7-azatridecane-1,13-diamine

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

Study period:

From 11 APR 1997 to 9 MAY 1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

GLP compliance:

yes (incl. QA statement)

Remarks:

dated 1991-10-14, according to German Chemikaliengesetz

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

The biochemical degradation of the test substance was investigated by inoculation with a suspension which was prepared by the following procedure:
5 L of the secondary effluent from an activated sludge waste water treatment plant (source: Gemeinde Nahe in Schleswig-Holstein, Germany, predominantly domestic) were filtered, discarding the first 200 mL.
The number of colony forming units of bacteria was determined on FP Agar Plates (direct counts after 48 h, aerobic heterotrophic bacteria).The filtered sewage water suspensions were diluted with mineral nutrient solution in such a way that the target end concentration of bacteria in the test flasks was between 10 and 1000 cfu/mL:
1 mL of filtrate containing 3,200,000 cfu/mL was diluted in 4 L of test medium obtaining a concentration of approximately 800 cfu/mL. This amount was within the target range.

Duration of test (contact time):

28 d

Initial conc.:

1.07 mg/L

Based on:

test mat.

Initial conc.:

4.5 mg/L

Based on:

ThOD/L

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

All glassware was cleaned before use. 21.4 mg of the test substance were dissolved in 100 mL, double-distilled water. 20 mL of
this solution were then diluted with air-saturated water (3 L). 1 mL/L of each of the four
nutrient solutions and the calculated amount of inoculum volume were added. The mixture
was filled to 4.0 L, obtaining an end concentration of 1.07 mg test substance/L. The total
theoretical oxygen demand (ThOD) was therefore below 4.5 mg/L - the half saturation
concentration. After mixing portions of this test liquid were distributed to 12 standardized
BOD-bottles. The start oxygen concentration was determined. After closing the bottles,
each was used for one single measurement of the oxygen content.
In a similar way the following parallel series were prepared:
- distilled water with nutrient solutions without inoculum (blank control series)
- distilled water with nutrient solutions with inoculum (inoculum blank series)
- a solution of sodium-acetate with nutrient solutions and inoculum (reference series for testing the activity of the inoculum)
- a solution of the test substance and sodium acetate with nutrient solutions and inoculum
(series for testing an inhibitory effect of the test substance, inhibition test).

Test temperataure: 20 deg C, climate chamber

The oxygen content in the aqueous test solutions was determined electrochemically at the
following dates during the test: 0 d, 7 d, 14 d, 17 d, 21 d, 28 d. As it turned out during the
measurements that the original schedule would not be sufficient to capture the 10 d window, the additional
measurement performed on day 17 was carried out. The raw data can be found in section "Any other information on results including tables".

Inhibition Test
It should be tested whether the test substance inhibits biochemical degradation processes. In
this "inhibition test" the biodegradation of the reference substance (sodium acetate) was
observed in the presence of the test substance. Since the O2-demand during the degradation
of sodium acetate is known from the reference series it can be judged whether in the
presence of the test substance there is possibly less oxygen consumption than that
corresponding to the sum of the test substance's and reference substance's consumption,
each one measured for itself. In case of a distinct negative value of the difference*
during the inhibition test one can assume that the test substance has an inhibitory
effect on the activity of the composite inoculum and, therefore, that the observed
degradability of the test substance is falsified by its inhibition effect on the composite
inoculum.

(*) O2-consumption (test substance + reference substance) -[O2-consumption (test substance) + O2-consumption (reference substance)]

Reference substance:

acetic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

7 d

Parameter:

% degradation (O2 consumption)

Value:

49

Sampling time:

14 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

100

Sampling time:

17 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

100

Sampling time:

28 d

Details on results:

For the test substance the following results were obtained:
1 % after 7 days,
49 % after 14 days,
100 % after 17 days,
100 % after 21 days,
100 % after 28 days.
Additionally, the nitrite and nitrate concentrations in the samples collected after 28 d were
determined. No nitrite was found and the nitrate concentration corresponded well to the
theoretical concentration:
Theoretical end concentration of nitrate in sample: 0.92 mgJL
Analysed end concentration of nitrate in sample: 0.95 mg/L
Therefore, the test substance is readily biodegradable according to the Guideline.

