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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
15.08.2005 - 15.11.2005
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study, GLP
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Version / remarks:
1984
Deviations:
yes
Remarks:
deviations in pH at concentration of 1 mg/l to 16 mg/l with no relevance
GLP compliance:
yes
Analytical monitoring:
yes
Vehicle:
no
Details on test solutions:
10 litres of culture medium were prepared. Test substance concentrations of 1, 2, 4, 8, 16, 32, 64, 128 mg/L were chosen. 400 mg Butyldiglycol
methacrylate were weighed into a 1000 ml graduated flask and filled up with culture medium.
To receive the desired test concentrations the corresponding volumes of the stock solution (400 mg/L) are pipetted into 1000 ml graduated flasks:

Concentration of test
substance
[mg/L] to be tested Amount of stock solution in mL pipetted ad 500mL
1 2.5
2 5
4 10
8 20
16 40
32 80
64 160
128 320

For the control group 7 test vessels were filled up with 100 ml culture medium. One vessel was used as blank value, the others were inoculated with 106 cells of algal suspension according to the calculation of the titre from the measurement with the Coulter Counter.
Four test vessels were filled up each with 100 ml of the prepared test concentrations; the remaining solution was needed to determine the pH-value
at the beginning of the test and for analytical determinations by the test site.
Afterwards the appropriate volumes (containing 106 cells) of the algae pre-culture were added to three of the four test vessels, one was used as
blank value for the photometric measurement.
All vessels were incubated for 72 hours under the described conditions.
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Common name: Desmodesmus subspicatus
- Strain: 86.81
- Source : Collection of Algae Cultures, Institute for Plant physiology, University of Göttingen, Germany.
- Age of inoculum (at test initiation): 3 days
- Method of cultivation: One ml of the sterile solution was diluted into two 300 ml conical flasks with 100 ml of fresh sterile culture medium. Two
weeks old stock cultures were discarded.
The culture flasks were stored in an incubator (Tritec, FRG, type: KBP 6395LL). The temperature was 25 +- 1 ·C and the Iighting supplied is 0.72 x 10 E20 photons per m2s = 8000 ± 1000 Lux, measured with a spherical collector.
To facilitate transfer of carbon dioxide the algal medium was continuously stirred .
To ensure the sterility of the stock cultures, once a week , stock cultures were spread on Caso- and Columbia-agar plates with an inoculation loop. The agar plates were incubated like the submerged algae cultures and were evaluated the following Monday.
Contaminated stock cultures were discarded.

Precultivation
Three days before the start of the main experiment three flasks with culture medium described above were prepared. Each flask was filled up with 100 ml culture medium and 1 x 106 algae (10,000 cells per ml) were added.
After three days of incubating the cell concentration had to be at least 16 x 104 cells per ml.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
no
Hardness:
no data
pH:
There have been deviations in the environmental test conditions with regard to the pH values which deviated by more than one unit during the test at the concentrations of 1 mg/l to 16 mg/l and the control. These observed pH differences were marginal higher
than one unit because of the high algal growth, but of no relevance for the result of the study. Temperature in the incubator was within the stated
range.
Nominal and measured concentrations:
The following nominal concentrations of the test substance Butyldiglycol methacrylate were tested: 1, 2, 4, 8, 16, 32, 64, 128 mg Butyldiglycol methacrylate /L culture medium.
The nominal concentrations did not deviate from the analytically determined concentrations of the test substance. The analytically determined
amount of the test substance after 0, 24, 48 and 72 hours was 91 % to 97 % of the nominal concentrations. After 72 h
an outlier at the concentration of 16 mg/L was observed with a retrieval rate of 77 %, but the value for 128 mg/L was 96 % at this time point.
Details on test conditions:
TEST SYSTEM
- Test vessel: 300 ml conical flasks with cotton-wool plugs
- Material, size, headspace, fill volume: 100 ml
- Aeration: no
- Initial cells density: 10 E6
- Control end cells density:
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- No. of vessels per vehicle control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes


WATER PARAMETERS
double distilled water


OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Light intensity and quality: Iighting supplied is 0.72 x 1020 photons per m2s = 8000 ± 1000 Lux, measured with a spherical collector.


Reference substance (positive control):
no
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
34 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
95 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
32 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
27 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
51 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
16 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Details on results:
There have been deviations in the environmental test conditions with regard to the pH values which deviated by more than one unit during the test at the concentrations of 1 mg/l to 16 mg/l and the control. These observed pH differences were marginal higher than one unit because of the high algal growth, but of no relevance for the result of the study. Temperature in the incubator was within the stated range.
Reported statistics and error estimates:
A t-test was performed. At a = 0.05 = 95 % significant level the biomass for each replicate was compared to the values of the control. For the concentrations of 32, 64 and 128 mg/l a significant difference (significant lower) was observed.
At a = 0.05 = 95 % significant level the growth rate for each replicate was compared to the values of the control. For the concentration of 64 and 128 mg/l a significant difference (significant lower) was observed.

Table of calculated areas, growth rates and their reduction

 

Control

 

1 mg/l

2 mg/l

4 mg/l

8 mg/l

16 mg/l

32 mg/l

64 mg/l

128 mg/l

Area

 

2.05

2.15

2.51

2.39

2.84

2.08

1.63

0.32

0.23

Reduction [%]

0

-5

-22

-16

-39

-1

20

84

89

Growth rates

0.065323

0.067060

0.070152

0.0701520

0.068791

0.064206

0.060674

0.053436

0.010642

Reduction [%]

0

-3

-7

-7

-5

2

7

18

84

Validity criteria fulfilled:
yes
Conclusions:
Butyldiglycol methacrylate was tested acc. OECD 201 with Desmodesmus subspicatus. ErC250 (72h) = 95 mg/l, ErC10 (72h)=34 mg/l, NOEC (72h)=32 mg/l.
Executive summary:

Butyldiglycol methacrylate was tested acc. OECD 201 with Desmodesmus subspicatus. ErC50 (72h) = 95 mg/l, ErC10 (72h)=34 mg/l, NOEC (72h)=32 mg/l. EbC50 (72h) = 51 mg/l, ErC10 (72h)=27 mg/l, NOEC (72h)=16 mg/l.

Algae were exposed to nominal concentration of 1; 2; 4; 8; 16; 32; 64; and 128 mg /L for 72 hr. 

This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

Results Synopsis

Algae, static, 72 h: 

ErC50:  95 mg /L      

ErC10: 34 mg /L                      

Endpoint effected: growth rate

NOTE: Any of data in this dataset are disseminated by the European Union on a right-to-know basis and this is not a publication in the same sense as a book or an article in a journal. The right of ownership in any part of this information is reserved by the data owner(s). The use of this information for any other, e.g. commercial purpose is strictly reserved to the data owners and those persons or legal entities having paid the respective access fee for the intended purpose.

Description of key information

Based on growth rate EC50 (72h) = 95 mg/l and EC10 (72 h) = 34 mg/l

Key value for chemical safety assessment

EC50 for freshwater algae:
95 mg/L
EC10 or NOEC for freshwater algae:
34 mg/L

Additional information

One study in freshwater algae is available for BDGMA, which is considered reliable without restriction (Klimisch score 1).

In a 72 hour acute toxicity study, the cultures of Desmodesmus subspicatus (Strain 86.81) were exposed to BDGMA to nominal concentration of 1; 2; 4; 8; 16; 32; 64; and 128 mg /L for 72 hrs.

ErC50 (72h) = 95 mg/l, ErC10 (72h)=34 mg/l, NOEC (72h)=32 mg/l.