisms (species):

other: bacteria

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

60 min

Remarks on exposure duration:

30 - 60 min

Test temperature:

21 °C

Duration:

60 min

Dose descriptor:

EC50

Effect conc.:

225 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: laboratory sludge

Duration:

60 min

Dose descriptor:

EC50

Effect conc.:

360 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: activated sludge

Duration:

60 min

Dose descriptor:

EC50

Effect conc.:

> 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: lake sediment

from laboratory sludges: EC50 = >500, 225, and 410 mg/L
from activated sludges: EC50 = 360 and >500 mg/L
from lake sediment: EC50 = >500 mg/L

Reference 10

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

Population growth impairment assay

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

DMSO up to 5 % in stock solutions, stated that final concentration did not exceed 0.75 % (w/w not specified)
This concentration does not alter population growth.

Test organisms (species):

Tetrahymena pyriformis

Test type:

static

Water media type:

freshwater

Limit test:

no

Test temperature:

27 ± 1 °C

pH:

7.35

Duration:

48 h

Dose descriptor:

IC50

Effect conc.:

121 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: Schultz, 1996

Duration:

48 h

Dose descriptor:

IC50

Effect conc.:

130 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: Schultz, 1999+2003

The 50% growth inhibitory concentration (IC50) is determined by Probit Analysis of Statistical Analysis System (SAS)

Validity criteria fulfilled:

not applicable

Reference 11

Endpoint:

activated sludge nitrification inhibition testing

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Principles of method if other than guideline:

Inhibition of nitrification process

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Test type:

static

Water media type:

freshwater

Limit test:

no

Remarks on exposure duration:

2 to 4 h incubation period

Test temperature:

25 °C

pH:

7.6 - 7.8

Dissolved oxygen:

> 1 mg/L

Details on test conditions:

pre-cleaned activated sludge in particle-free communal waste water (BOD5: 250 mg/l; NH4-N/l: 50-80 mg)
50-80 mg/L ammonia
0.003 mol/L NaHCO3
0.002 mol/L (NH4)2SO4

Duration:

4 h

Dose descriptor:

other: EC75

Effect conc.:

11.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of nitrification rate

Remarks on result:

other: duration 2 to 4 h

major scope of study was to develop method

Validity criteria fulfilled:

not applicable

Executive summary:

Nitrification inhibition by m-cresol was measured by a method similar to ISO/DIS 9509 yielding an EC75 of 11.4 mg/L during a 2 -4 h incubation period (Tomlinson, Boon, and Trotman, 1966).

Reference 12

Endpoint:

toxicity to microorganisms, other

Remarks:

Tetrahymena pyriformis

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

Test procedure according to T.W. Schultz (1993) Aquatic toxicology of nitrogen heterocyclic molecules: Quantitative structure-activity relationship, in J.O. Nriagu, (Ed.) Aquatic Toxicology, Wiley, New York, 1983, 579-612.

GLP compliance:

no

Specific details on test material used for the study:

purchased from commercial sources (Aldrich Chemical Co., Milwaukee, WI, U.S.A. or Pfaltz and Bauer Inc., Sanford, CT, U.S.A.) and not repurified.

Analytical monitoring:

no

Vehicle:

yes

Remarks:

dimethylsulfoxide (DMSO)

Details on test solutions:

Due to solubility and toxicity differences, stock solutions of the individual test compounds were prepared in dimethylsulfoxide (DMSO) at a number of concentrations: 5000,
10000, 25000, or 50000 mg/L. In all cases the amount of stock solution added to the cultures was less than 0.75%. Such levels have no effect on Tetrahymena growth.

Test organisms (species):

Tetrahymena pyriformis

Details on inoculum:

Axenic cultures used.

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

60 h

Nominal and measured concentrations:

5 concentrations tested and a control

Details on test conditions:

- Cell-population levels were estimated spectrophotometrically
- Assayed in duplicate for a minimum of 3 replicates.

