2-methylpentane-1,5-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 1997-04-11 to 1997-05-09

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study performed according to relevant guidelines and compliant to GLP

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly 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) 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.:

1.1 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

22.0 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 (according to OECD 301 D) and the calculated amount of inoculum volume were added. The mixture was filled to 4.0 L, obtaining an end concentration of 1.10 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).
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.

Calculation of the Theoretical Oxygen Demand for sodium acetate was performed according to the guideline.
TOD = 0.78 mg O2/mg Sodium-acetat (5.6 mg/L correspond to 4.4 mg O2/L)

The TOD of the test substance was calculated using the formula:
TOD(NO3) [mg/mg] = (16[2c+1/2(h—cl)+5/2n+3s+(5/2)p+(1/2)na-o])/M
...and the following data given by the sponsor:
Empirical Formula: C6H16N2
Molecular Weight: 116.2 g/mole
TOD (NO3) = 3.992 mg O2/mg active ingredient
Since the test substance contained 99 % active ingredient, the TOD was calculated to be: TOD (NO3) = 4.032 mg O2/mg test substance.

Reference substance:

acetic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

7 d

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

46

Sampling time:

17 d

Parameter:

% degradation (O2 consumption)

Value:

102

Sampling time:

21 d

Parameter:

% degradation (O2 consumption)

Value:

102

Sampling time:

28 d

Details on results:

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: 1.17 mg/L.
Analysed end concentration of nitrate in sample: 1.22 mg/L.

Result of the inhibition test:
The result indicates that an inhibiting effect on the biochemical degradation of the reference substance at the concentration tested cannot be excluded.

Results with reference substance:

Within 14d the reference substance was completely degraded (102%).

O2 -Determinations

			mg O2/Lafter x days
Series	Flask No.	Calculations	0	7	14	17	21	28
Blank with- out Inocul- UM	BC1			8.97	8.96	8.97	8.96	8.95
	BC2			8.98	8.96	8.96	8.94	8.94
	Mean	mbc=(C1+C2)/2	8.98	8.98	8.96	8.97	8.95	8.95
Blank with Inoculum	B1			8.97	8.94	8.94	8.96	8.92
	B2			8.96	8.97	8.92	8.92	8.91
	Mean	mb=(C1+C2)/2	8.98	8.97	8.96	8.93	8.94	8.92
Test Subst. 1.10 mg/L +Inoculum	S 1			8.94	6.91	4.38	4.42	4.39
	S2			8.92	6.90	4.40	4.40	4.42
	Mean	ms = (C1+C2)/2	8.98	8.93	6.91	4.39	4.41	4.41
Ref.-subst. 5.70 mg/L +Inoculum	R1			7.97	4.42	4.41	4.38	4.37
	R2			7.98	4,41	4.46	4.40	4.42
	Mean	mr = (C1 + C2)/2	8.98	7.98	4.42	4.44	4.39	4.40
Inhibition Test: T.S.: 1.10 mg/L R.S.: 5.70 mg/L	I1			8.00	4.98	2.74	1.82	1.67
	I2			8.04	5.03	2.71	1.84	1.74
	Mean	mi= (C1 +C2)/2	8.98	8.02	5.01	2.73	1.83	1.71

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

In a ready biodegradability test according to OECD 301 D the test item proved to be readiliy biodegradable (including complete nitrification) fulfilling the 10-day window requirements.

Executive summary:

The biochemical degradability of the test substance at 20 deg C was determined according to the OECD-Guideline No. 301 D (reliability category 1, compliant to GLP). The test item was found to be readiliy biodegradable fulfilling the 10 -day window requirement (102% within 21d). Additional nitrate measurements in the 28 d samples confirmed a total nitrification of the test substance during the test period. Moreover it was found that an inhibiting effect on the biochemical degradation of the reference substance at the concentration tested could not be excluded.

Description of key information

Readily biodegradable (including full nitrification), fulfilling the 10-day window requirement.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

The biochemical degradability of MPMD at 20 deg C was determined according to the OECD-Guideline No. 301 D (reliability category 1, compliant to GLP). The test item was found to be readily biodegradable, fulfilling the 10 -day window requirement (102% within 21d). Additional nitrate measurements in the 28 d samples confirmed a total nitrification of the test substance during the test period. Moreover, it was found that an inhibiting effect on the biochemical degradation of the reference substance at the concentration tested could not be excluded.