Quaternary ammonium compounds, C12-14 (even numbered) alkyl(hydroxyethyl)dimethyl, C12 alkylbis(hydroxyethyl)methyl, chlorides and amines, C12-14 (even numbered) alkyldimethyl, chlorides

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance is readily biodegradable

Cross-reference

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From November 02, 2005 to December 01, 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

according to guideline

Guideline:

ISO 14593:1999 (Water quality - Evaluation of ultimate aerobic biodegradability of organic compounds in aqueous medium - Method by analysis of inorganic carbon in sealed vessels (CO2 headspace test))

Deviations:

not specified

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 310 (Ready Biodegradability - CO2 in Sealed Vessels (Headspace Test)

Deviations:

not specified

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic (adaptation not specified)

Details on inoculum:

The inoculum used was secondary effluent, from a laboratory treatment unit treating sewage from Newton Abbot Sewage treatment works. This sewage was predominantly domestic in origin. On the day of the test the effluent was filtered through a Whatman G/FC filter paper, and sparged with CO2 free air for at least two hours at pH 6.5 0.2, to remove any dissolved carbon dioxide. After this time the effluent was neutralised, to pH 7.0 ± 0.2, and allowed to stand for one hour. The prepared inoculum was added to the test bottles at a concentration of 10% of the final volume.

Duration of test (contact time):

ca. 28 d

Initial conc.:

ca. 17.9 mg/L

Based on:

IC (inorganic carbon)

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

Test substance
Supply of the test substance was arranged by Global Product EHS, Huntsman, B 3078 Everberg, Belgium. The test substance was received at Brixham Environmental Laboratory on 26 May 2005 and assigned the Brixham test substance number 05-0219. The test substance (Batch FM00926) was supplied as a clear, pale straw liquid. A certificate of analysis (dated 21 February 2005) stated the sample contained 39.2% active matter. The sample was stored at ambient temperature, in the container in which it was received until required for testing, when an appropriate subsample was provided for the test operator. The carbon content of the molecule was calculated as 74.4% carbon. Based on a nominal active matter content of 40%, test substance additions were based on test substance containing 29.8% carbon.

Reference substance
The reference substance employed was sodium benzoate as recommended in the ISO guideline. The carbon content of the molecule was calculated as 58%.

Linear alkyl benzene sulfonate (LAS) - Sodium dodecylbenzenesulfonate
A sample of LAS was obtained from Sigma-Aldrich Co Ltd, The Old Brickyard, New Road, Gillingham SP8 4XT, UK. The substance was received at Brixham Environmental Laboratory on 28 October 2005 and assigned the Brixham test substance number 05-0361. The test substance (Batch #063K0146) was supplied as a light yellow powder. A certificate of analysis (QC acceptance date June 2003) stated the sample contained approx 80% alkyl-benzene sulfonate. The sample was stored at ambient temperature, in the container in which it was received until required for testing, when an appropriate subsample was provided for the test operator. The carbon content of the molecule was calculated as 62.1% carbon. The substance contained 80% active matter, so test substance additions were based on LAS containing 49.7% carbon.

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (inorg. C analysis)

Remarks:

Test substance + LAS

Value:

ca. 78

Sampling time:

28 d

Key result

Parameter:

% degradation (inorg. C analysis)

Remarks:

Positive control

Value:

ca. 104

Sampling time:

28 d

Key result

Parameter:

% degradation (inorg. C analysis)

Remarks:

LAS

Value:

ca. 52

Sampling time:

28 d

Biodegradation

The TOC results for the sodium benzoate, test substance and LAS stock solutions were 378, 350 and 366 mg C l-1 respectively (within ± 10% of the nominal values). The mean TOC concentrations measured at the start of the study were 22.3 mg/L in the sodium benzoate bottles, 36.9 mg l-1 in the test substance and LAS bottles, and 19.2 mg l-1 in the LAS bottles. These measured values were used in the results calculations (Table 2).

