2-(chloromethyl)-4-methylquinazoline

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:

2007-01-16 to 2007-03-12

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

2006

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

1992

GLP compliance:

yes (incl. QA statement)

Remarks:

dated 2006-12-21

Analytical monitoring:

yes

Details on sampling:

- Concentrations: samples were taken from the test media of each test concentration and the control at the start and at the end of the test
- Sample storage conditions before analysis: All samples were analysed directly after sampling.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
A stock solution with a concentration of 800 mg/L was prepared with test item and Algal Mineral Salts Medium. The work solution was prepared as a 100-fold dilution of the stock solution. The test solutions were prepared from this work solution and Algal Mineral Salts Medium. The test medium was freshly prepared just before the start of the test (= introduction of algae).

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Strain: Pseudokirchneriella subcapitata (Selenastrum capricornutum) (Printz-Starr).
- Source (laboratory, culture collection): Georg-August-Universität Göttingen, Albrecht-von-Haller-Institut für Pflanzenwissenschaften Experimentelle Phykologie und Sammlung von Algenkulturen (SAG), Nikolausberger Weg 18, 37073 Göttingen, Germany
- Age of inoculum (at test initiation): 4 d
- Method of cultivation: The stock cultures are small algal cultures that are planted on agar regularly. These are transferred to fresh medium at least once every two months under standardised conditions according to the test guidelines.
ACCLIMATION
- Acclimation period: 4 d
- Culturing media and conditions (same as test or not): same as test

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

no data

Test temperature:

22.0-24.2 °C

pH:

8.46 - 8.73 at test start
7.82 - 8.96 at test end

Dissolved oxygen:

no data

Salinity:

not applicable

Nominal and measured concentrations:

- Nominal: 0.34; 0.75; 1.65; 3.64 and 8.00 mg test item /L

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flasks of 250 mL volume, covered with air-permeable stoppers
- Material, fill volume: with 100 mL test medium
- Method: continuously shaking
- Initial cells density: approximately 10.000 algal cells per mL test medium
- Control end cells density: The cell numbers were determined at 0, 24, 48 and 72 hours after starting the test
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6 for the untreated control

GROWTH MEDIUM
- Standard medium used: yes, Mineral Salts Test Medium (according to OECD 201) without Na2EDTA x 2H2O

OTHER TEST CONDITIONS
- Sterile test conditions: no data
- Adjustment of pH: no
- Light intensity and quality: 7798 lux, ensured with fluorescent lamps, spectral range of 400-700 nm


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : pH and Water Temperature; behaviour of the test item in test medium
- Determination of cell concentrations: manual cell counting using a microscope with counting chamber

TEST CONCENTRATIONS
- Range finding study: yes, not performed in compliance with GLP-regulations
- Results used to determine the conditions for the definitive study: The test concentrations are based on the results of the range-finding test.

Reference substance (positive control):

yes

Remarks:

potassium dichromate (tested twice a year)

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 95% CL 1.25 - 1.56

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

2.44 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL 2.18 - 2.73

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Remarks on result:

other: 95% CL 0.99 - 1.23

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.34 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: biomass, growth rate and yield

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

0.75 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: biomass, growth rate and yield

Details on results:

EC50 values based on statistical determination (Probit Analysis (a = 0.05), statistical software program Toxstat, Western EcoSystems Technology).
- Exponential growth in the control (for algal test): yes
- Unusual cell shape: shape of the algal cells growing was obviously not affected

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Reference substance:
The ErC 50 of Potassium dichromate: 0.99 mg/L, (95 % confidence limits: 0.88 – 1.12 mg/L)
The EbC 50 of Potassium dichromate: 0.52 mg/L, (95 % confidence limits: 0.46 – 0.59 mg/L)
(The date of the last study - Study Code: 06/315-022AL - with reference item is: 28 November - 01
December 2006.)

Reported statistics and error estimates:

Mean values and standard deviations of cell concentrations were calculated for each treatment at the start, after 24 h, 48 h and at the end of the test (72 hours after the start of the test) using Excel for Windows software. Percentage inhibition of area A, growth rate r and yield Y were calculated using EXCEL for Windows software. The EC50 values of the test item and their confidence limits were calculated using Probit analysis. The analysis was done using the statistical software program “TOXSTAT 3.5”. For the determination of the LOEC and NOEC, the calculated mean biomass b (area under the growth curve) and growth rates r at the test concentrations were tested on significant differences to the control values by Bonferroni t Test by TOXSTAT software.

The test item had a statistically significant inhibitory effect on the growth (based on the growth rates) of Pseudokirchneriella subcapitata after the exposure period of 72 hours in the concentration range of 0.75 – 8.00 mg test item/L (Bonferroni t-Test, a=0.05).

Validity criteria fulfilled:

yes

Conclusions:

A 72-h EbC50 value of 1.4 mg/L, ErC50 of 2.44 mg/L and EyC50 of 1.1 mg/L for Pseudokirchneriella subcapitata were determined for the test item under the conditions of the test.

Executive summary:

The purpose of this study was to determine the effect of the test item on the growth of the unicellular green algal species Pseudokirchneriella subcapitata (Selenastrum capricornutum). Exponentially growing cultures of Pseudokirchneriella subcapitata were exposed to various concentrations of the test item over several generations under defined conditions.

The algal growth in relation to a control culture was determined over a fixed test period of 72 hours and thus, over several algal generations. The test method of application and the test species Pseudokirchneriella subcapitata were recommended by the test guidelines.

The nominal test item concentrations were 0.34; 0.75; 1.65; 3.64 and 8.00 mg test item /L.

The test item concentrations were measured in the range of 105 % to 113 % of the nominal values at the start of the test and from 86 % to 103 % of the nominal values at the end of the test. The deviation of the measured concentrations from the nominal values was lower than 20 % throughout the test. Therefore, all reported biological results are related to the nominal concentrations of the test item. It can be stated that under the test conditions the test item was sufficiently stable during a period of 72 hours.

Description of key information

After 72 hours an EbC50 value of 1.4 mg/L, an ErC50 value of 2.44 mg/L and an EyC50 value of 1.1 mg/L were determined for the substance according to OECD 201. In addition an NOEC of 0.34 mg/L was determined.

Key value for chemical safety assessment

EC50 for freshwater algae:

2.44 mg/L

EC10 or NOEC for freshwater algae:

0.34 mg/L