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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Aerobic Aquatic Water/Sediment Systems (OECD 308):

DT50 in water: 38 - 327 days at 25 °C M-267001-01-2

DT50 in water/sediment: 69 - 578 days at 25 °C M-267001-01-2

 

Anaerobic Aquatic Water/Sediment Systems (OECD 308; EPA Subdivision N Pesticide Guideline 162-3 (Anaerobic Aquatic Metabolism):

DT50 in water: 75.0 - 84.0 days at 20 °C M-250846-01-1 and M-250839-01-2

DT50 in water/sediment: 227.0 - 273.0 days at 20 °C M-250846-01-1 and M-250839-01-2

 

Aerobic Biodegradation in soil (OECD Guideline 307; USEPA Pesticide Assessment Guidelines. Subdivision N § 162 -1 Aerobic Soil Metabolism; PMRA DACO Number 8.2.3.4.2):

DT50 soil: 11.0 – 72.0 days at 19.8 - 25.1 °C, M-078563-01-2, M-078931-01-2, M-261658-01-2

 

Anaerobic Biodegradation in soil (OECD 307; USEPA Pesticide Assessment Guidelines. Subdivision N§162 -2 Anaerobic Soil Metabolism; PMRA DACO Number 8.2.3.4.4):

DT50 soil: > 120 days at 20 °C, M-254009-02-1

Remark: Since its 32nd meeting the Member State Committee has started to require new simulation degradation studies to be carried out around neutral pH values and at 12 °C, which is understood as the mean temperature of European surface waters (ECHA 2014: Guidance on Information Requirements and Chemical Safety Assessment, Chapter R.11). None of the present biodegradation studies has been performed at 12 °C and the determined degradation rates were not extrapolated to European mean temperature.

Additional information

Screening test on ready biodegradability

Data not available.

 

Aerobic Aquatic Water/Sediment Systems

The test substance dissipated only moderately from the water in two water/sediment systems under aerobic conditions (M-267001-01-1). The calculated DT50 values for the dissipation from the water phase were 38 and 327 days for the water-sandy loam and water-silty clay loam sediment systems, respectively. In the total test system, the calculated DT50 values were 69 and 578 days for the water-sandy loam and water-silty clay loam sediment systems, respectively. No major transformation products were detected in the water or sediment phases. The sole minor transformation product was 2-methylsulfonyl-4-(trifluorormethyl)benzoic acid which did not exceed 3% in the total system of either water-sediment system.

In the water-sandy loam sediment system, non-extractable [14C]-residues in sediment increased from 14.1% at day 11 to 73.2% of the applied amount at study termination. At the end of the study, <1% of the applied radioactivity was present as either CO2 or organic volatile compounds.
In the water-silty clay loam sediment system, non-extractable [14C]-residues in sediment increased from 0.7% at day 0 to 11.8% of the applied amount at study termination. At the end of the study, <0.1% of the applied radioactivity was present as either CO2 or organic volatile compounds.

 

Anaerobic Aquatic Water/Sediment Systems

The anaerobic biotransformation of test substance radiolabeled as [Pyrazole-3-14C] (M-250846-01-1) or [Phenyl-UL-14C]- (M-250839-01-2) (5-Hydroxy-1,3-dimethyl-1H-pyrazol-4-yl)[2-(methylsulfonyl)-4-(trifluoromethyl)phenyl]-methanone was studied in identical pond water/sediment systems for 365 days in the dark at 20 ± 1 °C. For the [Pyrazole-3 -14C] labeled test substance the half-lives using first-order nonlinear degradation kinetics in anaerobic water and in the entire system were 75 days (k = 0.0093 day-1; r² = 0.56) and 227 days (k = 0.0031 day-1; r² = 0.46), respectively. For the [Phenyl-UL-14C] labeled test substance, the half-lives using first-order nonlinear degradation kinetics in anaerobic water and in the entire system equaled 84 days (k= 0.0083 day-1; r² = 0.63) and 273 days (k = 0.0025 day-1; r² = 0.40), respectively. No major transformation products were detected in the water or sediment phases of either test system. There was no degradation of test substance in either anaerobic test system, but test substance partitioned to the sediment and formed bound residues.

 

Aerobic Biodegradation in Soil

The biotransformation of radiolabeled [phenyl-U-14C]- and [pyrazole-3-14C]-[(5-hydroxy-1,3-dimethylpyrazol- 4-yl)(2-mesyl-4-trifluoromethylphenyl)methanone] was studied in two US soils, a loamy sand (US loamy sand) and silt loam (US silt loam) (M-078563-01-2, M-078931-01-2, respectively) for 358 days under aerobic conditions in the dark, at 25 °C and 75% of 1/3 bar moisture. A third soil, a sandy loam (EU sandy loam) collected from Monheim, Germany, was also studied for 120 days under aerobic conditions in the dark, at 20 °C (M-261658-01-2). The calculated DT50 values of the test substance in aerobic soils via simple first order kinetics, ranged from 11 to 72 days. For both the loamy sand and silt loam soils, there was an apparent bi-phased nature to the modeling kinetics. For the EU sandy loam soil, the simple first order half-life of the [phenyl-UL-14C] and [pyrazole-3-14C] test substance equaled 34 (r² = 0.96) and 30 days (r² = 0.95), respectively.

