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Ecotoxicological information

Toxicity to terrestrial arthropods

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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:
key study
Study period:
2008
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: guideline study
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
other: study report with recalculated toxicity data from authors
Title:
Unnamed
Year:
2008

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
ISO 11267 (Inhibition of Reproduction of Collembola by Soil Pollutants)
Deviations:
no
Principles of method if other than guideline:
not applicable
GLP compliance:
no
Application method:
soil

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): CoCl2.6H2O
- source: VVWR, Belgium
- Other: No other parameters reported
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
not applicable

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
To confirm the nominal cobalt concentrations in the soil, soils were digested in hot acid (HCI:HN03, 1:5 v/v, microwave heating)

Test substrate

Vehicle:
no
Details on preparation and application of test substrate:
All the soils were thoroughly mixed with concentrations of CoCL2.6H2O and moisture content was between 50 and 60% of water holding capacity (WHC). After spiking, samples were allowed to equilibrate for one week under the same conditions as those used for the toxicity tests.

Test organisms

Test organisms (species):
Folsomia candida
Animal group:
Collembola (soil-dwelling springtail)
Details on test organisms:
TEST ORGANISM
- Common name: springtail
- Source: University of Ghent Aquatic Lab
- Age at test initiation (mean and range, SD): 10-12 day old

ACCLIMATION
Cultures of F. candida were kept on a moist substrate of plaster of Paris and
pulverised chemical activated charcoal in a ratio of 8: 1 (w/w). Organisms were transferred to new
breeding containers every 3 days which allowed breeding containers with eggs to be kept
separately. From these containers, 10-12 day old organisms were collected and used in the toxicity
tests.

Study design

Study type:
laboratory study
Limit test:
no
Total exposure duration:
28 d
Post exposure observation period:
not reported

Test conditions

Test temperature:
20 ± 1°C
pH (if soil or dung study):
4.3-7.5
Humidity:
50-60% of water holding capacity
Photoperiod and lighting:
light-dark cycle of 16 - 8 hours (400 - 600 lux).
Details on test conditions:
At the beginning of 28-day chronic tests, 10
synchronised collembola of 10 - 12 days old, were transferred into glass vessel containing 30g soils
(wet weight). Tests were carried out at a soil moisture content of 50 - 60% of the water holding
capacity (WHC). Granulated dry yeast was added weekly on the soil surface as food. The tests were
performed at 20 ± 1°C and at a light-dark cycle of 16 - 8 hours (400 - 600 lux). At the end of the
tests, adults and juveniles were counted after extracting them by flotation.

TEST SYSTEM
- Test container (material, size): glass vessel
- Amount of soil or substrate: 30 g ww
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
The soils tested were 10 natural soils exhibiting large variance in soil characteristics. see table 1 below.

OTHER TEST CONDITIONS
- Photoperiod: 16/8 light/dark
- Light intensity: 400-800 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : reproduction

