Decamethylenediamine

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:

2008-06-23 to 2008-07-03

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

The analytical monitoring was conducted at three test concentrations (1.5, 13.6 and 60 mg/l) and in the control at the start (0h) and at the end of the test (48h). After 48h, 2 ml-samples were taken both from additional test vessels (without Daphnia) and from the test vessels with Daphnia to check the influence of the test organisms.

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: a stock solution with 33.0 mg of the test item in 495.52 ml algal growth medium was prepared and stirred for about 60 min with a magnetic stirrer. The dissolved test material resulted in a stock solution concentration of 66.6 mg/l. By diluting the test solution with the algal inoculum suspension the concentrations intended were achieved. The other test solutions were obtained by diluting the stock solution with algal growth medium
- Controls: dilution water

The recovery rates [%] for the test item in the test solutions B (1.5 mg/l), E (13.6 mg/l) and G (60 mg/l) were as follows:

At the start of the test (0h):
B: 97.3%, E: 97.1%, G: 97.8%

At the end of the test (72h):
B: 94.7%, E: 96.3%, G: 97.5% (with algae)
B: 98.7%, E: 99.3%, G: 99.8% (wihtout algae)

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISMS
- "DESMODESMUS SUBSPICATUS" CHODAT (current scientific name)
- Source/supplier: German Environmental Agency (UBA), Berlin-Marienfelde
- Laboratory culture: twice a week the stock suspension is diluted 1:17 into fresh Holm-Hansen medium under sterile conditions to keep it in exponential growth
- Light intensity: 136.4 µEm-2s-1 +/- 7.0% for 24h/day.
- Pretreatment: 3 day preculture: 3 days before the start of the test, 0.7 ml of the algae stock suspension were diluted with 49.3 ml algal growth medium (according to OECD 201) to obtain a starting conc. of 10000 cells/ml; after 3 days, the cell number was determined using a Coulter Counter Z2.
- Controls: yes, 6 replicates

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

23.6 to 23.9 degree C

pH:

0 h: 7.7-9.5
72 h: 7.9-8.1

Nominal and measured concentrations:

Nominal concentrations A to G (0 hours): 0.7, 1.5, 3.1, 6.5, 13.6, 28.6, 60.0 mg/l 
Measured concentrations  (72 hours, without algae): B: 1.48, E: 13.5, G: 59.9 mg/l
Measured concentrations  (72 hours, with algae): B: 1.42, E: 13.1, G: 58.5 mg/l

Details on test conditions:

DILUTION WATER
- according to guideline
- MODIFICATIONS, if applicable

TEST SYSTEM
- Test type: static
- Exposure vessel type: sterile erlenmeyer flasks (250 ml), incubated in an temperature controlled water bath
- Test volume: 100 ml
- Number of replicates: 3, controls: 6
- Intensity of irradiation: 136.4 µEm-2s-1 +/- 7.0%
- Photoperiod: 24 h/d light
- Agitation: magnetic stirrer

TEST PARAMETER:
- "CHLOROPHYLL FLUORESCENCE" was determined at 0, 24, 48 and 72h and was measured at an exciation wave length of 465 nm and an emission wave
length of 670 nm; fluorescence values were related to cell density values according to a calibration curve.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

3.12 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 1.32-6.33

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

12.68 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: n.d.

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

0.76 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 0.06-1.65

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

5.78 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: n.d.

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.36 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 0.01-0.98

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

< 0.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

3.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Results with reference substance (positive control):

REFERENCE SUBSTANCE
- potassium dichromate


RESULTS: TEST WITH REFERENCE SUBSTANCE
- Date: 2008-01
- Results: EyC50 (Yield) = 0.X35 mg/l (required 0.20 - 0.75 mg/L); ErC50 (growth rate) = 0.80 mg/l (required 0.6 - 1.4 mg/l)

Reported statistics and error estimates:

STATISTICS:
EC values as well as the NOEC and the LOEC were calculated with nominal concentrations using the statistical software ToxRat (ToxRat Solutions GmbH, Alsdorf). The inhibition of growth is plotted versus the concentration and a dose-response curve is calculated by probit analysis using linear Max. Likelihood regression. The ECx-values were calculated from the slope of the curve.

	Specific Growth Rate 72 h nominal concentration	Yield 72 h nominal concentration
EC50	12.68 mg/l	3.12 mg/l
95% CI	n.d.	1.32 – 6.33 mg/l
EC20	5.78 mg/l	0.76 mg/l
95% CI	n.d.	0.06 – 1.65 mg/l
EC10	3.83 mg/l	0.36 mg/l
95% CI	n.d.	0.01 – 0.98 mg/l
Slope of the curve	3.461	1.369
P(Chi²)	0.973	0.996
degrees of freedom	5	5
r²	0.563	0.787
NOEC	1.5 mg/l	0.7 mg/l
LOEC	3.1 mg/l	n.d.

Validity criteria fulfilled:

yes

Conclusions:

The EC50 based on growth rate was 12.68 mg/L and the NOEC was 1.5 mg/L indicating that the test substance may be harmful to algae.

Executive summary:

In a 72 hour toxicity study, the cultures of Desmodesmus subspicatus were exposed to decamethylenediamin

at nominal concentrations of 0.7, 1.5, 3.1, 6.5, 13.6, 28.6 and 60.0 mg/L under static conditions in accordance with OECD 201. The NOEC and EC₅₀values based on biomass (yield) were <0.7 mg/l and 3.12 mg/L, respectively. The NOEC and EC₅₀ values based on growth rate were 1.5 mg/l and 12.68 mg/L, respectively.

There were no compound related phytotoxic effects.

This toxicity study is classified as "reliable without restrictions".

Results Synopsis

Test Organism: Desmodesmus subspicatus

Test Type: Static

Growth rate:
72 hr E_rC₅₀: 12.68 mg/L    95% C.I.: n.d.
72 hr NOEC:  1.5 mg/L

Biomass (yield):
72 hr E_bC₅₀:  3.12 mg/L     95% C.I.:  1.32 to 6.33 mg/L
72 hr NOEC:  <0.7 mg/L

Description of key information

In a 72 hour toxicity study, the cultures of Desmodesmus subspicatus were exposed to decamethylenediamine at nominal concentrations of 0.7, 1.5, 3.1, 6.5, 13.6, 28.6 and 60.0 mg/L under static conditions according to TGD OECD 201. The NOEC and EC50 values based on growth rate were 1.5 mg/l and 12.68 mg/L, respectively. There were no compound related phytotoxic effects.

Key value for chemical safety assessment

EC50 for freshwater algae:

12.68 mg/L

EC10 or NOEC for freshwater algae:

1.5 mg/L