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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:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
2014
Reliability:
2 (reliable with restrictions)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2014
Report Date:
2014

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 222 (Earthworm Reproduction Test (Eisenia fetida/Eisenia andrei))
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: waxy pearl
Details on test material:
Identification:
Acetalization product between glucose and C20/22(even numbered)-alcohol
Batch: T30715
Purity: 100% commercial product
Dry Matter: 99.89%
Retest Date: 11 February 2016
Storage Conditions: At room temperature at 20 ± 5 °C, in the dark.

Sampling and analysis

Analytical monitoring:
not required

Test substrate

Vehicle:
no
Details on preparation and application of test substrate:
Since the test item is homogeneously dispersible in water (according to a pre-experiment), the test item was applied to the artificial soil by means of an aqueous application solution.
The application solution for the highest test concentration was prepared by mixing 5.000 g of the test item into 1000 mL purified water by ultrasonic treatment for 90 minutes at a temperature of 70 to 80 °C, punctuated by one minute stirring on a magnetic stirrer every ten minutes at room temperature. Thereafter, the application solution was stirred for 30 minutes at room temperature. After this treatment, the test item was homogeneously dispersed in the application solution. Parts of this application solution were further diluted with purified water to obtain the application solutions of the lower test concentrations.
Aliquots of 100 mL of the intensively stirred application solutions were incorporated into the artificial soil (500 g dry weight) of each replicate. The soil was intensely mixed in a laboratory mixer to make sure that the test item was distributed homogeneously in the test medium. Finally, 48.3 mL of purified water was mixed into the soil

Test organisms

Test organisms (species):
Eisenia fetida
Details on test organisms:
The study was performed with earthworms of the species Eisenia fetida. The worms were obtained from a synchronized culture maintained at Harlan Laboratories. During breeding and keeping, they were fed with suitable food (i.e., horse manure and potatoes).
For one day prior to the test start, the test organisms were acclimatized to the artificial soil and test temperature. The individual body wet weight of the test organisms at the start of the test ranged from 306 to 596 mg (the worms were weighed individually at the test start). The worms used were 3–4 months old adults with a clitellum. The age of the worms from the synchronized culture did not differ by more than four weeks.

Study design

Study type:
laboratory study
Substrate type:
artificial soil
Limit test:
no
Total exposure duration:
56 d
Remarks:
Adult earthworms were exposed to the test item for a period of four weeks. After this period, the adults were removed from the test vessels and the cocoons and juvenile earthworms remained in the treated soil for additional four weeks.

Test conditions

Test temperature:
During the entire test period, the room temperature was in the range of 19 to 22 °C.
pH:
The pH value in the test replicates was between 5.7 and 5.8 at the start and at the end of the test as well
Moisture:
Moisture content was 30% at test start and 36-37% at test termination after eight weeks
Details on test conditions:
Plastic boxes (approximate dimensions of length 16.5 cm, width 12 cm, area 200 cm2, height 9 cm) were used as test vessels. Each test vessel contained a defined amount of dry artificial soil, corresponding to a layer depth of approximately 5-6 cm. The test vessels were covered by transparent lids to prevent worms from escaping and to reduce evaporation during the test period. The lids were perforated to allow air exchange. The test vessels were labeled with the study number and all necessary additional information to ensure unique identification.
During the whole test period, they were kept in a temperature-controlled room, set at 20 ± 2 °C under a 16-hour light to 8-hour darkness photoperiod (light intensity within 559-637Lux).
For each treatment, four test vessels (replicates) with ten earthworms each were prepared. Thus, in total 40 test organisms were tested per treatment. However, for the control group, eight test vessels (replicates) with ten earthworms each were prepared, i.e. a total of 80 test organisms.
To demonstrate satisfactory test conditions, a positive control with the reference item Derosal® with the active ingredient carbendazim was performed.
Immediately after soil treatments (see Section 3.3.4), ten of the weighed test organisms were randomly placed on the soil surface of each test vessel.
Nominal and measured concentrations:
nominal concentrations
Reference substance (positive control):
yes
Remarks:
Derosal®

Results and discussion

Effect concentrations
Duration:
56 d
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
reproduction
Details on results:
Survival of Adults and Adverse Effects:
In the control group, the mortality rate of the adult test organisms after four weeks was 0%. Also at all test item concentrations up to and including 1000 mg/kg dry soil, no mortality was observed, with the exception of one dead earthworm in the lowest tested concentration of 62.5 mg/kg dry soil. This mortality rate of 2.5% was not estimated as a significant toxic effect, because according to the test guidelines, a mortality rate up to 10% is considered as natural, and additionally, no concentration-effect relationship was observed.

