Cobalt carbonate

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

other information

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Method similar to guideline. No analytical dose verification.

Data source

Reference

Reference 1

Reference Type:

publication

Title:

The growth response of the green alga Chlorella vulgaris to combined divalent cation exposure.

Author:

Rachlin JW, Grosso A

Year:

1993

Bibliographic source:

Archives of Environmental Contamination and Toxicology 24:16–20.

Reference 2

Reference Type:

secondary source

Title:

CICAD 69, Cobalt and inorganic cobalt compounds

Author:

WHO

Year:

2006

Materials and methods

Principles of method if other than guideline:

96 hour static test

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Cobalt dichloride

EC Number:

231-589-4

EC Name:

Cobalt dichloride

Cas Number:

7646-79-9

IUPAC Name:

cobalt(2+) dichloride

Details on test material:

- Name of test material (as cited in study report): "chloride salt" of cobalt
- Analytical purity: no data

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Test solutions consisted of the modified Bristol's medium (pH 6.5) as control, or solutions of this medium containing the 96- h EC50 concentrations of the cations Cd, Co and Cu in the following combinations: Cd + Cu, Cd + Go, Cu + Co, and Cd + Cu + Co. Test soutions were made in modified Bristol's medium using the chloride salts of the cations in appropiate concentrations so that results are reported as concentrations of the cations alone.

Test organisms

Test organisms (species):

Chlorella vulgaris

Details on test organisms:

TEST ORGANISM
- Common name: Green alga
- Strain: UTEX 30
- Source (laboratory, culture collection): UTEX
- Age of inoculum (at test initiation): For experiments an inoculum of an exponential growing culture was used.
- Method of cultivation: static, grown in chelator free modified Bristol´s medium


ACCLIMATION
- Culturing media and conditions (same as test or not): yes
- Any deformed or abnormal cells observed: no data

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test conditions

Test temperature:

19±1°C

pH:

6.5 at test start

Nominal and measured concentrations:

0.32, 0.56, 1.0 mg Co/L (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: erlenmeyer flask 125ml, fill volume 50ml
- Aeration: no
- Initial cells density: no data
- Control end cells density: no data
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3


GROWTH MEDIUM
- Standard medium used: yes


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: chelateor-free modified Bristol medium
- Culture medium different from test medium: no


OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: not during test
- Photoperiod: 16:8 L:D
- Light intensity and quality: Illumination was maintained at 280 foot candles (3.08 Klux, 7.84 W m-2)


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: hemocytometer

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

0.56 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

Co

Basis for effect:

growth rate

Any other information on results incl. tables

The EC50 was estimated by probit analysis: 0.522 ± 0.38 ppm (9.0 µM). This was confirmed in a series of runs in which test concentrations of cobalt at 0.56 ppm (9.5 µM) yielded a 50.7 % reduction in growth of the test Chlorella cultures.