C4-C10 branched and linear hydrocarbons (light) – Naphtha

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

(Q)SAR

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

This endpoint has been reviewed, assessed and accepted by UK-HSE as competent authority for the notification of a new substance [EC number: 481-730-0; Data from UK-Notification Dossier by Shell U.K. Limited in accordance with Directive 92/32/EEC (Articles 7/8/9/12) O.J.L 154, Volume 35, 5 June 1992; Notification Report 06-31-0125-00 from 1st Nov, 2006].

Justification for type of information:

QSAR prediction: migrated from IUCLID 5.6

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

other: review

Title:

Unnamed

Year:

2006

Materials and methods

Test guideline

Qualifier:

no guideline required

Deviations:

not applicable

Principles of method if other than guideline:

The toxicity of the representative chemical components of the substance to algae have been calculated in accordance with the methods described by Peter Fisk Associates (2006) using QSARs for non-polar narcotics. The QSARs take the form of a generic equation:
log(LC50, EC50 or NOEC) = a log(Kow) + b
where a and b are constants equal to the slope and the intercept on the y axis of the regression equation and Kow is octanol-water partition coefficient of each component under consideration.

GLP compliance:

no

Remarks:

not applicable (calculated by QSAR)

Test material

Reference

Name:

Unnamed

Type:

Constituent

Type:

Constituent

Sampling and analysis

Analytical monitoring:

not required

Test solutions

Vehicle:

not specified

Test organisms

Test organisms (species):

other: not applicable (calculated by QSAR)

Study design

Test type:

other: not applicable (calculated by QSAR)

Water media type:

not specified

Remarks on exposure duration:

not applicable (calculated by QSAR)

Results and discussion

Effect concentrations

Effect concentrations 1

Dose descriptor:

EL50

Effect conc.:

0.55 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: not applicable (calculated by QSAR )

Effect concentrations 2

Dose descriptor:

NOELR

Effect conc.:

0.24 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: not applicable (calculated by QSAR )

Any other information on results incl. tables

see attached full study report at "5.2.1 Biodegradation in water: screening tests" [ Attachment 8, page 5 -12]

Applicant's summary and conclusion

Validity criteria fulfilled:

not applicable

Remarks:

calculated by QSAR

Conclusions:

Results calculated by QSAR [using the methods described in the report by Peter Fisk Associates (2006)]:
- the substance could be acutely toxic to algae at a loading rate of 0.55 mg/l (EL50)
- the substance has a predicted chronic NOEL of 0.24 mg/l to algae.

The predicted acute EL50 value for algae of 0.55 mg/l falls just below the lowest measured values that are in the range 1-10 mg/l, although there is
one exceptional value indicating a lower order of toxicity [reported in the environmental hazard property summary review by Peter Fisk Associates (2006) - see Attachment 8 or below 'Cross-reference to other study': CONCAWE-study]. The predicted chronic NOEL for algae is in the range 0.1-1.0 mg/l. The prediction is consistent with a reported NOEC to algae of 0.1 mg/l for a light solvent refined naphtha [see also 'Environmental hazard property summary review by Peter Fisk Associates (2006)'].

Conclusion: Naphtha (Fischer-Tropsch), light, C4-10 - branched and linear, could be chronically (and also acutely) toxic to algae at a loading rate of 0.1-1.0 mg/l .

Classification: The substance should be classified in the EU as R50-53 i.e. 'Very toxic to aquatic organisms' and 'May cause long-term adverse effects in the aquatic environment'. The basis of this classification is the predicted EL50 of 0,55 mg/l and the presence of components with log Kow >3. The biodegradability does not affect this.