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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

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Endpoint:
toxicity to soil macroorganisms except arthropods: long-term
Remarks:
The time frame of 10 days is sufficient as DITA is readily biodegradable.
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH
Ditridecyl adipate is appropriate for read-across because it is considered as a similar substance, based on similar structure, toxicokinetic and toxicological and ecotoxicological profile useful for this interpolation (please see also read-across justification attached in chapter 13).
Reason / purpose:
read-across: supporting information
GLP compliance:
yes
Key result
Duration:
14 d
Dose descriptor:
LC50
Effect conc.:
> 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Key result
Duration:
14 d
Dose descriptor:
NOEC
Effect conc.:
>= 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
- Mortality at end of exposure period: No earthworms died or showed other effects during the 14-day exposure period.
- Total mass of adults at beginning of test: Individual weight of 10 earthworms at test start was 420 ± 90 mg.
- Changes in body weigth of live adults (% of initial weight) at end of exposure period: In the control the reduction in mean earthworm weight was < 20% (2.8%). A statistically (p < 0.05) significant reduction of 14% in mean earthworm weight was found at 1000 mg/kg soil dw, the highest concentration tested. However, this reduction was considered to be biologically not significant (< 20%).
Endpoint:
toxicity to soil macroorganisms except arthropods: short-term
Type of information:
experimental study
Adequacy of study:
key study
Study period:
26 Jun - 10 Jul 2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 207 (Earthworm, Acute Toxicity Tests)
Version / remarks:
adoptd 1984
Qualifier:
according to
Guideline:
EU Method C.8 (Toxicity for Earthworms: Artificial Soil Test)
Version / remarks:
adopted 2008
GLP compliance:
yes
Analytical monitoring:
no
Vehicle:
yes
Details on preparation and application of test substrate:
- Method of mixing into soil: The batch of the test item tested was a clear colourless liquid with a purity of > 99%. Since the test substance was insoluble in Milli-RO water (tap water purified by reverse osmosis), acetone (≥ 99.8%) was used as a solvent. Solubility in Milli-RO water and organic solvent was based on a pre-test performed at NOTOX B.V. Preparation started with a stock solution prepared at a loading rate of 4 g test substance per 10 mL acetone (stock A). No special treatment other than careful mixing was necessary to dissolve the test substance. Stocks B through E were subsequently diluted (0.5 mL of higher stock was made up to 5 mL with acetone) from stock A through D, respectively. The colour of the stocks ranged from clear and yellow in stock A, thought clear and slight yellow in stock B to clear and colourless in stocks C to E. Subsequently, 1.45 mL of stocks B to E were spiked on 10 g silver sand. For the highest concentration 5.24 mL of stock A was spiked on 40 g of sand and the solvent control received 5.24 mL of acetone on 40 g sand. Each sand - test substance mixture was thoroughly mixed and subsequently left for to allow the solvent to evaporate. Soil pH was set with 11.4 g CaCO3 per kg of artificial soil (Merck, Darmstadt, Germany). Spiked quartz sand was added to artificial soil (dry artificial soil, CaCO3and Milli-RO water mixed for 10 minutes) and the whole was mixed for another 10 min using a mixing device.
- Controls: solvent control with acetone
- Chemical name of vehicle: acetone
- Evaporation of vehicle before use: yes
Test organisms (species):
Eisenia fetida
Animal group:
annelids
Details on test organisms:
TEST ORGANISM
- Common name: Earthworm (Eisenia fetida fetida)
- Source: Earthworms were bred at the NOTOX B.V. facilities.
- Age at test initiation: 4 months with clitellum
- Weight at test initiation: 420 ± 90 mg

BREEDING CONDITIONS
- Method of breeding: Each batch is started ith adult earthworms with well-developed clitella, by placing 100 of them into ca. 15 litres of culture medium in a plastic container. Adults were removed between day 14 and 28 and juveniles were allowed to hatch from the cocoons produced by the adults. Batches were split up and fresh culture medium was added in case of overcrowding. Worms were transferred to fresh medium regularly.
- Culture medium: Mixture of 40% sphagnum peat and 60% pot soil humidified with tap water. The pH of the mixture is 6.0 ± 1.0. When necessary, the medium was humidified with tap water during breeding.
- Feeding: Every 7 - 10 days with oat meal

ACCLIMATION
- Acclimation period: 24 h
- Acclimation conditions (same as test or not): same as test
- Health during acclimation (any mortality observed): Mortality within 24 hours prior to the test was less than 10%.
Study type:
laboratory study
Substrate type:
artificial soil
Limit test:
yes
Total exposure duration:
14 d
Test temperature:
20 ± 2 °C
pH:
6.5 - 6.6 at test start
7.4 at test end
Moisture:
35 - 37%
Details on test conditions:
TEST SYSTEM
- Test container (material, size): 1.8 L glass with lid
- Amount of soil or substrate: 500 g/vessel
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4
- No. of replicates per vehicle control: 4

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Artificial soil as described in the guidelines: 10% sphagnum peat, 20% kaolin clay, 70% industrial sand M32; pH was adjusted by addition of calcium carbonate.
- Water content: 25 - 42% of the dry weight

OTHER TEST CONDITIONS
- Photoperiod: continuous light
- Light intensity: 515-654 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
- Mortality and clinical effects were observed on day 7 and 14 of exposure.
- Ten earthworms were weighed individually prior to the start of the test. For all vessels the cumulative weight of the ten earthworms per vessel was recorded. The latter was also done for all vessels at the end of the test.

VEHICLE CONTROL PERFORMED: yes

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: solvent control, 0.1, 1.0, 10, 100 and 1000 mg/kg soil dw
- Results used to determine the conditions for the definitive study: No mortality or other effects occurred up to the highest test concentration.
Nominal and measured concentrations:
Nominal: vehicle control and 1000 mg/kg soil dw
Reference substance (positive control):
yes
Remarks:
2-chloroacetamide
Key result
Duration:
14 d
Dose descriptor:
LC50
Effect conc.:
> 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Key result
Duration:
14 d
Dose descriptor:
NOEC
Effect conc.:
>= 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
- Mortality at end of exposure period: No earthworms died or showed other effects during the 14-day exposure period.
- Total mass of adults at beginning of test: Individual weight of 10 earthworms at test start was 420 ± 90 mg.
- Changes in body weigth of live adults (% of initial weight) at end of exposure period: In the control the reduction in mean earthworm weight was < 20% (2.8%). A statistically (p < 0.05) significant reduction of 14% in mean earthworm weight was found at 1000 mg/kg soil dw, the highest concentration tested. However, this reduction was considered to be biologically not significant (< 20%).
Results with reference substance (positive control):
- Results with reference substance valid? yes
- Test date: 05 Jan - 19 Jan 2012
- LC50 (14d): 75 mg/kg soil dw, 95% CL: 56 - 100 mg/kg soil dw
Reported statistics and error estimates:
To determine the effect of the test item on body weight of Eisenia fetida fetida, control data were compared with the data of the 1000 mg/kg soil dw treatment with the Two sample t-test (TOXSTAT Release 3.5, 1996, D.D. Gulley, A.M. Boelter, H.L. Bergman) after checking for normality (Chi-square) and homogeneity of variance (F-test).
Validity criteria fulfilled:
yes
Conclusions:
The test substance is not harmful to soil macroorganisms.

Description of key information

LC50/NOEC(14d) > 1000/ >= 1000 mg/kg  (nominal) for mortality of Eisenia foetida (OECD 207, read across)

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:
1 000 mg/kg soil dw

Additional information

The time frame of 10 days is sufficient as DITA is readily biodegradable.