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In a weight of evidence approach the calculated log Koc (from log Kow) as reported in the OECD Screening Information Data Sets document for dimethyl terephthalate (main component of the UVCB submission substance) was compared with the calculated log Koc (from experimental log Kow = 3.2) by three further methods (KOCWIN; according to Sablijic and Güsten, 1995; according to Gerstl, 1990). As the results are in close agreement (SIDS: 2.49; KOCWIN: 2.56; Sablijic and Güsten 2.62; Gerstl 2.27), the value calculated by KOCWIN was taken as the program was updated and improved recently with several phthalates (structural isomers to terephthalates) in the large and diverse training set.

Calculated log Koc-values from 7 minor components of relevance of the UVCB have values (as calculated by KOCWIN) in close proximity, as would be expected for a grouping apporach (range: 1.62 to 2.96). For one of these substances (CAS: 99 -75 -2), also the methods of Sablijic and Güsten (1995) as well as Gerstl (1990) have been applied, again yielding very similar results (KOCWIN: 2.35; Sablijic and Güsten 2.37; Gerstl 1.93). Thus, the Koc-value of the main constituent, dimethyl therephthalate, is deemed most relevant and representative for the UVCB substance as a whole.