Dialkylheteromonocyclium alkanoate

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Details on test solutions:

TEST ITEM: 1,3-Dimethyl-1H-imidazol-3-iumpropanoate
Stock solution: 400 mg/L, freshly prepared with dilution water
Dispersion treatment: Agitation
Test concentrations (nominal): 25.0 - 50.0 - 100 - 200 - 400 mg/L (factor 2)
CONTROL: Six replicates (without test item) were tested under the same test conditions as the test replicates.

Test organisms

Test organisms (species):

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

Details on test organisms:

Test organism: Pseudokirchneriella subcapitata HINDÁK, SAG 61.81 Chlorophyta, Chlorophyceae
Reason for the selection of the test organism: Pseudokirchneriella subcapitata is a suitable green alga species according to the guideline.
Origin: Sammlung von Algenkulturen (SAG), Pflanzenphysiologisches Institut der Universität Göttingen, Nikolausberger Weg 18, D-37073 Göttingen
Method of cultivation: Fresh stocks are prepared every month on Z-Agar. Light intensity amounted to 35-70 µE*m-2*s-1 for 24 hours per day.
Culture medium: Nutrient medium Z according to LÜTTGE et al. (1994).

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Hardness:

0.24 mmol CA+Mg/L

Test temperature:

21.5-24°C

pH:

7.07-9.09

Nominal and measured concentrations:

nominal 25, 50, 100, 200 and 400 mg/L

Details on test conditions:

TEST METHOD: Static procedure
Exposure duration: 72 hours
Replicates: 3 replicates per concentration level and 6 for the control
Test container: Sterile Erlenmeyer flasks, volume: 250 mL, sealed with cotton wool plugs
Test volume: 100 mL
Dilution water: According to the guideline

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

155 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

253 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 400 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 5

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

200 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Results with reference substance (positive control):

The toxicity of potassium dichromate (SIGMA, batch number 1450864V, purity 100.3 %, CAS RN 7778-50-9) to the unicellular freshwater green alga
Pseudokirchneriella subcapitata was determined over a period of 72 hours.
EC50 Growth rate inhibition was 0.718 mg/L (nominal concentration)

Any other information on results incl. tables

After 72 hours algae were transferred from the two highest concentrations (200 – 400 mg/L) and the control to fresh untreated medium and allowed to grow for further 4 days under test conditions. The test item effect was observed to be reversible at these concentrations. Therefore, there is potential for recovery following exposure up to nominal 400 mg test item/L (highest test concentration).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In this study 1,3-Dimethyl-1H-imidazol-3-iumpropanoate was found to inhibit the growth of the freshwater green alga Pseudokirchneriella
subcapitata after 72 hours with the following effect value (nominal test item concentrations): The EC50-value for
inhibition of specific growth rate (ErC50) after 72 hours was > 400 mg/L. The NOEC-value for inhibition of specific growth rate was 100 mg/L.
All effect values are given based on nominal test item concentrations.