4,4'-methylenebis(cyclohexylamine)

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:

1990-05-14 - 1990-05-17

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test procedure according to national standard with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: German Industrial Standard DIN 38412, Part 9

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

- stock solution: 400 mg test substance / L bidest. water 80 mg solvent (Tween 80) / L bidest. water
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Tween 80

Details on test organisms:

TEST ORGANISM
- Common name: Scenedesmus subspicatus CHODAT
- Source (laboratory, culture collection): Supplier: Sammlung für Algenkulturen der Universität Goettingen
- medium: according to DIN 38 412, Part 9
- cultivation flasks/volume: 250 ml-Erlenmeyer flasks, 100 ml liquid volume
- reinoculation: once per week

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

pH:

pH range at start: - 8.2 (control [w/o Tween 80], control [w Tween 80]) - 10.9 (200 mg/L)
pH range after 72 h: - 9.0 (control [w Tween 80]) - 9.6 (141.42 mg/L)

Nominal and measured concentrations:

- test concentrations (nominal): 35.36, 50, 70.71, 100, 141.42, 200 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: test tubes
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: glass, 10-mL liquid volume
- Aeration: shaken twice a day to hold cells in suspension
- Initial cells density: 10000 cells/mL
- replicates: per concentration, control (w/o Tween 80), control (w Tween 80): 4; additional non-inoculated samples were prepared to check intrinsic fluorescence of the test substance

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Photoperiod: continuous
- Light intensity and quality: artificial light, approx. 120 µE/(m2*s)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: fluorimeter: 0, 24, 48 and 72 h (fluorescence: in-vivo chlorophyll-a fluorescence at 685 nm as a size for the biomass (pulsed excitation with light flashes having a wavelength of 435 nm)

TEST CONCENTRATIONS
- Spacing factor for test concentrations: ca. 1.4
- Justification for using less concentrations than requested by guideline: not applicable

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

>= 141.42 - <= 200 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: based on not pH-adjusted test solutions

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

ca. 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: based on not pH-adjusted test solutions

Duration:

72 h

Dose descriptor:

EC90

Effect conc.:

>= 141.42 - <= 200 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: based on not pH-adjusted test solutions

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

< 35.36 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: based on not pH-adjusted test solutions

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

>= 141.42 - <= 200 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: based on not pH-adjusted test solutions

Duration:

72 h

Dose descriptor:

EC90

Effect conc.:

>= 141.42 - <= 200 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: based on not pH-adjusted test solutions

Biomass, growth rate and inhibition data

Test concentration	Biomass	Growth rate	Inhibition	Inhibition
nominal (mg/L)	B	µ	%, biomass	%, growth rate
solvent control	1.88	1.17
0.00	1.75	1.17	7.10	-0.29
35.36	1.55	1.08	17.53	7.66
50.00	1.59	1.10	15.67	5.60
70.71	1.61	1.12	14.65	4.27
100.00	1.51	1.05	19.88	10.33
141.42	1.26	0.99	33.07	14.91
200.00		-0.40	100.00	100.00

pH values at 0 h and 72 h

Test concentration (mg/L)	pH
	0 hour	72 hour
0 (control)	8.2	9.2
0 (solvent control)	8.2	9.0
35.36	8.4	9.4
50.00	8.5	9.5
70.71	8.6	9.6
100.00	8.8	9.4
141.42	9.3	9.6
200.00	10.9	9.2

Conclusions:

Based on the nominal initial concentrations of the test item, the 72 -hour EC50 for green algae biomass (non pH adjusted) was between 141,42 and 200 mg/L.

Executive summary:

The toxicity of the test item was determined according to German Industrial Standard DIN 38412, Part 9.

The study was conducted under static conditions over a period of 72 hours with a negative control a solvent control and six nominal test concentrations: 35.36, 50, 70.71, 100, 141.42, 200 mg/L. TWEEN 80 was used as a solving agent.These chosen concentrations were based on the results from a range finding toxicity with the test item. The solutions were not pH adjusted.

16000 mg/L green algae Scenedesmus subspicatus were exposed with the test item in 10 mL test medium in glass tubes at20 ±1°C under permanent light. The tubes were stirred twice a day against sedimentation of algae. pH values were determined at initiation and termination of the study.

Based on the nominal initial concentrations of the test item, the 72 -hour EC50 for green algae biomass (non pH adjusted) was between 141,42 and 200 mg/L.

Description of key information

The EC50 / EC10 for aquatic algae and cyanobacteria was based on the 72 hour growth rate inhibition from the key study on Desmodesmus subspicatus (BASF, 1990). 

Key value for chemical safety assessment

EC50 for freshwater algae:

141.42 mg/L

EC10 or NOEC for freshwater algae:

100 mg/L

Additional information

The 72-hour ECr50 of 141.42 mg/L (ECr10 of ~100mg/L) for non-pH adjusted solution for Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) was the representative value for the short-term toxicity of 4,4'-methylenebis(cyclohexylamine) to aquatic algae and cynaobacteria. This value represented one of the three short-term aquatic toxicity values for each of three trophic levels (fish, aquatic invertebrates, and aquatic algae and plants). The lowest of the three short-term aquatic toxicity values from each of the three trophic levels was used as the point of departure for the derivation of the PNEC_{aquatic (freshwater)}.