Naphtha (Fischer-Tropsch), light, C4-10-branched and linear

Bioaccumulation: aquatic / sediment

Administrative data

Endpoint:

bioaccumulation: aquatic / sediment

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was well documented and meets generally accepted scientific principles, but was not conducted in compliance with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Principles of method if other than guideline:

A biomimetic extraction technique using solid-phase microextraction (SPME) in conjunction with gas chromatography (GC) was employed to assess the level of water soluble hydrocarbons and hence the potential toxicity of water accommodated fractions (WAFs) for a range of GTL products. In addition, the toxicity of WAFs was also monitored using an in-vitro MicrotoxTM assay, a biosensor-based measurement system based on Vibro Fischeri bacteria.
From previous work applying the SPME-GC technique, the level of soluble hydrocarbons observed in WAFs from petroleum substances relates directly to their toxicity generated with a MicrotoxTM in-vitro system, with fractions with a SPME-GC peak area greater than 100 000 causing any detectable change in light emission for the bacteria demonstrating toxicity.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

481-740-5

EC Name:

-

Cas Number:

848301-67-7

Molecular formula:

main general molecular formula: CnH(2n+2)

IUPAC Name:

C8-C26 branched and linear hydrocarbons – Distillates

Sampling and analysis

Details on sampling:

Samples of WAF were taken at 24 hours and 48 hours. Due to equipment error the crude oil gasoline was only sampled after 48 hours.

Test solutions

Details on preparation of test solutions, spiked fish food or sediment:

WAF Preparation:
WAFs were prepared at a 100 mg/L loading rate by the addition of 0.2 g of the sample to 2 L of purified water. The WAFs were prepared in 2 L conical flasks with glass/PTFE taps at the base and sealed with a ground glass stopper to prevent the loss of the more volatile components of the sample. All samples have densities lower than of water so formed a thin layer on the surface of the water. The sample tap was positioned at the base of the conical flask to prevent any contamination of the WAF sample with the test substance when sampling. Also all flasks were cleaned by rinsing with toluene and then with acetone solution before use. The samples were stirred for 24 hours under ambient laboratory conditions using a magnetic stirrer at 250 rpm. At each of the time points the stirrer motors were switched off and the WAFs allowed to settle for 1 hour. To prevent contamination surrounding the tap area of the flask a small portion of the WAF was first decanted off and discarded before samples for SPME and MicrotoxTM analysis were taken via the taps at the base of the flask. The stirring of the samples was then resumed till the next time point. The SPME analysis required 19.5g of the WAF to be sampled into a Wheaton vial. The sample for MicrotoxTM was collected in 4 ml dram vials with a minimum of 2.5 ml of sample for analysis.

Applicant's summary and conclusion

Conclusions:

In this study the majority of GTL samples (including the registration substance 'Distillates (Fischer-Tropsch), C8-26-branched and linear') analysed using SPME-GC indicated a low total peak area for soluble hydrocarbons (on average less than 12 000) and hence toxicity, with no detectable toxicity using the MicrotoxTM assay. The low total peak area for soluble hydrocarbons for these substances is indicative of a low potential to bioaccumulate
The related C8-C16 and C4-C10 samples, consisting of shorter chain hydrocarbons, produced a more soluble hydrocarbon fraction, and the latter one resulted in a moderate level of toxicity detected with the MicrotoxTM assay. The level of toxicity seen with the C4-C10 sample is, however, considerably less than that seen with the crude oil gasoline.