3-(methylthio)propionaldehyde

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1992-12-07 - 1993-02-04

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

yes

Remarks:

Three separate tests with 3 test conc. each were performed. In one of the tests (conc. range 10 - 50 mg/L) the control biomass did not increase expon. by a factor of at least 16 within 72 h.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

No details given

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- Strain: SAG 86.81
- Source (laboratory, culture collection): obtained from Pflanzenphysiologisches Institut, University of Göttingen, Germany
- Age of inoculum (at test initiation): exponential growth phase after 3 days of incuabtion
- Method of cultivation:

ACCLIMATION
- Acclimation period: 3 days
- Culturing media and conditions (same as test or not): same as in test

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

23 °C ± 2 °C

pH:

at the beginning: 8.0 - 8.1, after 72 h: 8.1 - 9.6

Nominal and measured concentrations:

Nominal concentrations tested:
Test 1: 10, 25 and 50 mg/L
Test 2: 1, 2.5 and 5 mg/L
Test 3: 0.1, 0.25 and 0.5 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: no details given
- Initial cells density: Test 1: 2.0E+05, Test 2: 1.1E+05, Test 3: 1.2 E+05 cells/mL
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 3

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to OECD guideline
15 mg/L NH4Cl
12 mg/L MgCl2 x 6H2O
18 mg/L CaCl2 x 2H2O
15 mg/L MgSO4 x 7H2O
1.6 mg/L KH2PO4
0.08 mg/L FeCl3 x 6H2O
0.1 mg/L Na2 EDTA x 2H2O
0.185 mg/L H3BO3
0.415 mg/L MnCl2 x 4H2O
3x 10-3 mg/L ZnCl2
10-5 mg/L CoCl2 x 2H2O
7x10-3 mg/L Na2MoO4 x 2H2O
50 mg/l NaHCO3

OTHER TEST CONDITIONS
- Photoperiod: continuous illumination
- Light intensity and quality: 400-700 nm, 8000 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable)
- Determination of cell concentrations: cell numbers (with spectrophotometer) after 0, 24, 48 and 72 h

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

2.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

1.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

5.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

2.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

Growth rates decreased over time, but the validity criteria of 16-fold increase over 72 h was fulfilled in Test 2 and 3.

Experiment 1:

Cell density:

Conc. (mg/L)	Cell count / mL x10E+05 24 h	Cell count / mL x10E+05 48 h	Cell count / mL x10E+05 72 h
Control 1	4.2	1.2	2.0
0.1	4.1	1.3	2.1
0.25	4.2	1.1	1.9
0.5	3.9	1.0	1.8

 

 

Experiment 2:

Cell density:

Conc. (mg/L)	Cell count / mL x10E+05 24 h	Cell count / mL x10E+05 48 h	Cell count / mL x10E+05 72 h
Control 2	4.9	1.1	1.7
1.0	4.3	86	1.6
2.5	3.3	55	85
5.0	2.5	37	56

 

Experiment 3:

Cell density:

 

Conc. (mg/L)	Cell count / mL x10E+05 24 h	Cell count / mL x10E+05 48 h	Cell count / mL x10E+05 72 h
Control 3	5.1	0.13	0.23
10	3.0	2.9	2.6
25	2.3	2.0	1.7
50	2.3	2.0	1.7

 

Growth rates:

 

Experiment 1:

 

Conc. (mg/L)	0-24 h	0-48 h	0-72 h
Control 1	1.261	1.154	0.929
0.1	1.229	1.191	0.954
0.25	1.253	1.108	0.921
0.5	1.179	1.06	0.903

 

Experiment 2:

 

Conc. (mg/L)	0-24 h	0 -48 h	0 -72 h
Control 2	1.556	1.161	0.945
1.0	1.363	1.028	0.892
2.5	1.099	0.805	0.682
5.0	0.821	0.607	0.542

 

 

Experiment 3:

 

Conc. (mg/L)	0-24 h	0 -48 h	0 -72 h
Control 3	0.936	0.924	0.782
10	0.140	0.000	-0.054
25	0.140	0.000	-0.054
50	0.405	0.186	0.087

 

 

% inhibition compared to controls:

 

Experiment 1:

 

Conc. (mg/L)	0-24 h	0-48 h	0-72 h
0.1	2.5	-3.2	-2.7
0.25	0.6	4.0	0.9
0.5	6.5	8.1	2.9

 

Experiment 2:

 

Conc. (mg/L)	0-24 h	0 -48 h	0 -72 h
1.0	12.4	11.4	5.6
2.5	29.4	30.7	27.9
5.0	47.3	47.8	42.6

 

Experiment 3:

 

Conc. (mg/L)	0-24 h	0-48 h	0 -72 h
10	85.1	100	106.9
25	85.1	100	106.9
50	56.7	79.9	88.8

 

control values are means of 3 experiments

 

The cell count in the controls in experiments 1 and 2 was >than a factor of 16 higher at the end of the study than at t=0. In experiment 3 the factor was only 10.45 and the validity criterion was not fullfilled.

