Fatty acids, C16-18 and C18-unsatd., Me esters, distn. residues

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Remarks:

read-across from supporting substance (analogue or surrogate)

Adequacy of study:

key study

Study period:

From April 22,1999 to May 20,1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well described GLP compliant study conducted to recognized international test guidelines

Qualifier:

according to guideline

Guideline:

other: ISO/TC 147/SC 5/WG 4N 141 (BODIS TEST)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Fatty acids, C6-24 and C6-24-unsatd., Me esters, distn. residues- Physical state: black , brown semisolid- Analytical purity:100% - Storage condition of test material: room temperature- Solubility: < 10% in water, soluble in acetone, hexane and dichloromethane

Oxygen conditions:

aerobic

Inoculum or test system:

other: natural see water fortified with mineral nutrients

Details on inoculum:

- Water filtered: no

Duration of test (contact time):

ca. 28 d

Initial conc.:

ca. 40 g/L

Based on:

ThOD/L

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS- Composition of medium: Natural seewater- Solubilising agent: composition of mineral nutrient (g/L)KH2PO4 8.5K2HPO4 21.7Na2HPO4.2H2O 29.92NH4Cl 0.5CaCl2 31.84MgSO4.7H2O 22.5FeCl3.6H2O 0.25EDTA 0.4- Test temperature: 20 ± 1°C- pH: 8- pH adjusted: noSAMPLING- Sampling frequency:Dissolved oxygen at 7, 14, 2l and 28 days. All bottles reaerated to saturation after each measurement and the same bottles measured at each timepoint.

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

ca. 61.37

Sampling time:

28 d

Results with reference substance:

% Degradation of benzoic acid salt (28 days) = 77.35 %

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Dehylub 1757 biodegraded by 61.37% over 28 days and showed an inhibition of 10.80% to seawater bacteria. Dehylub 1757 achieved a plateau by day 14 of the test. The Oxygen blank and reference oil degradation, were within formal and informal limits of acceptability respectively. The soluble reference material, sodium benzoate, degraded by more than 60% in the first fourteen days, indicating that the seawater used in the test contained a satisfactory population of viable bacteria.

Executive summary:

Study number 306 -l8 was commissioned to determine the aerobic degradability in seawater (Bodis test) of Dehylub 1757 and OMC 233.

The test vessels are closed glass bottles with a known volume of aqueous test mixture (66.6%) and air (33.3%).The degradation is followed by weekly measurements of the BOD in the aqueous phase for a 28 day period.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Remarks:

read-across from supporting substance (analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well described GLP compliant study conducted to recognized international test guidelines

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

no

GLP compliance:

no

Remarks:

study was made in 1986 but VTB laboratories were certified DIN ISO 9001

Specific details on test material used for the study:

Fatty acids, C6-24 and C6-24-unsatd., Me esters, distn. residues- Physical state: black , brown semisolid- Analytical purity:100% - Storage condition of test material: room temperature- Solubility: < 10% in water, soluble in acetone, hexane and dichloromethane

Oxygen conditions:

aerobic

Inoculum or test system:

other: minucipal sewage treatment plant

Details on inoculum:

The test was inoculated with effluent of the sewage treatment plant Hochdahl (1 ml/L / about 10^3 ' 10^5 cells/ml). The effluent fiom the sewage treatment plant predominantly treating domestic sewage was Hltered through a coarse paper lilter, the first 200 ml being discarded.

Duration of test (contact time):

ca. 30 d

Initial conc.:

ca. 2 mg/L

Based on:

test mat.

Initial conc.:

ca. 5 mg/L

Based on:

test mat.

Details on study design:

TEST CONDITIONS- Composition of medium: mineral test medium- Solubilising agent:Due to the insufficient water solubility a homogeneous distribution of KE l757 was achieved by ultrasound dispersion and stabilisation by an inert emulsifier. The dispersing agent was nonylphenol ethoxylate additionally with 5 propylenoxyd units (NP 9,5 EO SPO). The used proportion of test substance to emulsitier was 1:1. The final concentration of test substance was 2 respectively 5mg/l.CONTROL AND BLANK SYSTEM- Inoculum blank:The oxygen-consumption resulting from biodegradation of the test substance by the micro-organisms, corrected for uptake by the blank inoculum and run in parallel, is expressed as a percentage of ThOD (Theoretical Oxygen Demand) or COD (Chemical Oxygen Demand)

Reference substance:

other: dodecyl sulphate

Parameter:

% degradation (O2 consumption)

Value:

> 87 - < 122

Sampling time:

30 d

Validity criteria:

A test is considered valid if the results of the parallel assays at the end of the test or at the end of the time window, do not differ from each other by more than 20 % and if the percentage degradation of the reference compound reached the pass level within 14 days. Oxygen depletion in the inoculum blank should not exceed 1,5 mg dissolved oxygen per litre alter 30 days. The residual concentration of oxygen in the test bottles should not fall below 0.5 mg/l at any time.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Under the described test conditions 87 - 122 % of the test substance was degraded within the 30 day test period. Since the pass level (= 60% ThOD for respirometric methods according to the OECD-Guideline 301) was reached within the 10-day window, KE-1757 is classified as readily biodegradable.

Executive summary:

The ultimate biodegradability of KE-1757 was tested in the Closed Bottle Test (OECD 301D). Under the chosen conditions 87 - 122 % of the test substance was degraded within the 30 day test period. The pass level (= 60% ThOD for respirometric methods according to the OECD-Guideline 301) was reached within the 10-day time window and in conformity with the evaluation criteria, KE·l757 can be regarded as readily biodegradable.

Description of key information

The substance is readily biodegradable in fresh water , not biodegradable in seawater.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

The ultimate biodegradability of KE-1757 was tested in the Closed Bottle Test (OECD 301D). Under the chosen conditions 87 - 122 % of the test substance was degraded within the 30 day test period. The pass level (= 60% ThOD for respirometric methods according to the OECD-Guideline 301) was reached within the 10-day time window and in conformity with the evaluation criteria, KE·l757 can be regarded as readily biodegradable.

The tested substance biodegraded by 61.37% over 28 days and showed an inhibition of 10.80% to seawater bacteria. It achieved a plateau by day 14 of the test.