Benzene, C15-16-alkyl derivs.

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.001 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.001 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

0.041 mg/L

Assessment factor:

1

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

1.65 mg/kg sediment dw

Assessment factor:

1

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.165 mg/kg sediment dw

Assessment factor:

1

Extrapolation method:

equilibrium partitioning method

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

0.33 mg/kg soil dw

Assessment factor:

10

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

In cases where no data were available on the target substance, Benzene, C15-16-alkyl derivs., data were read-across from LAB, C10-13 due to the structural similarity and similar physicochemical properties of these compounds.

Conclusion on classification

In general, for the classification and PBT assessment of Benzene, C15 -16 -alkyl derivs., in cases where no data were available on the target substance, data were read-across from a structurally similar material (the test substance).

Linear alkylbenzenes, at concentrations up to and exceeding the water solubility limit, had no short-term effects on all three trophic levels tested (fish, invertebrates and algae).

The 21-d NOEC for Daphnia magna is 0.0075 mg/L, which is below the water solubility limit. The study was a flow-through GLP-compliant U.S. EPA guideline test using acetone as a solvent.

The solvent concentration (1 mL/L) was above the currently recommended levels for solvent addition (<0.1 mL/L) (OECD 2000, OECD 2008). Test concentrations were verified by analytical measurements (Gledhill et al. 1991) which may have included increased levels of the test substance in solution as a result of high solvent concentrations.

Although no long-term toxicity study is available for fish, LAB is thought to be slightly more potent on a long-term basis to Daphnia magna than they are to other species, even though LAB likely has a narcotic mode of toxic action.

These findings are supported by the results of the available toxicity tests with all three trophic levels. In a GLP-compliant OECD 203 guideline study with zebra fish (Danio rerio) which was extended to 21 days, no adverse effects were observed at a measured concentration of 0.058 mg/L (Fernandez et al. 2000a). In a GLP-compliant OECD 202 guideline study with Daphnia magna using C10 and C12 LAB homologues, which bracket commercial LAB with an average chain length of C11.6, the 48-h EC50 for D. magna was above the water solubility limit of 0.041 mg/L. However, an extension of the exposure period to 96-h and beyond showed an EC50 below the water solubility limit (Fernandez et al. 2000b). Both tests were carried out using acetone; the final concentration of acetone was <0.1 mL/L.

Only a slight inhibition of the growth rate (3.8%) was observed in an OECD guideline 201 study with Desmodesmus subspicatus (previously known as: Scenedesmus subspicatus) at a concentration of 0.1 mg/L (Verge et al. 2000), the exposure period was 72 hours. No growth inhibition was observed when LAB was maintained within its solubility limit. The final concentration of acetone was 1.0 mL/L, the LAB concentrations were not verified by analytical measurement.

It can therefore be concluded that in long-term tests with more sensitive life stages, fish would be less sensitive to LAB than Daphnia magna. Therefore an assessment factor of 10 for the freshwater compartment and 100 for the marine compartment are justified.