Reference substance (positive control):

not specified

Duration:

60 h

Dose descriptor:

IC50

Effect conc.:

76.06 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: 95% CL: 63.49 - 88.17

Reported statistics and error estimates:

Biological response was determined using probit analysis in the Statistical Analysis System software. In this analysis, Y equaled the % control absorbance and X equaled the concentration of toxicant in mg/L.

Validity criteria fulfilled:

not applicable

Reference 13

Endpoint:

toxicity to microorganisms, other

Remarks:

Tetrahymena pyriformis

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

Test procedure according to T.W. Schultz (1993) Aquatic toxicology of nitrogen heterocyclic molecules: Quantitative structure-activity relationship, in J.O. Nriagu, (Ed.) Aquatic Toxicology, Wiley, New York, 1983, 579-612.

GLP compliance:

no

Specific details on test material used for the study:

purchased from commercial sources (Aldrich Chemical Co., Milwaukee, WI, U.S.A. or Pfaltz and Bauer Inc., Sanford, CT, U.S.A.) and not repurified.

Analytical monitoring:

no

Vehicle:

yes

Remarks:

dimethylsulfoxide (DMSO)

Details on test solutions:

Due to solubility and toxicity differences, stock solutions of the individual test compounds were prepared in dimethylsulfoxide (DMSO) at a number of concentrations: 5000,
10000, 25000, or 50000 mg/L. In all cases the amount of stock solution added to the cultures was less than 0.75%. Such levels have no effect on Tetrahymena growth.

Test organisms (species):

Tetrahymena pyriformis

Details on inoculum:

Axenic cultures used.

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

60 h

Nominal and measured concentrations:

5 concentrations tested and a control

Details on test conditions:

- Cell-population levels were estimated spectrophotometrically
- Assayed in duplicate for a minimum of 3 replicates.

Reference substance (positive control):

not specified

Duration:

60 h

Dose descriptor:

IC50

Effect conc.:

52.05 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: 95% CL: 16.03 - 71.65

Reported statistics and error estimates:

Biological response was determined using probit analysis in the Statistical Analysis System software. In this analysis, Y equaled the % control absorbance and X equaled the concentration of toxicant in mg/L.

Validity criteria fulfilled:

not applicable

Reference 14

Endpoint:

toxicity to microorganisms

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

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

DIN 38412-27 (Pseudomonas putida Zellvermehrungshemmtest)

Principles of method if other than guideline:

Method: Cell multiplication inhibition test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

a stock solution was prepared; to achive the test concentrations a defined amount of the stock solution was dissolved

Test organisms (species):

Pseudomonas putida

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

16 h

Test temperature:

25 °C

Duration:

16 h

Dose descriptor:

other: TT

Effect conc.:

33 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

TT = Toxicity threshold; determined at 3% effect compared to control

Validity criteria fulfilled:

not specified

Executive summary:

For Pseudomonas putida a NOEC of 33 mg/l was obtained in a cell multiplication inhibition test during 16 hours of exposure.

Reference 15

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Reason / purpose for cross-reference:

reference to same study

Principles of method if other than guideline:

cell multiplication inhibition test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

a stock solution was prepared; to achive the test concentrations an defined amount of the stock solution was dissolved

Test organisms (species):

Entosiphon sulcatum

Details on inoculum:

holozoic bacteriovorous flagellate

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

25°C

pH:

initial pH 6.9

Duration:

72 h

Dose descriptor:

other: TT

Effect conc.:

17 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

TT = Toxicity threshold; determined at 5 % effect compared to control

Executive summary:

In a cell multiplication inhibition test conducted with Entosiphon sulcatum a 72h-NOEC of 17 mg/l is determined (Bringmann, 1978).

