Registration Dossier

Ecotoxicological information

Toxicity to terrestrial plants

Currently viewing:

Administrative data

Endpoint:
toxicity to terrestrial plants: 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 (2005). EPS 1/RM/45 Biological Test Method: Test for Measuring Emergence and Growth of Terrestrial Plants Exposed to Contaminants in SOil. Method Development and Application Section, Environment Canada, Ontario.
Deviations:
no
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):
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

open allclose all
Species:
other: Elymus lanceolatus
Plant group:
Monocotyledonae (monocots)
Details on test organisms:
Common name: Northern wheat grass supplied by Pickseed Canada Inc.
Species:
Trifolium pratense
Plant group:
Dicotyledonae (dicots)
Details on test organisms:
Common name: Red clover supplied by William Dam Seeds Ltd, Ontario

Study design

Test type:
seedling emergence toxicity / vegetative vigour test
Study type:
laboratory study
Substrate type:
artificial soil
Limit test:
no
Total exposure duration:
21 d
Remarks:
14 days for T. pratense and 21 days for E. lanceolatus
Post exposure observation period:
No data

Test conditions

Test temperature:
24 ± 3 degrees C for 16 hour in light and 15 ± 3 degrees C for 8 hour of darkness.
pH:
pH 7.0 ± 0.5
Moisture:
No data
Details on test conditions:
Test vessels were 1-L polypropylene vessels filled with 500g wet weight test soil. Five seeds were planted in each test vessel. Six replicates were used for controls, four replicates used for the five lowest concentrations and three replicates for the remaining test concentrations. Full spectrum lighting was provided (300 ± 100 umol m-2 s).
Nominal and measured concentrations:
Nominal test concentrations of 0, 20 to 5000 mg/kg dry weight and 0, 123 to 1000 mg/kg dry weight for E. lanceolatus and T. pratense, respectively.
Reference substance (positive control):
not specified

Results and discussion

Effect concentrationsopen allclose all
Species:
Trifolium pratense
Duration:
14 d
Dose descriptor:
EC50
Effect conc.:
> 1 076 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
seedling emergence
Species:
Trifolium pratense
Duration:
14 d
Dose descriptor:
EC50
Effect conc.:
> 1 076 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: Shoot length and shoot mass (same value)
Species:
Trifolium pratense
Duration:
14 d
Dose descriptor:
EC50
Effect conc.:
> 1 076 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: Root length and root mass (same value)
Species:
other: Elymus lanceolatus
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
> 3 100 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
seedling emergence
Species:
other: Elymus lanceolatus
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
> 3 100 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: Shoot length and shoot mass (same value)
Species:
other: Elymus lanceolatus
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
> 3 100
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: Root length and root mass (same value)
Species:
Trifolium pratense
Duration:
14 d
Dose descriptor:
EC25
Effect conc.:
> 1 076 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
seedling emergence
Species:
Trifolium pratense
Duration:
14 d
Dose descriptor:
EC25
Effect conc.:
> 1 076 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: Shoot and root length and mass (same value)
Species:
other: Elymus lanceolatus
Duration:
21 d
Dose descriptor:
EC25
Effect conc.:
> 3 100 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: Shoot length and shoot mass (same value)
Species:
other: Elymus lanceolatus
Duration:
21 d
Dose descriptor:
EC25
Effect conc.:
931 mg/kg soil dw
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: Root mass
Details on results:
The test substance is relatively non-toxic to plants. There were no significant adverse effects on seedling emergence or growth with the exception of Elymus lanceolatus root mass, which was reduced to 931 mg/kg (dw) at the EC25 level after 21 days.
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 14 and 21-day study, T. E. lanceolatus and T. pratense were exposed to the test substance and reported no adverse effects at >3100 and >1076 mg/kg dw, respectively. EC25 values relating to root mass (growth) were 931 and >1076 mg/kg dry wt soil, respectively.
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 two plant species tests, no adverse effects were observed on emergence and growth at the EC50 level. An effect on root mass was observed in E. lanceolatus of 931 mg/kg dw at the EC25 level.