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Environmental fate & pathways

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Study reports are available for the ready biodegradability test, the inherent biodegradability test and adsorption/desorption test. Hydrolysis test and simulation tests were waived. The BCF result was calculated with a QSAR model. The results are summarized as below:

Alkylated Naphthalene was not readily biodegradable under the conditions of the modified Sturm test. Degradation of 1 -2% was observed after 28 days.

Determination of inherent biodegradability: CO2 in sealed vessels (headspace test) with Alkylated Naphthalene was performed according to the modified test method based on the OECD guideline No. 310, 2006. The relative biodegradation values calculated from the measurements performed during the test period revealed no significant biodegradation of Alkylated Naphthalene. Thus, Alkylated Naphthalene is designated as not inherently biodegradable.

The HPLC method using soil-adsorption-reference data was applied for the determination of the adsorption coefficient (Koc) of Alkylated naphthalene. The Koc and log Koc values of the test substance at neutral pH were >4.3 × 105and >5.63 respectively.

In accordance with Column 2 of REACH, Annexes VIII the tests do not need to be conducted if the substance is highly insoluble in water (water solubility: <3.75 µg/L ). Thus the hydrolysis test was waived.

The test substance meets the Persistence or Very Persistence criteria from the available inherent biodegradability test (56 d degradation: 4.4 %) according to the modified test method based on OECD guideline 310, only if the CSA indicates the need to investigate further degradation of the substance in future. Thus, no more simulation tests are necessary.

The bioaccumulation potential of Alkylated Naphthalene was estimated using the BCFBAF model which is part of the EPIWIN suite of models developed by the U.S. Environmental Protection Agency. The EPIWIN program calculates BCF values using both the Meylan model and the Arnot and Gobas model.

As no definite measured log Kow is available for the substance (measurements resulted in a value >8.2, which was the upper limit of validated by the analytical method) the BCF QSAR model was used by allowing the model to calculated the Log Kow from the structure of the substance.

The range of BCF estimates for the 4 components of the UVCB substance are 0.9 to 190 using the Arnot-Gobas model and 3 to 309 based on the Meylan model. The mono-alkylatednaphthalene component which has the lowest concentration (3.3%) had the highest BCF in models (190 and 309). All values are considerably less than the EU PBT criterion of 2000 for BCF.