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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

To determine the biodegradation characteristics of Hydrocarbons C11-C14, n-alkanes, isoalkanes, cyclics, aromatics (2-25%), undecan-1-ol and dodecan-1-ol the following key studies have been conducted:
- OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test) with Alchisor TAL (Cidaria 1998;
- OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test) with Shellsol H (ExxonMobil 1995);
- OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test) with decan-1-ol (Richterich 2002);
- OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test) with dodecan-1-ol (Werner 1993.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

Alchisor TAL 123 can be characterised according to three constituents: Hydrocarbons C11-C14, n-alkanes, isoalkanes, cyclics, aromatics (2-25%), undecan-1-ol and dodecan-1-ol. As defined in the Read-Across Justification Document in section 13, data provided for these constituents when considered together is representative of Alchisor TAL 123 and suitable for assessment purposes. Study data for each constituent has been evaluated and considered together. In a protective approach the most sensitive study result from across the three constituents has been identified and used to address the endpoint in question.

 

Alchisor TAL123 was assessed for ready biodegradability in a reliable (Klimisch 1), GLP compliant OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test) study. In this test Alchisor TAL 123 biodegraded to an extent of 78% after 28 days with an unacclimated sewage sludge inoculum. The test substance did not achieve 60% degradation with a 10-day window for ready biodegradability; Alchisor TAL 123 degraded nearly 56% within the 10-day window. As Alchisor TAL 123 is a mixture, the 10-day window test is not applicable as the only determination of ready biodegradability as different components of the mixture can degrade preferentially (reference TG 103C). Consequently according to this study Alchisor TAL 123 can be considered readily biodegradable. In addition available information for the constituents of Alchisor TAL 123 supports this finding.

 

Hydrocarbons C11 -C14, n-alkanes, isoalkanes, cyclics, aromatics (2-25%)

 

Shellsol H (identified as a mixture of aliphatic and aromatic hydrocarbons) was assessed for ready biodegradability in a reliable (Klimisch 1), GLP compliant OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test) study. In this test Shellsol H biodegraded to an extent of approximately 75% after 28 days with an unacclimated sewage sludge inoculum. The test substance was determined to be readily biodegradable.

 

Undecan-1-ol

Evidence to support the ready biodegradability of the C11 alcohol, undecan-1-ol focuses on tests with both a C10 and C12 alcohol. In an OECD 301D test Richterich 2002 assessed the biodegradation potential of lorol C10 1-decanol. 88% degradation of the test substance was reported within 30 days. Werner 1993 reported on an OECD 301D test with the C12 alcohol, dodecan-1-ol. 79% degradation of the test item was reported within 28 days and so a result of ready biodegradable was recorded. Read-across based on the grouping of substances (category approach) was applied to this data set and consequently provides a weight of evidence confirming that undecan-1-ol is readily biodegradable.

Dodecan-1-ol

A variety of different studies have been conducted with the C12 alcohol, dodecan-1-ol. A reliable (Klimisch 2), GLP compliant test was conducted according to OECD 301D (Werner 1993) with dodecan-1-ol. 79% degradation of the test item was reported within 28 days. The test substance was determined to be readily biodegradable. Dodecan-1-ol was reported as readily biodegradable in a number of other tests. The Vista Chemical Company 1994 reported on a test performed in accordance with EPA OPPTS 835.3100. This EPA guideline corresponds to OECD 301B except for a deviation in which dichloromethane (30ml) is utilized to increase the bioavailability of the alcohol. In this test dodecan-1-ol was found to be inherently biodegradable. Morris 1991, Henkel 1992 and P&G 2009 all found the test item to be readily biodegradable. The evidence presented here indicates that dodecan-1-ol can be regarded as being readily biodegradable.

 

In accordance with the protective approach defined above the most sensitive study result from all the constituents can be applied to the full Alchisor TAL 123 endpoint. As detailed above the selected representative constituents of Alchisor TAL 123 are reported to be readily biodegradable. In addition to the Alchisor TAL 123 specific study, this data for constituents of Alchisor TAL 123 provides further evidence to support the assertion that it is readily biodegradable.