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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1992-09-01 to 1992-09-04
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report Date:
1992

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EU Method C.3 (Algal Inhibition test)
Version / remarks:
Cited as Directive 87/302/EEC, part C, p. 89 (Algal inhibition test)
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
2,2,4(or 2,4,4)-Trimethyladipic acid of Hüls AG, produced 25 March 1992. Sample from continuous production, storage tank FA 975.
Purity 90 % w/w, sample ID 3630/81389, sample No. 1324/920707

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no
Details on test solutions:
STOCK AND TEST SOLUTION AND THEIR PREPARATION
- Concentration of vehicle/solvent: 1 g test substance/l was dissolved in deionized water. No vehicle or solvent was used.

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISMS
- Strain: Scenedesmus subspicatus (CHODAT (86.81 SAG))
- Source/supplier: Origin: Institute "Wasser-, Boden- und Lufthygiene",  Berlin; further bred inhouse
- Laboratory culture: A preculture is seeded from a stock culture by  transfer 3 days prior to begin of test. Test cultures are seeded from the  latter.
- Initial cell concentration: approximately 20,000 cells/ml

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h

Test conditions

Hardness:
no data available
Test temperature:
24 +/- 2 °C
pH:
pH: 4.2-8.1 (beginning); 4.6-9.7 (end of test)
Dissolved oxygen:
no data available
Nominal and measured concentrations:
6; 10; 20; 30; 60; 100 mg/l (nominal)
Details on test conditions:
TEST SYSTEM
- Renewal of test solution: no
- Exposure vessel type: Sterile-aerated Erlenmeyer flasks on light benches
- Number of replicates: 5 (test substance) or 8 (control)
- Intensity of irradiation: approx. 7000-9000 lux, white
- Photoperiod: light

TEST PARAMETER
- Light absorption at 685 nm, related to cell density via  calibration curve

STATISTICAL METHODS   
- Probit analysis (Cavalli-Sforza, 1972)
Reference substance (positive control):
not specified

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
10 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
cell number
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
25.8 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
cell number
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
41.6 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
cell number
Duration:
72 h
Dose descriptor:
EC90
Effect conc.:
67 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
cell number
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
29.3 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
56 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC90
Effect conc.:
107.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: Value extrapolated

Any other information on results incl. tables

Cell density data: 
  Cells/ml after 0; 24; 48; 72 hours (mean)
  Control:       2; 10; 50; 163 (x 10,000)
    6 mg/l:      2; 11; 52; 164 (x 10,000)
   10 mg/l:      2; 12; 57; 163 (x 10,000)
   20 mg/l:      2; 12; 57; 138 (x 10,000)
   30 mg/l:      2; 11; 52; 105 (x 10,000)
   60 mg/l:      2;  5; 11;  24 (x 10,000)
  100 mg/l:      2;  2;  3;   2 (x 10,000)

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Conclusions:
The lowest EC50 (based on cell numbers) of 2,2,4(or 2,4,4)-trimethyladipic acid for Desmodesmus subspicatus was calculated to be 41.6 mg/L indicating that the test substance may be harmful to algae.
Executive summary:

The growth inhibition effects of 2,2,4(or 2,4,4)-trimethyladipic acid on Scenedesmus subspicatus were determined by Hüls AG (1992) according to EU-method C.3. Six concentrations ranging from 6 to 100 mg/L were tested over a period of 72 hours. The following endpoints were derived:

EbC50 (72 hours): 41.6 mg/L

ErC50 (72 hours): 56 mg/L

The study was assessed as "reliable without restrictions". However, pH values ranged from 4.2 to 9.7 and may have affected the results.