Fatty acids, C16 and C18-unsaturated, methyl esters, chlorinated

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:

January 31, 2022

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)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

WAF preparation:
Loading rates (nominal concentrations): A stock elution was prepare using a nominal concentration of 1000 mg/L. After adding salts, it was then diluted to get all the tested concentrations.
Sample weight: Direct addition of 1000 mg (actial weight = 999.8 mg) per liter for the stock elution
Ambient temperature 20°C. Orbital shaker 100 rpm- 7 days.
At the end of shaking, the eluate is slightly turbid and whitish, partly jellified and hard to filter. After longer decantation a thin a whitish layer settles on the bottom of the container.
Filtration: With vacuum filtration apparatus and membranes with 0.45 µm pores of cellulose nitrate. After filtrations, the stock eluate was added with the salts and dilutions were prepared using the cultivation medium. Oxygenation of the eluate and its dilutions followed, via air insufflation for 30’ prior to starting the test and acclimatation to test temperature (20 °C).

Analytical monitoring:

not specified

Details on sampling:

To obtain the medium to be tested with the sample, appropriate volumes of the stock WAF (added with salts) and its dilutions and of the algae inoculum were used. For the negative control, the WAF is replaced by the algae culture medium prepared using distilled water.
Tested concentrations from 50 mg/L to 1000 mg/L.

Vehicle:

no

Test organisms (species):

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

Test type:

not specified

Water media type:

other: ASTM Type III water

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

23 °C

pH:

8.1

Nominal and measured concentrations:

A stock elution was prepare using a nominal concentration of 1000 mg/L.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 0.7 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat. (dissolved fraction)

Remarks:

The WAF of different congeners C19Cl4 - C19Cl9 has been determined, the higher concentration determined was 0.7 mg/L for congener C19Cl4. This has been used as worst case for EC50 determination.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 0.7 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat. (dissolved fraction)

Remarks:

The WAF of different congeners C19Cl4 - C19Cl9 has been determined, the higher concentration determined was 0.7 mg/L for congener C19Cl4. This has been used as worst case for EC50 determination.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

Acute toxicity: ErC50 > 1000 mg/L
After a 72h.exposure, growth rates at some tested concentrations are significantly different from that of the control. Nonetheless, the maximum percentage of inhibition of the average growh rate is %Ir 8.22%±0.04% for r the maximum tested concentration (1000 mg/L). Being %Ir < 50%, we have ErC50 > 1000 mg/L.
Chronic toxicity: NOEC ≥ 250 mg/L; ErC10 > 1000 mg/L
Based on the Dunnett’s Test, the maximum sample concentration with no significant difference from the control is 250 mg/L Thus, we have that the No Observed Effect Concentration NOEC ≥ 250 mg/L. Its actual value ranging between 250 and 500 mg/L. As above, being maximum %Ir <10%, we have ErC10 > 1000 mg/L

Validity criteria fulfilled:

yes

Conclusions:

Acute toxicity: ErC50 > 1000 mg/L
Chronic toxicity: NOEC ≥ 250 mg/L; ErC10 > 1000 mg/L

Executive summary:

Algae were exposed to the test substance in a range of concentrations to evaluate values of acute (ErC50) and chronic toxicity (NOEC, ErC10), by comparing the growth rated with those of the negative control after 24h, 48h and 72h. Overall, the following results were obtained:

Acute toxicity: ErC50 > 1000 mg/L
Chronic toxicity: NOEC ≥ 250 mg/L; ErC10 > 1000 mg/L

Description of key information

The substance has a nominal ErC10 > 1000 mg/L. 

Key value for chemical safety assessment

EC50 for freshwater algae:

1 000 mg/L

EC10 or NOEC for freshwater algae:

1 000 mg/L