Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Stability

Phototransformation in air

Degradation rates for gas-phase reactions of the test substance with hydroxyl radicals and ozone in the atmosphere were calculated using the AOPWIN program, v1.92, which is based on the Atkinson structure-activity relationship method. The calculated degradation rate of the test substance with hydroxyl radicals (OH) is 193.5x10E-12cm3 molecule-1 sec-1. The atmospheric degradation half-life of the test substance due to reactions with ozone is 0.004 days.

 

Hydrolysis

The purpose of a study (Huntington Life Sciences, JHW0005, 2014) according to EPA OPPTS 835.2120 (Hydrolysis of Parent and Degradates as a Function of pH at 25°C, 1998) was to provide information on the hydrolytic degradation of the test substance when introduced into sterile aqueous solutions buffered at a pH of 4, 7 and 9. The calculated halflives were 1261 days at 10°C, 133 days at 25°C and 9.84 days at 50°C. Based on the various pH buffers examined, it can be concluded that hydrolysis would be a possible degradation route in the aquatic environment only under basic conditions.

 

Phototransformation in water

In a key study (Huntingdon Life Sciences, JHW0006, 2014) according to OECD 316 (2008) the test substance was photolytically degradable in both pH 7 buffer and natural water at 25°C. The DT50 values were 28 (pH 7 buffer) and 12 equivalent days (natural water) of latitude 40°N summer sunlight, respectively, or 78 (pH 7 buffer) and 34 equivalent days (natural water) of Tokyo spring sunlight.

 

Phototransformation in soil

The photolysis of the radiolabelled test substance was studied in a test (BASF Crop Protection, 394791, 2013) on a soil obtained from New Jersey according to OECD guideline (Phototransformation of Chemicals on Soil Surfaces, Draft Document 2002). The DT50 of the test substance was determined to be 40.7 days for the sterilized soils in the dark control samples.

 

Biodegradation

Biodegradation in water: screening test

The ready biodegradability of the test substance was examined in a study (BASF SE, 39483, 2014) according to the OECD 301 B (CO2 evolution, modified Sturm test). The degree of biodegradation after an exposure period of 28 days was < 10 % CO2/ThCO2 in this test. The test substance was found to be not readily biodegradable under the test conditions. 

 

Biodegradation in water and sediment: simulation test

The degradation of the radiolabeled test substance was investigated in a study (BASF Crop Protection, 394794, 2013) according to OECD 308 (2002) unter aerobic water/sediment systems under dark conditions.  The DT50 values for the parent compound in the water phase were ≤ 3 days. In the sediment, parent DT50 values were determined to be 121-371 days. For the whole system, DT50 values of 76 to 86 days were calculated.

 

Biodegradation in soil

A key study (BASF SE, 394788, 2015) was conducted according to OPPTS 835.4100 (2008). The test substance degraded quickly in two soils when incubated under aerobic conditions at a soil moisture of 40% of the maximum water holding capacity and a temperature of 20°C. Best-fit DegT50(degradation DT50) values in soil LUFA 2.2 (pyranone label), soil LUFA 2.2 (pyranone/pyridine label), NJ soil (pyranone label) and NJ soil (pyranone/pyridine label) for the test substance were 6.4 days (FOMC), 6.1 days (FOMC), 11.3 days (FOMC) and 4.0 days (FOMC), respectively. The DegT90 values ranged from 50.5 to 115.8 days.

 

Bioaccumulation

Bioaccumualation: aquatic/sediment

In a flow-through bioconcentration key study (Eco-Science Corporation, ES2011-A01C, 2011) according to Guidelines for Registration of Agricultural Chemicals, 2-9-17 - Fish Bioconcentration (Japan , 2000) C. carpio were exposed to the test substance at nominal concentrations of 0.018 and 0.18 mg/L for an uptake period of 28 days. The BCF50 of the test substance was determined to be 0.059.

 

Transport and distribution

Adsorption/desorption

In a key study (BASF SE, 394801, 2015) according to OECD 106 (2000) the adsorption and desorption behaviour of the radiolabelled test substance was determined on four US soils and two European soils, which covered a range of pH (in water) from 5.5 to 7.8, a range of organic carbon content from 0.81% to 1.40% and four different USDA textural classes: silt loam, loam, loamy sand and sandy loam. The resulting Freundlich adsorption coefficients, KF, ranged from 6.66 to 30.11 mL/g for the six soils. The KFoc values ranged from 765 to 3708 mL/g. The 1/n values ranged from 0.71 to 0.84. For desorption isotherms, the KF ranged from 10.54 to 33.95 mL/g and the KFoc values ranged from 1205 to 4119 mL/g for the six soils. The higher desorption values indicate the test substance is not readily desorbed following adsorption to soil. Simple adsorption coefficients, Kd, for the highest isotherm concentration tested ranged from 4.49 to 20.17 mL/g, with Koc values ranging from 516 to 2439 mL/g.