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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:
experimental study
Adequacy of study:
key study
Study period:
2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Peer-reviewed study of soil ecotoxicity tests undertaken by Environment Canada as part of Canada's Chemical Management Plan programme. Ecotoxicity studies were carried out in accordance with Environment Canada testing protocols.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
2013

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: Environment Canada 2007. EPS 1/RM/47 Biological Test Method: Test for Measuring Survival and Reproduction of Springtails Exposed to Contaminants in Soil. Method Development and Applications Section, Environment Canada, Ontario.
Deviations:
no
GLP compliance:
not specified
Application method:
soil

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
not specified
Details on test material:
Supplier: Sigma-Aldrich
Purity: >98%
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:
Soil samples from each test were monitored at the start and end of each study for soil pH, moisture content and test substance concentration. Soil moisture content was also monitored through out the test with deionized water added as necessary.

Test substrate

Vehicle:
yes
Details on preparation and application of test substrate:
A sandy soil (Valcartier, Quebec) was collected, sieved and homogenized in 2008. The test soil was selected to maximise chemical recovery and bioavailability to the test organisms, as prior tests conducted in a clay loam soil, rich in organic matter resulted in poor chemical recovery. However, preliminary tests using the sandy soil demonstrated that the soil was less than optimal for reproduction, and therefore, the soil was amended with air-dried, hand-sieved (2-mm) Sphagnum sp. peat moss, on a dry weight basis, to increase overall organic matter content without compromising chemical recovery. The soil was amended with 2.5% peat. Calcium carbonate was added to peat-amended soils to counteract the acidity of the peat and maintain the original soil pH.

The test substance has low very water solubility. Soil treatments were prepared using stock solutions made with pure acetone allowed to evaporate for 24 hours. A solvent control mix of soil and acetone at the highest volume of solution was also prepared.

Formulated artificial soil was included as a negative control treatment for all tests to ensure that test cultures were healthy and to confirm test validity. This soil was formulated using 10% air-dried, hand-sieved (2-mm) Sphagnum sp. peat moss, 20% kaolin clay, 70% silica sand, deionized water, and calcium carbonate (to adjust the soil pH to 7.0 ± 0.5).

Test organisms

Test organisms (species):
Folsomia candida
Animal group:
Collembola (soil-dwelling springtail)
Details on test organisms:
Established cultures of Folsomia candida were used for the collembolan tests, with ten age-synchronized (10-12 d old) individuals added to each replicate.

Study design

Study type:
laboratory study
Limit test:
no
Total exposure duration:
28 d
Post exposure observation period:
No data

Test conditions

Test temperature:
20 ± 3 degrees C
pH (if soil or dung study):
pH 7.0 ± 0.5
Humidity:
No data
Photoperiod and lighting:
16 h of light (ranging from 610 ± 89 to 1352 ± 64 lux) and 8 h of dark
Details on test conditions:
Environment Canada test protocols (2007) were followed such that 30 g wet wt of test soil were allotted to 125-mL glass test vessels; five replicates were included for the controls and all remaining concentrations had three replicates. Nominal test concentrations for the test substance ranged from 0, 39 to 1000 mg kg-1 dry wt. Test vessels were incubated at 20 ± 3 degrees C for 16 h of light (ranging from 610 ± 89 to 1352 ± 64 lux) and 8 h of dark (Environment Canada, 2007). The Collembola were fed baker's yeast biweekly and were aerated weekly. Test measurements included: mean adult survival and mean juvenile production at the end of the test (day 28).
Nominal and measured concentrations:
Test concentrations were 0, 39 to 1000 mg/kg dry weight soil.
Reference substance (positive control):
not specified

Results and discussion

Effect concentrationsopen allclose all
Duration:
28 d
Dose descriptor:
LC50
Effect conc.:
89 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
other: Lower and upper 95% confidence limits are 81 to 98 mg/kg dry wt soil.
Duration:
28 d
Dose descriptor:
LC100
Effect conc.:
>= 147 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
mortality
Duration:
28 d
Dose descriptor:
other: IC50
Effect conc.:
89 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
reproduction
Remarks on result:
other: Lower and upper 95% confidence limits are 44 to 149 mg/kg dry wt soil.
Duration:
28 d
Dose descriptor:
other: IC25
Effect conc.:
59 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
reproduction
Remarks on result:
other: Lower and upper 95% confidence limits are 3.0 to 141 mg/kg dry wt soil.
Details on results:
A significant reduction in F. candida adult survival and reproduction was observed (IC50 of 89 mg/kg dry wt), although the authors state that the reason for the difference in toxicity between the earthworm and Collembola is uncertain.
Results with reference substance (positive control):
No data
Reported statistics and error estimates:
No data

Any other information on results incl. tables

Measured test concentrations were linearly correlated with nominal values (r = 0.92) for the test substance. The mean (± standard error) percent recovery was 90 ± 3.4% at the beginning of the test, and 77 ± 2.9% at the end of the test. On average, a 12 ± 3.0% loss was observed between the beginning and end of tests.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
During a 28-day study, adult survival and reproduction in F. candida reported LC50 and IC50, respectively, of 89 mg/kg dry wt soil when exposed to the test substance. An IC25 for the reproductive endpoint was determined to be 59 mg/kg dry wt soil.
Executive summary:

Soil ecotoxicity testing was conducted in support of Environment Canada's Chemical Management Plan (CMP). The effect of the test substance on plant growth (Elymus lanceolatus and Trifolium pratense) and soil invertebrate survival and reproduction (Folsomia candida and Eisenia andrei) were assessed using a field-collected sandy soil. The test substance was persistent throughout testing (up to 63 d) with an average recovery of 77 ± 2.9% at test end. In the 28 -day Collembola test, adult lethality and reproductive endpoints were reported at 89 mg/kg dry wt (LC50 and IC50, respectively) and an IC25 of 59 mg/kg dry wt soil for reproduction.