Alkenes, C10-12, C11-rich

Toxicity to aquatic algae and cyanobacteria

Description of key information

Experimental and calculated values are used to indicate the range of toxicity expected.

Additional information

Data on the toxicity of alkenes to algae is available for the carbon number range C6 -C14. Two QSAR have also been run to support the experimental data (Nabholz and Mayo-Bean, 2009; DiToro et al, 2010). The available data is summarised in the table below.

The experimental data indicates that toxicity to algae increases with carbon number from C6-C12, as log Kow increases. At carbon numbers above this acute toxicity is not observed at the limits of solubility. The QSAR values are in good agreement with the experimental data, although DiToro et al (2010) predicts that toxicity is no longer observed at C12. As experimental data is available at C6, C10, C12 and C14 this is used as key, with values for C8 filled by read across from the available experimental data and QSAR values.

Summary

·        C6 – toxicity is observed at 1 – 10 mg/l (Hoberg, 2003b)

·        C8 – toxicity is set at 1 – 10 mg/l based on weight of evidence

·        C10 and C12 – toxicity is set at <1 mg/l (Brixham Environmental Laboratories 2010e and f)

·        >C12 – no toxicity to algae and aquatic plants is expected (Hudson, 1999; Thompson and Swigert, 1995)

Major Carbon Number	6	8	10	12	14
Experimental	Hexene EC50 >5.5mg/l M	nd	Dec-1-ene EC50 1-1.8 mg/l N	Dodec-1-ene EC50 0.25-0.5 mg/l N	Tetradec-1-ene > sol Tetradecene > sol
ECOSAR	EC50 3.2mg/l	EC50 1.1mg/l	EC50 0.3mg/l	EC50 0.09mg/l	EC50 >sol
PETROTOX	EL50 8.4mg/l	EL50 1.5mg/l	EL50 0.3mg/l	EL50 >sol	EL50 >sol

M = measured. N = nominal.

At C14 and above the log Kow of the substance is above 6.4, the maximum log Kow within ECOSAR. These values should therefore be viewed as indicative.