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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
calculation (if not (Q)SAR)
Remarks:
estimated by calculation
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Remarks:
The study was conducted according to an appropriate national standard method and it was compliant with GLP. The test substance evaporated and was degraded substantially in the test medium.
Justification for type of information:
Please refer to attached justification documents
Principles of method if other than guideline:
Validation set derived from 48-hour to 72-hour results from reliable studies conducted in accordance with OECD 201.
GLP compliance:
no
Test organisms (species):
other: Green algae
Details on test organisms:
Validation set data are taken from tests with P. subcapitata and D. subspicatus.
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
1.5 mg/L
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
0.7 mg/L
Conc. based on:
test mat.
Basis for effect:
growth rate
Conclusions:
ErC50 of 1.5 mg/l and ErC10 of 0.7 mg/l in green algae are predicted for decan-1-ol based on test results for analogous aliphatic alcohols. These values are considered to be reliable.
Executive summary:

ErC50 of 1.5 mg/l and ErC10 of 0.7 mg/l in green algae are predicted for decan-1-ol based on test results for analogous aliphatic alcohols. These values are considered to be reliable.

Description of key information

Toxicity to algae: 72-96 hr ErC50 1.5 mg/l and ErC10 0.7 mg/l (QSAR)

Key value for chemical safety assessment

EC50 for freshwater algae:
1.5 mg/L
EC10 or NOEC for freshwater algae:
0.7 mg/L

Additional information

There are no reliable measured algal toxicity data available for decan-1-ol (CAS 112 -30 -1), therefore a quantitative prediction has been performed. A 72 - 96 h ErC50 value of 1.5 mg/l and ErC10 of 0.7 mg/l have been estimated for the effects of decan-1-ol on growth rate of green algae. In a static exposure study it is likely that significant biodegradation of test substance is to be expected, particularly in view that green algae are capable of metabolising aliphatic alcohols. The estimate is based on regression of the category data set. Key reliable measured data for the neighbouring chain length alcohols, octan-1-ol (CAS 111-87-5) and dodecan-1-ol (112-53-8) are read-across to support this interpolative prediction.

 

Discussion of trends in the Category of C6-24 linear and essentially-linear aliphatic alcohols:

The data for single carbon chain length LCAAs show toxicity to increase from an ErC50 of 80 mg/L for C6 to 0.33 mg/L for C12. The C14 and C16 LCAAs were not toxic to algae, indicating a toxicity cut-off at C14 and above. Two of the studies determined NOECs that are suitable for assessing long-term toxicity. A NOEC of 11 mg/L has been reported for hexan-1-ol based on measured exposure concentrations. A test with dodecanol resulted in a 72-h EC0 (equivalent to a NOEC) value of 0.085 mg/L.

Other algal studies used a WAF methodology and/or used test concentrations greater than the limit of water solubility and/or did not report a NOEC or equivalent statistic.

The data for mixed carbon chain length LCAAs (commercial products) shows that substances containing LCAAs with carbon numbers in the ranges of C7-9 to C12-15 exerted toxicity at concentrations of between 3.1 and 0.043-0.092 mg/L. At these concentrations all the constituents are likely to have been fully dissolved. For the C12-18 and C14-15 multi-constituent substances there was evidence of toxic effects in tests conducted on water-accommodated fractions prepared at loading rates that will have exceeded the solubility of some constituents.