1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-1H-1,2,4-triazole

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:

07 Mar 1990 to 04 Apr 1990

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Version / remarks:

12. May 1981

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Inoculum: Bacteria collected from sludge of the sewage treatment plant of CH-4153 Reinach on 06/03/90. The was carried out the method described in the guideline.

Duration of test (contact time):

28 d

Initial conc.:

10.9 mg/L

Based on:

test mat.

Initial conc.:

20.7 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST DESIGN
- Test concentrations: 1200 mL of the mineral solution with the inoculum were aerated for 24 hours in the test vessel. In 300 ml, mineral solution 15 mL Polyoxyethylene-Sorbitan-mono oleate (solution of 30 mg in 100 mL bidist. water) and 16.4 rsp. 31.1 mg of test substance were added and homogenized. This solution was given to the test vessel which was immediately connected to the CO2 traps.
- Blank: Water as specified in the guideline containing 15 mL of the Polyoxy-ethylene-Sorbitan monooleate solution.
- Vessels: 2L flasks (dark brown glass) equipped with gas inlet and magnetic stirrer.
- Water: The test medium was prepared according to the method described in the guideline.
- Temperature: 20 - 24 °C
- Air: ~ 25 mL/mon purified from carbon dioxide.

Reference substance:

aniline

Test performance:

Theoretical carbon dioxide evolution per concentration:
- Test substance: 10.9 mg/L resulted in 28.82 mg CO2/1.5L
- Test substance: 20.7 mg/Lresulted in 54.65 mg CO2/1.5L
(This calculation is based on the chemical formula in consideration of the purity of 91.1%.)

Key result

Parameter:

% degradation (CO2 evolution)

Value:

0

Sampling time:

28 d

Remarks on result:

other: The biodegradation was calculated for 10.9 mg test substance/L

Parameter:

% degradation (CO2 evolution)

Value:

3

Sampling time:

28 d

Remarks on result:

other: The biodegradation was calculated for 20.7 mg test substance/L

Details on results:

No biodegradation was observed throughout the test

Table. CO₂ evolution and Biodegradation for the blank, reference and substance.

	CO2 evolution measured								Biodegradation
	Blank					Reference			Reference
	1		2	mean		1	2		1		2	mean
day	[mg]		[mg]	[mg]		[mg]	[mg]		%		%	%
2	4.3		4.9	4.6		4.2	4.8		0		0	0
5	7.9		8.9	8.4		33.0	64.3		29		66	47
9	10.4		11.9	11.1		75.0	81.2		75		82	79
12	11.5		13.0	12.2		83.3	88.1		84		89	86
16	13.1		14.4	13.8		90.5	93.7		90		94	92
19	13.5		15.1	14.3		91.8	94.7		91		95	93
23	14.4		15.6	15.0		94.0	100.1		93		100	96
27	15.4		16.5	15.9		94.9	100.3		93		99	96
28	15.9		16.5	16.2		98.3	100.9		97		100	98
Substance		CO2 evolution measured						Biodegradation
		10.9 mg/L			20.7 mg/L			10.9 mg/L		20.7 mg/L
Day		[mg]			[mg]			%		%
2		4.3			4.0			-1		-1
5		7.6			8.5			-3		0
9		10.2			12.4			-3		2
12		11.8			14.0			-2		3
16		13.9			15.6			0		3
19		14.3			16.1			0		3
23		15.1			17.2			0		4
27		15.6			17.8			-1		3
28		15.9			18.0			-1		3

The negative degradation values are within the variation of the method.

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The substance is not biodegradable in this test.

Executive summary:

The biodegradability of the test substance was investigated in a CO₂ evolution test using domestic aerobic activated sewage sludge in accordance with OECD TG 301 B  and in compliace with GLP criteria. The test substance concentrations were 10.9 mg/L and 20.7 mg/L in the test and the blank control of the emulsifier and the reference substance were included in the test. The results showed a maximum of 3% degradation (based on theoretical carbon dioxide) within 28 days. During the study 0 % biodegradation occurred at the lower concentration and 3 % in the higher. Based on these findings, it is concluded that the test substance is not readily biodegradable.

Description of key information

The substance is not biodegradable under the test conditions, OECD TG 301B, Bader 1990.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

There is one OECD TG 301 B followed and GLP complied study available for this endpoint. The ready biodegradability of the substance was investigated in a CO2 evolution test using domestic aerobic activated sewage sludge. The test substance concentrations were 10.9 mg/L and 20.7 mg/L. The results showed a maximum of 3% degradation (based on theoretical carbon dioxide) within 28 days. Therefore, it is concluded that the test substance is not readily biodegradable (Bader 1990, Reliability 1).