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Toxicity to microorganisms

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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:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
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
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:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
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
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:
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).

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:
reference to same study
Qualifier:
according to
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).

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:
reference to same study
Qualifier:
equivalent or similar to
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).

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:
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
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:
reference to same study
Qualifier:
equivalent or similar to
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
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:
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.

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
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:
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
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:
reference to same study
Reason / purpose:
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).

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:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
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
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:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
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
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:
reference to same study
Qualifier:
according to
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.

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:
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).

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:
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
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:
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
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:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
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
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:
reference to same study
Reason / purpose:
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.

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:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
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
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:
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.

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:
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.

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:
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
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:
reference to same study
Reason / purpose:
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.

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