Reference 16

Endpoint:

toxicity to microorganisms

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

Reason / purpose for cross-reference:

reference to same study

Principles of method if other than guideline:

cell multiplication inhibition test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

a stock solution was prepared; to achive the test concentrations a defined amount of the stock solution was dissolved

Test organisms (species):

Uronema parduzci

Details on inoculum:

holozoic bacteriovorous ciliate

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

20 h

Test temperature:

25 °C

pH:

initial pH 6.9

Duration:

20 h

Dose descriptor:

other: TT

Effect conc.:

31 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

TT = Toxicity threshold; determined at 5 % effect compared to control

Validity criteria fulfilled:

not specified

Reference 17

Endpoint:

toxicity to microorganisms

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

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

cell multiplication inhibition test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

a stock solution was prepared; to achieve the test concentration a defined amount of the stock solution was dissolved

Test organisms (species):

Chilomonas paramaecium

Details on inoculum:

saprozoic flagellates

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

20 °C

pH:

initial pH 6.9

Duration:

48 h

Dose descriptor:

other: TT

Effect conc.:

132 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

TT = toxicity threshold; determined at 5% effect compared to control

Validity criteria fulfilled:

not specified

Reference 18

Endpoint:

toxicity to microorganisms, other

Remarks:

Tetrahymena pyriformis

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

Test procedure according to T.W. Schultz (1993) Aquatic toxicology of nitrogen heterocyclic molecules: Quantitative structure-activity relationship, in J.O. Nriagu, (Ed.) Aquatic Toxicology, Wiley, New York, 1983, 579-612.

GLP compliance:

no

Specific details on test material used for the study:

purchased from commercial sources (Aldrich Chemical Co., Milwaukee, WI, U.S.A. or Pfaltz and Bauer Inc., Sanford, CT, U.S.A.) and not repurified.

Analytical monitoring:

no

Vehicle:

yes

Remarks:

dimethylsulfoxide (DMSO)

Details on test solutions:

Due to solubility and toxicity differences, stock solutions of the individual test compounds were prepared in dimethylsulfoxide (DMSO) at a number of concentrations: 5000,
10000, 25000, or 50000 mg/L. In all cases the amount of stock solution added to the cultures was less than 0.75%. Such levels have no effect on Tetrahymena growth.

Test organisms (species):

Tetrahymena pyriformis

Details on inoculum:

Axenic cultures used.

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

60 h

Nominal and measured concentrations:

5 concentrations tested and a control

Details on test conditions:

- Cell-population levels were estimated spectrophotometrically
- Assayed in duplicate for a minimum of 3 replicates.

Reference substance (positive control):

not specified

Duration:

60 h

Dose descriptor:

IC50

Effect conc.:

203.39 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: 95% CL: 157.76 - 262.86

Reported statistics and error estimates:

Biological response was determined using probit analysis in the Statistical Analysis System software. In this analysis, Y equaled the % control absorbance and X equaled the concentration of toxicant in mg/L.

Validity criteria fulfilled:

not applicable

Reference 19

Endpoint:

activated sludge nitrification inhibition testing

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline available

Principles of method if other than guideline:

No guideline available at the moment of testing. Inhibition of nitrification process.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

4 h

Remarks on exposure duration:

2 to 4 h incubation period

Test temperature:

25 °C

pH:

7.6 - 7.8

Dissolved oxygen:

> 1mg/L

Details on test conditions:

pre-cleaned activated sludge in particle-free communal waste water (BOD5: 250 mg/l; NH4-N/l: 50-80 mg)
50-80 mg/L ammonia
0.003 mol/L NaHCO3
0.002 mol/L (NH4)2SO4

Duration:

4 h

Dose descriptor:

other: EC75

Effect conc.:

12.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of nitrification rate

Remarks on result:

other: duration 2 to 4 h

major scope of study was to develop method

Validity criteria fulfilled:

not applicable

Executive summary:

Nitrification inhibition by o-cresol was measured by a similar method yielding an EC75 of 12.8 mg/L during a 2 - 4 h incubation period.

Reference 20

Endpoint:

toxicity to microorganisms, other

Remarks:

Tetrahymena pyriformis

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

Test procedure according to T.W. Schultz (1993) Aquatic toxicology of nitrogen heterocyclic molecules: Quantitative structure-activity relationship, in J.O. Nriagu, (Ed.) Aquatic Toxicology, Wiley, New York, 1983, 579-612.

