Reaction products of 1H-Imidazole-1-ethanol, 4,5-dihydro-, 2-(C7-C9 odd-numbered alkyl) derivs. and sodium hydroxide and chloroacetic acid

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

15.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Recalculated for target

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

14.8 mg/L

Nominal / measured:

nominal

Conc. based on:

other: expressed as solid content

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

ca. 4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Recalculated for target

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

ca. 3.8 mg/L

Nominal / measured:

nominal

Conc. based on:

other: expressed as solid content

Basis for effect:

growth rate

Details on results:

- Observation of abnormalities (for algal test): no data
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no data
- Effect concentrations exceeding solubility of substance in test medium: not applicable

Results with reference substance (positive control):

No data

 Average Growth rates and Yield (Y):

Nominal test item concentration (mg/L; aqueous solution)	Average growth rateµ (day^-1) and inhibition of µ (Ir)		Yield Y and inhibition of Y (Iy)
	0-72 h		0-72 h
	µ	Ir (%)	Y	Iy (%)
Control	1.57	0.0	55.0	0.0
1.0	1.60	-2.0	60.5	-10.1
10	1.40*	10.6	34.6*	37.0
100	0.22*	86.0	0.5*	99.2
263 (100 mg solids/L)	0.34*	78.1	0.9*	98.3
EC50	39 mg/L (aqueous solution)		13 mg/L (aqueous solution)
95% Confidence Interval	Not determined		12-17 mg/L

*Mean value significantly lower than in the control (according to a Dunnett’s-test, one-sided,α= 0.05)

Validity criteria fulfilled:

yes

Remarks:

1) Multiplication in the control: 111 (should be >16); 2) Coefficient of variation of average specific growth rate in controls: 0.013% (should be <7%); 3) Mean coefficient of variation for section-by-section growth rates in the control:can not be verified

Conclusions:

In a 72h Algal growth Screening test with Miranol Ultra L-32 (Amphoacetates C12), an EC50 (growth rate) of 14.8 mg/L (expressed as solid content) was determined. This result is read across to Amphoacetates C8-C10.

Executive summary:

In a screening test for algal growth inhibition with Miranol Ultra L-32 (Amphoacetates C12), concentrations of 0, 1.0, 10, 100 and 263 mg/L (aqueous solution) were tested on Desmodesmus subspicatus. For each concentration and for the control, there were 3 replicates. There was no analytical monitoring. The algal biomass was determined by measurement of the algal cell density using an electronic particle counter (Coulter Counter, Model ZM), at t=72h only. The measurements were performed in duplicate. An 72h-ErC50 (growth rate) of 14.8 mg/L (expressed as solid content) and an 72h-ErC10 (growth rate) of approximately 3.8 mg/L (expressed as solid content) were determined from the results of this study. One of the validity criteria can not be verified (the other 2 are fulfilled). This result is read across to Amphoacetates C8 -C10.

Description of key information

 In a 72h Algal growth Screening test with Miranol Ultra L-32 (Amphoacetates C12), an 72h-ErC50 (growth rate) of 14.8 mg/L was determined (based on solid content). This result is read across to Amphoacetates C8-C10.

Key value for chemical safety assessment

EC50 for freshwater algae:

14.8 mg/L

EC10 or NOEC for freshwater algae:

3.8 mg/L

Additional information

In a screening test for algal growth inhibition with Miranol Ultra L-32 (Amphoacetates C12), concentrations of 0, 1.0, 10, 100 and 263 mg/L (aqueous solution) were tested on Desmodesmus subspicatus. For each concentration and for the control, there were 3 replicates. There was no analytical monitoring. The algal biomass was determined by measurement of the algal cell density using an electronic particle counter (Coulter Counter, Model ZM), at t=72h and not at t=24h and t=48h. The measurements were performed in duplicate. An 72h-ErC50 (growth rate) of 14.8 mg/L (expressed as solid content) was determined. One of the validity criteria can not be verified (the other 2 are fulfilled). This result is read across to Amphoacetates C8-C10.