Tall oil, maleated

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Study initiation date: December 12 2013. Experimental completion date: December 12, 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

yes

Remarks:

Change of study director

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Lot/batch number QD16

Analytical monitoring:

not required

Vehicle:

no

Details on test solutions:

Test item (tall oil, maleated) is insoluble in water. The test item concentrations for the range finding test were created via direct addition of the test item to the test vessel as follows: 5.0 mg into 500 mL for the 10 mg/L test concentration, 50.1 mg for the 100 mg/L test concentration and 500.0, 500.1, and 500.2 mg for the 1000 mg/L test concentration. The required amount of test item for each concentration was weighted (using an analytical balance) on to a glass weight boat.

Test organisms (species):

activated sludge

Details on inoculum:

An aerobic inolculum containing an active microbial population was prepared one day prior to test initiation. The inoculum was prepared using activated sludge collected from the Guelph wastewater Treatment plant, Guelph, Ontario.

Test type:

other: non-renewal

Water media type:

other: Reverse Osmosis (R.O.) water

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20 ±2 °C

Nominal and measured concentrations:

10, 100 and 1000 mg/L

Details on test conditions:

Test solutions:
3 inoculum controls
3 test concentrations (single exposures of 10 and 100 mg/L; triplicate exposures of 1000 mg/L)
1 anoxic control
3 reference toxicant concentrations

Aeration: 0.5 - 1 L/min
O2 determination: oxygen electrode
Samling intervals: test vessels are set up with 15 minutes intervals between vessels for measurements

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Basis for effect:

inhibition of total respiration

Results with reference substance (positive control):

The reference toxicant (3,5-dichlorophenol) achieved a 3-hour EC50 of 17.4 mg/L indicating that the test system was acceptable for the determination of activated sludge respiration inhibition.

Reported statistics and error estimates:

The 3-hour EC50 and 95% confidence intervals of the test item and reference toxicant were calculated using AquaTox SOP # 397 (AquaTox 2013b), which provides details regarding the analysis of acute toxicity data. Statistical analysis was performed using the CETIS (2007) program to calculate the EC50 and its 95% confidence limits, according to Non linear Regression (reference item) and Equal Variance t Two-Sample Test (test item).

Validity criteria fulfilled:

yes

Conclusions:

Based on the results of the range finding test, the 3 hour EC50 for the test item tall oil, maleated was reported to be >1000 mg/L

Executive summary:

AquaTox testing & Consulting Inc was retained by the Sponsor's Representative, Intertek Cantox, to conduct a study to determine the activated sludge resporation inhibition of the MeadWestvaco test item, tall oil maleated (CAS # 68152-93-2). The study was conducted in accordance with Aquatox Study plan 162775293-600 entitled "Tall oil, maleated: Activated Sludge Respiration inhibition test (OECD 209)" and AquaTox standard operating procedure (SOP) #397, which are based on the OECD Guideline 209 (OECD 2010). This study was conducted following OECD Principles of Good Laboratory Practice (GLP) (OECD 1998).

A range finding test which included single exposure of 10 and 100 mg/L of the test item and triplicate exposures of 1000 mg/L was initiated on 2013-12-12. The quality of the test system was confirmed through the use of a reference toxicant (3,5-dichlorophenol). Results of the range finding test showed that there was no statistically significant inhibition of oxygen uptake between any of the test exposures and the controls. In accordance with sections 39 and 40 of OECD 209 no further testing was required. The 3-hour EC50 for the test item tall oil, maleated was reported to be >1000 mg/L.

Description of key information

3-hour EC50 Tall oil, maleated >1000 mg/L

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L