Registration Dossier

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: Study precedes adoption of OECD Guideline. However, the ECETOC task force on Cyanides evaluated the data and found its conclusions to be valid and consistent with other studies.

Data source

Reference
Reference Type:
publication
Title:
Vergleichende wasser-toxikologische Untersuchungen an Bakterien, Algen und Kleinkrebsen
Author:
Bringmann G, Kühn, R
Year:
1959
Bibliographic source:
Gesundheits-Ingenieur 80, 115 - 120

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
no
Remarks:
preceeds establishment of GLP protocols

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
-Source (laboratory, culture, collection): Cultured at testing facility Bundesgesundheitsamt, Institut fur Wasser-, Boden- und Lufthygiene, Berlin-Dahlem, Germany
Method: Cultivation of stock cultures performed in 100 ml of a culture medium consisting of municipal wastewater and a nutrient solution (NO3 570 mg/L, CaSO4 200 mg/L, KH2PO4 140 mg/L, MgSO4 90 mg/L, FeCl3 3 mg/L) at daylight at 24 degrees C in 300 ml Erlenmeyer flasks. One week prior to testing, aliquots of the cultures are transferred into new culture medium and incubated for 1 week at 24 degrees C and illumination (24 hr fluorescent tubes Osram NHI 40 W and Osram HNT 40 W). Algae are filtered into distilled water. The turbidity of the culture is determined.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no

Test conditions

Details on test conditions:
DETAILS ON TEST CONDITIONS
TEST SYSTEM
-Test vessel: Type: closed glass tubes
-Type: closed
-Material, size, headspace, fill volume: closed galls tubes, diameter 18 mm
-Aeration: No
-Initial cell density: No data
-Control end cell density: No data

GROWTH MEDIUM:
-Detailed composition if non-standard medium was used: filtered waste water (membrane filer 0.6-1.0 micron)

TEST MEDIUM/WATER PARAMETERS:
-Source/preparation of dilution water: River Havel (Gatow, Germany)
-Culture medium different from test medium: Yes

OTHER TEST CONDITIONS
-Sterile test conditions: No
-Adjustment of pH: No
-Photoperiod: 24 h
-Light intensity: Fluorescent tubes Osram HNI 40 W and Osram HNT 40 W

EFFECT PARAMETERS MEASURED (with observation intervals, if applicable):
-Determination of cell concentrations: colorimetric measurements of turbidity of the test cultures after 96 h at end of test.

TEST CONCENTRATIONS:

Results and discussion

Effect concentrations
Duration:
96 h
Dose descriptor:
LOEC
Effect conc.:
0.16 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass

Applicant's summary and conclusion

Validity criteria fulfilled:
not applicable
Conclusions:
In a 96 hour acute toxicity study, the cultures of Desmodesmus subspicatus (reported as Scenedesmus subspicatus) were exposed to potassium cyanide at nominal concentrations of potassium cyanide (CAS-No. 151-50-8) under static conditions. No guideline was followed, but the aim of the study was to develop test methods to determine whether pollutants affect self-purification of surface waters. The 96h LOEC value based on cell density (turbidity of the test cultures) was 0.16 mg active ingredient./L.

Potassium cyanide (KCN, CAS-No. 151-50-8) is very toxic against the green algae Desmodesmus subspicatus. KCN, with a pKa of 9.11 at 30°C, is dissociated and protonated at the pH and temperature of the test conditions; thus, the active toxic principal is the cyanide ion.
Results Synopsis

Test Organism: Desmodesmus subspicatus (reported as Scenedesmus subspicatus)
Test Type: Static

96 hr LOEC: 0.16 mg active ingredient/L
Endpoint(s) Effected: Growth inhibition