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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Administrative data

Link to relevant study record(s)

Description of key information

BCF < 500

Key value for chemical safety assessment

BCF (aquatic species):
260 dimensionless

Additional information

Assessment of the parent compound Benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-,C7-9-branched alkyl esters (CAS: 125643 -61 -0)

In an OECD 305 flow through test on Rainbow trout, a low bioaccumulation potential of Benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-,C7-9-branched alkyl esters was established with a maximum BCF(whole fish) of 260. Fish were exposed to 0.05 or 0.25 μg/L of [ring-U-14C] Benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-,C7-9-branched alkyl esters (cited as TK11014 or Irganox L135/1135) during 35 days (CIBA 2006, Huntington Life Sciences No: CBG0865/063570).

The exposure was followed by a depuration period of 28 days. At the low exposure concentration, the bioconcentration factor was determined as 112 in the edible fraction, as 361 in the non-edible fraction and as 258 in the whole fish based on the total radioactivity. After 18 days, 90% of the radioactivity was eliminated from the fish. At the high concentration the bioconcentration factor was determined as 112 in the edible fraction, as 371 in the non-edible fraction and as 260 in the whole fish. Chromatographic analysis of the fish extracts showed that TK 11014 accounted for 25 – 40% of the radioactive dose.

Corresponding bioconcentration factors for the parent substance were low and mean values were in the range 50 - 201, the lowest values related to tihe edible portion of fish.

During exposure 58 – 82 % of the radioactivity was the test substance, and Metilox acid was identified as the major metabolite. Its content was highest on day 35, when it accounted for 35% of the radioactive dose.

As a worst case the BCF(whole fish) based on total radioactivity of 260 was used.

Supporting assessment of the major degradation product Metilox acid (CAS: 20170-32-5)

The bioconcentration of Metilox acid was tested in a study on the uvcb substance CAS 179986 -09 -5. One constituent of this substance is Metilox (CAS 6386 -38 -5). Metilox acid (CAS: 20170-32 -5) was identified as relevant transformation product.

The study was conducted according to OECD guideline 305 C. At 50 ug/l, the bioconcentration factor was determined to be 60-223 and 121-532 at 5 ug/l, respectively, after 8 weeks of exposure. The exposure concentration is well below the solubility limit of Metilox acid in water.