acetalization product between glucose and C16-18(even numbered)- alcohol

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Endpoint:

bioaccumulation in aquatic species: fish

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Conclusions:

Considering REACH Annex IX 9.3.2 criteria, bioaccumulation in aquatic species, preferably fish, may be proposed. However, as the substance is poorly soluble in water, exposure of the aquatic compartment is unlikely: this test is not proposed to be performed.
The substance is an UVCB which is insoluble in water, so test methods are not applicable.
The log Kow ranging 2.4- 7.7 for individual components of the substance suggests a high bioaccumulation potential. BCF is below 2000.
However, no accumulation of the substance is expected based on the various metabolic pathways and excretion routes which can be expected for the substance.

Executive summary:

The study to determine the partition coefficient (log K_OW) gives data ranging from 2.4 to 7.7, indicating high bioaccumulation potential.

The substance contains about 85 % of 1-hexadecanol (log K_OW = 6.7) and 1-octadecanol (log K_OW= 7.7). The alkyl chain length has the highest impact on the log K_OW value.

A quantitative estimation of the bioconcentration factor (BCF) for fish can be performed according to the parabolic equation given in the Guidance on information requirements and chemical safety assessment (Chapter R.7c) for substances having a log Pow > 6 (with log K_OW = 7.7):

Parabolic equation:

log BCFfish = -0.20 x (log K_OW)² + 2.74 x log K_OW – 4.72

log BCFfish  = -0.20 x (7.7)² + 2.74 x 7.7 – 4.72

log BCFfish  = 4.52

BCFfish  = 33 113 L/kg

A BCF of 224 L/kg was estimated by BCFWIN using log K_OW of 7.7. However, this method delivers many underestimations of BCFs. Hence, this QSAR-method is not reliable for estimating the bioaccumulation potential of the substance.

BCFWIN and equation lead to very different results.

Considering REACH Annex IX 9.3.2 criteria, bioaccumulation in aquatic species, preferably fish, may be proposed. However, as the substance is poorly soluble in water, exposure of the aquatic compartment is unlikely: this test is not proposed to be performed. The substance is an UVCB which is insoluble in water, so test methods are not applicable. The log Kow ranging 2.4- 7.7 for individual components of the substance suggests a high bioaccumulation potential. BCF is below 2000. However, no accumulation of the substance is expected based on the various metabolic pathways and excretion routes which can be expected for the substance.

Description of key information

Considering REACH Annex IX 9.3.2 criteria, bioaccumulation in aquatic species, preferably fish, may be proposed. However, as the substance is poorly soluble in water, exposure of the aquatic compartment is unlikely: this test is not proposed to be performed. The substance is an UVCB which is insoluble in water, so test methods are not applicable. The log Kow ranging 2.4- 7.7 for individual components of the substance suggests a high bioaccumulation potential. 

Furthermore, with regard to metabolic pathways of alkyls polyglucosides and fatty alcohols, it is anticipated that alkyl polyglycosides are 100% absorbed by oral ingestion, followed by ready hydrolysis and metabolism of the resulting cleavage products, sugar and fatty alcohol, in common mammalian physiological pathways. And long chained alcohols are generally highly efficiently metabolised and there is limited potential for retention or bioaccumulation for the parent alcohols and their biotransformation products (see section 7.1).

In addition, in fish, it is suggested that the fatty alcohol in various tissues of carp, which seems to be a substrate of acyl CoA: alcohol acyltransferase, is one of the most important key precursor to form wax esters. And wax esters have been known for a long

time as a prominent lipid class of some aquatic animals. (Mankura et al., 1986; Mankura et al., 1987). Mankura et al. 1987 shown a rapid biotransformation into tissue lipids in fish (carp), for oleyl alcohol (C18, unsaturated). Bioaccumulation of fatty alcohol is unlikely in fish. 

To conclude, the rapid degradation , the various metabolic pathways and excretion routes which can be expected for the substance, shown that the bioaccumulation of the substance is unlikely.

References:

Mitsumasa Mankura and Mitsu Kayama. Wax Ester Synthesis by Carp Hepatopancreas Preparation, 1986. Journal of Japan Oil Chemists' Society Vol. 36, No. 4, 244-253.

Mitsumasa Mankura, Noriaki Iijima, Mitsu Kayama and Satoshi Aida. Plasma Transport form and Metabolism of Dietary Fatty Alcohol and Wax Ester in Carp, 1987. Nippon Suisan Gakkaishi 53(7), 1221-1230.