From the inhibition test, a slightly inhibitory effect of tthe test substance on degradation of the reference substance can be deduced.
For the difference D of [DO Depletion (test substance) + DO Depiction (reference substance)] - [DO Depletion (test substance + reference substance)] the follwing values were obtained:
-0.05 (7d); -1.72 (14d); -2.07 (17d); -2.06 (21d); -1.88 (28d)

Results with reference substance:

For the reference substance the following results were obtained:
22 % after 7 days,
102 % after 14 days,
101 % after 17 days,
103 % after 21 days,
102 % after 28 days.

O2 consumption: raw data table

Flask No.	mg O2 after x days
Day	0	7	14	17	21	28
BC1		8.97	8.96	8.97	8.96	8.95
BC2		8.98	8.96	8.96	8.94	8.94
Mean	8.98	8.98	8.96	8.97	8.95	8.95
B1		8.97	8.94	8.94	8.96	8.92
B2		8.96	8.97	8.92	8.92	8.91
Mean	8.98	8.97	8.96	8.93	8.94	8.92
S1		8.92	6.75	4.48	4.44	4.45
S2		8.96	6.75	4.41	4.45	4.44
Mean	8.98	8.94	6975	4.45	4.45	4.45
R1		7.97	4.42	4.41	4.38	4.37
R2		7.98	4.41	4.46	4.40	4.42
Mean	8.98	7.98	4.42	4.44	4.39	4.40
I1		8.00	3.92	2.02	1.96	1.79
I2		8.00	3.94	2.01	1.94	1.82
Mean	8.98	8.00	3.93	2.02	1.95	1.81

BC = Blanc without inoculum

B = Blank with inoculum

S = Test substance 1.07 mg/L plus Inoculum

R = Reference substance 5.7 mg/L plus Inoculum

I = Inhibition test: Test substance 1.07 mg/L, refrence substance 5.70 mg/L

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

In a test for ready biodegradability (closed bottle test according to OECD 301D) the test substance proved to be ready biodegradable meeting the 10-day window.

Executive summary:

The biochemical degradability of the test substance Bis(hexamethylene)triamine at 293 K (20 deg C) was

determined according to the OECD-Guideline No. 301 D and to EC Method C.4 -E and compliant to GLP (reliability category 1).

The mineral nutrient solution was prepared according to the prescriptions of the Guideline, the

inoculum was a composite made from equal parts of the total effluent and the reflux of an

activated sludge plant. The oxygen depletion was measured after 7, 14, 17 21 and 28 days by

means of an oxygen electrode.

Control- and blank-series without test substance were run simultaneously and the effectiveness

of the inoculum was confirmed (in a third series with sodium-acetate as the reference substance)

and found to be 102 % after 28 days under the conditions of the test.

The theoretical oxygen demand (ThOD) was calculated:

ThOD = 4.198 mg O2/mg test substance.

For the test substance, thefollowing biodegradability was found:

1 % after 7 days,

49 % after 14 days,

100 % after 17 days,

100 % after 21 dayS,

100 % after 28 days.

Additionally, nitrate measurements in the 28 d samples confirmed a total nitrification of the test

substance during the test period.

Therefore the test substance is classified as readily biodegradable according to the guidelines.

Moreover it was found that an inhibitory effect of the test substance on the biochemical degradation of the reference

substance at the concentration tested could not be excluded.

Description of key information

The biochemical degradability of the test substance Bis(hexamethylene)triamine at 293 K (20 deg C) was determined according to the OECD Guideline No. 301 D and to EC Method C.4 -E and compliant to GLP (reliability category 1).

Control- and blank-series without test substance were run simultaneously and the effectiveness of the inoculum was confirmed.

For the test substance, the following biodegradability was found:

1 % after 7 days,

49 % after 14 days,

100 % after 17 days,

100 % after 21 dayS,

100 % after 28 days.

Additionally, nitrate measurements in the 28 d samples confirmed a total nitrification of the test substance during the test period.

Therefore the test substance is classified as readily biodegradable according to the guidelines, meeting the 10 days window. Moreover it was found that an inhibitory effect of the test substance on the biochemical degradation of the reference substance at the concentration tested could not be excluded.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable