3-(2-{4-[2-(4-cyanophenyl)vinyl]phenyl}vinyl)benzonitrile

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

None

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
According to the results of a pre-experiment (without GLP), the test item is nearly insoluble in test water. Therefore, a filtrate of a supersaturated dispersion of the test item and dilutions of the filtrate were prepared. The undiluted filtrate and the dilutions 1:2.2, 1:4.6, 1:10, and 1:22 were tested. Additionally, a control was tested in parallel (test water without test item). A supersaturated dispersion with a concentration of nominal 100 mg/l (loading rate) was prepared by weighing 450 mg of the test item into 4500 ml test water. No auxiliary solvent or emulsifier was used. The test item was mixed into the test water as homogeneously as possible by ultrasonic treatment for 15 minutes and by intense stirring for 7 days at room temperature in the dark to dissolve a maximum concentration of the test item in the dispersion. The long stirring period of the dispersion of 7 days was chosen according to the results of a pre-test (without GLP) which showed that the test item is hardly soluble in test water. The supersaturated dispersion of the test item was filtered through a glass microfibre filter (Whatman GF/C, maximum pore size approximately 1.2 urn) after the stirring period of 7 days just before the preparation of the test media. A filter with a pore size of approximately 1.2 µm was chosen since the test item concentrations in a filtrate filtered over a membrane filter with a smaller pore size of 0.45 urn were below the limit of quantification of the analytical method (pre-experiment without GLP). The undiluted filtrate of the supersaturated stock dispersion with the maximum concentration of dissolved and very finely dispersed test item was used as the highest concentrated test medium. Additionally, adequate volumes of the filtrate were diluted with test water for the preparation of test media with lower test item concentrations. No additional dilution step was inserted. The actual concentrations of the test item in the test media were analytically determined. The test media were prepared just before addition of algae.
The test concentrations were based on the results of a range-finding and of a first main test and on the results of a pre-experiment to the solubility of the test item (without GLP). However, loading rates in excess of nominal 100 mg/l or test item concentrations above the maximum concentration which could be dissolved or very finely dispersed in test water were not tested according to the guidelines.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Strain:Strain No. 86.81 SAG
- Source (laboratory, culture collection):supplied by the "Sammlung von Algenkulturen, Pflanzenphysiologisches Institut der Universität Göttingen", D-37073 Göttingen. The algae had been grown in the RCC laboratories under standardized conditions according to the test guidelines

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Post exposure observation period:

No data

Hardness:

0.24 mmol/l (= 24 mg/l) as CaC03

Test temperature:

No data

pH:

No data

Dissolved oxygen:

No data

Salinity:

No data

Nominal and measured concentrations:

Nominal concentration : 100 mg/l

Details on test conditions:

TEST SYSTEM
The test was started (0 hours) by inoculation of 10,000 algal cells per ml test medium. These cells were taken from an exponentially growing pre-culture, which was set up 3 days prior to the test at the same conditions as in the test. The test design included three replicates per test concentration and six replicates of the control. Volumes of 15 ml algal suspension for each replicate were continuously stirred by magnetic stirrers in 50-ml Erlenmeyer flasks. The flasks were covered with glass dishes. They were incubated in a temperature controlled water bath at a temperature of 22 °C (see Table 7), and continuously illuminated at the measured light intensity of about 8600 Lux (mean value), range: 8000 to 9200 Lux (minimum and maximum value of measurements at 9 places distributed over the experimental area at the surface of the test media). This illumination was achieved by fluorescent tubes (Philips TLD 36W/840), installed above the test flasks. The test vessels were labeled with the RCC study number and all necessary additional information to assure unmistakable identification.

Reference substance (positive control):

not specified

Duration:

72 d

Dose descriptor:

NOEC

Effect conc.:

> 0.018 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

biomass

Details on results:

The test item FAT 60253/A had no inhibitory effect on the growth (biomass and growth rate) of Scenedesmus subspicatus during the exposure period of 72 hours up to and including the undiluted filtrate with the mean measured test item concentration of 0.018 mg/l (loading rate of 100 mg/l). Thus, this test concentration was determined as the 72-hour NOEC (highest concentration tested without toxic effects after a test period of 72 hours) The NOEC might even be higher but concentrations of the test item above the maximum concentration which could be dissolved or very finely dispersed in the test water were not tested, according to the guidelines. The 72-hour LOEC (lowest concentration tested with toxic effects) and the 72-hour EC50 for the algal biomass b and the growth rate u were clearly higher than the solubility limit of the test item in the test water. These parameters could not be quantified due to the absence of a toxic effect of FAT 60253/A up to the highest test concentration which could be dissolved or very finely dispersed in the test water.

Results with reference substance (positive control):

None

Reported statistics and error estimates:

None

None

Validity criteria fulfilled:

yes

Conclusions:

The test item FAT 60253/A had no inhibitory effect on the growth (biomass and growth rate) of Scenedesmus subspicatus during the exposure period of 72 hours up to and including the undiluted filtrate with the mean measured test item concentration of 0.018 mg/l (loading rate of 100 mg/l). Thus, this test concentration was determined as the 72-hour NOEC (highest concentration tested without toxic effects after a test period of 72 hours).

Executive summary:

The influence of the test item FAT 60253/A on the growth of the green algal species Scenedesmus subspicatus CHODAT was investigated in a 72-hour static test according to the Commission Directive 92/69/EEC, C.3,1992, and the OECD Guideline No. 201, 1984. Due to the very low water solubility of the test item, a supersaturated stock dispersion of the test item with a loading rate of nominal 100 mg/l was continuously stirred at room temperature in the dark over 7 days. Then, the dispersion was filtered. The undiluted filtrate with the maximum concentration of dissolved and very finely dispersed test item and the dilutions 1:2.2, 1:4.6, 1:10, and 1:22 were used as test media. Additionally, a control was tested in parallel. The test item FAT 60253/A had no inhibitory effect on the growth (biomass and growth rate) of Scenedesmus subspicatus during the exposure period of 72 hours up to and including the undiluted filtrate with the mean measured test item concentration of 0.018 mg/l (loading rate of 100 mg/l). Thus, this test concentration was determined as the 72-hour NOEC (highest concentration tested without toxic effects after a test period of 72 hours). The NOEC might even be higher but concentrations of the test item above the maximum concentration which could be dissolved or very finely dispersed in the test water were not tested, according to the guidelines. The 72-hour LOEC (lowest concentration tested with toxic effects) and the 72-hour EC50 for the algal biomass b and the growth rate u were clearly higher than the solubility limit of the test item in the test water. These parameters could not be quantified due to the absence of a toxic effect of FAT 60253/A up to the highest test concentration which could be dissolved or very finely dispersed in the test water.

Description of key information

The test item FAT 60253/A had no inhibitory effect on the growth (biomass and growth rate) of Scenedesmus subspicatus during the exposure period of 72 hours up to and including the undiluted filtrate with the mean measured test item concentration of 0.018 mg/l (loading rate of 100 mg/l). Thus, this test concentration was determined as the 72-hour NOEC (highest concentration tested without toxic effects after a test period of 72 hours)

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:

0.018 mg/L

Additional information

The influence of the test item FAT 60253/A on the growth of the green algal species Scenedesmus subspicatus CHODAT was investigated in a 72-hour static test according to the Commission Directive 92/69/EEC, C.3,1992, and the OECD Guideline No. 201, 1984. Due to the very low water solubility of the test item, a super saturated stock dispersion of the test item with a loading rate of nominal 100 mg/l was continuously stirred at room temperature in the dark over 7 days. Then, the dispersion was filtered. The undiluted filtrate with the maximum concentration of dissolved and very finely dispersed test item and the dilutions 1:2.2, 1:4.6, 1:10, and 1:22 were used as test media. Additionally, a control was tested in parallel. The test item FAT 60253/A had no inhibitory effect on the growth (biomass and growth rate) of Scenedesmus subspicatus during the exposure period of 72 hours up to and including the undiluted filtrate with the mean measured test item concentration of 0.018 mg/l (loading rate of 100 mg/l). Thus, this test concentration was determined as the 72-hour NOEC (highest concentration tested without toxic effects after a test period of 72 hours). The NOEC might even be higher but concentrations of the test item above the maximum concentration which could be dissolved or very finely dispersed in the test water were not tested, according to the guidelines. The 72-hour LOEC (lowest concentration tested with toxic effects) and the 72-hour EC50 for the algal biomass b and the growth rate u were clearly higher than the solubility limit of the test item in the test water. These parameters could not be quantified due to the absence of a toxic effect of FAT 60253/A up to the highest test concentration which could be dissolved or very finely dispersed in the test water.