Table 2: Carbon results

	Blank	Reference substance (nominal 20 mg C l^-1)	Test substance + LAS (total nominal 40 mg C l^-1)	LAS (nominal 20 mg C l^-1)
Day 0 stock solution TOC (mg l^‑1)	-	378	350 + 366	366
Day 0 test bottles TOC (mg l^-1)	3.04 3.65 2.45	21.8 22.7 9.31^a	38.9 36.1 35.8	20.3 18.6 18.7
Mean (mg l^-1)	3.05	22.3^b	36.9	19.2
Standard deviation	0.60	-^b	1.71	0.95
Day 28 test bottles IC (mg l^-1)	2.30 2.44 3.85	24.8 26.6 26.7	30.7 31.8 32.5	12.5 12.2 13.6
Mean (mg l^-1)	2.86	26.0	31.7	12.8
Standard deviation	0.86	1.07	0.91	0.74
Biodegradation^c(%)	- - -	98 106 107	75 78 80	50 49 56
Mean (%)	-	104	78	52
Standard deviation	-	4.93	2.52	3.79

a: Anomalous value, not included in mean

b: Calculated on two values only; standard deviation not calculated

c: % Biodegradation = [(IC concentration in test bottle – Mean IC concentration in control) / Initial mean measured TOC in test bottle] × 100

The inorganic carbon analysis results, which are summarised in Table 2, show that sodium benzoate (the reference substance) attained a maximum level of biodegradation (based on evolved carbon dioxide) of 104%. This is over 60% degradation, as expected for a biodegradable substance, thus confirming that the activated sludge contained viable organisms.

The inorganic carbon results for test substance with LAS, show that, after 28 d, the mixture had degraded by 78%. LAS alone had degraded by 52%. Since the percentage biodegradation of LAS was lower than that of the mixture of LAS and test substance, the value of 78% represents a minimum value for test substance.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Under the study conditions, the test substance was determined to be readily biodegradable.

Executive summary:

A study was conducted to determine the readiliy biodegradability of the test substance, C12-14 HEDMAC (active: 39.2 %), using CO2 headspace test, according to OECD Guideline 310 and ISO-14593 Guideline, in compliance with GLP. A reduced version of the test was performed, as a screening test, with organic carbon measurements on Day 0 and inorganic carbon analysis on Day 28 only. In order to mitigate microbial toxicity of the test substance, an equimolar amount of Linear Alkyl benzene Sulfonate (LAS) was added to the test bottles. An inoculum used was secondary effluent, from a laboratory treatment unit treating sewage from Newton Abbot Sewage treatment works, domestic origin. The test bottles were set up for the test as per experimental design. In the study, inoculum blanks, positive control (sodium benzoate at 20 mg/L), test substance plus LAS (17.9 mg/L test substance + 21.1 mg/L LAS) as well as LAS (21.1 mg/L), each these group bottles were prepared in triplicate. Test bottles sacrificed on Day 0 were analysed for total organic carbon (TOC). The mean of these measurements were used for the results calculations. The remaining bottles were incubated at 22 ± 2°C, with shaking, for 28 d. Carbon dioxide generated as a result of mineralisation of organic carbon arising from any ultimate biodegradation was then measured using a Dohrman DC-190 carbon analyser. For inorganic carbon measurement (Day 28), 1 mL of 10 M sodium hydroxide solution was added to the appropriate test bottles, and shaken for at least one hour. The increase in alkalinity (to pH >10) and equilibration resulted in the total absorption of gaseous inorganic carbon from the headspace into the liquid phase, which was subsequently analysed for Inorganic Carbon (IC). The TOC results for the sodium benzoate, test substance and LAS stock solutions were 378, 350 and 366 mg C/L respectively (within ± 10% of the nominal values). The mean TOC concentrations measured at the start of the study were 22.3 mg/L in the sodium benzoate bottles, 36.9 mg/L in the test substance and LAS bottles, and 19.2 mg/L in the LAS bottles. These measured values were used in the results calculations. The inorganic carbon analysis results show that the reference substance attained a maximum level of biodegradation (based on evolved carbon dioxide) of 104%, thus confirming that the activated sludge contained viable organisms. The inorganic carbon results for test substance with LAS, show that, after 28 d, the mixture had degraded by 78%. LAS alone had degraded by 52%. Since the percentage biodegradation of LAS was lower than that of the mixture of LAS and test substance, the value of 78% represents a minimum value for test substance. As the test substance biodegraded by over 60% within 28 d, it can be considered biodegradable according to the criteria specified in the Detergent Regulation of the European Parliament. The study had met all the validity criteria. Under the study conditions, the test substance was considered to be readily biodegradable (Daniel, 2006).