Growth of Adults:
The mean body weight of the adult worms in the control had increased during the 4-week exposure period on average by 174 mg per worm (45% of the mean initial weight). At all test concentrations of Acetalization product between glucose and C20/22(even numbered)-alcohol, the mean increase in body weight was between 33% and 44% and statistically not significantly different than in the control (results of a Dunnett t-test, two-sided, α = 0.05).

Reproduction:
In the control, an average of 91 juvenile worms per test vessel were found (corresponding to a mean reproduction rate of 9.1 juveniles per surviving adult). The coefficient of variance of the reproduction rate per test vessel in the control was 19%. Thus, the validity criteria of the test guidelines (at least 30 juveniles per test vessel, coefficient of variance of the reproduction ≤30%) were fulfilled. The internal historical mean (for all studies performed since 1999) of resulting juvenile earthworms per control vessel is 154 (SD ± 58).
At all test item concentrations up to and including 1000 mg/kg dry soil, the mean reproduction rates per replicate corresponded to 78-104% of the control value without a concentration-effect relationship. According to the results of a Welch t-test (one-sided smaller, α = 0.05), the mean reproduction rates were not statistically significantly reduced up to and including the highest test item concentration of 1000 mg Acetalization product between glucose and C20/22(even numbered)-alcohol per kg dry soil.
Results with reference substance (positive control):
At the single concentration of the reference item Derosal (8.33 mg formulation/kg dry soil, i.e. 5 mg a.i./kg dry soil), the mortality rate of the adult worms was 0%.
The mean decrease of 10% in body wet weight of the earthworms in the positive control during the exposure period was significantly different to the control (results of a Student-t-test, two-sided, α = 0.05, Table 2).
The reproduction rate of Eisenia fetida in the positive control was nearly completely inhibited.
Therefore, the results of the positive control demonstrated adequate test conditions and the sensitivity of the test animals.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
In conclusion, taking into account the survival, growth and reproduction rates of the exposed adult test organisms, the highest concentration of Acetalization product between glucose and C20/22(even numbered)-alcohol without toxic effects on Eisenia fetida (NOEC) after the test period was determined to be at least 1000 mg/kg dry soil. The NOEC might even be higher, but concentrations in excess of 1000 mg/kg dry soil were not tested. The lowest concentration with toxic effects (LOEC) could not be quantified, but was higher than 1000 mg/kg dry soil.
Executive summary:

The toxic effects of the test item Acetalization product between glucose and C20/22(even numbered)-alcohol on survival, growth, and reproduction of the earthworm Eisenia fetida were assessed during a test period of eight weeks based on the OECD Guidelines for Testing Chemicals, Test No. 222 (April 2004) and the International Standards ISO 11268-2: 1998(E). The test item Acetalization product between glucose and C20/22(even numbered)-alcohol was homogeneously mixed into artificial soil at the following test concentrations: 62.5, 125, 250, 500 and 1000 mg/per kg dry soil. Additionally, a control treatment (substrate without test item) and a reference item treatment (Derosal®) were tested in parallel. Adult earthworms were exposed in treated soils for a period of four weeks. After this period, the adults were removed from the test vessels and the survival and growth rate were determined. The cocoons and juvenile earthworms remained in the vessels for additional four weeks. The reproduction rate was determined by counting the number of offspring hatched from the cocoons after this additional test period.

In conclusion, taking into account the survival, growth and reproduction rates of the exposed adult test organisms, the highest concentration of Acetalization product between glucose and C20/22(even numbered)-alcohol without toxic effects on Eisenia fetida (NOEC) after the test period was determined to be at least 1000 mg/kg dry soil. The NOEC might even be higher, but concentrations in excess of 1000 mg/kg dry soil were not tested. The lowest concentration with toxic effects (LOEC) could not be quantified, but was higher than 1000 mg/kg dry soil. The reproduction rate of Eisenia fetida in the positive control was nearly completely inhibited, confirming adequate test conditions and the sensitivity of the test animals.