 

 

Results for biomass:

3 experiments with 3 concentration ranges were performed:

 

Experiment 1:

 

Conc. (mg/L)	Cell count x10E+05 initial	Cell count x10E+05 24 h	Cell count x10E+05 48 h	Cell count x10E+05 72 h	Count inh.
0.1	1.2	4.1	13	21	0
0.25	1.2	4.2	11	19	0.1
0.5	1.2	3.9	10	18	14.3
Results control (mean of 3 controls)
1.2	1.2	4.2	12	20

 

 

Experiment 2:

 

Conc. (mg/L)	Cell count x10E+05 initial	Cell count x10E+05 24 h	Cell count x10E+05 48 h	Cell count x10E+05 72 h	Count inh.
1.0	1.1	4.3	8.6	16	15.4
2.5	1.1	3.3	5.5	8.5	51.9
5.0	1.1	2.5	3.7	5.6	71.2
Results control
	1.1	4.9	11	17

 

 

Experiment 3:

 

Conc. (mg/L)	Cell count x10E+05 initial	Cell count x10E+05 24 h	Cell count x10E+05 48 h	Cell count x10E+05 72 h	Count inh.
10.0	2.0	3.0	2.9	2.6	91.1
25.0	2.0	2.3	2.0	1.7	100
50.0	2.0	2.3	2.0	1.7	100
(values are means of 3 single experiments)
Results control
	2.0	5.1	13	23

 

 

Based on the data of all 3 experiments the original study derived the following values:

EbC50 = 2.45 mg/L (0-72h)

ErC50 = 7.4 mg/L (24-72h)

NOEC = 0.25 mg/L

 

If only the experiments fullfilling the validity criteria are used (exp. 1 and 2) the following values were derived:

 for biomass:

EbC50 = 2.1 mg/L

EbC10 = 0.6 mg/L

NOEC = 0.5 mg/L

LOEC = 1.0 mg/L

 

for growth rate:

ErC50 = 5.7 mg/L

NOEC = 1.0 mg/L

LOEC = 2.5 mg/L

Validity criteria fulfilled:

yes

Remarks:

for Test 2 and Test 3

Conclusions:

The ErC50 (72 h) was 5.7 mg(L (ErC10 (72 h): 3.1 mg/L).

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

1984

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

- Sampling method: At start and end of exposure period

Vehicle:

not specified

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Strain: ATCC 22662

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

23±2°C

Nominal and measured concentrations:

Nominal test substance concentrations: 0.988, 1.48, 2.22, 3.33 and 5.00 mg/L

Details on test conditions:

TEST SYSTEM
- Fill volume: 100 mL
- Initial cells density: 10000 cells mL
- No. of vessels per concentration (replicates): 3


OTHER TEST CONDITIONS
- Photoperiod: continous illumination
- Light intensity and quality: 4000 - 5000 lux


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.5

Reference substance (positive control):

not specified

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

2.25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1.48 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Description of key information

ErC50 (72 h): 5.7 mg/L (nominal, OECD 201)

ErC10 (72 h): 1.3 mg/L (nominal, OECD 201)

Additional information

The toxicity of the substance to freshwater algae Desmodesmus subspicatus was tested in a study following OECD guideline 201 (GLP). The study was split into three separate tests investigating the toxicity at different substance concentration ranges. In Test 1 the nominal test concentrations of 10, 25 and 50 mg/L were tested. In Test 2 the algal growth at nominal concentrations of 1, 2.5 and 5 mg/L was tested. Test 3 was perforemd with nominal test substance concentrations of 0.1, 0.25 and 0.5 mg/L. The validity criteria were only fulfiled by Test 2 and Test 3. Based on the results determined in these tests an ErC50 (72 h) of 5.7 mg/L was determined (ErC10 (72 h): 1.3 mg/L) based on the nominal concentrations. In a supporting study conducted according to OECD 201 with Pseudokirchneriella subcapitata an ErC50 (72 h) of 2.25 mg/L (nominal) was determined. The reported NOEC (72 h) was 1.48 mg/L (nominal). The test was conducted with nominal substance concentrations of 0.988, 1.48, 2.22, 3.33 and 5.00 mg/L. An analytical dose verfication by HPLC analysis was performed.