VEHICLE CONTROL PERFORMED: no

TEST CONCENTRATIONS
The concentrations of cobalt (added as CoCh.6H20 , VWR, Belgium) were chosen in logarithmic series. The ranges of concentrations were selected based on (1) results of cobalt toxicity in two artificial soils OECD and LUF A.2 to E. albidus (Lock et aI. , 2006) and of the range finding tests 6 with three soils (Kasterlee, bcuven and Brecy) using E. fetida; ana \2) the linear relationship between metal toxicity (expressed as ECso) and the Cation Exchange Capacity (CEC) of the soils observed in previous studies (Lock et ai., 2003 ; Van Eeckhout et ai., 2005).
Nominal and measured concentrations:
not reported
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
28 d
Dose descriptor:
EC10
Effect conc.:
155.5 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
other: added Co in Kasterlee soil
Basis for effect:
reproduction
Remarks on result:
other: 95% CL: 87.5-278
Duration:
28 d
Dose descriptor:
EC10
Effect conc.:
666.4 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
other: added Co in Leuven soil
Basis for effect:
reproduction
Remarks on result:
other: 95% CL: 467-949
Duration:
28 d
Dose descriptor:
EC10
Effect conc.:
673 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
other: added Co in Brecy soil
Basis for effect:
reproduction
Remarks on result:
other: 95% CL: 357-1245
Duration:
28 d
Dose descriptor:
EC10
Effect conc.:
448 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
other: added Co in Canada soil
Basis for effect:
reproduction
Remarks on result:
other: 95% CL: 253-791
Duration:
28 d
Dose descriptor:
EC10
Effect conc.:
14.3 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
other: added co in Athens soil
Basis for effect:
reproduction
Remarks on result:
other: 95% CL: 2.5-58.2
Duration:
28 d
Dose descriptor:
EC10
Effect conc.:
108.5 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
other: added Co in Jyndevad
Basis for effect:
reproduction
Remarks on result:
other: 95% CL: 79-148
Duration:
28 d
Dose descriptor:
EC10
Effect conc.:
241.1 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
other: added Co in Aluminusa soil
Basis for effect:
reproduction
Remarks on result:
other: 95% CL: 136-419
Duration:
28 d
Dose descriptor:
EC10
Effect conc.:
754 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
other: added Co in Woburn soil
Basis for effect:
reproduction
Remarks on result:
other: 95% CL: 478-1185
Duration:
28 d
Dose descriptor:
EC10
Effect conc.:
747 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
other: added Co in Sidney soil
Basis for effect:
reproduction
Remarks on result:
other: 95% CL: 511-1092
Duration:
28 d
Dose descriptor:
EC10
Effect conc.:
741 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
other: added Co in Souli II soil
Basis for effect:
reproduction
Remarks on result:
other: 95% CL: 306-1773
Details on results:
not reported
Results with reference substance (positive control):
not applicable
Reported statistics and error estimates:
From the obtained concentration-response relationships, the ECsos and EClOs (with
95% confidence limits) were calculated using the log-logistic response model (Haanstra et ai. ,
1995).
k
y = l+(~JS
X50
Where
y = response of measured endpoint (e.g.
number of juveniles or cocoons)
k = response of measured endpoint at x = 0
s = slope parameter
x = concentration (on a linear scale)
Xso = ECso (median effective concentration)
9
The above mentioned model is re-parameterized to estimate both ECso and ECIO together in one run
of the program:
k
Where
y = response of measured endpoint (e.g.
number of juveniles or cocoons)
k = response of measured endpoint at x = 0
x = concentration (on a linear scale)
Xso = ECso (median effective concentration)
x)O = ECso (10% effective concentration)
Model fitting and the calculations of the 95% confidence limits was carried out using LevenbergMarquardt
(Levenberg, 1944; Marquardt, 1963), which is included in the Statistica 6.0 Software
(Statsoft, Tulsa, OK). Comparison among ECso values based on the 95% confidence limits was
performed following procedure described in Sprague and Fogels (1977).
Reproduction of F candida, E. fetida and E. albidus after 28 or 42 days of exposure were
statistically compared with those in the control soils using analysis of variance (ANOV A) followed
by the Dunnett-test. When the assumption of normality or homogeneity of variance was not met, a
non parametric analysis (Mann Whitney U-tests) was applied. Results of these analyses are
expressed as p-values, with p < 0.05 were considered significant. These analyses were used to
derive the No Observed Effect Concentration (NOEC) and Lowest Observed Effect Concentration
(LOEC) values for the different soils. The relationship between the toxicity data (NOEC, EClOs and
ECsos) and the soil parameters were investigated using linear regression analysis (Statistica 6.0).

Any other information on results incl. tables

According to REACH guidance Chapter R.10 (Table R.10 -1) EC10 values are used preferentially for PNEC derivation, therefore NOEC values are only presented as supporting information.

     
 Duration  Endpoint  Effect conc.  Nominal/measured  Conc.based on  Basis for effect
  28 d   NOEC  157 mg/kg soil dw   meas. (not specified)   other: total Co measured in Kasterlee soil   reproduction
  28 d   NOEC 607  mg/kg soil dw   meas. (not specified)   other: total Co measured in Leuven soil   reproduction
  28 d   NOEC  841 mg/kg soil dw   meas. (not specified)   other: total Co measured in Brecy soil   reproduction
  28 d  NOEC   368 mg/kg soil dw   meas. (not specified)   other: total Co measured in Canada soil   reproduction
  28 d   NOEC  52 mg/kg soil dw   meas. (not specified)   other: total Co measured in Athens soil   reproduction
  28 d   NOEC  86 mg/kg soil dw   meas. (not specified)   other: total Co measured in Jyndevad   reproduction
  28 d   NOEC  320 mg/kg soil dw   meas. (not specified)   other: total Co measured in Aluminusa soil   reproduction
  28 d   NOEC  630 mg/kg soil dw   meas. (not specified)   other: total Co measured in Woburn soil   reproduction
  28 d   NOEC 699  mg/kg soil dw   meas. (not specified)   other: total Co measured in Sidney soil   reproduction
  28 d   NOEC 787  mg/kg soil dw  meas. (not specified)   other: total Co measured in Souli II   reproduction

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
In total, 10 ECI0 values were selected for PNEC derivation: from 14.3 mg added Co/kg (Athens soil) to 753.7 mg added Co/kg (Woburn soil).
Executive summary:

not applicable