L-p-mentha-1(6),8-dien-2-one

Toxicity to aquatic plants other than algae

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic plants other than algae

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Justification for type of information:

Data is from Committee for Risk Assessment RAC -ECHA

Qualifier:

according to guideline

Guideline:

other: ISO standard proposal: “water quality – Duckweed growth inhibition test” (2000) and a draft OECD guideline:

GLP compliance:

not specified

Analytical monitoring:

yes

Vehicle:

not specified

Details on test solutions:

Test solutions were renewed every 2 days.

Test organisms (species):

Lemna minor

Test type:

semi-static

Water media type:

other: SIS medium

Limit test:

no

Total exposure duration:

8 d

Nominal and measured concentrations:

4.6, 10, 22, 46 and 100 mg/L

Details on test conditions:

TEST SYSTEM
- No. of colonies per vessel: 4 plants
- No. of fronds per colony: 10
- No. of vessels per concentration (replicates): 3 (highest concentration, which had six replicates)
- No. of vessels per control (replicates): 6

TEST MEDIUM: SIS test medium was used

OTHER TEST CONDITIONS
- Photoperiod: continuous lighting
- Light intensity and quality: 85-96 µE m-2 s-1.

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol.

Key result

Duration:

4 d

Dose descriptor:

EC50

Effect conc.:

52 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 0-4 days

Duration:

6 d

Dose descriptor:

EC50

Effect conc.:

65 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 0-6 days

Duration:

8 d

Dose descriptor:

EC50

Effect conc.:

75 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 0-8 days

Duration:

8 d

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: other details not available

Average growth rate at each test substance concentration was compared with the control value and the percentage reduction in growth was calculated

Validity criteria fulfilled:

not specified

Conclusions:

The EC 50 value was determined to be 52 mg/L, 65 mg/L and 75 mg/L after exposure of test chemical for 0-4, 0- 6- and 0-8 days respectively on aquatic plant Lemna minor. The NOEC value was determined to be 10 mg/L.

Executive summary:

An experiment was conducted to determine the toxicity of test chemical to aquatic plants according to the ISO standard proposal: “water quality – Duckweed growth inhibition test” (2000) and a draft OECD guideline. The aquatic plant used in this experiment was Lemna minor. The test solutions were renewed every 2 days. The nominal concentration used in study were 4.6, 10, 22, 46 and 100 mg/L along with the control the reference substance (positive control) used was 3,5-dichlorophenol. SIS medium is used as test medium. Three replicates were used for each concentration except the highest concentration and control, which had six replicates. Each replicate (vessel) contains four plants with 10 fronds. The experiment was conducted by using continuous light with intensity of 85-96 µE m-2 s-1. The concentration of test chemical was measured at initiation of experiment after 2 and 6 days of exposure. Frond numbers were counted at the start, after 4, 6 days and at the end of the test of 8 days, simultaneously numbers of affected fronds were recorded. Average growth rate at each test substance concentration was compared with the control value and the percentage reduction in growth was calculated. The mean analytical recovery was 98.1%. Mean actual recoveries were between 91 and 98% of nominal in samples in the period 0-2 days. At day 6 concentrations were above 84%, except at the lowest level (72%). The EC 50 value was determined to be 52 mg/L, 65 mg/L and 75 mg/L after exposure of test chemical for 0-4, 0- 6- and 0-8 days respectively. The NOEC value was determined to be 10 mg/L.

Description of key information

The EC 50 value was determined to be 52 mg/L,  65 mg/L and 75 mg/L after exposure of test chemical for 0-4, 0- 6- and 0-8 days respectively on aquatic plant Lemna minor.  The NOEC value was determined to be 10 mg/L.

Key value for chemical safety assessment

EC50 for freshwater plants:

75 mg/L

EC10 or NOEC for freshwater plants:

10 mg/L

Additional information

An experiment was conducted to determine the toxicity of test chemical to aquatic plants according to the ISO standard proposal: “water quality – Duckweed growth inhibition test” (2000) and a draft OECD guideline. The aquatic plant used in this experiment was Lemna minor. The test solutions were renewed every 2 days. The nominal concentration used in study were 4.6, 10, 22, 46 and 100 mg/L along with the control the reference substance (positive control) used was 3,5-dichlorophenol. SIS medium is used as test medium. Three replicates were used for each concentration except the highest concentration and control, which had six replicates. Each replicate (vessel) contains four plants with 10 fronds. The experiment was conducted by using continuous light with intensity of 85-96 µE m-2 s-1. The concentration of test chemical was measured at initiation of experiment after 2 and 6 days of exposure. Frond numbers were counted at the start, after 4, 6 days and at the end of the test of 8 days, simultaneously numbers of affected fronds were recorded. Average growth rate at each test substance concentration was compared with the control value and the percentage reduction in growth was calculated. The mean analytical recovery was 98.1%. Mean actual recoveries were between 91 and 98% of nominal in samples in the period 0-2 days. At day 6 concentrations were above 84%, except at the lowest level (72%). The EC 50 value was determined to be 52 mg/L, 65 mg/L and 75 mg/L after exposure of test chemical for 0-4, 0- 6- and 0-8 days respectively. The NOEC value was determined to be 10 mg/L.