Tall oil, potassium salt

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

anaerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

A mixed population of sewage treatment micro-organisms was obtained on 18 March 2019 from the final effluent stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, UK, which treats predominantly domestic sewage. The sample of effluent was filtered through coarse filter paper (first approximate 200 mL discarded) and maintained on aeration in a temperature controlled room at 21 ±1 °C prior to use.

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

The test substance was dissolved in an auxiliary solvent prior to being adsorbed onto a filter paper and subsequent dispersal in test media. Using this method the test substance was evenly distributed throughout the test medium and the surface area of test substance exposed to the test organisms was increased thereby increasing the potential for biodegradation.
The biodegradation of the test substance was assessed by the measurement of daily oxygen consumption values on Days 0 to 28. Control solutions with inoculum and the reference substance aniline, and a toxicity control were used for validation purposes.

Reference substance:

aniline

Key result

Parameter:

% degradation (O2 consumption)

Value:

72

Sampling time:

28 d

Details on results:

The test substance attained 72% biodegradation after 28 days and therefore it can be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301.
The toxicity control attained 58% biodegradation after 14 days and 68% biodegradation after 28 days thereby confirming that the test substance was not toxic to the sewage treatment micro-organisms used in the test.
Aniline (procedure control) attained 62% biodegradation after 14 days in a 10-Day Window and 72% biodegradation after 28 days thereby confirming the suitability of the inoculum and test conditions.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test substance attained 72% biodegradation after 28 days and hence can be considered as readily biodegradable.

Executive summary:

A study was conducted to assess the ready biodegradability of the test substance according to the OECD Guideline 301F (Manometric respirometry method), EU method C.4 -D and US EPA Fate, Transport, and Transformation Test Guidelines OCSPP 835.3110. The test substance at a concentration of 100 mg/L was exposed to sewage treatment microorganisms with mineral medium in sealed culture vessels in diffuse light at temperatures between 20 and 22ºC for 28 days. The inoculum was sourced from a sewage treatment plant treating predominantly domestic sewage. The test substance was dissolved in an auxiliary solvent prior to being adsorbed onto a filter paper and subsequent dispersal in test media. Using this method the test substance was evenly distributed throughout the test medium. The biodegradation of the test substance was assessed by the measurement of daily oxygen consumption from Days 0 to 28. Control solutions with inoculum, the reference substance, aniline, and a toxicity control were used for validation purposes. The test substance attained 72% biodegradation after 28 days. As the test substance is a UVCB, the 10-day window criteria does not apply. Aniline attained 62% biodegradation after 14 days with greater than 60% degradation being attained in a 10-Day window and 72% biodegradation in 28 days. Under the study conditions, the test substance was considered as readily biodegradable (Best, 2019).

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

A study was conducted to assess the ready biodegradability of the test substance according to the OECD Guideline 301F (Manometric respirometry method), EU method C.4 -D and US EPA Fate, Transport, and Transformation Test Guidelines OCSPP 835.3110. The test substance at a concentration of 100 mg/L was exposed to sewage treatment microorganisms with mineral medium in sealed culture vessels in diffuse light at temperatures between 20 and 22ºC for 28 days. The inoculum was sourced from a sewage treatment plant treating predominantly domestic sewage. The test substance was dissolved in an auxiliary solvent prior to being adsorbed onto a filter paper and subsequent dispersal in test media. Using this method the test substance was evenly distributed throughout the test medium. The biodegradation of the test substance was assessed by the measurement of daily oxygen consumption from Days 0 to 28. Control solutions with inoculum, the reference substance, aniline, and a toxicity control were used for validation purposes. The test substance attained 72% biodegradation after 28 days. As the test substance is a UVCB, the 10-day window criteria does not apply. Aniline attained 62% biodegradation after 14 days with greater than 60% degradation being attained in a 10-Day window and 72% biodegradation in 28 days. Under the study conditions, the test substance was considered as readily biodegradable (Best, 2019).