Cobalt di(acetate)

Toxicity to terrestrial arthropods

Administrative data

Endpoint:

toxicity to terrestrial arthropods: long-term

Type of information:

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

Adequacy of study:

other information

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study, analytical dose verification.

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Ecotoxicity of cobalt to the springtail Folsomia candida.

Author:

Lock K

Year:

2004

Bibliographic source:

Comparative Biochemistry and Physiology, Part C, Pharmacology, Toxicology & Endocrinology 139:195–199.

Reference 2

Reference Type:

secondary source

Title:

Cobalt and inorganic cobalt compounds

Author:

WHO

Year:

2006

Bibliographic source:

CICAD 69

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

ISO 11267 (Inhibition of Reproduction of Collembola by Soil Pollutants)

GLP compliance:

no

Application method:

soil

Test material

Test material information

Constituent 1

Reference substance name:

Cobalt dichloride, hexahydrate

IUPAC Name:

Cobalt dichloride, hexahydrate

Constituent 2

Reference substance name:

7791-13-1

EC Number:

616-574-6

Cas Number:

7791-13-1

IUPAC Name:

7791-13-1

Details on test material:

- Analytical purity: p.a.

Sampling and analysis

Analytical monitoring:

yes

Test substrate

Vehicle:

no

Details on preparation and application of test substrate:

- Method of mixing into soil: Cobalt was added as aqueous solutions of chloride salt (CoCl2*6H2O, UCB, Leuven, Belgium, pro analysis). Cobalt was spiked in a logarithmic series with four concentrations per order of magnitude. Concentrations were chosen on the basis of range finding tests. Three replicates were spiked per test concentration. Soils were spiked per replicate treatment. The volume of the added cobalt solution was the same for the different test concentrations. pH was not adjusted after addition of the cobalt solution. Control soils were treated in the same way as the spiked treatments. After spiking, soils were equilibrated for 1 week before testing.

Test organisms

Test organisms (species):

Folsomia candida

Animal group:

Collembola (soil-dwelling springtail)

Details on test organisms:

TEST ORGANISM
- Common name: Springtail
- Source: obtained from Aquasense (Amsterdam, The Netherlands)
- Age at test initiation (mean and range, SD): 10–12 days old

ACCLIMATION/HOUSING
Animals were cultured on a substrate of plaster of Paris and pulverised chemical activated charcoal in a ratio of 8:1 (w:w). Granulated dry yeast (Oetker, Veenendaal, The Netherlands) was added weekly as a food. Cultures have been maintained in the laboratory for at least 7 years at 20 °C and in complete darkness.

Study design

Study type:

laboratory study

Limit test:

no

Total exposure duration:

4 wk

Test conditions

Test temperature:

20±1°C

pH (if soil or dung study):

7.08-7.32 for all concentrations (OECD soil)
5.36-5.91 for all concentrations (LUFA2.2 soil)

Humidity:

55% of water holding capacitiy

Photoperiod and lighting:

16:8 L:D, 400-800lx

Details on test conditions:

TEST SYSTEM
- Test container (material, size): glass vessel
- Amount of soil or substrate: 30 g wet weight of soil
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 3
- No. of replicates per control: 3

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
Tests were carried out in standard artificial soil (OECD 1984) and a standardized field soil (LUFA2.2).

OTHER TEST CONDITIONS
- Photoperiod: 16:8 L:D
- Light intensity: 400-800 lx


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
total number of juveniles at the end of test
soil parameter at the beginning and the end

Nominal and measured concentrations:

0, 180, 320, 560, 1000, 1800 mg Co / kg soil d.w. (OECD soil)
0, 56, 100, 180, 320, 560 mg Co / kg soil d.w. (LUFA2.2 soil)

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

1 480 mg/kg soil dw

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Co

Basis for effect:

reproduction

Remarks on result:

other: in standard artificial soil OECD

Effect concentrations 2

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

409 mg/kg soil dw

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Co

Basis for effect:

reproduction

Remarks on result:

other: in standard field soil LUFA2.2

Effect concentrations 3

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

1 000 mg/kg soil dw

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Co

Basis for effect:

reproduction

Remarks on result:

other: in standard artificial soil OECD

Effect concentrations 4

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/kg soil dw

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Co

Basis for effect:

reproduction

Remarks on result:

other: in standard field soil LUFA2.2

Effect concentrations 5

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

1 800 mg/kg soil dw

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Co

Basis for effect:

reproduction

Remarks on result:

other: in standard artificial soil OECD

Effect concentrations 6

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

180 mg/kg soil dw

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Co

Basis for effect:

reproduction

Remarks on result:

other: in standard field soil LUFA2.2

Any other information on results incl. tables

In both soils, control mortality of F. candida was smaller than 10%. Survival was not significantly affected at the tested cobalt concentrations.

The difference in toxicity of the two different soil tests, can be explained by the higher pH and cation exchange capacity which decreased cobalt bioavailability in the OECD soil. When expressed as pore water concentrations, 28-day EC50s were similar: 159 mg Co/L in OECD and 174 mg Co/L in LUFA 2.2, which corresponded with calculated Co2+ activities of 0.953 and 1.20 mmol/L, respectively.