Glycerides, C8-18 and C18-unsatd.

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From Jan. 12, 2004 to Jan. 17, 2004

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study was conducted according to ISO 10253 guideline. GLP compliance not reported.

Justification for data waiving:

other:

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2004

Report date:

2004

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Glycerides, C8-18, C18-unsatd.

IUPAC Name:

Glycerides, C8-18, C18-unsatd.

Constituent 2

Reference substance name:

Glycerides, C8-18 and C18-unsatd.

EC Number:

266-946-3

EC Name:

Glycerides, C8-18 and C18-unsatd.

Cas Number:

67701-28-4

Molecular formula:

Triglycerides containing a glycerol backbone esterified to fatty acids with a carbon chain length of C8-18 as well as unsaturated C18 fatty acids

IUPAC Name:

Tri(C8-18 and C18-unsatd. fatty acyl)glycerol

Details on test material:

- Name of test material (as cited in study report): Coconut oil (CAS N° 8001-31-8, EC N° 232-282-8); under the SDA nomenclature, the name of this substance is ‘Glycerides, C8-18 and C18-unsatd.’
- Physical state: Brown, cream solid
- Storage condition of test material: 4 °C, under dark

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Sampling and analysis

Analytical monitoring:

not specified

Details on sampling:

Not applicable

Test solutions

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Water accommodated fraction (WAF) methodology
- Preparation: WAFs were prepared by adding test material to the test medium (sterile marine algal media) to give loading rates of 10, 100 and 1,000 mg/L. In order to mix the test material, which was solid at room temperature, the sample was microwaved on full power for approximately 2 minutes until it became liquid. The contents of the WAF vessels were then stirred using a magnetic stirrer, at 300 rpm, for 24 h, in a controlled environment room set at 20±2 °C and then left to settle for a minimum of 2 h (range 2 – 4 h), to allow the undissolved material to separate out. The aqueous phases - the WAFs – were then drawn off via the tap for use in the tests. Control media was sterile marine algal media.

Test organisms

Test organisms (species):

Skeletonema costatum

Details on test organisms:

TEST ORGANISM
- Common name: Diatom
- Source (laboratory, culture collection): Scottish Association for Marine Science Research Services Ltd, Dunstaffnage, Oban, Scotland
- Method of cultivation: Cultures were maintained in autoclaved nutrient enriched natural seawater under constant illumination (nominal 6000 lux) at 20±2 °C in a Gallenkamp orbital incubator and shaken at 100 cycles min-1

Study design

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

No data

Test conditions

Hardness:

No data

Test temperature:

20±2 °C

pH:

Control: 8.5 at the start to 9.2 after 72 h
Test: 8.5 at the start to 8.3 - 9.3 after 72 h

Dissolved oxygen:

No data

Salinity:

No data

Nominal and measured concentrations:

Nominal concentration: 10, 100 and 1,000 mg/L
1,000 mg/L was equivalent to 4 mg total carbon/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): Erlenmeyer flasks closed with ground glass stoppers
- Material, size, headspace, fill volume: 250 mL flasks filled with 100 mL test solution
- Initial cells density: 10,000 cells/mL
- No. of vessels per concentration (replicates): Three
- No. of vessels per control (replicates): Six


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Natural seawater, collected off the beach at Kinmel Bay to the west of Rhyl, Flintshire, N. Wales
- Total organic carbon for medium: 31 mg/L


OTHER TEST CONDITIONS
- Sterile test conditions: Yes
- Light intensity and quality: 6,700-8,200 lux
- Temperature: 20±2 °C


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Particle counting was performed on the contents of each flask at the start of the test and after 24, 48 and 72 h of incubation using electronic particle counter (Coulter Model ZM)
- Other: At the end of the test, estimations of the mean chain length of S. costatum for one flask from each test concentration were made by microscopic examination of at least 50 chains in a 1 mL sub sample.

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol; 1.5 mg/L

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

10 - 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

100 - 1 000 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): yes

Results with reference substance (positive control):

- Results with reference substance: Valid
- Average specific growth rate was not reduced over 72 h compared to the control, but that a reduction of 26% was seen in Skeletonema costatum biomass (as measured by area under the growth curve).

Reported statistics and error estimates:

None

Any other information on results incl. tables

Table 1: Growth of Skeletonema costatum exposed to WAFs of coconut oil and 1.5 mg/L solution of reference compound 3,5-DCP

Treatment	Mean reduction in area under the growth curve (A) relative to unfiltered controls (%)			Mean reduction in average specific growth rate (µ) relative to unfiltered controls (%)			Mean number cells per chain
	0-24 h	0-48 h	0-72 h	0-24 h	0-48 h	0-72 h	72 h
Control	-	-	-	-	-	-	3.4
Control (filtered)	17	8.3	-1.6	10	1.4	-6	2.4
Coconut 10 mg/L	-31	-16	-9.9	-21	-6.4	-3.2	3.2
Coconut 100 mg/L	96	84	57	92	48	-2	4.1
Coconut 1000 mg/L	100	100	100	100	>100	>100	0
3,5-DCP (1.5 mg/L)	32	38	26	13	13	-5.6	3.4

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Remarks:

No data on coefficient of variation

Conclusions:

Based on the results, the 72 h EbL50 and ErL50 of the test material were determined to be between 10 - 100 and 100 - 1,000 mg/L, respectively.

Executive summary:

A study was conducted to evaluate the acute toxicity of the coconut oil to Skeletonema costatum under static conditions. The procedures followed ISO 10253 (Water quality - Marine Algal Growth Inhibition Test with Skeletonema costatum and Phaeodactylum tricornutum).

 

Skeletonema costatum were exposed to water accommodated fractions prepared from the test material at concentrations ranging from 10-1,000 mg/L for 72 h and the range of loading rates within which a 50% reduction in algal growth occurred after 72 h was determined on the basis of both the area under the growth curve (EbL50) and specific growth rate (ErL50).

 

Based on the results, the 72 h EbL50 and ErL50 of the test material were determined to be 10 - 100 and 100 - 1,000 mg/L, respectively.