Cyclopentane, methoxy-

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29 November 2002 - 19 May 2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to EC and OECD test guidelines, and in compliance with GLP; on this basis the study is considered reliable without restrictions.

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Analytical purity: 99.9%
- Lot/batch No.: 020618

Analytical monitoring:

yes

Details on sampling:

Duplicate 100 mL samples were taken from control and test stock solutions (all concentrations) at 0 hours and from culture vessels (replicates pooled) at 72 hours. Samples were not filtered to remove algal cells before analysis.

Vehicle:

no

Details on test solutions:

Identity and concentration of auxiliary solvent for dispersal: The test substance was directly spiked into test vessels
containing diluent medium. These were stirred for 30 minutes
to assist dispersion. Preliminary investigations into the
solubility and stability indicated that the test substance
was volatile. Therefore, each vessel was sealed with a
tightly fitted screw lid.

Test organisms (species):

Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Strain: CCAP 278/4

Test type:

static

Limit test:

no

Total exposure duration:

72 h

Test temperature:

23 - 24°C

pH:

Start: 7.6 - 7.9
End (72 hours): 9.5 - 10.5

Nominal and measured concentrations:

Nominal: 2.2, 4.6, 10, 22, 46, and 100 mg/L
Measured: 2.4, 4.4, 11, 22, 49, and 95 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass bottles
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 600 mL capacity, 600 mL fill volume
- Initial cells density: Approximately 10^4 cells/mL
- Control end cells density:2.1 x 10^5 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes (as recommended in EU method C3)

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: Not required
- Light intensity and quality: 6240 - 7020 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Cell densities measured using a particle counter at 0 and 24 hours, and using a haemacytometer at 48 and 72 hours.
- Other:

TEST CONCENTRATIONS
Initial range finding indicated that the EC50 was likely to be greater than 100 mg/L, with a NOEC around 10 mg/L. Definitive tests were then conducted which indicated that the NOEC was below 10 mg/L. Therefore the test range was selected to estimate the NOEC value.

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

< 2.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

2.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): 16-fold increase in cell concentrations in 72 hours
- Observation of abnormalities (for algal test): No abnormalities seen

Validity criteria fulfilled:

yes

Conclusions:

Growth inhibition of Selenastrum capricornutum by the substance was seen at 2.2 mg/L under the conditions of this test.
The EC50 in terms of both biomas and growth rate was greater than 100 mg/L. The No Observed Concentration (NOEC) in terms of biomass was less than 2.2 mg/L; the NOEC in terms of growth rate was 2.2 mg/L.

Description of key information

72 hour EbC50 and ErC50 (Selenastrum Capricornutum) >100 mg/L

72 hour NOEC (biomass) <2.2 mg/L

72 hour NOEC (growth rate) = 2.2 mg/L

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

2.2 mg/L

Additional information

An algal growth inhibition study was conducted (Huntingdon Life Sciences, 2003) to determine the effect of the substance on the growth of Selenastrum Capricornutum (new name Pseudokirchnerella Subcapitata). The study was conducted according to OECD test guideline 201 and EC method C3, and in compliance with GLP.

Triplicate algal cultures were exposed to the substance at concentrations 2.2, 4.6, 10, 22, 46, and 100 mg/L and incubated under continuous illumination for 72 hours. Six replicate contol cultures were also incubated concurrently with the test samples.

Biomass was affected by treatment with the substance at all levels, and so the No Observed Effect level in terms of Biomass was less than 2.2 mg/L, the lowest concentration tested. An effect on growth rate was also seen at all levels, but was less pronounced; as the reduction in growth rate was less than 10% at the lowest level, the NOEC in terms of growth rate was concluded to be 2.2 mg/L. The EC₅₀ in terms of both biomass and growth rate was greater than 100 mg/L, the highest concentration tested.