Tall oil, maleated

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:

Range finding test: 10-14 June 2013 First definitive test: 12-16 August 2013 Second definitive test: 2-6 September 2013 Third definitive test: 16-20 September 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

ISO 10253 (Water quality - Marine Algal Growth Inhibition Test with Skeletonema costatum and Phaeodactylum tricornutum)

Version / remarks:

The method followed for this study was cefas SOP 2113: "A 72h growth inhibition test for the marine alga Skeletonema costatum (GLP)", based on the guideline ISO 10253(2006)

Deviations:

yes

Remarks:

During the study, five deviations from the study plan occurred. The deviations were determined not to have affected the validity of the study.

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

Initially a solubility study was attempted using the whole product EnvaMul 600. However, as the substance is extremely difficult to transfer it was not possible to dissolve in seawater and was treated as insoluble. As EnvaMul 600 contains a mixture of components test solutions were prepared as water accomodated fractions (WAFs). A WAF is an aqueous medium containing only that fraction of a substance which remain in the aqueous phase after the preparation procedure is terminated. WAFs are prepared in glass aspirators with a tap at the bottom and a bung in the top to prevent loss of volatiles.

Test organisms (species):

Skeletonema costatum

Details on test organisms:

Test organism : Skeletonema costatum CCAP strain 1077/5. The original culture was obtained from Brixham Environmental laboratory.

Test type:

static

Water media type:

other: natural seawater, filteres to 0.2 µm collected from Lowestoft bay

Limit test:

no

Total exposure duration:

72 h

Test temperature:

20.0 - 21.0 °C

pH:

7.5 - 8.2

Salinity:

31.7 - 32.4 %

Nominal and measured concentrations:

10, 22, 46, 100 and 220 mg/L

Details on test conditions:

Light: constant 6710 - 9550 lux

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

51.4 mg/L

Conc. based on:

act. ingr. (dissolved fraction)

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

10 mg/L

Conc. based on:

act. ingr. (dissolved fraction)

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 10 mg/L

Conc. based on:

act. ingr. (dissolved fraction)

Basis for effect:

growth rate

Results with reference substance (positive control):

EC50 after 72 h for reference test substance (3,5-dichlorophenol) was 0.84 mg/L (confidence limits:0.64 - 1.11). The treshold criteria are between 0.7 - 2.5 mg/L. The validity criteria are met.

Reported statistics and error estimates:

The data were analysed using CETIS statistical software and following Cefas SOP 2100: "The use of the statistical software CETIS"
The EC50 was calculated by linear interpolation and the LOEC and NOEC were calculated using the Wilcoxon/Bonferroni adjusted test.

Validity criteria fulfilled:

yes

Conclusions:

The median lethal concentration (EC50) of test item Envamul 600 was 51.4 mg/L, with 95% confidence limits between 46.5 to 55.2 mg/L over 72 hours.
In addition, the No Observed Effect Concentration (NOEC was <10 mg/L and the Lowest Observed Effect Concentration (LOEC) was 10 mg/L

Executive summary:

A 72 hour acute toxicity assay was conducted with the test item ENVAMUL 600 using the marine algae Skeletonema costatum. The method followed for this study was cefas SOP 2113: "A 72h growth inhibition test for the marine alga Skeletonema costatum (GLP)", based on the guideline ISO 10253(2006).

A solubility study was attempted using the whole product EnvaMul 600, however as the substance is extremely difficult to transfer it was not possible to dissolve in seawater and was treated as insoluble. A Water Accommodated Fraction (WAF) was prepared and used to create the test concentrations (dilution water: natural seawater, filtered to 0.2 µm).

A rangefinder test and a definitive test were conducted.

The definitive study was conducted with 3 replicates per concentration with 6 reps for the control. According to the rangefinding test results, the test concentrations were chosen as 0 (control), 10, 22, 46, 100 and 220 mg/L Envamul 600. The test was conducted in 250 ml glass conical flasks as a static exposure for 72 hours.

RESULTS:

EC50: 51.4 mg/L

NOEC: <10 mg/L

LOEC: 10 mg/L

Description of key information

A 72 hour acute toxicity assay was conducted using the marine algae Skeletonema costatum. The method followed for this study was cefas SOP 2113: "A 72h growth inhibition test for the marine alga Skeletonema costatum (GLP)", based on the guideline ISO 10253(2006).

According to the range-finding test results, the test concentrations were chosen as 0 (control), 10, 22, 46, 100 and 220 mg/L Envamul 600. The test was conducted in 250 ml glass conical flasks as a static exposure for 72 hours.

RESULTS:

EC50: 51.4 mg/L

NOEC: <10 mg/L

LOEC: 10 mg/L

Key value for chemical safety assessment

EC50 for marine water algae:

51.4 mg/L

EC10 or NOEC for marine water algae:

10 mg/L