Isotridecanol, ethoxylated

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:

17 May - 11 Jul 2019

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))

Version / remarks:

2016

Principles of method if other than guideline:

Food was provided on day 0 (test start) instead of day 1 due to good experience with this procedure. At test end, the soil moisture deviated by more than 10 % from the initial value in the control and the treatment rates 62.5 to 1000 mg test item/kg SDW. The room temperature decreased to minimum 16 °C and increased to maximum 23 °C for in total about 44 h corresponding to 3.33 % of the definitive exposure time. These deviations are considered to have no impact on quality and integrity of the study.

GLP compliance:

yes

Remarks:

Staatliches Gewerbeaufsichtsamt Hildesheim, Germany

Analytical monitoring:

yes

Details on sampling:

- Concentrations: control and 62.5, 125, 250, 500, 1000 and 2000 mg test item/kg SDW (day 0, 55)
- Sampling method: pooled samples of all respective replicates

Vehicle:

no

Details on preparation and application of test substrate:

- Method of mixing into soil: respective test item amount for each test item concentration was weighed out, dispersed in demineralised water (200 mL) and added to the artificial soil (2440 g SDW). test medium was thoroughly mixed to ensure a homogenous distribution.

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

TEST ORGANISM
- Common name: earthworm
- Source: breeding stock culture maintained at the test facility
- Age at test initiation: 2-12 months, difference of age did not deviate by more than 1 month
- Weight at test initiation: 0.35 - 0.58 g

ACCLIMATION
- Acclimation period: 2 days

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

8 wk

Test temperature:

16 - 23°C

pH:

6.23 - 6.80

Moisture:

19.4 - 25.6% of dry weight

Details on test conditions:

TEST SYSTEM
- Test container: round plastic boxes (diameter: 15 cm, bottom surface area: 177 cm2 , height: 14 cm)
- Amount of soil or substrate: 610 g
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4
- No. of replicates per control: 8

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Composition (if artificial substrate): 5 % peat, air-dried and finely ground, 20 % kaolin (kaolinite content > 30 %), 74 % air-dried quartz sand (sand with > 50 % particle size of 0.05 - 0.2 mm), 0.25 % calcium carbonate (CaCO3) to achieve a pH of 6.0 ± 0.5)
- Maximum water holding capacity: 27%
- Pretreatment of soil: Two days before test start the artificial soil was pre-moistened with demineralised water to achieve a moisture content corresponding to 27 % of the WHCmax of the artificial soil.
- Storage: The moistened soil was kept covered to prevent evaporative water losses.

OTHER TEST CONDITIONS
- Photoperiod: 16 h light and 8 h dark
- Light intensity: 400 - 800 lux

EFFECT PARAMETERS MEASURED: day 0 and 28: body weight, day 28: mortality and morphological changes of the adult, day 56: number of offspring (juveniles)

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study
- Test concentrations: 1, 10, 100, 1000 mg/kg SDW
- Results used to determine the conditions for the definitive study: Mortality after 14 days: 0% (control), 0% (1 mg/kg SDW), 0% (10 mg/kg SDW), 0% (100 mg/kg SDW), 5% (1000 mg/kg SDW)

Nominal and measured concentrations:

Nominal concentrations: 0 (control), 62.5, 125, 250, 500, 1000, 2000 mg/kg SDW
Mean mesured concentrations: day 0: < LOQ (control), 64.1, 120, 229, 507, 1014, 1913 mg/kg SDW, day 7: 1629 mg/kg SDW (2000 mg/kg SDW), day 55: < LOQ (control), < LOQ, 24.8, 47.1, 88.5, 241 mg/kg SDW (2000 mg/kg SDW not determined)

Reference substance (positive control):

yes

Remarks:

Carbendazim

Duration:

56 d

Dose descriptor:

EC10

Effect conc.:

122 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: 95% confidence limits: 155 - 129 mg/kg soil dw

Duration:

56 d

Dose descriptor:

NOEC

Effect conc.:

125 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Details on results:

- Mortality at end of exposure period: 6.25 (control), 2.5, 0, 2.5, 0, 15, 100%
- Total mass of adults at beginning of test: 610 g
- Changes in body weight of live adults (% of initial weight) at end of exposure period: 12.3 (control), 7.63, 7.10, 2.13, 8.25, 2.78, - %

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels: LOEC: 1 mg/kg SDW

Table 1: Mortality of Adult Earthwormsin [%]after 28 Days of Exposure

 

Application rate	Replicate
[mg test item/kg SDW]	1	2	3	4	5	6	7	8	Mean
Control	0	0	0	10	30	0	0	10	6.25
62.5	10	0	0	0	-				2.5
125	0	0	0	0					0
250	0	0	0	10					2.5
500	0	0	0	0					0
1000	30	10	20	0					15
2000#	100	100	100	100					100

#) 100 % mortality on day 7

Table 2: Body Weight Changes of the Adult Earthworms

 

