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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

No bioaccumulation is expected

Key value for chemical safety assessment

BCF (aquatic species):
0.5 dimensionless

Additional information

According to the REACH Regulation, Annex IX, Column 2, the substance does not need to be tested due to the low potential for bioaccumulation (log Kow < 3) and a low potential to cross biological membranes (high molecular weight, high polarity).

Nevertheless, several bioaccumulation studies are available on the analogous substance CAS 13863-31-5 and they demonstrated no bioaccumulation in fish. Bluegills (Lepomis machrochirus) was exposed to the test item in dynamic flowthrough tankwater systems, in order to determine at what degree this substance accumulate in portions of the fish, which may be consumed by humans. The concentration tested was 0.1 mg/l, the exposure period was 35 days and the elimination phase was from 7 to14 days. During the tests, fish and water were periodically sampled and analysed. A further accumulation study using 14C-labeled substance was performed at concentrations of 0.01 and 0.001 mg/l; exposure phase was of 30 days, while elimination phase of 14 days. Only sporadic trace concentrations (less than 0.05 mg/kg) of the test item were present in the fish at exposure levels of 1 mg/l. In most instances, no detectable substance was found.

The data indicates that there is no tendency for the substance to be taken up and stored in the fish. In the case of the 14C-substance, at both the concentrations tested, the levels of radioactivity found in the fish were approximately equal to those found in the tankwater throughout study. Furthermore the absence of accumulated radioactivity demonstrated that neither parent compound, nor possible metabolites of the substance are accumulated in fish (Ganz, 1975).

The test substance was also tested to determine its potential for significant accumulation in the flesh of the Bluegill (Lepomis macrochirus) and channel catfish (Ictalurus punctatus). The test was conducted at the following concentrations: 50 µg/l, 5 µg/l, and 0.5 µg/l total test substances (the study was conducted with five agents administrated in the same solutions). The results of the bluegill analyses exposed to a nominal concentration of 50 µg/l total agents (12.5 µg/l of each one) indicate that no accumulation of the substance of the interest was observed at measurable levels (i.e., greater than 10 µg/kg). At the concentration of 5 and 0.5 µg/l(1.25 and 0.125 µg/l, respectively) no measurable accumulation was detected (Sturm, 1974).

In the Bionomics Inc. and Ciba Geigy Ltd. (1972-1973) study sixty Bluegill were continuously exposed to the chemical in water for a period of at least 28 days. After this period, the fish were transferred for a period of 7 days to uncontaminated water and after this period they were sampled. Generally the test item concentration were not determinable in tissues or were too low to be quantified. In one case, a value of 0.03 mg/kg close to the sensitivity limit (0.01 mg/kg) was measured, confirming that the bioaccumulation potential of the test substance is considered negligible.

The CAS 13863-31-5 analogous substance is the methyl/hydroxyethylamino derivative, disulphonated sodium salt, member of the Stilbene Fluorescent Whitening Agents category. It is the least water soluble among all the category members and thus it is expected to be the member in which the absorption is the most favourite process; this characteristic make it the most potentially bioaccumulative and therefore the conservative preferred representative.

For completeness sake, the Bioconcentration Factor (BCF) value was calculated using BCFBAF v3.01 tool, an application contained in the EpiSuite 4.1[1]. The estimation takes into account the substance is a ionic compound. The BCF estimated value from regression-based method is 0.5 (BCF = 3.175 l/kg wet-wt), in agreement with the common value of non bioaccumulative substances.

[1] EpiSuite is the suite of physical/chemical property and environmental fate estimation programs developed by the EPA’s Office of Pollution Prevention Toxics and Syracuse Research Corporation (SRC).