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Short-term toxicity to aquatic invertebrates

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Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Justification for type of information:
α-Pinene is a bicyclic monounsaturated monoterpene and (-)-α-pinene is an enantiomeric form of α-pinene. Therefore, data on (-)-alpha pinene can be extrapolated to alpha-pinene. (see read-across justification document in section 13).
Reason / purpose:
read-across source
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
0.475 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
other: mobility and behaviour
Remarks on result:
other: 95 % CL = 0.248-1.132
Details on results:
See table 6.1.3/2.
- Mortality of control: No
- After 24 h of exposure, immobilizations were 0, 0, 0, 0, 0, 25 and 50 % at 0, 0.156, 0.242, 0.361, 0.511, 0.685 and 1.190 mg/L, respectively. After 48 h of exposure, immobilizations were 0, 0, 35, 40, 35, 60 and 100 % at the respective concentrations.
- EC50 values at 24 and 48 h were 1.124 (0.934-1.598) and 0.475 (0.248-1.132) mg/L respectively, based on the average of measured concentrations.
Results with reference substance (positive control):
- Results with reference substance valid: Yes
- Historical data (dated: 09 January 2013): EC50 (24 h): 0.97 mg/L
Reported statistics and error estimates:
- Effective concentrations including the 95 % confidence intervals were determined using Probit analysis by the software ToxRat® Professional.

Table 6.1.3/2: Acute immobilization of daphnids after 24 and 48 hours in the final test

Nominal concentration (mg/L)

Replicate

Number of daphnids exposed

Response at 24 h

Response at 48 h

Number

Total %

Number

Total %

Control

1

2

3

4

5

5

5

5

0

0

0

0

0

0

0

0

0

0

0.2

1

2

3

4

5

5

5

5

0

0

0

0

0

0

0

0

0

0

0.3

1

2

3

4

5

5

5

5

0

0

0

0

0

1

3

1

2

35

0.4

1

2

3

4

5

5

5

5

0

0

0

0

0

2

4

1

1

40

0.7

1

2

3

4

5

5

5

5

0

0

0

0

0

3

1

1

2

35

1.0

1

2

3

4

5

5

5

5

1

2

2

0

25

2

4

4

2

60

1.5

1

2

3

4

5

5

5

5

3

2

2

3

50

5

5

5

5

100

Validity criteria fulfilled:
yes
Remarks:
mortality in control < 10 % (no immobilisation observed); dissolved oxygen concentration at the end of test ≥ 60 % of the air-saturation value in all vessels
Conclusions:
The 48 h EC50 for (-)-alpha-pinene to Daphnia magna was estimated to be 0.475 (0.248-1.132) mg/L, based on the average of measured concentrations.
Executive summary:

An acute aquatic toxicity study was performed on Daphnia magna with (-)-alpha-pinene in accordance with GLP and OECD Guideline 202. Following a preliminary range-finding test and a previous test, twenty daphnids (four replicates, five daphnids/replicate) were exposed to an aqueous solution of the test item, (-)-alpha pinene, at the required nominal test concentrations of 0.2, 0.3, 0.4, 0.7, 1.0 and 1.5 mg/L. The immobility of the daphnids was determined in a semi-static 48-h test by visual observation after 24 and 48 h.

The concentrations of the test item were determined by chemical analyses at the start (t = 0 h), at t = 24 h (new and old solutions) and at the end of the test (t = 48 h). The test item levels were found to be not stable throughout the test. Indeed, concentrations measured in freshly prepared solutions and in 24-h old solutions revealed that the concentration of the test item was not satisfactorily maintained within ± 20 % of the initial concentration throughout the test. Thus, the evaluation of the effects on Daphnia magna was based on the geometric means of the measured concentrations: 0.156, 0.242, 0.361, 0.511, 0.685 and 1.190 mg/L.

After 24 h of exposure, immobilizations were 0, 0, 0, 0, 0, 25 and 50 % at 0, 0.156, 0.242, 0.361, 0.511, 0.685 and 1.190 mg/L, respectively. After 48 h of exposure, immobilizations were 0, 0, 35, 40, 35, 60 and 100 % at the respective concentrations. The EC50 values at 24 and 48 h were 1.124 (0.934-1.598) and 0.475 (0.248-1.132) mg/L respectively, based on the average of measured concentrations.

Description of key information

48h-EC50 for freshwater invertebrates of (-)-alpha-pinene was 0.475 mg/L.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
0.475 mg/L

Additional information

One reliable study is available for (-)-alpha-pinene and is selected as key study. The toxicity of (-)-alpha pinene to freshwater Daphnia magna was studied according to OECD 202 and GLP. Daphnids were exposed to substance at nominal test concentrations of 0.2, 0.3, 0.4, 0.7, 1.0 and 1.5 mg/L over a test period of 48 hours (semi-static test, daily renewal, closed conditions). Concentrations were analytically verified at the start and daily until the end of the test (old and new test media). The concentration of the test item was not satisfactorily maintained within ± 20% of the initial concentration throughout the test. Thus, the endpoint was based on the geometric means of the measured concentrations. The 48h-EC50 was determined to be 0.475 mg/L, the EC0 and EC100 were 0.156 mg/L and 1.190 mg/L, respectively.

Thus the 48h-EC50 is valid for key value for chemical safety assessment.