Isodecyl acrylate

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil macroorganisms except arthropods: long-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-01-10 to 2017-08-03

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 222 (Earthworm Reproduction Test (Eisenia fetida/Eisenia andrei))

Deviations:

yes

Remarks:

Minor deviations not considered to have affected the outcome of the study: temperature ranged from 18.1 to 22.6°C (Study plan: 18.0 - 22°C). Worms partly below the minimum weight at the beginning of the trial: 302-600mg (Study Plan: 400-600 mg).

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Details on preparation and application of test substrate:

Composition of Artificial Soil
Sphagnum Peat
10 % of dry matter of artificial soil.
The peat was air dried and pulverized before use.

Kaolin Clay
20 % of dry matter of artificial soil.
Bolus alba (white clay), pharmaceutical quality.

Quartz Sand
70 % of dry matter of artificial soil.
Fine quartz sand (round grains) was used.

Calcium Carbonate CaCO3
Analytical grade, used for pH adjustment.

Preparation of Artificial Soil
The dry constituents of the soil were mixed thoroughly in a well-ventilated area.

Determination of Maximum Water Holding Capacity (WHC)
WHC of the artificial soil was determined in accordance with procedures described in the guideline. A defined quantity (19.6 g) of the test soil substrate was collected using a glass tube. The bottom of the tube was covered with a piece of filter paper and then placed on a rack in a water bath. The tube was gradually submerged until the water level was above to the top of the soil. It was then left in the water for 3 hours. Since not all water absorbed by the soil capillaries could be retained, the soil sample was allowed to drain for a period of 2 hours by placing the tube onto a bed of very wet finely ground quartz sand contained within a covered vessel (to prevent drying).

The sample was weighed and dried to a constant mass at 105 °C and then weighed again. The water holding capacity (WHC) could then be calculated as follows:

WHC(in % dry soil)=(S-T-D)/D*100
Where:
S = water-saturated substrate + mass of tube + mass of filter paper
T = tare (mass of tube + mass of filter paper)
D = dry mass of substrate
The water holding capacity (WHC) was determined as 74.13 % related to dry soil.

Preparation of test soil
The constituents were mixed to obtain a homogeneous substrate. The pH of the final mix-ture was measured as 6.0.
A small part of this mixture was used for the 24 hour acclimatisation of the animals used in this test.
The artificial soil described above was divided into 10 portions of an appropriate amount (e.g. 550 g per replicate, or 4400 g total for the blank control group and 2200 g per treat-ment group) The required amount of test item was added to each portion using amounts of demineralised water need for the adjustment of the water content of the artificial soil to 40% to 60% of the maximum water holding capacity calculated in relation to dry matter. For the blank control only deionised water was used. Afterwards it was well mixed. Then, the soil portions were divided into 8 (blank control) or 4 (treatments) portions of 500 g dry weight and each portion was put into a 1 l glass preserving jar.

Test organisms (species):

Eisenia andrei

Animal group:

annelids

Details on test organisms:

Specifications
Species/Strain: Eisenia andrei BOCHÉ
Age: at least 2 months with clitellum
Weight: 302 – 600 mg (range in this study)

Animal Rearing
Eisenia andrei is bred in the LAUS GmbH throughout the year. The animals are kept for the use in toxicity tests. The keeping is performed following SOP 11501001 (“Hälterung von Eisenia andrei“), edition 7, valid from 17. March 2014 which is in accordance to OECD Guideline 222.
Vessels: polyethylene containers with a volume of 20 L
Medium: horse dung

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

56 d

Test temperature:

18.1 - 22.6 °C ambient temperature

pH:

5.8 - 6.3

Moisture:

WHC (%): 53.83 - 56.71

Details on test conditions:

Duration 56 days
Observation times 28 days and 56 days after the beginning of the trial
Lightning Photoperiod 16 h with 800 lux (Osram L 18 W/840 tubes, cool white spectrum)
Test vessel glass preserving jars, nominal volume 1 L
Replicates (Blank Control) 8 vessels, each containing 500 g artificial soil (dry weight) and 10 worms
Replicates (Treatments) 4 vessels, each containing 500 g artificial soil (dry weight) with test item and 10 worms

Nominal and measured concentrations:

Treatments test item 0.1 / 0.32 / 1 / 3.2 / 10 / 32 / 100 / 320 / 1000 mg/kg (dry matter) nominal concentration

Reference substance (positive control):

no

Remarks:

Benomyl (CAS-No. 17804-35-2) was used as positive control and was tested in a separate reference GLP study (16051903R1007) in August 2016.

