(2,6-xylyloxy) acetic acid

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

02 Jun - 24 Jun, 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: done under OECD method and GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

ISO DP 6060 (Water Quality - Determination of the Chemical Oxygen Demand)

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Remarks:

OECD

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

430-910-7

EC Name:

-

Cas Number:

13335-71-2

Molecular formula:

Hill formula: C10H12O3 CAS formula: C10H12O3

IUPAC Name:

2-(2,6-dimethylphenoxy)acetic acid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

Effluent from a strongly aerated laboratory activated sludge plant was kept under aerobic conditions. To prepare the inoculum, the sample was filtered through a course filter and the first 200ml discarded.

Duration of test (contact time):

28 d

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Inhibition effects, if any, were checked by testing together the test article (2mg/L) and the reference substance, sodium acetate (2mg/L)

Test solns were incubated in the dark at 20±1°C and analysed for dissolved oxygen at 7, 14, 21 and 28 days.

Reference substance

Reference substance:

other: sodium acetate

Results and discussion

Preliminary study:

A-172245.0 may not be termed as readily biodegadeable.
There was no evidence of inhibitory effects on the bacteria inoculum at 2mg/L.

% Degradation

% Degradation 1

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

7 d

% Degradation 2

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

14 d

% Degradation 3

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

21 d

% Degradation 4

Parameter:

% degradation (O2 consumption)

Value:

2.47

Sampling time:

28 d

Details on results:

Since the biodegradation in the 2 series of bottles containing 2mg/L sodium acetate + 2mg/L A-172245.0 on day 14 was 81.4% (i.e. greater than 25% of the ThOD), it can be assumed that the test article has no significant inhibitory effect on the bacteria inoculum.
Since the biodegadability of the test article did not exceed the pass level of 60%, determinations for nitrites and nitrates were not performed.

BOD5 / COD results

Results with reference substance:

Sodium acetate attained 69.87%, 84.62%, 94.23% and 98.08% biodegredation after 7, 14, 21 and 28 days respectively.

Any other information on results incl. tables

COD: 2.025 O₂/mg (average value)

ThOD NH3 (without nitrification): 2.042 O₂/mg

ThOD of the reference substance: 0.780 O₂/mg

BOD on days 7,14, 21 and 28 were 0, 0, 0 and 0.05 mg O₂/mg

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: not readily biodegradable

Conclusions:

COD: 2.025 O2/mg (average value)
ThOD NH3 (without nitrification): 2.042 O2/mg
ThOD of the reference substance: 0.780 O2/mg
BOD on days 7,14, 21 and 28 were 0, 0, 0 and 0.05 mg O2/mg

Executive summary:

A-172245.0 may not be termed as readily biodegadeable.

There was no evidence of inhibitory effects on the bacteria inoculum at 2mg/L.