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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

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Administrative data

Endpoint:
toxicity to soil macroorganisms except arthropods: long-term
Type of information:
experimental study
Adequacy of study:
key study
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 2004. EPS 1/RM/43 Biological Test Method: Tests for Toxicity of Contaminated Soil to Earthworms (Eisenia andrei, Eisenie fetida or Lumbricus terrestris). Method Development and Applications Section, Environment Canada, Ontario.
Deviations:
yes
Remarks:
Test container size varied from protocol.
GLP compliance:
not specified

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):
No data

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):
Eisenia sp.
Animal group:
annelids
Details on test organisms:
Established cultures of Eisenia andrei were used for the earthworm tests.

Study design

Study type:
laboratory study
Substrate type:
natural soil
Limit test:
no
Total exposure duration:
63 d
Post exposure observation period:
No data

Test conditions

Test temperature:
20 ± 3 degrees C
pH:
pH to 7.0 ± 0.5
Moisture:
According to the test protocol, deionised water is added to the soil until a moisture content equivalent to circa 70% water holding capacity is reached.
Details on test conditions:
Environment Canada test protocols (2004) were followed; however, because of the increased density of the test soil, 250 mL glass jars were used instead of the recommended 500 mL Each test vessel had 230 g wet wt of test soil, and two sexually mature adults (ranging from 372 ± 82 to 390 ± 83 mg) were added to each replicate. Test vessels were incubated for 35 d, after which the adults were removed, and the test vessels incubated for another 28 d; there were ten replicates per test concentration. Nominal test concentrations for the test substance ranged from 0, 23 to 3000 mg/kg dry wt.Test vessels were incubated at 20 ± 3 degrees C for 16 h of light (ranging from 728 ± 341 to 899 ± 392 lux) and 8 h of dark (Environment Canada, 2004). Test organisms were fed between one-quarter and one-half a teaspoon of cooked oatmeal (Quaker OatsTM "quick" 3-5 min oatmeal) biweekly. Test measurements included: mean adult survival on day 35, mean juvenile production and mean individual juvenile dry mass at test end (day 63).
Nominal and measured concentrations:
Test concentrations = 0, 39 to 1000 mg/kg dry wt soil
Reference substance (positive control):
not specified

Results and discussion

Effect concentrationsopen allclose all
Duration:
35 d
Dose descriptor:
LC50
Effect conc.:
> 2 651 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks:
Adult lethality at 35 days
Duration:
35 d
Dose descriptor:
other: LC25
Effect conc.:
> 2 651 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks:
Adult lethality at 35 days
Duration:
63 d
Dose descriptor:
other: IC50
Effect conc.:
> 2 651 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
reproduction
Duration:
63 d
Dose descriptor:
other: IC25
Effect conc.:
> 2 651 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
reproduction
Duration:
63 d
Dose descriptor:
other: IC50
Effect conc.:
> 2 651 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: Juvenile dry mass
Duration:
63 d
Dose descriptor:
other: IC25
Effect conc.:
1 758 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: Juvenile dry mass
Details on results:
There was no significant effect on adult survival or juvenile production.
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:
The study concluded that the test substance is relatively nontoxic to earthworms (IC50 of >2651 mg/kg dry wt).
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. The test substance was not toxic to E. andrei (IC50s > 2651 mg kg- 1).