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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

For MDEA-Esterquat C18 satd. a BCF of the same order of magnitude as the BCF of the structurally related source substance DODMAC (13 L/kg) is expected.

Key value for chemical safety assessment

BCF (aquatic species):
13 L/kg ww

Additional information

Although not required under REACH Annex VIII following information about bioaccumulation aquatic/sediment will be given:

No experimental data for MDEA-Esterquat C18 satd. are available. Measured BCF data are available for Dimethyldioctadecyl ammonium chloride (DODMAC, CAS-No. 107-64 -2). DODMAC has a chemical structure similar to the target substance and is the molecular moiety of the target substance (MDEA-Esterquat C18 satd. ) for which the highest bioaccumulation potential is to be expected (1). MDEA Esterquat C18 satd. differs from DODMAC by the ester linking groups between the alkyl chains (of C18 chain length) and the headgroup (effectively the dimethyl ammonium group).

Regarding the BCF of the MDEA Esterquat C18 satd., the BCF is expected to be lower than that of DODMAC:

The chemical structure of the MDEA-Esterquat C18 satd. includes, in contrast to DODMAC, two polar ester moieties that lower BCF and which are susceptible to biodegradation and/or hydrolysis which also will result in a lower BCF of the MDEA Esterquat C18 satd. DODMAC is poorly biodegradable and much more stable than MDEA Esterquat C18 satd. For DODMAC no abiotic degradation is to be expected, for biotic degradation in water the degradation rate is very low (1.4 x 10E-4/d) (EU RAR, 2009).

Juvenile fish (Pimephales promelas) were exposed to DODMAC for 24 h under flow-through conditions, followed by a depuration period of 72 h. Without Humic acid, a BCF of 103.8 L/kg could be calculated based on the uptake rate constant (k1) of 1.35 mg/g x h and the depuration rate constant (k2) of 0.013 mg/g x h. With the addition of 1 mg/L and 6.8 mg/L Humic acid, the BCF was 37.5 and 2.8 L/kg, respectively (Versteeg & Shorter, 1992).

Based on naturally occurring concentrations of dissolved organic carbon (DOC) in the range of 2 to 10 mg/L in rivers and lakes, and 50% of the DOC being fulvic and humic acids (Thurman, 1985), the BCF obtained with the addition of 1 mg/L Humic acid can be considered to be most relevant.

The measured BCF values for similar substances (DODMAC, DHTDMAC(2)) are 12-32 (BUA Report 191, 1997) 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 for MDEA Esterquat C18 satd. is 70.8 L/kg (BCFBAF v3.01; CFCS 2015).

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 (Comber et al., 2003 in Hera, 2008).

For MDEA Esterquat C18 satd. 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 to the conclusion that the bioaccumulation potential of the registration substance is expected to be low (3).

(1) for a fatty acid derivative like the registration substance, bioaccumulation potential increases with increasing chain length of the fatty acid (within certain limits). Compound I has the longest fatty acid chain length among the molecules forming the registration substance.

(2) DHTDMAC: Dihydrogenated Tallow Alkyl Dimethyl Ammonium Chloride

(3) REACH Regulation, Annex XIII: a substance fulfils the bioaccumulation criterion when the bioconcentration factor (BCF) is higher than 2000

References:

EU, 2009: European Union Summary Risk Assessment Report - dimethyldioctadecylammonium chloride (DODMAC) - with addendum, available online: http://publications.jrc.ec.europa.eu/repository/handle/111111111/5276

 

HERA, 2008:Esterquats Environmental Risk Assessment Report, available online: http://www.heraproject.com/files/17-E-01-03-2008%20%20HERA%20EQ%20Environment%20Final%20Draft.pdf

191 BUA-Report: Dioctadecyl Dimethyl Ammonium Chloride (DODMAC) CAS-No. 107-64-2, Dihydrogenated Tallow Alkyl Dimethyl Ammonium Chloride (DHTDMAC) CAS-No. 61789-80-8,1. Dezember 1997

Comber MH,de Wolf W, Cavalli L, van Egmond R, Steber J, Tattersfield L, Priston RA. Assessment of bioconcentration and secondary poisoning of surfactants. Chemosphere. 2003 Jul;52(1):23-32

Thurman EM, Organic Geochemistry of Natural Waters. 1985, Springer

Versteeg DJ & Shorter JS. Effect of organic carbon on the uptake and toxicity of quaternary ammonium compounds to the fathead minnow, Pimephales promelas. Environmental Toxicology and Chemistry. 1992 Apr;11(4):571 -580