Alkanes, C16-47, branched and linear

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: Not stated

Key result

Duration:

48 h

Dose descriptor:

NOELR

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: Not stated

Details on results:

RESULTS
Validation of Mixing Period
Pre-study work (see Appendix 2 in attached section) indicated that there was no significant increase in the amount of total organic carbon by
extending the preparation period for longer than 24 hours.

Range-finding Test
Cumulative immobilisation data from the exposure of Daphnia magna to the test material during the range-finding test are given in Table 1 -see
section any other information on results .

No immobilisation was observed at the 1.0, 10 and 100 mg/l loading rate WAFs.

Based on this information, a single loading rate of four replicates, of 100 mg/l, using a stirring period of 23 hours followed by a 1-Hour standing period, was selected for the definitive test. This experimental design conforms to a "Limit test" to confirm that no immobilisation or adverse reactions to exposure were observed.

Definitive Test
Immobilisation data
Cumulative immobilisation data from the exposure of Daphnia magna to the test material during the definitive test are given in Table 2 see sectionany other information on results.

There was no immobilisation in 20 daphnids exposed to a 100 mg/l loading rate WAF for a period of 48 hours. Inspection of the immobilisation
data gave the following results:
Time (h) EL*50 (mg/l) 95% Confidence limits
(mg/l)
24 >100 -
48 >100 -

The No Observed Effect Loading rate after 24 and 48 hours exposure was 100 mg/l loading rate WAF. The No Observed Effect Loading rate is
based upon zero immobilisation at this loading rate.

Evaluation of data
An estimate of the EL*50 values was given by inspection of the immobilisation data.

Results with reference substance (positive control):

Positive Control

The positive control (Harlan Laboratories Ltd Project Number: 0039/1069) was conducted between 09 December 2008 and 11 December 2008.

Cumulative immobilisation data from the exposure of Daphnia magna to the reference material (Harlan Laboratories Ltd Project No: 0039/1069) during the positive control are given in Table 3 - see section any other information on results.

The relationship between percentage immobilisation and concentration at 24 and 48 hours is given in Figures 1 and 2 - see attachement Appendix-3)

Inspection of the immobilisation data at 3 hours and analysis of the immobilisation data by the probit method (Finney 1971) at 24 and 48 hours based on the nominal test concentrations gave the following results:

Time (h)
EC50 (mg/l) 95% Confidence limits
(mg/l)
3 > 3.2 -
24 0.82 0.71 - 0.94
48 0.71 0.61 - 0.81

The No Observed Effect Concentration after 24 and 48 hours was 0.32 mg/l. The No Observed Effect Concentration is based upon zero
immobilisation at this concentration.

The slopes and their standard errors of the response curves at 24 and 48 hours were 8.1 (SE = 1.7) and 8.6 (SE = 1.8) respectively.

The results from the positive control with potassium dichromate were within the normal range for this reference material. The mean 48-Hour EC50 value calculated from all positive controls was 0.78 mg/l (sd = 0.21).

Table1: Cumulative Immobilisation Data in the Range-finding Test

Nominal Loading Rate (mg/l)	Cumulative Immobilised Daphnia (Initial Population: 10 Per Replicate)
	24 Hours	48 Hours
Control	0	0
1.0	0	0
10	0	0
100	0	0

Table 2: Cumulative Immobilisation Data in the DefinitiveTest

Nominal Loading Rate (mg/l)		Cumulative Immobilised Daphnia (Initial Population: 5 Per Replicate)
		24 Hours			48 Hours
		No. Per Replicate	Total	%	No. Per Replicate	Total	%
Control	R1	0	0	0	0	0	0
Control	R2	0			0
Control	R3	0			0
Control	R4	0			0
100	R1	0	0	0	0	0	0
100	R2	0			0
100	R3	0			0
100	R4	0			0

