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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Substances in the category Rosin, Hydrogenated rosin and their salts are considered readily biodegradable.

Key value for chemical safety assessment

Additional information

All of the members of this category are UVCB substances that are ionizable and many exhibit low solubility. They are inherently difficult to test for many environmental parameters. A number of biodegradation studies have been performed on these substances with varying results. Highly variable results are believed to be due to solubility and bioavailability issues as well as ionization effects caused by slight differences in pH of the media utilized in the studies.

A number of reliable studies are available for members of this category that indicate that substances in the category are readily biodegradable, meeting the 10-day window. Studies are available for Resin acids and rosin acids, magnesium salts (Harlan Laboratories, 2010b) and Resin acids and rosin acids, calcium zinc salts (Harlan Laboratories, 2010a) that determine these substances to be readily biodegradable. In addition a study is available for Rosin (Akzo Nobel, 1999a). During sample preparation in this study the sample was mixed with NaOH and heated to 75°C, this would convert the test item to Resin acids and rosin acids, sodium salts, another category member. This study determined the test item to be readily biodegradable. A study is available for Tall oil rosin, considered equivalent to Rosin, (Akzo Nobel, 1999b). During sample preparation the test item in this study is also believed to convert to Tall oil rosin, sodium salts, considered equivalent to Resin acids and rosin acids, sodium salts. The test item was determined to be readily biodegradable.

A number of studies are available that indicate the substances are readily biodegradable, but not meeting the 10 -day window. However, as these substances are complex UVCBs, the 10 day window criterion does not apply and these substances are also considered to be readily biodegradable. Studies with this result are available for Rosin (Wildlife International, 1998a) and Hydrogenated rosin, potassium salts (Harlan Laboratories, 2010c).

An enhanced biodegradation study is available for Rosin (Harlan Laboratories, 2010d). This study used modifications for a poorly soluble substance; these were larger test vessels and an increased amount of biomass. The substance was determined to be readily biodegradable under the conditions of the test. Due to the modifications to the study design this study is used as a supporting study only.

An inherent biodegradation study is available for Resin acids and rosin acids, potassium salts (Inveresk Research, 2002a). This indicates that the substance is inherently biodegradable.

A number of tests with Rosin (Notox (1988a); Laboratory for Applied Biology (1992a); Harlan Laboratories (2010e)), Hydrogenated rosin (Inveresk Research (2002,b); Notox (1988b)), Rosin, reaction products with formaldehyde (Safepharm Laboratories, 1993a) and Hydrogenated rosin potassium salts (Eastman, 2004a), determined that the test items did not meet the strict ready biodegradability criteria under the conditions of the test.

Due to the stringent test conditions in biodegradation studies, ECHA's Guidance on Information Requirements and Chemical Safety Assessments R7b: Endpoint specific guidance recommends that consistent positive results should supersede negative results. As a number of reliable studies are available for different members of this category indicating that the substances are readily biodegradable, members of the category Rosin, Hydrogenated rosin and their salts are considered readily biodegradable.