GLP compliance:

no

Specific details on test material used for the study:

purchased from commercial sources (Aldrich Chemical Co., Milwaukee, WI, U.S.A. or Pfaltz and Bauer Inc., Sanford, CT, U.S.A.) and not repurified.

Analytical monitoring:

no

Vehicle:

yes

Remarks:

dimethylsulfoxide (DMSO)

Details on test solutions:

Due to solubility and toxicity differences, stock solutions of the individual test compounds were prepared in dimethylsulfoxide (DMSO) at a number of concentrations: 5000,
10000, 25000, or 50000 mg/L. In all cases the amount of stock solution added to the cultures was less than 0.75%. Such levels have no effect on Tetrahymena growth.

Test organisms (species):

Tetrahymena pyriformis

Details on inoculum:

Axenic cultures used.

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

60 h

Nominal and measured concentrations:

5 concentrations tested and a control

Details on test conditions:

- Cell-population levels were estimated spectrophotometrically
- Assayed in duplicate for a minimum of 3 replicates.

Reference substance (positive control):

not specified

Duration:

60 h

Dose descriptor:

IC50

Effect conc.:

119.62 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: 95% CL: 99.57 - 155.38

Reported statistics and error estimates:

Biological response was determined using probit analysis in the Statistical Analysis System software. In this analysis, Y equaled the % control absorbance and X equaled the concentration of toxicant in mg/L.

Validity criteria fulfilled:

not applicable

Reference 21

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

Nitrification (activity of Nitrosomonas): Inhibition of nitrification, comparable to ISO/DIS 9509
methanogens: CH4 release from acetate in the presence of chemical additives
aerobic heterotrphs: inhibition of respiration according to Owen WF (1979) Bioassay for monitoring biochemical methane potential and anaerobic toxicity. Water Res. 13, 485 (prolonged incubation compared with ISO 8192)

GLP compliance:

no

Analytical monitoring:

no

Test organisms (species):

Nitrosomonas sp.

Details on inoculum:

Nitrosomonas: seed bacteria were obtained from mixed liquor of activated sludge treatment plant
methanogens: anaerobic toxicity test cultue reared in the laboratory for 10 years
aerobic heterotrphs: seed bacteria were obtained from mixed liquor of activated sludge treatment plant

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

24 h

Remarks on exposure duration:

Methanogens 1, 2, 3, or 4 d, aerobic heterotrophs 15, 27, 38, and 49 h

Test temperature:

25 °C (methanogens 35 °C; aerobic heterotrophs 25 and 35 °C)

pH:

6.5 - 8 (methanogens and aerobic heterotrophs 7)

Dissolved oxygen:

not measured but atmospheric composition (by volumes):
Nitrosomonas: N2:O2 = 1.6
methanogens: N2:CO2 = 2
aerobic heterotrophs: N2:O2 = 1

Duration:

24 h

Dose descriptor:

IC50

Effect conc.:

27 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of nitrification rate

Remarks:

Nitrosomonas

Duration:

96 h

Dose descriptor:

IC50

Effect conc.:

91 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: methane production

Duration:

49 h

Dose descriptor:

IC50

Effect conc.:

260 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Validity criteria fulfilled:

not specified

Executive summary:

The effect of p-cresol on Nitrosomonas activity was measured as a nitrification inhibition method comparable to ISO/DIS 9509. The 24 h-IC50 was 27 mg/L (Blum and Speece 1991). For respiration, the 49 h-IC50 was 260 mg/L.