Application rate [mgtestitem/kg SDW]	Replicate	Mean body weights per replicate		Mean body weight change of earthworms
		Test start	28 days	Per replicate		Mean ± SD		Sig.
		[g]	[g]	[g]	[%]	[g]	[%]
Control	1	0.46	0.51	0.05	10.9	0.06 ± 0.01	12.3 ± 2.61	–
	2	0.45	0.51	0.06	13.3
	3	0.46	0.50	0.04	8.7
	4	0.46	0.52	0.06	13.0
	5	0.45	0.49	0.04	8.9
	6	0.45	0.52	0.07	15.6
	7	0.46	0.52	0.06	13.0
	8	0.46	0.53	0.07	15.2
62.5	1	0.45	0.46	0.01	2.2	0.04 ± 0.02	7.63 ± 5.15	No
	2	0.46	0.52	0.06	13.0
	3	0.45	0.47	0.02	4.4
	4	0.46	0.51	0.05	10.9
125	1	0.46	0.48	0.02	4.3	0.03 ± 0.02	7.10 ± 3.38	No
	2	0.46	0.48	0.02	4.3
	3	0.45	0.50	0.05	11.1
	4	0.46	0.50	0.04	8.7
250	1	0.45	0.41	-0.04	-8.9	0.01 ± 0.04	2.13 ± 9.32	No
	2	0.45	0.44	-0.01	-2.2
	3	0.46	0.50	0.04	8.7
	4	0.46	0.51	0.05	10.9
500	1	0.45	0.48	0.03	6.7	0.04 ± 0.02	8.25 ± 4.82	No
	2	0.46	0.47	0.01	2.2
	3	0.46	0.52	0.06	13.0
	4	0.45	0.50	0.05	11.1
1000	1	0.46	0.41	-0.05	-10.9	0.01 ± 0.04	2.78 ± 9.54	Yes
	2	0.45	0.50	0.05	11.1
	3	0.46	0.49	0.03	6.5
	4	0.45	0.47	0.02	4.4
2000	1	0.45	#	#	#	#	#	#
	2	0.46	#	#	#
	3	0.46	#	#	#
	4	0.45	#	#	#

#) not determinable due to 100 % mortality

SD = Standard deviation

Sig. = Statistical Significance (Step-down Jonckheere-Terpstra Test Procedure, α = 0.05) compared  to control

Table 3: Reproduction Rate (Number of Juveniles after 8 Weeks)

 

Application rate [mg test item/kgsoildry weight]	Replicate	Number of juveniles	Mean ± SD	CV [%]	[%] of control	Sig.
Control	1	131	124 ± 16.9	13.7	-	-
	2	140
	3	128
	4	135
	5	87
	6	119
	7	136
	8	119
62.5	1	126	123 ± 13.1	10.7	99.2	No
	2	128
	3	134
	4	104
125	1	123	119 ± 11.2	9.37	96.0	No
	2	103
	3	120
	4	129
250	1	44	59 ± 11.1	18.9	47.6	Yes
	2	67
	3	68
	4	58
500	1	53	22 ± 21.9	99.5	17.7	Yes
	2	4
	3	19
	4	10
1000	1	0	0 ± 0	0	0	Yes

SD = Standard deviation       

CV = Coefficient of variation

Sig. = Statistical Significance (William’s Multiple Sequential t-test Procedure, α = 0.05) compared to the control

Table 4: Validity criteria for OECD 222.

Criterion from the guideline to be satisfied in the controls	Outcome	Validity criterion fulfilled
Each replicate (containing 10 adults) to have produced ≥ 30 juveniles by the end of the test.	124	yes
The coefficient of variation of reproduction is ≤ 30%.	13.7%	yes
Adult mortality over the initial 4 weeks of the test is ≤ 10%.	6.25%	yes

Validity criteria fulfilled:

yes

Remarks:

For further details, refer to "Any other information on results incl. tables"

Description of key information

NOEC (56 d): 125 mg/kg soil dw (OECD 222)

Key value for chemical safety assessment

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

125 mg/kg soil dw

Additional information

One long-term study investigating the toxicity of Isotridecanol, ethoxylated on earthworms is available. The study was conducted with Eisenia fetida using artificial soil as test substrate (OECD 222). Earthworms were exposed to nominal concentrations of 62.5, 125, 250, 500, 1000, 2000 mg/kg soil dw. The test concentrations were analytically verified by LC MS/MS at days 0, 7 and 55. At day 28 of the study the mortality, body weight and morphological changes of adult worms was determined. No mortalities or differences in earthworm biomass occurred at test substance concentrations 62.5- 500 mg/kg soil dw. At the test item concentrations 1000 mg/kg and 2000 mg/kg 15 % and 100 % mortality occurred, respectively. At 1000 mg/kg the earthworm weight was significantly reduced compared to the control. The offspring was counted at day 56. No statistically significant differences in earthworm reproduction were observed at 62.5 and 125 mg/kg soil dw compared to the control. At test concentrations 250 to 1000 mg/kg soil dw the earthworm reproduction was statistically significantly reduced.

Based on the reproduction rate a NOEC 56 d of 125 mg/kg soil dw (nominal) was recorded.