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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

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Reference
Endpoint:
toxicity to soil macroorganisms except arthropods: long-term
Type of information:
experimental study
Adequacy of study:
key study
Study period:
28 June 2016 - 30 September 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 222 (Earthworm Reproduction Test (Eisenia fetida/Eisenia andrei))
GLP compliance:
yes (incl. certificate)
Analytical monitoring:
not required
Details on sampling:
Not required by TG OECD 222
Vehicle:
yes
Details on preparation and application of test substrate:
Preparation of the test media
The batch of Diisodecyl azelate tested was a UVCB liquid substance. Test item was not sufficiently soluble in Milli-RO water but sufficiently soluble in acetone to allow preparation of stock solution.
A stock solution of 0.20 g/mL was prepared in the test. No other treatment than vigorous shaking was needed to completely dissolve the test substance in acetone. Lower stock solutions were prepared by diluting the stock with acetone.
A small amount of quartz sand (see Table) was spiked with a respective acetone stock and subsequently, acetone was allowed to evaporate (at
least 30 minutes in the reproduction test). Test media were prepared as indicated in the Table. All components were mixed (per group) with laboratory mixer for 10-14 minutes. Thereafter, medium was distributed between test vessels. A small amount of medium from each group was left for determination
of moisture content and pH. The appearance of media was similar to the control treatment.

Treatment of Test Media is hown in the Table.
Test organisms (species):
Eisenia fetida
Animal group:
annelids
Details on test organisms:
Species: Earthworm (Eisenia fetida)(Michaelsen)
Source: Bias Labs Ltd, United Kingdom.
Reason for selection: This system has been an internationally accepted
species.
Validity of batch: Mortality within 24 hours prior to the test was
less than 10%.
Characteristics: Between 2 months and 1 year old.
Final test: Reared from a cohort of cocoons laid
between 6 and 18 January 2016. Mean individual
weight 416 ± 45 mg (determined based on
replicate A and B of the control treatment)
Study type:
laboratory study
Substrate type:
artificial soil
Limit test:
no
Total exposure duration:
56 d
Remarks:
28-day adult exposure until removal, remaining 28-day exposure for cocoons and juveniles.
Post exposure observation period:
Not required in OECD TG 222
Test temperature:
20-24⁰C
The temperature during the reproduction test was higher than 22⁰C (max 24⁰C) for a
period of 2 hours.
Evaluation: Provided the total exposure period, this was negligible.
pH:
7.2-7.5
Range-finding and the reproduction test: The pH of the acclimatisation and test medium
was higher than 6.5, with a maximum of 7.5.
Evaluation: Validity criteria were met, and all worms were in good condition, hence it was
assumed not to have affected the results.
Moisture:
59-65 % MWHC
Soil moisture was higher than 60% MWHC, with a maximum of 68% MWHC in the
range-finding test and 62% MWHC in the reproduction test.
Evaluation: earthworms tolerate high medium moisture very well.
Details on test conditions:
Reproduction test: on one occasion the light: dark regime was approximately 12:12, due to
failure of time switch.
Evaluation: Provided the total exposure period, this was negligible.
Nominal and measured concentrations:
Not required by OECD TG 222
Reference substance (positive control):
yes
Remarks:
Separate GLP-Compliant Study
Key result
Duration:
56 d
Dose descriptor:
NOEC
Effect conc.:
>= 500 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
reproduction
Key result
Duration:
28 d
Dose descriptor:
NOEC
Effect conc.:
>= 500 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Key result
Duration:
28 d
Dose descriptor:
NOEC
Effect conc.:
>= 500 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth
Details on results:
Overall NOEC is equal to 500 mg Diisodecyl azelate / kg dry weight
Results with reference substance (positive control):
ER50 Reproduction with Carbendazim 1.1 mg a.s./kg dry weight (95% CI 0.57 - 1.9)
NOEC Mortality with Carbendazim <1.0 mg a.s./kg dry weight
Reported statistics and error estimates:
No statistical significance observed at the highest rate tested for all endpoint parameters
  Group mean reproduction and the effects on reproduction at the end of the reproduction test
 Diisodecyl azelate Nominal conc. [mg/kg d.s.]  Mean  %Reduction
 Blank control  247.5#  -
 Solvent control  219.1#  -
 21  195.3  10.9
 47  196.5  10.3
 103  233.5  -6.6
 227  236.8  -8.0
 500  220.3  -0.5

# there was statistically significant difference between control treatments

  Mean earthworm weight and weight change at day 28 day of exposure in the reproduction test

 Diisodecyl azelate Nominal conc. [mg/kg d.s.]

 Mean

 % Change#

 Blank control

 4.031

 -

 Solvent control

 4.224

 -

 21

 3.883

 8.1

 47

 4.308

 -2.0

 103

 4.582

 -8.5

 227  4.317  -2.2
 500  3.340  -2.8

# Negative numbers indicate increase of weight when compared with the control

Validity criteria fulfilled:
yes
Conclusions:
The overall NOEC of Diisodecyl azelate on the survival, growth and reproduction to the Earthworm , Eisenia fetida was determined to be 500 mg/kg dry weight soil.
Executive summary:

Effect parameters (mg/kg d.s)

 Parameters  Diisodecyl azelate Nominal conc. [mg/kg d.s.]
 56d-NOEC reproduction  500
 28d-NOEC survival  500
 28d-NOEC weight  500
 Overall NOEC  500

Description of key information

NOEC (56 d): 500 mg/ kg dry weight soil (for survival, growth and reproduction, Eisenia fetida, OECD 222, nominal)

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for soil macroorganisms:
500 mg/kg soil dw

Additional information

One study was conducted in order to evaluate long-term toxicity effects to earthworm. The study was performed under GLP and according to the OECD guideline 222. The toxic effects of Diisodecyl azelate (CAS 28472-97-1, Charles River, 2016) on survival, growth, and reproduction of the earthworm Eisenia fetida were assessed during a period of eight weeks. The batch of the test item is a liquid UVCB substance. The main study was performed based on the results of the preceding 14-day range finding test. Acetone stock solutions were prepared and spiked onto quartz sand. Subsequently, the coated sand was mixed with OECD artificial soil. 40 worms per group were exposed to 21, 47, 103, 227 and 500 mg/ kg dry weight of artificial soil and 80 worms each to a control (blank) and a acetone treated (solvent) control. The following endpoints were recorded: biomass of adult animals, mortality of adult worms and reproduction. Under the conditions of the present study the test item did not significantly reduce the growth, survival and reproduction of Eisenia fetida up to the highest nominal concentration of 500 mg/kg d.w. after 56 days of exposure, representing the NOEC. The 56-day EC50 for reproduction exceeded the highest concentration tested, i.e. was above 500 mg test item/kg d.w.