Tetradecanol

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

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:

no hazard identified

Sediment (freshwater)

Hazard assessment conclusion:

no hazard identified

Sediment (marine water)

Hazard assessment conclusion:

no hazard identified

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

0.428 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential to cause toxic effects if accumulated (in higher organisms) via the food chain

Additional information

Tetradecanol (C14, CAS 112-72-1) has a water solubility of 1.3 mg/l at 23˚C pH 5.5, and a log K_ow of 5.5. It has no hydrolysable structural features and would be expected to be stable in water. It is rapidly biodegradable.

Tetradecanol is a member of a category of long chain aliphatic alcohols (LCAAs) with a carbon chain length range of C6-C24. The Category is limited to linear and essentially-linear aliphatic alcohols.

As carbon number increases, short- and long-term aquatic toxicity generally increase (i.e. decreasing E(L)C₅₀ and NOEC values observed) up to a threshold carbon number, above which there are no effects at the limit of solubility. For short term effects the threshold is between C13 and C14; for chronic effects it is between C15 and C16. The observed threshold in carbon number is associated with limitations on the degree to which predictable effects are expressed at the limit of solubility, which is low for the longer-chain alcohol structures in the category.

Evidence across the Category of C6-24 long-chain aliphatic alcohols (LCAAs) supports the conclusion that a similar level of susceptibility is exhibited for all three taxonomic groups in the short-term data set.

 

Alcohols in the Category have toxicity consistent with non-polar narcosis effects, in line with the very many organic non-polar narcotic organic substances that have been extensively studied and described in literature by various authors. Therefore the LCAAs in this category should be considered in the context of neutral organics.

Long-term toxicity testing across the category has been carried out with fish and Daphnia, and there are measured long-term data with invertebrates available for tetradecanol. However, significant biodegradation losses of substance in the test system still occurred, despite measures taken to prevent this. A full report detailing properties and trends across the LCAAs category, as well as further discussion on measures to prevent test substance losses is available: ECOTOXICITY Alcohols C6-24 Category report.

Quantitative structure-activity relationships ((Q)SAR’s) for estimating toxicity to fish and Daphnia have been developed. It is possible to apply these relationships to predict short- and long-term toxicity endpoints for other members of the Category. Further details are described in the ECOTOXICITY Alcohols C6-24 Category report.

Reduced assessment factors have been used to derive PNECs:

Basis for setting of assessment factor

 

The purpose of assessment factors is to take a laboratory result and estimate a PNEC that applies to the environment itself. In summary, and as is well-known, the purpose of the factors is to account for uncertainty in:

1.     Intra-laboratory variability

2.     Inter-laboratory variability

3.     Duration

4.     Sensitivity of the environmental ecosystem relative to the range or organisms actually tested.  

For one substance standing alone, the factor of 10 is considered in the Guidance to apply to three long term NOECs or EC_x values for the aquatic compartment. Similarly an assessment factor of 50 is specified when deriving a PNEC when two long-term NOECs or EC₁₀s for different taxonomic groups are available.  

Why is the Guidance default of 10 a reasonable number for long-term data? A reasoned discussion is set out in the table below, along with an application of the same logic to tetradecanol.  

Table 1 A basis of understanding assessment factors and application to long-term studies with alcohols  

	General rationale when three trophic levels have been studied	Members of the C6-24 Alcohols Category
1. Intra-laboratory variability	For well-performed studies with good chemical analysis point 1 is negligible	This applies. Use 1
2. Inter-laboratory variability	A factor of 2 to 5 would be realistic	For the long-chain alcohols, the inter-laboratory variation is much lower, because the substances are archetypal exemplars of non-polar narcotics. Use 2
3. Duration	When a full set of long-term NOECs or ECxvalues are available, the contributing factor associated with point 3 (duration) is relatively minor, and can be ignored.	This is definitely the case for the ecosystem, in which alcohols are ubiquitous, so duration is irrelevant. Use 1
4. Sensitivity of the environmental ecosystem	For point 4 (ecosystem sensitivity), a value of 2 to 5 is realistic	For non-polar narcotics, many species of organism have been studied, so the uncertainty regarding lab to field extrapolation should also be reduced. The ecosystem is adapted to alcohols. Suggest 2.5
Conclusion	The geometric mean of the range of the two contributing factors is 10. Whilst not set out in Guidance, such a breakdown is a reasonable basis of the factors and is consistent with such extrapolations in mammalian toxicology.	AF = 1*2*1*2.5 = 5 is implied

