Schiff bases, C11-14-tert-alkyl methylene

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:

72 hours

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Guideline study to GLP, reported 2018

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Test Substance: Reaction products of C11-C14 tert-alkylamine and formaldehyde
Activity: >98% active
Batch / Lot: HMK/370/12/1
CAS # & Composition: >98% reaction products of C11-C14 tert-alkylamine and formaldehyde (CAS# 68607-67-0)
Stability: Stable
Quoted Solubility: Insoluble in water
Observed Appearance: Clear, very pale, straw-like colored liquid

Analytical monitoring:

yes

Details on sampling:

The concentrations of the test substance were verified by chemical analysis at time 0 and 72 hours

Vehicle:

no

Details on test solutions:

Based on the results of the preliminary range-find test the following nominal test, concentrations were assigned to the definitive test: 0.1, 0.2, 0.4, 0.8, 1.6, and 3.2 mg/L.

Test organisms (species):

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

Details on test organisms:

Pseudokirchneriella subcapitata (formerly known as Selenastrum capricornutum UTEX #LB1648) culture used in this study was obtained from a stock maintained in freshwater algal assay medium

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

Prepared using OECD Recommended Freshwater Algal Culture Medium

Test temperature:

20 C

pH:

Initial pH 8.1, reduced to as low as 7.41 during the course of the study

Nominal and measured concentrations:

Definitive test: nominal 0.1, 0.2, 0.4, 0.8, 1.6, and 3.2 mg/L.
Definitive test: measured 0.09, 0.17, 0.36, 0.68, 1.6, and 2.8 mg/L.

Details on test conditions:

Environmental chamber (set at 20 C), was used and continuously illuminated by 6000 - 10,000 lux of light provided by overhead fluorescent lights.
Flasks, 250 mL in size, were randomly placed on the power unit and rotated continuously at ca 100 oscillations per minute

Reference substance (positive control):

not required

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1.46 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.43 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Validity criteria fulfilled:

yes

Key value for chemical safety assessment

EC50 for freshwater algae:

1.46 mg/L

Additional information

Based on yield of the end of the Formaldehyde, reaction products with ethylenediamine, the results obtained were: NOEC = 1.0 mg/L and EC50 = 5.3 mg/L.