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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study, with acceptable restrictions (e.g. non-GLP, no analytical verification of test item concentrations).

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1989
Report Date:
1989

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: German Industrial Standard DIN 38412, Part 9
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- test substance: N-Methylacetamide
- purity: no data

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Common name: green algae

Study design

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

Test conditions

Details on test conditions:
- No. of algae in test flasks at test start: 10000 cells/ml
- test substance: colorless
- tubes were incubated for 96 h at 21-25 °C
- samples were taken at regular intervals (0, 24, 48, 72, 96 h)
- measurements: cell number determined fluorometrically
- pH values: 0 and 96 h
- number of replicates: 4
- test concentrations: 0 (control), 10, 25, 50, 100, 250, and 500 mg/l
- reference substance: potassium dichromate
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 500 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
299 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate

Any other information on results incl. tables

RS-Freetext:
Effect values:

Growth rate (mg/l)
------------------
72 h 96 h
ErC0: 50.000
ErC10: 298.984 (36.450- > 500) 237.648 (121.459-464.984)
ErC50: > 500 (24.742- > 500) > 500 (> 500- > 500)

Biomass integral (mg/l)
-----------------------
72 h 96 h
EbC0: 50.000
EbC10: 176.667 (39.035- > 500) 155.185 (45.228-532.470)
EbC50: 505.177 (45.958- > 500) 400.366 (63.795- > 500)

pH at test start (0 h) and at test end (96 h)
---------------------------------------------
0 h 96 h
0 (control) 7.81 7.99
10 7.81 7.93
25 7.80 7.83
50 7.80 7.95
100 7.80 7.89
250 7.79 7.85
500 7.77 7.73

The temperature in all vessels was 21.3 °C.

Data evaluation
---------------
72 h: Growth Inhibition Rate related
rate of biomass (%) inhibition (%)
0 (control) 0.96 ---- ----
10 0.98 -0.2 -1.7
25 0.99 -2.9 -2.8
50 0.97 6.2 -1.0
100 0.92 9.8 4.8
250 0.88 18.4 8.1
500 0.81 28.2 16.2

Applicant's summary and conclusion