 

Although in the case of tetradecanol specifically, a full set of long-term results are not available, the predictability of trends across the category, the low acute-to-chronic ratio and the potential for metabolism mean that the duration factor (point 3) does not need to be inflated.

On the basis of this logic, an assessment factor of 10 is very conservative for deriving PNECs in the chemical safety assessment of this substance. However, an assessment factor of 10 has been applied to the lowest NOEC or ECx value to derive aquatic PNECs.

For further discussion please refer to the attached ECOTOXICITY Alcohols C6-24 Category report.

Read-across data

Supporting data have been read-across from the mixture, Alcohols C14-C15 (CAS 75782-87-5) for fish and algae, to support the view that C14 is non-toxic at the limit of solubility.

 

Justification for Read-across 

1. HYPOTHESIS FOR THE CATEGORY APPROACH

The hypothesis is that the category members have similar structures and short-term toxicity to fish and algae effects which vary in strength across the category, forming a regular pattern (Scenario 4 in the RAAF). The interpretation of the observed trends of variation of this property across the category is discussed in the endpoint summary. 

 

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)

Please refer to the test material identity information within each endpoint study record and to the endpoint summary. The source chemicals and the target chemical are linear aliphatic alcohols which are members of the long chain linear aliphatic alcohol Category.

 

The long chain linear aliphatic alcohol Category has at its centre an homologous series of increasing carbon chain length alcohols. The category members are structurally very similar. They are all primary aliphatic alcohols with no other functional groups. The category members are linear or contain a single short-chain side-branch at the 2-position in the alkyl chain, which does not significantly affect the properties (‘essentially linear’). The category members have saturated alkyl chains or contain a small proportion of naturally-occurring unsaturation(s) which does not significantly affect the properties. The branched and unsaturated structures are considered to have such similar properties that their inclusion in the category is well justified.

Impurities: Linear and/or ‘essentially linear’ long chain aliphatic alcohols of other chain lengths may be present. These are not expected to contribute significantly to the properties in respect of this endpoint due to predictable trends (see point 3). 

There are no impurities present at above 1% which are not category members or which would affect the properties of the substance.

 

3. CATEGORY JUSTIFICATION

The category members are structurally very similar (see point 2) and are biochemically very similar. The metabolic synthesis and degradation pathways are well established. This Category is associated with a consistency and predictability in the physicochemical, environmental, and toxicological property data across its members.

 

The context of trends observed in this property across the range of chain lengths covered by this Category is described in the Endpoint Summary and in the Category Report attached in Section 13.

 

In this registration, the information requirement is fulfilled by data with the registration substance itself, with supporting read-across data from one or more members of the category with similar or same chain length, for which the comparability is strongest (in view of the similar physico-chemical properties of the source and target substances as well as similar position in terms of category trends).

 

4. DATA MATRIX

A data matrix for the C6-24 alcohols Category is attached in Section 13.

Conclusion on classification

Tetradecanol has reliable short-term E(L)C₅₀ values for fish, invertebrates and algae of >1 mg/l, 3.2 mg/l and >10 mg/l, respectively. It has a reliable EC₁₀ of 2.9 mg/l in algae and 0.0063 mg/l in Daphnia, as well as a NOEC of 0.0016 mg/l in Daphnia.

The substance is readily biodegradable and very rapidly biodegraded in non-sterilised systems.  

These data are consistent with the following classification under Regulation (EC) No 1272/2008 (as amended) (CLP):

Acute toxicity: Not classified.

Chronic toxicity: Category 1 An M-factor of 1 applies (chronic toxicity NOEC value 0.001 < NOEC ≤ 0.01 mg/l, rapidly degradable substances).