Reference 22

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Principles of method if other than guideline:

O2 measured with an optical scanning respirometer; endpoint: inhibition of respiration rate

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

2 h

Remarks on exposure duration:

Preincubation 2 h and meaurements another 2 h

Test temperature:

20 ± 1 °C

pH:

7.0 ± 0.1

Dissolved oxygen:

measured via optical scanning respirometer

Reference substance (positive control):

yes

Remarks:

several other chemicals tested e.g. pentachlorophenol and 2,4-dinitrotoluol

Duration:

2 h

Dose descriptor:

IC50

Effect conc.:

439.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Validity criteria fulfilled:

not specified

Executive summary:

The sensitivity of activated sludge to p-cresol was determined by a respiration inhibition test according to OECD Guideline 209. The 2h IC50 for respiration inhibion of microorganisms is 440 mg/L.

Reference 23

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

Population growth impairment assay

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

DMSO up to 5% in stock solutions, stated that final concentration did not exceed 0.75% (w/w not specified)
This concentration does not alter population growth.

Test organisms (species):

Tetrahymena pyriformis

Test type:

static

Water media type:

freshwater

Limit test:

no

Test temperature:

27 ± 1 °C

pH:

7.35

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

157 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: 95% CL: 105.99-200.58

The 50% growth inhibitory concentration (IC50) is determined by Probit Analysis of Statistical Analysis System (SAS)

Validity criteria fulfilled:

not applicable

Reference 24

Endpoint:

activated sludge nitrification inhibition testing

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline available

Principles of method if other than guideline:

Inhibition of nitrification process
No guideline available at the moment of testing.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Test type:

static

Water media type:

freshwater

Limit test:

no

Remarks on exposure duration:

2 to 4 h incubation period

Test temperature:

25 °C

pH:

7.6 - 7.8

Dissolved oxygen:

> 1 mg/L

Details on test conditions:

pre-cleaned activated sludge in particle-free communal waste water (BOD5: 250 mg/l; NH4-N/l: 50-80 mg)
50-80 mg/L ammonia
0.003 mol/L NaHCO3
0.002 mol/L (NH4)2SO4

Duration:

4 h

Dose descriptor:

other: EC75

Effect conc.:

16.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of nitrification rate

Remarks on result:

other: duration 2 to 4 h

2 - 4 h incubation period

major scope of study was to develop method

Validity criteria fulfilled:

not applicable

Executive summary:

Nitrification inhibition by p-cresol was also measured by a similar method yielding an EC75 of 16.5 mg/L during a 2 - 4 h incubation period.

Reference 25

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Qualifier:

no guideline followed

Principles of method if other than guideline:

Growth of Tetrahymena pyriformis over a duration of 24 h

GLP compliance:

no

Analytical monitoring:

no

Details on test solutions:

Stock solutions of the test chemical were prepared and stored in the refrigerator. Water soluble compounds were directly dissolved in the water, only slightly soluble compounds were dissolved in dimethyl sulphoxide (DMSO). Tests were conducted at DMSO concentrations smaller than 5000 mg/L, whereas DMSO did not effect growth of T.pyriformis at a concentration of 10000 mg/L.

Test organisms (species):

Tetrahymena pyriformis

Details on inoculum:

Tetrahymena pyriformis was preserved in a sterile medium of 2% proteose peptone at 20 °C which was renewed at 2 to 4 week intervals. 24 h prior to test begin, the culture was pre-cultured at 30 °C.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

24 h

Details on test conditions:

- tests were carried out under sterile conditions
- the stock solution, incubation media and pre-cultured T.pyriformis were combined
- cell counting after 24 h, no agitation

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

160 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: cell number

Validity criteria fulfilled:

not applicable

Executive summary:

The EC50(24 h) with respect to growth of Tetrahymena pyriformis accounts for 160 mg/L testing p-cresol.

Description of key information

Based on all available information (weight-of-evidence) and following an analogue read-across and worst case approach the lowest effect value of 11.4 mg/L (4h-EC75) determined for nitrification inhibition of activated sludge microorganisms after exposure to m-cresol was considered as key value for the chemical safety assessment.