R₁– R₄= Replicates 1 to 4

Table 3: Cumulative Immobilisation Data in the Positive Control

Nominal Concentration (mg/l)	Cumulative Immobilised Daphnia (Initial Population: 10 Per Replicate)
	3 Hours				24 Hours				48 Hours
	R1	R2	Total	%	R1	R2	Total	%	R1	R2	Total	%
Control	0	0	0	0	0	0	0	0	0	0	0	0
0.32	0	0	0	0	0	0	0	0	0	0	0	0
0.56	0	0	0	0	1	1	2	10	2	2	4	20
1.0	0	0	0	0	7	8	15	75	9	9	18	90
1.8	0	0	0	0	10	10	20	100	10	10	20	100
3.2	0	0	0	0	10	10	20	100	10	10	20	100

R₁– R₂= Replicates 1 and 2

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test material to the freshwater invertebrate Daphnia magna has been investigated and gave a 48-Hour EL*50 of greater than 100 mg/l loading rate WAF. Correspondingly the No Observed Effect Loading rate was 100 mg/l loading rate WAF.

Executive summary:

Introduction.

A study was performed to assess the acute toxicity of the test material ‘Distillates (Fischer-Tropsch), heavy, C18-50 - branched, cyclic and linear’ to

Daphnia magna. The method followed that described in the OECD Guidelines for Testing of Chemicals (April 2004) No 202, "Daphnia sp, Acute Immobilisation Test" referenced as Method C.2 of Commission Regulation (EC) No. 440/2008.

Methods.

Following a preliminary range-finding test, twenty daphnids (4 replicates of 5 animals) were exposed to a Water Accommodated Fraction (WAF) of the test material, at a single nominal loading rate of 100 mg/l for 48 hours at a temperature of 21ºC under static test conditions. Immobilisation and any adverse reactions to exposure were recorded after 24 and 48 hours.

A positive control conducted approximately every six months used potassium dichromate as the reference material. Daphnia magna was exposed to an aqueous solution of the reference material at concentrations of 0.32, 0.56, 1.0, 1.8 and 3.2 mg/l for 48 hours at a temperature of approximately 20°C under static test conditions. Immobilisation and any adverse reactions to exposure were recorded after 3, 24 and 48 hours.

Results.

The 48-Hour EL^[1]₅₀for the test material to Daphnia magna based on nominal loading rates was greater than 100 mg/l loading rate WAF and correspondingly the No Observed Effect Loading rate was 100 mg/l loading rate WAF. It was considered unnecessary and unrealistic to test at loading rates in excess of 100 mg/l. The test material is a complex mixture and hence compound specific analysis of the WAFs was not performed. However samples of the control and 100 mg/l loading rate WAF were taken at 0 (fresh media) and 48 hours (old media) for Total Organic Carbon (TOC) analysis. Given the toxicity cannot be attributed to a single component or a mixture of components but to the test material as a whole, and the dissolved organic carbon concentrations were below the limit of quantitation at 0 and 48 hours, the results were based on nominal loading rates only.

The 48-Hour EC₅₀for the reference material to Daphnia magna based on nominal concentrations was 0.71 mg/l with 95% confidence limits of 0.61 – 0.81 mg/l. The No Observed Effect Concentration was 0.32 mg/l.

[1] EL = Effective Loading rate

Description of key information

The 48 -hour EL₅₀ of the read across substance GTL Base Oil Distillates was determined to be >100 mg/L (Daphnia magna).

This data is used for read across to Alkanes, C16-47, branched and linear.

Additional information

The short-term toxicity of read across substance GTL Base Oil Distillates with the freshwater invertebrate Daphnia magna (water flea) has been determined in a study conducted in accordance with OECD Test Guideline 202. 

WAFs of the sample were prepared by stirring for approximately 23 hours and left to stand for 1 hour before drawing off the aqueous phase – the WAF – for testing. Static exposures were then carried out according to GLP.

Total Organic Carbon (TOC) analysis of the freshly prepared test preparations showed amount of carbon present within the control and the 100 mg/L loading rate WAF test vessels to be less than the limit of quantitation (LOQ) for the method within fresh and old media. Therefore the results from the TOC analysis did not provide definitive evidence of the stability of the test preparations.

The test results, expressed as the EL₅₀ value, showed that the sample was not hazardous to Daphnia magna at a loading rate of 100 mg/l.