Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Hydrolysis

The test item is a complex mixture for which the test guideline for hydrolysis is not recommended. This is not only because components could have different hydrolytic rates but also hydrolysis products can be analytically indistinguishable from their starting material.

The test item was determined* to have a water solubility value of less than or equal to 1.14 E-04 g/l; this meant the hydrolysis test would need to be performed at 5.7 E-05 g/l or lower. Therefore, it was considered that the solution concentration required for the test was impractically low to perform the test as individual components would be much lower than this.

The main functional groups in the test item are thiadiazoles and hydroxyls. Neither of these readily hydrolyse at environmentally relevant temperatures and pHs, so it would be expected that the test item is hydrolytically stable.

Biodegradation

In a key study performed in accordance with OECD 301B CO2 Evolution Test. The inoculated mineral medium was dosed with a known amount of test substance (measured as 10 mg carbon/L) as the nominal sole source of organic carbon and aerated with CO2-free air. The CO2 produced from the mineralization of organic carbon within the test chambers is displaced by the flow of CO2 -:free air and trapped as K2CO3 in KOH trapping solution. The amount of CO2 produced by the test substance (corrected for that evolved by the blank inoculum) is expressed as a percentage of the theoretical amount of CO2 (TCO2) that could have been produced if complete biodegradation of the test substance occurred over the 28-day study period.

The average percent biodegradation for the test material was 17.4%.

The test material cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No 301B.

Bioaccumulation

The substance will not bioaccumulate.The experimentally derived Log Pow value for the substance has been identified as > 9.4. QSAR calculations of Log Pow for the components determined that Log Pow >10 for the majority of the components. ECHA Guidance on Information requirements and chemical safety assessment Chapter R11: PBT assessment (page 28) on determination of bioaccumulation potential states: The aquatic BCF of a substance is probably lower than 2000 L/kg if the calculated log Kow is higher than 10.

Adsorption/desorption

The determination was carried out using a HPLC screening method, designed to be compatible with Method C19 Adsorption Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 121 of the OECD Guidelines for Testing of Chemicals, 22 January 2001.

The Koc has been determined to be greater than 4.27 E05, log10Koc >5.63.

Henry's Law Constant

Henry's law constant was calculated to be less than or equal to 1.27E-05 Pa.m3/mol at 25 °C. This value indicates a low rate of volatilisation from surface water is expected.

Environmental distribution

The substance is predicted to partition mainly to soil (35.6 - 51.4%) and sediment (35.6 - 61.2%)