2-benzylheptanol

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 2000-10-17 and 2000-10-19

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

1992

Deviations:

yes

Remarks:

The EC50 value was calculated as geometric mean of EC0 and EC100 and furthermore the lower concentrations were not analytically determined.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

The EC50 value was calculated as geometric mean of EC0 and EC100 and furthermore the lower concentrations were not analytically determined.

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Sampling schedule of the chemical analysis:
- Stock solution: at 0 hours
- Control: at 0 and 48 hours
- Test concentrations: at 0 and 24 hours
The test concentrations 0.5, 1 and 2 mg/L were not analytically determined as the measured concentrations to be expected were below the quantitation limit of the TOC determination method (2 mg/L).
- Stock solution: The stock solution was prepared to give the desired series of test concentrations. To achieve this 54.2 mg of the test substance were added to 1 litre of dilution water.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Preparation of the test solution: The dilution water was treated with an ultra turrax for 60 seconds and afterwards stirred for 24 h an a magnetic stirrer.
- Test water: M4 Medium
- Method: stock solution
- Controls: yes. Blank control
- Evidence of undissolved material: yes. The undissolved particles of the test substance were removed by filtration.

Test organisms (species):

Daphnia magna

Details on test organisms:

ACCLIMATION
- Acclimation period: A population of parthenogenetic females of synchronized age structure is maintained since more than 15 years in the test facility.
- Acclimation conditions: constant temperature conditions (20 +/- 1 °C) at a 16 : 8 hour
light-dark photoperiod (illumination: < 1000 lux). The culture water (so-called “M4 medium”) is partly renewed once a week.
- Type and amount of food: The Daphnia are exclusively fed with unicellular green algae (Scenedesmus subspicatus CHODAT)
- Feeding frequency: ad libitum
- Health during acclimation (any mortality observed): Mortalities of parent Daphnia during the culture period are recorded daily in a semiquantitative way, no mortality is observed.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

Not performed

Hardness:

15.4 °dH (274.9 mg/L CaCO3)

Test temperature:

20 - 20.5 °C

pH:

7.6 - 7.8

Dissolved oxygen:

8.4 - 8.7 mg/L
95.1 - 98.4 %

Salinity:

No data

Conductivity:

No data

Nominal and measured concentrations:

- Nominal concentrations: 0.5, 1, 2, 4 and 8 mg/L
- Measured concentrations: Measured concentrations of the nominal concentrations 4 and 8 mg/L, which were checked for their TOC, ranged from 105 -120 % of nominal values at 0 hours, and correspond to 120% of nominal values at 24 hours, respectively. TOC values were calculated corresponding to the analytical recovery rate of the highest test concentration as the concentration to be measured was below the quantitation limit of the TOC method (2 mg/L).

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers
- Volume of the test vessels: 50 mL
- Aeration: None
- Type of system: static
- No. of organisms per vessel: 10 neonates per vessel
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 0
- No. of vessels per vehicle control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water (so-called “M4 medium”, originally described in Water Research 24 (9): 1157-1167), prepared according to the recommendations of Bundesgesundheitsamt Berlin. This standard dilution water is used for both, the maintenance of the test animals and the preparation of stock and test solutions of the test substance.
- Culture medium different from test medium: No
- Intervals of water quality measurement: Temperature, oxygen, and pH value were measured after 24 and 48 hours.

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 : 8 hours (light-dark)
- Illumination: < 1000 lux

EFFECT PARAMETERS MEASURED: Alteration of the normal mobility behaviour and the loss of locomotory actions of the neonates, observed at 24 and 48 hours.

TEST CONCENTRATIONS
- Range finding study: yes
- Test concentrations (nominal): 0.5, 1, 2, 4 and 8 mg/L
- Measured concentrations: Measured concentrations of the nominal concentrations 4 and 8 mg/L, which were checked for their TOC, ranged from 105 — 120 % of nominal values at 0 hours, and correspond to 120% of nominal values at 24 hours, respectively. TOC values were calculated (corresponding to the analytical recovery rate of the highest test concentration) as the concentration to be measured was below the quantitation limit of the TOC method (2 mg/L).

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

EC0

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC100

Effect conc.:

2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

1.2 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

2.3 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

other: Geometric mean EC0/EC100

Effect conc.:

1.7 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Behavioural abnormalities:
- Mortality of control: No mortality
- Other adverse effects control: No found
- Abnormal responses: No data was provided.
- Effect concentrations exceeding solubility of substance in test medium: No

Results with reference substance (positive control):

Not performed

Reported statistics and error estimates:

Not performed

Table 1: Immobilisation of Daphnia magna after 24 and 48 h

Nominal concentration test substance [mg/L]	Immobile daphnids
	absolute		Cumulative %
	24 h	48 h	24 h	48 h
Control	0	0	0	0
0.5	0	0	0	0
1	0	0	0	0
2	20	0	100	100
4	20	0	100	100
8	20	0	100	100

 

 

Table 2: Results - Analysis

Nominal concentration test substance [mg/L]	Chemical analysis
	TOC values [mg/L]		Test substance [mg/L]
	0 h	48 h	0 h	48 h
Control	< 2	< 2	-	-
0.5	0.44	0.5	0.53	0.6
1	0.9	1	1.1	1.2
2	1.8	2	2.1	2.4
4	4	4*	4.8	4.8*
8	7	8*	8.4	9.6*

 

TOC values were calculated (corresponding to the analytical recovery rate of the highest test concentration) as the concentration to be measured was below the quantitation limit of the TOC method ( 2 mg/L).

* The figures marked by asterisk have already been measured after 24 hours of exposure because of early 100 % immobilisation rates of the daphnids.

Validity criteria fulfilled:

yes

Conclusions:

The EC50 was calculated to be 1.7 mg/L (geom. mean of EC100 and EC0), the EC100 was determined to be 2.3 mg/L (geom. mean measured) and the EC0 was determined to be 1.2 mg/L (geom. mean measured).

Executive summary:

In a static key immobilization test Daphnia magna (< 24 h old) were exposed to the test item for 48 hours according to OECD 202 (1992) under GLP conditions. The Daphnia were exposed to a range of concentrations, nominally 0.5, 1, 2, 4 and 8 mg/L of the test substance dissolved in water.  Measured concentrations ranged from 105 - 120 % of nominal values at 0 hours, and correspond to 120% of nominal values at 48 hours, respectively. The EC50 was calculated to be 1.7 mg/L (geom. mean of EC100 and EC0), the EC100 was determined to be 2.3 mg/L (geom. mean measured) and the EC0 was determined to be 1.2 mg/L (geom. mean measured).

Description of key information

In a static immobilization test to Daphnia magna according to OECD 202 the EC50 was determined to be 1.7 mg/L after 48 hours exposure under GLP conditions.

 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1.7 mg/L

Additional information

A static Daphnia magna immobilization test were performed according to OECD 202 (1992) under GLP conditions. The Daphnia were exposed to a range of concentrations, nominally 0.5, 1, 2, 4 and 8 mg/L of the test substance dissolved in water.  Measured concentrations ranged from 105 - 120 % of nominal values at 0 hours, and correspond to 120% of nominal values at 48 hours, respectively. The EC50 was calculated to be 1.7 mg/L (geom. mean of EC100 and EC0), the EC100 was determined to be 2.3 mg/L (geom. mean measured) and the EC0 was determined to be 1.2 mg/L (geom. mean measured).