Key result

Duration:

56 d

Dose descriptor:

NOEC

Effect conc.:

3.2 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Mortality, reproduction and weight change

Duration:

56 d

Dose descriptor:

EC10

Effect conc.:

0.19 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

56 d

Dose descriptor:

EC50

Effect conc.:

11 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Results with reference substance (positive control):

The 56d-EC50 of Benomyl (CAS-No. 17804-35-2) was tested in a current reference test. The value was determined as 1.4 mg/kg dry soil, lying within the required range of OECD Guideline 222 of 1 – 5 mg/kg.

Mortality of Adult Worms

Mortality of adult animals is presented in the following table.

Table8.1-a      Mortality after 28 days of adult worms

Concentration in mg/kg	Replicate No.	No. of living Worms after 28 Days	Mean Mortality of Adult Worms after 28 Days in %
Blank control	1	10	0.00%
	2	10
	3	10
	4	10
	5	10
	6	10
	7	10
	8	10
0.1	1	10	0.00%
	2	10
	3	10
	4	10
0.32	1	10	0.00%
	2	10
	3	10
	4	10
1	1	10	0.00%
	2	10
	3	10
	4	10
3.2	1	10	0.00%
	2	10
	3	10
	4	10
10	1	10	0.00%
	2	10
	3	10
	4	10
32	1	10	0.00%
	2	10
	3	10
	4	10

100	1	10	0.00%
	2	10
	3	10
	4	10
320	1	8	30.00%
	2	5
	3	8
	4	7
1000	1	0	100.00%
	2	0
	3	0
	4	0

 

Weight Change Adult Worms

Weight variation of adult animals is presented in the following table.

Table8.2-a      Weight change adult worms in 28 days

Concentration in mg/kg	Replicate No.	Total Weight Worms Day 0 in g	Total Weight Worms Day 28 in g	Weight Change Worms after 28 Days in %	Mean Weight Change Worms after 28 Days in %	Mean Weight Worms Day 28 in mg
Blank control	1	4.191	4.029	-4%	-2%	4.264
	2	4.600	4.241	-8%
	3	4.345	4.495	3%
	4	4.291	3.760	-12%
	5	4.613	4.121	-11%
	6	4.296	4.387	2%
	7	4.140	4.313	4%
	8	4.439	4.762	7%
0.1	1	4.047	4.360	8%	13%	4.471
	2	3.830	4.473	17%
	3	3.913	4.507	15%
	4	4.103	4.543	11%
0.32	1	4.007	3.981	-1%	4%	4.254
	2	3.968	4.312	9%
	3	4.494	4.522	1%
	4	3.946	4.202	6%
1	1	4.213	4.199	0%	5%	4.309
	2	3.927	3.744	-5%
	3	4.408	4.772	8%
	4	3.891	4.520	16%
3.2	1	4.011	4.389	9%	7%	4.658
	2	4.421	4.618	4%
	3	4.448	4.961	12%
	4	4.520	4.662	3%
10	1	4.137	4.742	15%	7%	4.459
	2	4.158	4.360	5%
	3	4.221	4.352	3%
	4	4.094	4.381	7%
32	1	3.989	4.247	6%	12%	4.542
	2	4.231	4.877	15%
	3	3.902	4.610	18%
	4	4.146	4.434	7%

100	1	4.297	5.087	18%	13%	4.669
	2	4.207	4.568	9%
	3	4.095	4.589	12%
	4	3.913	4.434	13%
320	1	4.233	3.834	-9%	-21%	3.153
	2	3.769	2.363	-37%
	3	3.742	3.136	-16%
	4	4.072	3.278	-19%
1000	1	4.257	0.000	-100%	-100%	0.000
	2	4.566	0.000	-100%
	3	4.375	0.000	-100%
	4	4.355	0.000	-100%

 

Reproduction

Reproduction in the single replicates is presented in the following table.

Table8.3-a      Number of juveniles produced after 56 days

Concentration in mg/kg	Replicate No.	Number of Juvenile Worms after 56 Days	Mean Number of Juvenile Worms after 56 Days	Inhibition of Reproduction compared to Blank control after 56 Days in %
Blank control	1	113	95	0.00
	2	109
	3	101
	4	86
	5	91
	6	94
	7	82
	8	87
0.1	1	72	80	16.12%
	2	101
	3	71
	4	76
0.32	1	87	73	23.20%
	2	61
	3	86
	4	59
1	1	106	88	7.73%
	2	66
	3	125
	4	55
3.2	1	56	60	37.61%
	2	102
	3	60
	4	20
10	1	40	46	51.77%
	2	55
	3	46
	4	43
32	1	45	38	59.90%
	2	44
	3	37
	4	27

100	1	46	32	66.19%
	2	37
	3	28
	4	18
320	1	2	3	96.59%
	2	4
	3	0
	4	7
1000	1	1	0	99.74%
	2	0
	3	0
	4	0

 

 pH, Water Content

The water content and the pH values were measured in each treatment at the start of the test and in the first replicate of each treatment at the end of the test.

