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Toxicity to microorganisms

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Reference
Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Experimental start date: 12th March 2007 Experimental completion date: 28th March 2007 Study completion date: 31st May 2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: - Study generated according to generally valid and/or internationally accepted testing guidelines - Performed according to GLP - Test parameters based on specific testing guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Version / remarks:
OECD Guideline No. 209 "Activated Sludge, Respiration Inhibition Test" (1984). Method C11 of Commission Directive 88/302/EEC "Activated Sludge Respiration Inhibition Test (1988).
Deviations:
yes
Remarks:
Yes Study Plan Amendment No. 1: Change of study director due to absence of the originally nominated Director.
Principles of method if other than guideline:
EU Commission Directive 88/302/EEC, Part C.11, Activated Sludge Respiration Inhibition Test, 1988.
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
See report
Vehicle:
not specified
Details on test solutions:
See Report
Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
see Report
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
3 h
Post exposure observation period:
see report
Test temperature:
20°C
pH:
7.4 to 8.4
Dissolved oxygen:
8.1 to 8.3
Salinity:
N/A
Nominal and measured concentrations:
See report
Details on test conditions:
See report
Reference substance (positive control):
yes
Remarks:
3,5 dichlorophenol
Duration:
3 h
Dose descriptor:
NOEC
Effect conc.:
> 1 000 mg/L
Details on results:
The test item FP-100 had no significant inhibitory effect (<15%) on the respiration rate of activated sludge after the incubation period of three hours at the limit test concentration of 1000 mg/L. Based on the physical appearance of the test suspension, the saturation concentration (water solubility limit of FP-100 under the test conditions) was <1000 mg/L and resulted in less than 15% inhibition after three hours contact time.

Thus, the 3-hour NOEC (EC15) of FP-100 to activated sludge microorganisms was at least 1000 mg/L. This value might even be higher, but concentrations above 1000 mg/L were not tested, The 3-hour EC20, EC50, and EC80 could not be calculated, but were clearly higher than 1000 mg/L.
Results with reference substance (positive control):
The 3-hour EC50 of the reference item 3,5-dichlorophenol (positive control) was calculated to be 14 mg/L (the 95% confidence limits could not be calculated). The 3-hour EC50 is within the guideline-recommended range of 5—30 mg/L, confirming suitability of the activated sludge used.

Reported statistics and error estimates:
See the tables in the attahced report

TOXICITY OF FP-100: The influence of FP-100 on the respiration rate of activated sludge is presented in Table 1 below.

 

The test item FP-100 had no significant inhibitory effect (<15%) on the respiration rate of activated sludge after the incubation period of three hours at the limit test concentration of 1000 mg/L. Based on the physical appearance of the test suspension, the saturation concentration (water solubility limit of FP-100 under the test conditions) was <1000 mg/L and resulted in less than 15% inhibition after three hours contact time.

 

Thus, the 3-hour NOEC (EC15) of FP-100 to activated sludge microorganisms was at least 1000 mg/L. This value might even be higher, but concentrations above 1000 mg/L were not tested, The 3-hour EC20, EC50, and EC80 could not be calculated, but were clearly higher than 1000 mg/L.

 

The oxygen consumption rates of the two controls (run at the start and at the end of the test) differed by 6% (guideline-recommended maximum variation: 15%).

 

TOXICITY OF 3,5-DICHLOROPHENOL (POSITIVE CONTROL): The results are presented in Table 1 below.

 

The 3-hour EC50 of the reference item 3,5-dichlorophenol (positive control) was calculated to be 14 mg/L (the 95% confidence limits could not be calculated). The 3-hour EC50 is within the guideline-recommended range of 5—30 mg/L, confirming suitability of the activated sludge used.

Validity criteria fulfilled:
yes
Conclusions:
The test item had no inhibitory effect on the respiration rate of activated sludge after the incubation period of three hours at the test item concentration of 1000 mg/ L. The saturation concentration (water solubility limit of FP-100 under the test conditions) was reached and no inhibitory effect was determined after three hours contact time.
Executive summary:

The inhibitory effect of the test item FP-100 on the respiration rate of aerobic wastewater microorganisms of activated sludge was investigated in a 3-hour respiration inhibition test according to the EU Commission Directive 88/302/EEC, Part C.11, and the OECD Guideline for Testing of Chemicals, No. 209.

 

In accordance with the EU Commission Directive 92/69/EEC (C1, C.2, and C.3), a limit test with a nominal test concentration of 1000 mg/L was performed.

 

In addition, two controls and three different concentrations of the reference item 3,5-dichlorophenol (5, 16, and 50 mg/L) were tested in parallel. The results of these treatments confirmed suitability of the activated sludge and the method used.

 

The test item had no inhibitory effect on the respiration rate of activated sludge after the incubation period of three hours at the test item concentration of 1000 mg/ L. The saturation concentration (water solubility limit of FP-100 under the test conditions) was reached and no inhibitory effect was determined after three hours contact time.

 

Thus, the 3-hour NOEC (EC15) of the test item FP-100 to activated sludge microorganisms was at least 1000 mg/L. This value might even be higher, but concentrations above 1000 mg/L were not tested. The 3-hour EC20, EC50, and EC80 could not be calculated, but were clearly higher than 1000 mg/L.

Description of key information

The test item had no inhibitory effect on the respiration rate of activated sludge after the incubation period of three hours at the test item concentration of 1000 mg/ L. The saturation concentration (water solubility limit of FP-100 under the test conditions) was reached and no inhibitory effect was determined after three hours contact time.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
1 000 mg/L

Additional information

The inhibitory effect of the test item FP-100 on the respiration rate of aerobic wastewater microorganisms of activated sludge was investigated in a 3-hour respiration inhibition test according to the EU Commission Directive 88/302/EEC, Part C.11, and the OECD Guideline for Testing of Chemicals, No. 209.

 

In accordance with the EU Commission Directive 92/69/EEC (C1, C.2, and C.3), a limit test with a nominal test concentration of 1000 mg/L was performed.

 

In addition, two controls and three different concentrations of the reference item 3,5-dichlorophenol (5, 16, and 50 mg/L) were tested in parallel. The results of these treatments confirmed suitability of the activated sludge and the method used.

 

The test item had no inhibitory effect on the respiration rate of activated sludge after the incubation period of three hours at the test item concentration of 1000 mg/ L. The saturation concentration (water solubility limit of FP-100 under the test conditions) was reached and no inhibitory effect was determined after three hours contact time.

 

Thus, the 3-hour NOEC (EC15) of the test item FP-100 to activated sludge microorganisms was at least 1000 mg/L. This value might even be higher, but concentrations above 1000 mg/L were not tested. The 3-hour EC20, EC50, and EC80 could not be calculated, but were clearly higher than 1000 mg/L.