1-Octanol, reaction products with phosphorus oxide (P2O5), potassium salts

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:

The experimental start date was 03 Aug 2018, and the experimental completion date was 15 Aug 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Version / remarks:

2011

GLP compliance:

yes

Specific details on test material used for the study:

Purity: UVCB; solid matter 41.4%

Analytical monitoring:

yes

Details on sampling:

- Concentrations: the control and the WAF at 100 mg solid matter/L
- Sampling method: At the end of the exposure period, the replicates with algae were pooled at each concentration before sampling
- Sample storage conditions before analysis: Samples were stored in a freezer (≤-15°C) until analysis at the analytical laboratory of the Test Facility

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Water Accommodated Fraction (WAF) loading rate of 100 mg solid matter/L

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Strain: NIVA CHL 1
- Source: In-house laboratory culture

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Hardness:

24 mg CaCO3/L

Test temperature:

22 - 23 °C

pH:

8.0 - 8.4

Nominal and measured concentrations:

Nominal: 100 mg solid matter/L
Measured: 54 mg solid matter/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL, all-glass with aluminium caps
- Type: closed
- Aeration: none
- Initial cells density: 1 x 10E4 cells/mL
- Control end cells density: 283.7 x 10E4 cells/mL
- No. of vessels per concentration: 6
- No. of vessels per control : 6

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Photoperiod: Continuously using TLD-lamps with a light intensity within the range of 85 to 86 μE.m-2.s-1

EFFECT PARAMETERS MEASURED :
- Determination of cell concentrations: At the beginning of the test, cells were counted using a microscope and a counting chamber.Thereafter, cell densities were determined by spectrophotometric measurement of samples at 680 nm using a spectrophotometer with immersion probe (path length = 10 mm); every 24-hours
- Other: At the end of the test microscopic observations were performed on the WAF at 100 mg solid matter/L and the control to observe for any abnormal appearance of the algae

TEST CONCENTRATIONS
combined limit/range-finding test maximum concentration 100 mg solid matter/L

Reference substance (positive control):

yes

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

< 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

< 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

- Exponential growth in the control: yes
- Observation of abnormalities none
- Unusual cell shape: normal and healthy appearance

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50: The EC50 for growth rate inhibition (72h-ERC50) was 0.90 mg/L
- Other: Within historical range

Validity criteria fulfilled:

yes

Conclusions:

The 72h-EL50 for inhibition of both growth rate (ERL50) and yield (EYL50) was >100 mg solid matter/L.

The 72h-NOELR for growth rate inhibition was <100 mg solid matter/L when based on statistical analysis and 100 mg solid matter/L when based on biological relevance.

The 72h-NOELR for yield inhibition was <100 mg solid matter/L when based on both statistical analysis and biological relevance.

The analytically confirmed average concentration of dioctyl phosphate in the test solution was 54 mg/L.

Executive summary:

The toxicity to algae of the test item was assessed following OECD 201. During a combined range-finding/limit test study, a study was performed with a maximum WAF of the test item at 100 mg solid matter/L. Microscopic observations at the end of the test revealed a normal and healthy appearance of the algal cells exposed to the WAF at 100 mg solid matter/L when compared to the control.  The 72h-EL50 for inhibition of both growth rate (ErL50) and yield (EyL50) was >100 mg solid matter/L. The 72h-NOELR for growth rate inhibition was <100 mg solid matter/L when based on statistical analysis and 100 mg solid matter/L when based on biological relevance. The 72h-NOELR for yield inhibition was <100 mg solid matter/L when based on both statistical analysis and biological relevance. The analytically confirmed average concentration of dioctyl phosphate in the test solution was 54 mg/L.

Description of key information

The toxicity to algae of the test item was assessed following OECD 201. During a combined range-finding/limit test study, a study was performed with a maximum WAF of the test item at 100 mg solid matter/L. Microscopic observations at the end of the test revealed a normal and healthy appearance of the algal cells exposed to the WAF at 100 mg solid matter/L when compared to the control.  The 72h-EL50 for inhibition of both growth rate (ErL50) and yield (EyL50) was >100 mg solid matter/L. The 72h-NOELR for growth rate inhibition was <100 mg solid matter/L when based on statistical analysis and 100 mg solid matter/L when based on biological relevance. The 72h-NOELR for yield inhibition was <100 mg solid matter/L when based on both statistical analysis and biological relevance. The analytically confirmed average concentration of dioctyl phosphate in the test solution was 54 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L