Key value for chemical safety assessment

EC50 for microorganisms:

11.4 mg/L

EC10 or NOEC for microorganisms:

17 mg/L

Additional information

Numerous data on the toxicity to microorganisms are available for constituents of Tar acids, Xylenol fraction (CAS 84989-06-0). These data are used to determine the hazard of Tar acids, Xylenol fraction (CAS 84989-06-0) by applying a weight of evidence and an analogue read-across approach. The studies were conducted with different species of microorganisms. From the table below it can be seen that available data demonstrate effect values for toxicity to aquatic microorganisms in a range from 11.4 to 890 mg/L. The most sensitive value of 11.4 mg/L (4h-EC75) was determined in a nitrification inhibition study for m-cresol (Tomlinson et al. 1966). These value is considered as worst case scenario for PNEC derivation and risk assessment.

For details on the read-across approach please refer to the analogue justification provided in IUCLID section 13.

Effect values determined in the numerous studies available are listed in the table below:

Source		Species	p-cresol	m-cresol	o-cresol
Tomlinson et al., 1966	Inhibition of nitrification rate	Activated sludge	EC75 (4h) = 16.5 mg/L	EC75 (4h) = 11.4 mg/L	EC75 (4h) = 12.8 mg/L
Bringmann et al., 1980	Growth inhibition	Chilomonas paramaecium (Protozoa, Cryptophyceae)	-	TT* (48h) = 114 mg/L	TT* (48h) = 132 mg/L
Bringmann & Kühn, 1980 & 1981	Growth inhibition	Uronema parduzci (Protozoa, Ciliata)	-	TT* (20h) = 62 mg/L	TT* (20h) = 31 mg/L
Bringmann & Kühn, 1976, 1977, 1979 & 1980	Growth inhibition	Pseudomonas putida (Bacteria)	-	TT* (16h) = 53 mg/L	TT* (16h) = 33 mg/L
Bringmann, 1978; Bringmann & Kühn, 1979, 1980, 1981	Growth inhibition	Entosiphon sulcatum (Protozoa, Flagellata)	-	TT* (72h) = 31 mg/L	TT* (72h) = 17 mg/L
Schultz & Riggin, 1985	Growth inhibition	Tetrahymena pyriformis (Protozoa, Ciliata)	IC50 (60h) = 168.25 mg/L	-	IC50 (60h) = 203.39 mg/L
Blum & Speece, 1991	Inhibition of nitrification rate	Nitrosomonas sp.	IC50 (24h) = 27 mg/L	-	-
Blum & Speece, 1991	Methane production	Nitrosomonas sp.	IC50 (96h) = 91 mg/L	IC50 (96h) = 890 mg/L	-
Blum & Speece, 1991	Inhibition of respiration rate	Nitrosomonas sp.	-	IC50 (49h) = 440 mg/L	-
Chan et al., 1999	Inhibition of respiration rate	Activated sludge	IC50 (2h) = 439.5 mg/L	-	-
Schultz et al., 1996 & 2003; Schultz, 1997 & 1999	Growth inhibition	Tetrahymena pyriformis (Protozoa, Ciliata)	EC50 (48h) = 157 mg/L	EC50 (48h) = 121 - 130 mg/L	-
Yoshioka, 1985	Growth inhibition	Tetrahymena pyriformis (Protozoa, Ciliata)	EC50 (48h) = 160 mg/L	-	-
Klecka & Landi, 1985	Inhibition of respiration rate	Activated sludge	-	IC50 (3h) = 461.4 mg/L	-
Liu, 1985	Not specified	Bacteria	-	EC50 (1h) = 225 - >500 mg/L	-
			2,4-xylenol	2,5-xylenol	4-ethylphenol
Schultz & Riggin, 1985	Growth inhibition	Tetrahymena pyriformis (Protozoa, Ciliata)	IC50 (60h) = 130.51 mg/L	IC50 (60h) = 119.62 mg/L	IC50 (60h) = 76.06 mg/L
			2,3,6-trimethylphenol	-	-
Schultz & Riggin, 1985	Growth inhibition	Tetrahymena pyriformis (Protozoa, Ciliata)	IC50 (60h) = 52.05 mg/L	-	-

* TT = toxicity treshold