2-Pyridinecarboxamide, 4-[4-[[[[4-chloro-3-(trifluoromethyl)phenyl]amino]carbonyl]amino]phenoxy]-N-methyl-

Biodegradation in soil

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in soil: simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Oct 2009 - Mar 2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

In this study transformation pathways and transformation rates were determined in one representative soil. According to OECD 307 aerobic and anaerobic studies with one soil type are generally sufficient for the evaluation of transformation pathways while rates of transformation should be determined in at least three additional soils. The representative soil was determined to be microbially viable throughout the study and the dissipation time of the test substance was 187 d at 20 °C which corresponds to 397 d at 12°C (which is the relevant temperature for evaluations under REACH). This values clearly indicate that the test substance is highly persistent in soil (>120 d for the P and > 180 d for the vP criteria) and the dissipation time is not assumed to substantially deviate for other soil types. Based on this, additional measures on soil type and temperature would not influence the outcome of the study regarding the biodegradation behavior of the test substance in soil. Therefore, the results from this study are considered reliable with restrictions.

Justification for type of information:

Sorafenib Tosylate was used as an analogue.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 307 (Aerobic and Anaerobic Transformation in Soil)

Deviations:

yes

Remarks:

One representative soil was used within the study. For details, please see 'Rationale for reliability incl. deficiencies'

Principles of method if other than guideline:

not relevant

GLP compliance:

yes (incl. QA statement)

Test type:

laboratory

Radiolabelling:

yes

Oxygen conditions:

aerobic

Soil classification:

USDA (US Department of Agriculture)

Soil no.:

#1

Soil type:

sandy loam

% Clay:

10.3

% Silt:

31.5

% Sand:

58.2

% Org. C:

2.21

pH:

7.1

CEC:

12.6

Soil No.:

#1

Duration:

120 d

Soil No.:

#1

Initial conc.:

1 000 other: ug/kg dry soil

Based on:

test mat.

Parent/product:

parent

Soil No.:

#1

% Degr.:

31.7

Parameter:

radiochem. meas.

Sampling time:

120 d

Key result

Soil No.:

#1

DT50:

397 d

Type:

(pseudo-)first order (= half-life)

Temp.:

12 °C

Remarks on result:

other: Value according to temperature correction by using the Arrhenius equation with the generic Ea-value (ECHA Guidance R.7b)

Soil No.:

#1

DT50:

187 d

Type:

(pseudo-)first order (= half-life)

Temp.:

20 °C

Remarks on result:

other: DT75=375; DT90=622 d

Transformation products:

not specified

Details on transformation products:

In the soil an average of 103% of the applied radioactivity was extractable on day 0. Thereafter, the extractable residue in the soil decreased steadily to an average of 66.4% at day 120. The nonextractable radioactivity increased continuously from an average of 1.4% at test start to an average of 31.7% at day 120. HPLC analysis of the extracts showed that all extractable radioactivity consisted of [14C]BAY 54-9085.

In the soil an average of 103% of the applied radioactivity

was extractable on day 0. Thereafter, the extractable residue

in the soil decreased steadily to an average of 66.4% at day

120. The non-extractable radioactivity increased constantly

from an average of 1.4% at test start to an average of 31.7%

at day 120.

HPLC analysis of the extracts showed that all extractable

radioactivity consisted of [14C]BAY 54-9085.

No volatile organic compounds were found in the ethylene

glycol traps throughout the study. The 14CO2 measured in

the KOH traps increased from an average of 0.01% on day 3

to an average of 0.54% on day 120

The DT50, DT75 and DT90 of the parent compound were

calculated to be 187, 375 and 622 days, respectively.

The biomass was determined to be 1.3, 1.0 and 0.8% of the

organic carbon content at test start, mid-study and test end

respectively.

Conclusions:

The DT50 of [14C] BAY 54-9085 in the aerobic sandy loam soil Sevelen was calculated to be 187 days. The soil was determined to be microbially viable throughout the study. No major metabolites were detected and only minor mineralization to CO2 was observed throughout the study.
The degradation of [14C] BAY 54-9085 is accompanied by increasing levels of non-extractable residues in soil. Overall, [14C] BAY 54-9085 is only slowly degraded in soil under aerobic conditions.

Executive summary:

This study about aerobic rate of degradation in soil is intended to provide information on: (1) the route of degradation (transformation pathway) of the parent compound in one representative soil, and (2) the nature and rate of formation and decline of transformation products. In one representative soil an average of 103% of the applied radioactivity was extractable on day 0. Thereafter, the extractable residue in the soil decreased steadily to an average of 66.4% at day 120. The non-extractable radioactivity increased constantly from an average of 1.4% at test start to an average of 31.7% at day 120. HPLC analysis of the extracts showed that all extractable radioactivity consisted of [14C] BAY 54-9085. No volatile organic compounds were found in the ethylene glycol traps throughout the study. The 14CO2 measured in the KOH traps increased from an average of 0.01% on day 3 to an average of 0.54% on day 120. The DT50, DT75 and DT90 of the parent compound were calculated to be 187, 375 and 622 days at 20°C, respectively. The biomass was determined to be 1.3, 1.0 and 0.8% of the organic carbon content at test start, mid-study and test end respectively.
In this study transformation pathways and transformation rates were determined in one representative soil. According to OECD 307 aerobic and anaerobic studies with one soil type are generally sufficient for the evaluation of transformation pathways while rates of transformation should be determined in at least three additional soils. The representative soil was determined to be microbially viable throughout the study and the dissipation time of the test substance was 187 d at 20 °C which corresponds to 397 d at 12°C (which is the relevant temperature for evaluations under REACH). This values clearly indicate that the test substance is highly persistent in soil (>120 d for the P and > 180 d for the vP criteria) and the dissipation time is not assumed to substantially deviate for other soil types. Based on this, additional measures on soil type and temperature would not influence the outcome of the study regarding the biodegradation behavior of the test substance in soil. Therefore, the results from this study are considered reliable with restrictions.

Description of key information

A guideline study according to OECD 307 (Aerobic and anaerobic Transformation in soil) under GLP was conducted to assess the biodegradation of [14C]BAY 54-9085 in soil. This study about aerobic rate of degradation in soil is intended to provide information on: (1) the route of degradation (transformation pathway) of the parent compound in one representative soil, (2) the nature and rate of formation and decline of transformation products. The soil was exposed to a nominal test concentration of 1000 µg/kg soil dw. HPLC analysis of the extracts showed that all extractable radioactivity consisted of [14C]BAY 54-9085. No volatile organic compounds were found in the ethylene glycol traps throughout the study. No major metabolites were detected and only minor mineralization to CO2 was observed throughout the study. The degradation of the test substance is accompanied by increasing levels of non-extractable residues in soil. The DT50, DT75 and DT90 of the test substance in aerobic sandy loam soil Sevelen were calculated to be 187, 375 and 622 days, respectively. This corresponds to a DT50 value of 397 days at 12°C (which is the relevant temperature for evaluations under REACH). Overall, the test substance is only slowly degraded in soil under aerobic conditions.

Key value for chemical safety assessment

Half-life in soil:

397 d

at the temperature of:

12 °C