Alcohols, C20-22, reaction products with phosphorus oxide (P2O5)

Bioaccumulation: aquatic / sediment

Description of key information

Introduction. The Quantitative Structure-Activity Relationship (QSAR) model BCFBAF (BCFWIN) v3.02 from EPI Suite v4.11 was used to calculate the Bioconcentration factor (BCF) of the consituents of the test item. This QSAR model predicts the endpoint value which would be expected when testing the substance under experimental conditions in a laboratory following the Organisation for Economic Cooperation and Development (OECD) Guideline for Testing of Chemicals No. 305, "Bioaccumulation in Fish: Aqueous and Dietary Exposure" (OECD, 2012). The criterion predicted was the log BCF. The model has been checked to be compliant with the OECD recommendations for QSAR modeling (OECD, 2004).

Method. The purpose of the in silico study was to determine the log BCF of the consituents of the test item. The determination is performed using different linear regression equations or fixed values, selected on the basis of an initial classification between ionic and non-ionic compounds and on the value of the predicted log KOW value. The linear regression equations are based on the relationship between the log BCF and the log KOW as published by Meylan et al. (1999). These equations take into account correction factors depending on the presence/absence of 12 fragments defined. The QSAR model has been trained and validated with experimental data from a quality reviewed BCF database (Arnot and Gobas, 2006). Finally the log BCF is predicted for each constituent defined for the test item.

As a UVCB substance, the complete composition of the test item with the associated concentration of the constituents is not known. The following constituents are considered to be representative of the test item.

Constituents	CAS-RN
1-Eicosanol, dihydrogen phosphate	42714-96-5
1-Docosanol, dihydrogen phosphate	23079-25-6
1-Eicosanol, hydrogen phosphate	42714-98-7
1-Docosanol, hydrogen phosphate	42714-99-8
1-Eicosanol	629-96-9
1-Docosanol	661-19-8

Log Kow

Constituents	log KOW	references
1-Eicosanol, dihydrogen phosphate	9.5	(KREATiS, 2020a)
1-Docosanol, dihydrogen phosphate	11	(KREATiS, 2020a)
1-Eicosanol, hydrogen phosphate	20	(KREATiS, 2020a)
1-Docosanol, hydrogen phosphate	22	(KREATiS, 2020a)
1-Eicosanol	9.7	(KREATiS, 2020a)
1-Docosanol	11	(KREATiS, 2020a)

Results. The results below are the log BCF for each constituents of the test item:

Constituents	log BCF
1-Eicosanol, dihydrogen phosphate	2.30
1-Docosanol, dihydrogen phosphate	1.57
1-Eicosanol, hydrogen phosphate	0.50
1-Docosanol, hydrogen phosphate	0.50
1-Eicosanol	2.20
1-Docosanol	1.57

Log BCF of the registered substance is ranged from 0.50 to 2.30 (3.16 to 201 L/kg). BCF is lower than the B criteria (BCF< 2000), the registered substance can be considered as not B and not vB.

Reference:

KREATiS (2020a) Determination of the n-octanol/water partition coefficient of the constituents of REACTION PRODUCTS BETWEEN C20/22 (even numbered) ALCOHOL AND PHOSPHORIC ANHYDRIDE. 000/SEP/KOW/19002. 12 March 2020