Fatty acids, C18-unsatd., phosphates

Endpoint summary

Description of key information

This substance is a complex mixture with different fate and physical chemical properties. Therefore, most of the critical physchem and environmental fate properties such as water solubility, octanol-water partition coefficient, adsorption coefficient, biodegradation and hydrolysis were determined in the laboratory through a extensive testing program.

The determination of the rate of hydrolysis of Fatty acids, C18-unsatd., phosphates was studied at pH values normally found in the environment (pH 4-9). At pH 4 and pH 7 a degree of hydrolysis of < 10% was observed after 5 days at 50°C. At pH 9, a degree of hydrolysis of ≥ 10% was observed after 5 days at 50°C. Adsorption coefficient was measured at 30 Degrees Celsius at two pH levels. Based on the results, the KOC of the susbtance was 5.63.

The biodegradation in water and soil is the most important fate process of this substance. Based on the CO2 Evolution screening tests and the supporting information on the probability of biodegradation estimated for the substance, this substance is considered as not readily biodegradable in water. In addition, the EPISUITE tool was used for estimation of the bioaccumulation potential of the substance.

A method was developed to determine the solubility of these major components since these components are the most soluble and interesting for the toxicity studies. Based on the water solubility study he overall range water solubility values were from 0.0235 g/L to 206 g/L. The log Kow determined for the substance (log Kow 4.6) indicates the adsorption potential and bioaccumulation of the substance. The vapour pressure of the substance was measured at 20 and 25 deg. Celsius. The vapour pressure was found to be < 0.0015 and <0.0067 Pa at 20 and 25 deg. C. The model used for exposure assessment and risk characterisation assumes that most of the substance is distributed to soil (see section 9.0.3.3 of CSR).