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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

The bioaccumulation is expected to be low.
No data are available on partially unsaturated TEA-Esterquat. Measured BCF data are available on a structurally closely related material, DODMAC (Dimethyldioctadecylammonium chloride, CAS-No. 107-64-2).

Key value for chemical safety assessment

BCF (aquatic species):
13 L/kg ww

Additional information

No data are available on TEA-Esterquats. According to REACH regulation (Annex XI, 1.5), the study on aquatic bioaccumulation does not need to be conducted for the substance under investigation if data from a structurally closely related material are available.

Measured BCF data are available on a structurally closely related material, DODMAC (Dimethyldioctadecylammonium chloride, CAS-No. 107-64-2). DODMAC has a chemical structure similar to the TEA-EQ Diester. TEA-Esterquats are UVBC substances. The main component is the dialkylester compound, besides smaller amounts of the monoalkyl- and trialkylester.

The molecular diester moiety of the registration substance for which the highest bioaccumulation potential is expected is the diester with saturated ester groups, chain length C18 (Compound I) and differs from DODMAC by the ester linking groups between the alkyl chains (of C18chain length) and the head group (effectively the quarternary ammonium group). Minor components are the TEA-Esterquat monoester and triester.

Regarding lipophilic properties of the registration substance, the registration substance bioaccumulation is expected to be lower than that for DODMAC: The chemical structure of the registration substance includes, in contrast to DODMAC, one, two or three polar ester moieties and one or two ethanol moieties that lower hydrophobic character. The monoester is considerably less lipophilic than the main component, TEA-Esterquat diester. The minor component, TEA-Esterquat triester with alkyl chain length C18, should be more lipophilic than the TEA-Esterquat diester. All TEA-Esterquats are biodegradable/hydrolysable which also will result in lower environmental concentrations for the registration substance. TEA-Esterquats are metabolised in higher organisms. The substances are de-esterified and further degraded via the fatty-acid metabolic pathway.

DODMAC is poorly biodegradable and much more stable than the registration substance. For DODMAC, no abiotic degradation is expected. The degradation rate is very low for biotic degradation in water (1.4·10-4day-1) (EU RAR, 2009).

Juvenile fish (Pimephales promelas) were exposed to the structurally similar substance DODMAC for 24 h under flow-through conditions, followed by a depuration period of 72 h. A BCF of 104 is calculated based on the uptake rate constant (k1) of 1.35 mg/g·h and the depuration rate constant (k2) of 0.013 mg/g·h (Versteeg & Shorter, 1992).

The measured BCF values for similar substances (DODMAC, DHTDMAC (Dihydrogenated Tallow Alkyl Dimethyl Ammonium Chloride)) are 12-32 (BUA-Report 191, 1995) and 13-256 (EU RAR, 2002). The conclusion for DODMAC was “bioaccumulation is indicated, but it is assumed that it is low under environmental conditions. A BCF of 13 l/kg is used in the risk assessment…” (EU RAR, 2009).

The calculated BCF value forTEA-Esterquatis 70.8 (BCFWIN v2.17).

The low bioavailability of the substance (due to rapid and strong sorption to negatively charged surfaces in the aquatic environment) in combination with the rapid (bio)degradation of the bioavailable fraction (mainly due to the hydrolysis of the ester bond), make high bioconcentration factors for the substance even more improbable (Comberet al., 2003 in Hera, 2008).

For TEA-Esterquats, a BCF of the same order of magnitude as the BCF of DODMAC (13 l/kg) is expected. The above information is considered as sufficient to support the conclusion that the bioaccumulation potential of the registration substance is expected to be low.