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

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

2008-2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 min

Duration:

30 min

Dose descriptor:

NOEC

Effect conc.:

>= 32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

The respiration rate in the test vessels was not relevantly inhibited. There was no concentration related effect. The NOEC was higher than the test range. The test material has a very low solubility, therefore, the activbated sludge was exposed to a saturated solution of the test material.

Validity criteria fulfilled:

yes

Conclusions:

Sorafenibtosylate had no concentration-depended inhibitory effect on the respiration rate of activated sludge in the tested range.

Executive summary:

The test substance sorafenibtosylate was incubated in aerated activated sludge with

microorganisms from a municipal sewage treatment plant including synthetic sewage feed for

approximately 30 min followed by the measurement of the respiration rate by an oxygen probe.

The synthetic sewage feed solution was made up of mainly peptone, meat extract and urea.

Sorafenibtosylate is only slightly soluble, therefore the test substance was directly introduced

into the test vessel. The amount was 0.5, 1, 2, 4 and 8 mg substance in 42 mL water,

ultrasonified for approximately 30 minutes and constantly stirred for approximately 30 minutes.

Subsequently, the inoculum and synthetic feed was added to each vessel. The resulting nominal

concentrations were 2, 4, 8, 16 and 32 mg/L. Additionally, a reference substance

(3,5-dichlorophenole) in three concentrations (5, 15 and 30 mg/L in test vessel) was prepared.

Since the test material was introduced directly, an analytical verification was not

essential for the interpretation of the results.

As a parameter for the activity of the sludge, the respiration rate was measured with an oxygen

probe. The decrease of the respiration rate was calculated on the basis of the oxygen

consumption per hour.

The respiration rate in the test vessels was not relevantly inhibited. There was no concentration

related effect. The NOEC was equal or higher than the solubility limit of the test substance.

The inhibitory effect of the test and the reference substance at a particular concentration was

expressed as a percentage of the mean respiration rate of the controls

Description of key information

A guideline study according to OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test) was performed under GLP to assess the toxicity of Sorafenib tosylate to microorganisms (inhibitory total respiration). The test substance was incubated in aerated activated sludge with microorganisms from a municipal sewage treatment plant including synthetic sewage feed for approximately 30 min followed by the measurement of the respiration rate by an oxygen probe. The test substance is only slightly soluble, therefore the test substance was directly introduced into the test vessel. The  nominal concentrations were 2, 4, 8, 16 and 32 mg/L. Since the test material was introduced directly, an analytical verification was not essential for the interpretation of the results. The test substance had no concentration-depended inhibitory effect on the respiration rate of activated sludge in the tested range. The NOEC was equal or higher than the solubility limit of the test substance (NOEC>/= 32 mg/L nominal concentration). 

 

 

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

32 mg/L