Fatty acids, tall-oil, manganese salts

Endpoint summary

Description of key information

The fate of Fatty acids, tall-oil, manganese salts in the environment is most accurately evaluated by separately assessing the fate of its constituents manganese cations and fatty acid, tall-oil anions. Since manganese cations and fatty acid, tall-oil anions behave differently in the environment, including processes such as stability, degradation, transport and distribution, a separate assessment of the environmental fate of each assessment entity is performed. Please refer to the data as submitted for each individual assessment entity.

 

Manganese cations: Abiotic and biotic degradation are not relevant and not expected to affect the fate of manganese cations in the environment. A 100-d adsorption / desorption study of manganese (2+) cations in 35 soils according to OECD 106 indicates that sorption is pH sensitive, and a median Kd value of 1355 L/kg was determined (pH range 3.0-8.5). Regarding Mn partitioning in sediments and suspended matter, a logKp (solids-water in sediment) and logKp (solids-water in suspended matter) of 4.57 and 3.78 were derived based on several European field studies, respectively. Manganese as essential trace nutrient in animals and plants is actively regulated in organisms and not expected to bioaccumulate.

 

Fatty acids, tall oil: Hydrolysis does not appear to be a relevant degradation process of tall oil in the environment. Available data point to a fast photodegradation of C16-18 fatty acids as contained in tall oil with half-live times in air of < 1 day.

Available data point to a ready biodegradability of tall oil (C16-18 fatty acids) under aerobic conditions. Hence, fatty acids are not expected to be persistent in water, sediment or soil due to a rapid microbial degradation. Transformation products of environmental concern are also not expected. Thus, fatty acids in tall oil, though rather immobile in soil, are rapidly degraded via the β-oxidation pathway, rendering adsorption/desorption processes less relevant.

QSAR-based estimates and a ready biodegradability point to a low bioaccumulation potential of C16-18 fatty acids as contained in tall oil in aquatic and soil organisms.

Additional information

Read-across approach

In the assessment of the environmental fate, ecotoxicity and toxicity of Fatty acids, tall-oil, manganese salts (CAS: 8030-70-4), a read-across approach from data for the metal cation (manganese) and the organic anion (fatty acids, tall-oil) is followed. This read-across strategy is based upon the observation that upon dissolution in aqueous media, Fatty acids, tall-oil, manganese salts completely dissociates and only is present in its dissociated form, i.e. as manganese cation and fatty acids, tall-oil anions. Data on the environmental fate, ecotoxicity and toxicity for both transformation products (manganese cation and fatty acids, tall-oil anions) together can therefore be combined in an additive approach to predict the corresponding properties of Fatty acids, tall-oil, manganese salts.

A detailed justification for the read-across approach is added as a separate document in section 13 of IUCLID.

Upon dissolution and dissociation of Fatty acids, tall-oil, manganese salts into the manganese cation and fatty acids, tall-oil anions, both ions will each show the proper (bio)degradation, bioaccumulation and partitioning behaviour in the environment, as reported for the corresponding ion. The environmental fate and behaviour for the manganese cation and fatty acids, tall-oil anions is predicted to be clearly different from each other, resulting in a different relative distribution over the environmental compartments (water, air, sediment and soil). Because the relative exposure to both constituent ions is hence predicted to be different from the original composition of Fatty acids, tall-oil, manganese salts, data for the ecotoxicological properties of this substance tested as such are considered less relevant for its effects and risk assessment and a read-across approach from data for both the manganese cation and fatty acids, tall-oil anions is preferred. The dose additivity approach is used to explain the ecotoxicological effects of Fatty acids, tall-oil, manganese salts based on the data for the individual transformation products (manganese cation and fatty acids, tall-oil anions).