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Long-term toxicity to aquatic invertebrates

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Description of key information

The NOEC based on reproductive output is = 1 mg/l

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater invertebrates:
1 mg/L

Additional information

The chronic toxicity of the test item Tall oil, compound with diethanolamine to the water fleaDaphnia magna was investigated in a reproduction test according to OECD guideline 211 under semi-static exposure conditions over a period of 21 days.

The test item is a poorly soluble UVCB substance. The test solutions consisted of Water Accomodated Fractions (WAFs) prepared separately for each test concentration by weighing the respective amount of test item in test water, stirring the resulting suspension for about 3 hours at room temperature in the dark and filtering it with glass fiber filter. The test media were replaced three times per week: each Monday, Wednesday and Friday of the test the test solutions were freshly prepared.

The loading rates tested were100, 31.6, 10, 3.16 and 1.00 mg/l.

Ten individual daphnids were exposed to each test concentration. A control was tested in parallel.

The test concentrations were determined by means of dissolved organic carbon (DOC) analysisat days 0, 9 and 19. These analyses confirmed the very limited solubility of the test item. The assessment of the toxicity was based on the loading rates of the test item.

A significant dose-dependent mortality was observed: at the loading rate of 100 mg/l, 9 out of 10 parental daphnids died, and at 31.6 mg/l 6 parental daphnids died over the course of the test. At all lower loading rates 10.0. 3.16 and 1.00 mg/l and in the control, no mortality was observed.

The time needed for each parental animal to produce the first living offspringwas on average 8.8, 7.7, 7.5, 11.0, 8.0 and 7.9 days in the100, 31.6, 10, 3.16 and 1.00mg/l loading rates and the control, respectively.

With respect to the endpoint reproductive output, the following effects compared to the control were observed: 76.9% at 100 mg/l loading rate, 44.2% at 31.6 mg/l, 7.9% at 10.0 mg/l and 8.4 % at 3.16 mg/l. No significant effects were observed at 1.00 mg/l.

With respect to the endpoint intrinsic rate of population increase, the following effects compared to the control were observed: 68.6% at 100 mg/l loading rate and 36.8% at 31.6 mg/l. No significant effects were observed at 10.0, 3.16 and 1.00 mg/l.

The results of the inhibition on the reproductive output as well as on the intrinsic rate of population increase of the test item onDaphnia magnaare summarized in the following table based on the loading rates:

Parameter (0-21 d)

Reproductive output

[mg/l]

Intrinsic rate of population increase [mg/l]

EC10

8.30

12.7

LOEC

3.16

31.6

NOEC

1.00

10.0

All validity criteria were fulfilled.

Based on the NOEC value, calculated for the reproductive output in the long-term toxicity study on Daphnia Magna, the test substance should be classified as Category Chronic 3 for the aquatic environment.