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Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 Jul - 12 Aug 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Qualifier:

according to guideline

Guideline:

EU Method C.20 (Daphnia magna Reproduction Test)

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1300 (Daphnid Chronic Toxicity Test)

GLP compliance:

yes (incl. QA statement)

Remarks:

Department of Health, United Kingdom

Analytical monitoring:

yes

Details on sampling:

- Concentrations: control, 1, 10, 100 mg/L
- Sampling method: Samples were taken after 0, 3 (old), 5 (fresh), 7 (old), 10 (fresh), 12 (old), 19 (fresh) and 21 (old) d

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Nominal amounts of test item (5.0, 50 and 500 mg) were each separately added to the surface of 5 liters of test water to give the 1.0, 10 and 100 mg/L loading rates, respectively. After the addition of the test item, the test water was stirred by magnetic stirrer using a stirring rate such that a vortex was formed to give a dimple at the water surface. The stirring was stopped after 95 hours and the mixtures allowed to stand for 1 hour. A wide bore glass tube, covered at one end with Nescofilm was submerged into the vessel, sealed end down, to a depth of approximately 5 cm from the bottom of the vessel. A length of Tygon tubing was inserted into the glass tube and pushed through the Nescofilm seal. Microscopic inspection of the WAFs showed no micro-dispersions or undissolved test item to be present. The aqueous phase or WAF was removed by mid-depth siphoning (the first approximate 75-100 mL discarded) to give the 1.0, 10 and 100 mg/L loading rate WAFs.
- Eluate: no
- Differential loading: yes
- Controls: yes, test medium control

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Source: in-house culture
- Age of parental stock (mean and range, SD): 1st instar Daphnia magna
- Feeding during test: Each daphnid received approximately 5 to 10 μL of an algal suspension (Desmodesmus subspicatus) and approximately 20 μL of Tetramin® flake food suspension daily. Feeding was at a level of approximately 0.1 to 0.2 mg carbon/daphnid/day, dependent on the age and size of the animals. Equal amounts of food were given to each daphnid.
- Culture conditions: Adult daphnia were maintained in 150 mL glass beakers containing Elendt M7 mediumat approximately 20 °C. The lighting cycle was controlled to give a 16 hours light and 8 hours darkness cycle with 20 minute dawn and dusk transition periods. Each culture was fed daily with a mixture of algal suspension (Desmodesmus subspicatus) and Tetramin® flake food suspension. Culture conditions ensured that reproduction was by parthenogenesis. Gravid adults were isolated the day before initiation of the test, such that the young daphnids produced overnight were less than 24 hours old. These young were removed from the cultures and used for testing. The diet and diluent water are considered not to contain any contaminant that would affect the integrity or outcome of the study.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Hardness:

248 - 268 mg/L as CaCO3

Test temperature:

21 - 22 °C

pH:

7.6 - 8.1

Dissolved oxygen:

8.0 - 9.0 mg O2/L

Nominal and measured concentrations:

nominal: control, 1, 10, 100 mg/L
measured control: < LOQ
measured 1 mg/L: < LOQ
measured 10 mg/L: 0.0202 mg/L (3 d), 0.0190 mg/L (5 d), < LOQ (7 d), 0.0181 mg/L (day 10), < LOQ (day 12), < LOQ (day 19), < LOQ (day 21)
measured 100 mg/L: 0.0240 mg/L (3 d), 0.0269 mg/L (5 d), 0.0233 mg/L (7 d), 0.0199 mg/L (day 10), < LOQ (day 12), 0.00780/0.00905 mg/L (day 19, duplicate samples), < LOQ (day 21, duplicate samples)

Details on test conditions:

TEST SYSTEM
- Test vessel: 150 mL glass vessels
- Type (delete if not applicable): closed with a plastic lid
- Material, size, headspace, fill volume: glass, 150 mL, headspace: 50 mL, fill volume: 100 mL
- Aeration: no
- Renewal rate of test solution (frequency/flow rate): renewed 3 times a week on days 3, 5, 7, 10, 12, 14, 17 and 19.
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to guideline
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light / 8 h dark with 20 min transition period
- Light intensity: 592 - 718 lux

EFFECT PARAMETERS MEASURED
- Mobility and length of the parental generation, numbers of live and dead F1 daphnia and the number of discarded unhatched eggs was counted every day.