At study termination, evolved 14CO2 accounted for 17.3% of the applied phenyl radiolabel, or 18.6% of the applied pyrazole radiolabel test substance in the US loamy sand soil. Evolved 14CO2 accounted for 40.5% of the applied phenyl radiolabel, or 33.5% of the applied pyrazole radiolabel in the US silt loam soil at study termination. For the German sandy loam soil, at study termination evolved 14CO2 accounted for 16.3% [phenyl-UL-14C] and 18.0% [pyrazole-3-14C] of the applied radioactivity, respectively. No significant amounts of organic volatiles were detected for either label or for any soil where volatilized [14C] ranged from < 0.1% (US silt loam, EU sandy loam) to ≤ 0.4% (US loamy sand) of applied. The only significant transformation product detected was the benzoic acid derivative (2-methylsulfonyl-4-trifluoromethylbenzoic acid), reaching a maximum level of 12.2% of the applied amount (US loamy sand), observed on the 7th day of incubation or 3.8% (US silt loam) of the applied amount on the 30th day of incubation. The benzoic acid metabolite was transient in nature in both US soil systems declining to minimal levels by test termination. For the German soil, test substance-benzoic acid, the single metabolite of significance derived from the phenyl moiety, achieved a maximum concentration of 8.9% of the applied radioactivity observed on the 14th day of incubation yet was transient and mineralized to 14CO2 yielding a concentration at the end of the study period of 2.3 % of the applied radioactivity.

Non-extractable [14C]-residues increased from 1.7% [Phenyl-UL-14C] or 1.9% [Pyrazole-3-14C] of the applied amount at day 0 to 43.2% or 44.8% of the applied, respectively, at the end of the study in the US loamy sand soil. For the US silt loam, non-extractable [14C]-residues increased from 0.4% [Phenyl-UL-14C] or 1.1% [Pyrazole-3-14C] of the applied amount at day 0 to 30.1 or 30.7% of the applied, respectively, at the end of the study. For the EU sandy loam, non-extractable [14C] residues increased from 2.0 % of applied at day 0 to a maximum of 60.1 % at the end of the study where the [Phenyl-UL-14C] radiolabel was employed. For the [Pyrazole-3-14C] radiolabeled test system, non-extractable [14C] residues increased from 2.7 % of applied at day 0 to a maximum of 62.1 % at the end of the study. Exemplary humic substance fractionation indicated these non-extractable residues to be of heterogeneous nature, associated with humic and fulvic acids, as well as with humin.

For both US soil systems, sterilized soil control test systems showed an absence of significant degradation of the test item. It was apparent however, with respect to extractability, that a distinct gradual increase in soil adsorption upon aging was observed for the residues, as seen by a steady decrease in extractable radioactivity in the 'mild' extraction, and a subsequent increase in extractable radioactivity in the 'aggravated' extraction.  Thus, the observed bi-phased kinetics is considered a function of increased adsorptivity of “aged” residues.

The formation of carbon dioxide in all three test system soils indicates the potential for mineralization of the test item and its transformation products. Therefore, the substance is not expected to have a potential for accumulation in the environment.

 

Anaerobic Biodegradation in Soil

The aerobic/anaerobic biotransformation of radiolabeled test substance, (5-hydroxy-1,3-dimethyl-1H-pyrazol-4-yl)[2-(methylsulfonyl)-4-(trifluoromethylphenyl)methanone, was studied in a loamy sand soil (M-254009-02-1). The calculated half-lives of the [phenyl-UL-14C] and [pyrazole-3-14C] radiolabeled test substance in the anaerobic soil/water systems using nonlinear first-order kinetics were both determined to be >120 days (k = 0.0009 day-1; r²=0.57 (phenyl)) and (k = 0.0008 day-1; r²=0.70 (pyrazole)).

At the end of the aerobic phase 1.3% and 0.0% of the applied radioactivity in the form of [Phenyl-UL-14C] was present as CO2 and volatile organic compounds, respectively. No more than 1.4% of additional CO2 and volatile organic compounds were produced throughout the anaerobic phase of the study. For the [Pyrazole-3-14C]-labeled test substance, at the end of the aerobic phase, 5.5% and 0.0% of the applied radioactivity was present as CO2 and volatile organic compounds, respectively. No more than 1.2% of additional CO2 and volatile organic compounds were produced throughout the anaerobic phase of the study.

For the [Phenyl-UL-14C] labeled test substance, the only major transformation product formed in the aerobic phase was the test substance benzoic acid derivative which formed at 9.3% of the applied radioactivity at day 30. No additional major transformation products were detected during the anaerobic phase of the study. The test substance benzoic acid derivative residues remained relatively stable during the anaerobic phase, ranging from 9.1 to 9.9% of the applied radioactivity in the total system. For the [Pyrazole-3-14C] labeled test substance, no major transformation products were formed during either the aerobic or anaerobic phases of the study.

In conclusion, significant anaerobic degradation in soil in not expected.