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Environmental fate & pathways

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Several biodegradation in water screening tests were found that were performed on analog and structurally similar substances. These include studies performed according to OECD Guidelines 301D, 301F and 301B. None of these available studies showed ready biodegradation after 28 days.

A 28-day aerobic ready biodegradability study (to OECD Guideline No. 301D – Closed Bottle Test) was carried out using an analog of the submission substance (CASN 70024-71-4; benzenesulfonic acid C16-C24 alkaryl derivative, calcium salt). The effects of the test substance on ready biodegradability were assessed based on the measurement of chemical oxygen demand (COD) using an activated sludge inoculum (from a domestic wastewater plant) that was not pre-adapted to the test substance. Test performance was evaluated using the reference substances sodium benzoate and aniline. There was only 8% degradation of the test substance after 28 days. There was 97% and 61% degradation of the reference substances sodium benzoate and aniline after 28 days meaning the test was considered valid.

A second 28-day aerobic ready biodegradability study (to OECD Guideline No. 301F – Closed Bottle Test) was carried out using an analog of the submission substance (CASN 70024-71-4). The effects of the test substance on ready biodegradability were assessed based on the measurement of oxygen uptake using an activated sludge inoculum (from a domestic wastewater plant) that was pre-adapted to the test substance for 14 days. Test performance was evaluated using the reference substance sodium benzoate. This toxicity study is classified as reliable without restriction (Klimisch Code 1) and satisfies the guideline requirement for biodegradation in water-screening tests. There was only 8.6% degradation of the test substance after 28 days. There was 89% degradation of the reference substance sodium benzoate after 28 days meaning the test was considered valid.

A third 28 -day aerobic ready biodegradability study (to OECD Guideline No. 301B – Modified Sturm Test) was carried out using an analogue of the submission substance (CASN 70024-71-4). The effects of the test substance on ready biodegradability were assessed based on the measurement of carbon dioxide evolution using an activated sludge inoculum (from a domestic wastewater plant) that was not pre-adapted to the test substance. Test performance was evaluated using the reference substance sodium benzoate. This toxicity study is classified as reliable without restriction (Klimisch Code 1) and satisfies the guideline requirement for biodegradation in water screening tests. There was only 9.1% degradation of the test substance after 28 days. There was 86% degradation of the reference substance sodium benzoate after 28 days meaning the test was considered valid.

A fourth 28-day aerobic ready biodegradability study (to OECD Guideline No. 301B – Modified Sturm Test) was carried out using an analogue of the submission substance (CASN 70024-71-4). The effects of the test substance on ready biodegradability were assessed based on the measurement of carbon dioxide evolution using an activated sludge inoculum (from a domestic wastewater plant) that was not pre-adapted to the test substance. Test performance was evaluated using the reference substance sodium benzoate. This toxicity study is classified as reliable without restriction (Klimisch Code 1) and satisfies the guideline requirement for biodegradation in water-screening tests.

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