Reference substance (positive control):

no

Duration:

21 d

Dose descriptor:

EL10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

NOELR

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

LOELR

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

reproduction

Details on results:

- Mortality of parent animals: 0%
- No. of offspring produced per day per female: 99.1 (control), 105.9 (1 mg/L), 103.4 (10 mg/L), 101.7 (100 mg/L)
- Body length and weight of parent animals: After 21 days the length of each surviving adult was determined. The results showed that there were no statistically significant differences (P≥ 0.05) between the control and the 1.0, 10 and 100 mg/L loading rate WAF test groups in terms of length of the daphnids after 21 days exposure to the test item.
- Visual observation of test solutions: clear and colorless (microscopic observation of the WAF)
- Time to first brood release or time to hatch: 7-9 d

Reported statistics and error estimates:

Results from the control and the each test group were compared using one way analysis of variance incorporating Bartlett's test for homogeneity of variance (Sokal and Rohlf 1981) and the Williams test for differences between treatment means when several dose levels are compared with a zero dose control (Williams 1971).

Table 1: Total cumulative production of live young

Nominal loading rate [mg/L]	Day
	1	2	3	4	5	6	7	8	9	10
Control	0	0	0	0	0	0	0	7	87	126
1	0	0	0	0	0	0	0	0	106	159
10	0	0	0	0	0	0	0	9	113	141
100	0	0	0	0	0	0	10	15	103	139

 

Nominal loading rate [mg/L]	Day
	11	12	13	14	15	16	17	18	19	20	21
Control	123	271	323	323	462	504	506	751	775	775	991
1	159	373	396	396	535	553	591	837	858	858	1059
10	141	299	326	326	480	521	527	764	811	811	1034
100	139	209	320	342	498	520	543	746	795	795	1017

Table 2: Body length of surviving adults at day 21

Nominal loading rate [mg/L]	Individual daphnia lengths [mm]
	1	2	3	4	5	6	7	8	9	10
Control	3.9	4.0	3.9	3.9	3.9	4.2	3.8	3.5	3.9	3.9
1	3.9	3.7	4.1	3.8	4.0	3.9	3.8	3.9	4.0	4.0
10	3.9	4.0	4.0	3.9	4.0	3.8	3.8	3.8	3.9	3.9
100	3.9	3.5	3.7	4.1	3.9	3.9	3.9	3.6	3.8	3.8

Reference 2

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Refer to analogue justification provided in IUCLID section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Duration:

21 d

Dose descriptor:

EL10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

NOELR

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

LOELR

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

reproduction

Description of key information

No effects up to the limit of water solubility (OECD 211).

Additional information

Since no studies investigating the long-term toxicity of fatty acids C5-10 esters with dipentaerythritol (CAS 70983-72-1) to aquatic invertebrates are available, in accordance to Regulation (EC) No 1907/2006, Annex XI, 1.5 a read-across to the structurally related source substance carboxylic acids, C5-9, hexaesters with dipentaerythritol (CAS 67762-52-1) was conducted. The source substance carboxylic acids, C5-9, hexaesters with dipentaerythritol is structurally similar to the target substance. Both substances are characterized by the same alcohol component (dipentaerythritol) fully esterified with fatty acids of C7, C8, C9 and C10 (target substance) and C5, C7, C9 (source substance. The difference in the chemical structure between both substances is not considered to affect the toxicity since both substances do not contain any functional group associated with a specific mode of action. This read-across is justified in detail in the analogue justification in IUCLID Section 13.

The study with the source substance was conducted according to OECD 211 (GLP) with Daphnia magna as test organism. Since the test item is poorly soluble in water three different loading rates were prepared (1, 10 and 100 mg/L). The water accommodated fractions (WAFs) were prepared by adding appropriate amounts of the test item to test medium followed by 95 h stirring and 1 h settling period. The aqueous phase was removed by mid-depth siphoning. Microscopic observations did not indicate any undissolved micro-dispersions or undissolved test material. After semi-static exposure for 21 days no significant effects on the survival and reproduction rate were determined. A NOELR (21 d) ≥ 100 mg/L was derived. The validity criteria are met indicating that the study results are considered to be valid (0% mortality of parent animals in control; mean number of living offspring per parent animal in the control: 99.1).

Based on the available result from one structurally related source substance (in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5) which is characterized by a similar ecotoxicological profile and comparable structure, it can be concluded that the same result is expected when testing the target substance.