Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Biodegradation in water: screening

Key study:

In a biodegradation study conducted according to Japanese Guideline study on microbial degradation of chemical substances (MHLW/PFSB Notification No. 1121002 Nov 21, 2003, METI/MIB Notification No. 2 Nov 13 2003, and MOE/EPB Notification No. 031121002 last revised Nov 20, 2006) under GLP conditions, degradation of Molyvan 855 averaged 57% (based on BOD) and elimination was 98% (based on residual test substance) after 28 days in sludge. The parent substance is fully eliminated with molybdenum turning to molybdic acid. Structurally modified, water soluble substances also were produced. (Mitsubishi Chemical Medience Corporation, 2009).

Supporting study:

In a study conducted according to Japanese Guideline, Degree of Decomposition of Chemical Substances by Microorganisms, etc. in Test Methods for New Chemicals based on Kanhogyo No. 5, Yakuhatsu No. 615 and kikyoku No. 392 (1984), similar degradation rates were observed. Decomposition averaged 61% (based on BOD) after 28 days in sludge, although overall decomposition of two primary substance constituents averaged 92% (based on TOC) and 97% (based on HPLC). (Kagakuhin Kensa Kyokai Foundation, 1987).

Biodegradation in water and sediment

According to 9.2.1.2 Column 2 of Annex IX of the European Union (EU) Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) 1907/2006 regulation, the simulation testing on ultimate degradation in surface water study need not be conducted if the substances is highly insoluble in water, or the substance is readily biodegradable. Experimental evaluation of the water solubility resulted only in a limit value (actual value <1.25 mg/L, slightly soluble) due to the necessity to employ a visual method. Subsequent computer modeling of

individual components, performed to provide definitive solubility data, resulted in a majority of the estimated values being within the “insoluble” classification range (actual values were 0.005 to 0.21 mg/L). Although Molyvan 855 does not meet the criteria for "readily biodegradable", degradation of the substance averaged 57% and 61% (based on BOD) and elimination was 98% and 97% (based on residual test substance) after 28 days in sludge in two biodegradation studies. This endpoint is, therefore, being waived.

Biodegradation in soil

According to 9.2.1.3 Column 2 of Annex IX of the European Union (EU) Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) 1907/2006 regulation, soil simulation testing (for substances with a high potential for adsorption to soil) study need not be conducted if the substance is readily biodegradable, or if direct and indirect exposure of soil is unlikely. Although Molyvan 855 does not meet the criteria for "readily biodegradable", degradation of the substance averaged 57% and 61% (based on BOD) and elimination was 98% and 97% (based on residual test substance) after 28 days in sludge in two biodegradation studies. Additionally, Molyvan 855 is considered immobile in soils based on the estimated adsorption coefficient (log10 Koc) values in the range of 3.52 to at least 5.43 for the dominant lauric acid and myristic acid reaction products. The less abundant fatty acid constituents resulted in estimated adsorption coefficient (log10 Koc) values in the range of 2.44 to at least 6.47. The upper value of each range was reported as a limit value due to possible additional reaction of the organic subunits, resulting in higher molecular weight species containing multiple coconut oil alkyl residue groups. It is acknowledged that such products would present even higher adsorption coefficients. This endpoint, therefore, is being waived.