3-(p-methoxyphenyl)-2-methylpropionaldehyde

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Remarks:

biodegradation study, measuring oxygen consumption

Type of information:

experimental study

Adequacy of study:

key study

Study period:

5 Feb 2013 to 8 March 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

1992

Qualifier:

according to guideline

Guideline:

other: EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Version / remarks:

2008

Qualifier:

according to guideline

Guideline:

other: EPA OPPTS 835.3110 (Ready Biodegradability)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Source of inoculum/activated sludge: Fresh activated sludge from a biological waste water treatment plant treating predominantly domestic sewage (Bois-de-Bay, Satigny, Switzerland) was used. The sludge was collected in the morning, washed three times in the mineral medium (by centrifuging at 1000 g for 10 minutes, discarding the supernatant and resuspending in mineral medium) and kept aerobic until used on the same day.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

30 d

Test temperature:

22 - 22.5 °C

pH:

7.4 - 7.6

Nominal and measured concentrations:

- Nominal concentration: 0 (control) and 30 mg/L

Key result

Duration:

30 d

Dose descriptor:

NOEC

Effect conc.:

30 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

TOXICITY
The test substance did not inhibit the intrinsic respiration of the inoculum at the test concentration (see 'Any other information on results incl. tables') and was therefore considered to be non-toxic to the inoculum at the test concentration of 30 mg/L.

Table: O2 uptake, biodegradation of test substance (mg O2/L, adjusted to nominal concentrations)

	Days		5	6	14	16	21	28	30
O2 uptake of sludge (inoculum blank)	1	B1	21.5	24.2	31.0	32.3	35.0	37.7	37.7
	2	B2	20.2	22.9	29.6	31.0	35.0	37.7	37.7
	mean	B	20.9	23.6	30.3	31.7	35.0	37.7	37.7
O2 uptake of test subst. + sludge	5	C1	28.3	32.3	76.5	80.6	90.0	94.0	95.4
	6	C2	26.9	29.6	75.5	84.9	93.1	98.5	99.8
O2 uptake of test substance		C1-B	7.4	8.7	46.2	49.0	55.0	56.3	57.7
		C2-B	6.1	6.1	45.2	53.3	58.1	60.8	62.1
% biodegradation of test substance		D1	10	12	64	67	76	78	79
		D2	8	8	62	73	80	84	85
	mean	D	9	10	63	70	78	81	82

Calculations:

B1, B2, C1, C2: experimental O2 uptake values

B = (B1 + B2) / 2

D1 = 100 * (C1 – B) / ThoD * [S]

D2 = 100 * (C2 – B) / ThoD * [S]

D = (D1 + D2)/2

[S]: Initial test substance concentration (mg/L)

ThOD test substance = 2.42 mg O2/mg

 

Validity criteria fulfilled:

yes

Conclusions:

The NOEC-value for microorganisms in activated sludge, based on the results of a ready biodegradation study, is 30 mg/L.

Executive summary:

The toxicity of the substance to microorganisms was determined in a ready biodegradability study according to OECD TG 301F and in compliance with GLP criteria. In this study, activated sludge from domestic sewage was exposed

to 30 mg/L test substance. The test substance did not inhibit the endogenous respiration of the inoculum and was found to be readily biodegradable. Therefore, the test substance was considered to be non-toxic to the inoculum. Based on these findings, the NOEC for microorganisms is 30 mg/L.

Description of key information

The toxicity of the substance to microorganisms was determined in a ready biodegradability study according to OECD TG 301F and in compliance with GLP criteria. In this study, activated sludge from domestic sewage was exposed to 30 mg/L test substance. The test substance did not inhibit the endogenous respiration of the inoculum and was found to be readily biodegradable. Therefore, the test substance was considered to be non-toxic to the inoculum. Based on these findings, the NOEC for microorganisms is 30 mg/L.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

30 mg/L