The measured soil parameters are presented in the following table.

Table8.4-a      pH values and water content

Concentration in mg/kg	pH Value Day 0	Water Content in % of WHC Day 0	Vessel No. Day 56	pH Value Day 56	Water Content in % of WHC Day 56
Blank control	5.8	51.95	1	5.9	56.71
0.1	5.9	52.20	9	6.0	54.59
0.32	5.9	50.92	13	6.0	55.46
1	5.8	51.55	17	6.1	54.48
3.2	6.1	51.97	21	6.2	53.83
10	6.0	51.33	25	6.1	56.25
32	6.0	51.99	29	6.1	56.33
100	6.2	51.08	37	6.3	56.44
320	6.2	52.01	33	6.1	55.77
1000	6.2	52.25	41	5.9	55.24

 

Validity criteria fulfilled:

yes

Conclusions:

The study was performed using 9 concentrations ranging from 0.1 to 1000 mg/kg dry soil. In each replicate, ten adult animals were exposed to the test item for 28 days in an artificial soil. After 28 days, the living adult animals were counted, and 56 days after the beginning of the trial, the number of juveniles produced was determined.

Five concentrations showed statistically significant inhibition of reproduction ranging from 52 to 100% compared to the control. Two concentrations showed mortality of the adult animals ranging between 30 % and 100 % after 28 days. None of the adult animals were found dead in the blank control after 28 days.

The 56d-EC50 of Benomyl (CAS-No. 17804-35-2) was tested in a current reference test. The value was determined as 1.4 mg/kg dry soil, lying within the required range of OECD Guideline 222 of 1 – 5 mg/kg.

No observations were made which might cause doubts concerning the validity of the study outcome. All validity criteria were met.

The result of the test can be considered valid.

Executive summary:

The study was performed using 9 concentrations ranging from 0.1 to 1000 mg/kg dry soil. In each replicate, 10 adult animals were exposed to the test item for 28 days in an artificial soil. After 28 days, the living adult animals were counted, and 56 days after the beginning of the trial, the number of juveniles produced was determined.

Five concentrations showed statistically significant inhibition of reproduction ranging from 52 to 100% compared to the control. Two concentrations showed mortality of 30 % (320 mg/kg nominal concentration) and 100 % (1000 mg/kg nominal concentration) of the adult animals after 28 days. None of the adult animals were dead in the blank control after the first 28 days.

 

The 56d-EC50 of Benomyl (CAS-No. 17804-35-2) was tested in a current reference test. The value was determined as 1.4 mg/kg dry soil, lying within the required range of OECD Guideline 222 of 1 – 5 mg/kg dry soil.

 

No observations were made which might cause doubts concerning the validity of the study outcome. The offspring number in each blank control replicate, the coefficient of variation of reproduction in the blank controls and adults mortality in the blank controls were all within the stated validity criteria in the guideline. All validity criteria were met.

 

The following results were determined for the test item Isodecyl acrylate (species: Eisenia andrei).

Parameter	Value	95% confidence interval
28d LC50	355 mg/kg	not determinable*
NOEC 56d	3.2 mg/kg	--
LOEC 56d	10 mg/kg	--
56d EC10	0.19 mg/kg	0.03 - 0.58 mg/kg
56d EC50	11 mg/kg	5.5 - 21 mg/kg

*not determined due to mathematical reasons or inappropriate data

 

Note: According to the guideline, NOEC is determined by comparing of the respective treatment with the blank control. Statistically insignificant variation is considered as “no observed effect”, although the EC10 which is read from the graph toxicity vs. concentration may lie lower.

Description of key information

The chronic toxicity of Isodecyl Acrylate (CAS 1330-61-6) to earthworms was tested in an experiment performed according to the OECD Test Guideline 222 and to GLP requirements.

The 56-day NOEC was 3.2 mg/kg dry soil and the 56-day EC10 was estimated to be 0.19 mg/kg dry soil (95% confidence interval: 0.03 - 0.58 mg/kg dry soil). The 56-day EC50 was calculated to be 11 mg/kg dry soil (5.5 - 21 mg/kg dry soil).

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for soil macroorganisms:

3.2 mg/kg soil dw