D-2-hydroxy-2-phenylacetic acid

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

26-05-2002 to 27-05-2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

L-2-hydroxy-2-phenylacetic acid

EC Number:

210-276-6

EC Name:

L-2-hydroxy-2-phenylacetic acid

Cas Number:

611-71-2

Molecular formula:

C8H8O3

IUPAC Name:

hydroxy(phenyl)acetic acid

Details on test material:

ChiPros (R)-Mandelsäure: (R)-mandelic acid (purity: 100 %; impurities: 0.1 % mandelic acid amide)

Sampling and analysis

Analytical monitoring:

no

Test organisms

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- preparation of inoculum: washed, conc. of dry matter: 5 g/l, aerated during the night, 50 ml were added to a total volume of 250 ml
- initial concentration during test: 1 g/L dry weight

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

30 min

Test conditions

Test temperature:

20 +- 2 °C

pH:

see table 1

Dissolved oxygen:

- oxygen concentration during aeration: > 2.5 mg/l
- oxygen concentration immediatley before measurement: > 6.5 mg/l
- duration of measurement of oxygen consumption: 8-10 min

Nominal and measured concentrations:

nominal: 1000 mg/L

Details on test conditions:

- test vessel: Erlenmeyer flask (250 ml)
- test volume: 250 ml

- test assays: blank control (3x), reference substance (3x) and test substance (1000 mg/l)
- synthetic medium: 8 ml (100-fold concentrated OECD medium)
- inoculum: 50 ml (final conc. of dry matter: 1 g/l)
- dilution water: deionised water

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Duration:

30 min

Dose descriptor:

other: EC20

Effect conc.:

> 1 000 mg/L

Results with reference substance (positive control):

- reference substance: 3,5-dichlorophenol

effect values for reference substance (30 min, mg/l):
EC20 ca. 3.3
EC50 ca. 15
EC80 ca. 85

Any other information on results incl. tables

Table 1: Oxygen consumption and pH values

Parameter	BC average		TS		RS1		RS2		RS3
	start	6 min	start	6 min	start	6 min	start	6 min	start	6 min
Oxygen concentration (mg/L)	6.8-7.8	5.0-6.5	6.9	5.0	6.9	5.0	8.1	7.1	8.6	8.3
oxygen consumption rate (mg O2/L/h)	18		19		19		10		3
specific oxygen consumption rate (mg O2/L/h)	18		19		19		10		3
change in oxygen consumption rate compared to BC (%)	-		-6		-6		44		83
pH before addition of inoculum (corrected)	7.1		7.6		7.2		7.3		7.0
pH after test end (30 min)	-		7.8		-		-		-

BC = blank control

RS = reference substance (reference substance conc.: RS1: 1 mg/l; RS2: 10  mg/l; RS3: 100 mg/l)

TS = test substance

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The inhibition of the degradation activity of activated sludge is not anticipated when introduced to biological treatment plants in appropriate low concentrations.

Executive summary:

 An experimental study according to OECD guideline 209 and GLP regulations was conducted to assess the toxicity to microorganism. An inoculum of domestic activated sludge with an initial concentration of 1 g/L dry weight was exposed to 1000 mg/L test item for 30 min in a static system. In addition, a reference substance (3,5-dichlorophenol) and a blank control was tested.  The respiration inhibition was determined based on the oxygen consumption. After 30 min no inhibition of the oxygen consumption was observed. The effect values were determined to be > 1000 mg/L. Therefore, an inhibition of the degradation activity of activated sludge is not anticipated when introduced to biological treatment plants in appropriate low concentrations.