2-ethylhexyl (4-chloro-2-methylphenoxy)acetate

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

28.09.2004 - 15.10.2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Cross-reference

Reason / purpose for cross-reference:

read-across source

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2004

Report date:

2004

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

(4-chloro-2-methylphenoxy)acetic acid

EC Number:

202-360-6

EC Name:

(4-chloro-2-methylphenoxy)acetic acid

Cas Number:

94-74-6

Molecular formula:

C9H9ClO3

IUPAC Name:

(4-chloro-2-methylphenoxy)acetic acid

impurity 1

Reference substance name:

Water

EC Number:

231-791-2

EC Name:

Water

Cas Number:

7732-18-5

Molecular formula:

H2O

IUPAC Name:

water

impurity 2

Reference substance name:

4-chloro-o-cresol

EC Number:

216-381-3

EC Name:

4-chloro-o-cresol

Cas Number:

1570-64-5

Molecular formula:

C7H7ClO

IUPAC Name:

4-chloro-2-methylphenol

Test material form:

solid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, adapted

Details on inoculum:

Activated sludge from biological sewage refinery „Pszczyna" in Pszczyna was collected in quantity about 5 dm3 into plastic vessels. Activated sludge was immediately transported to laboratory in a period of time shorter than 60 minutes.
After transport activated sludge was siveed using a sieve with diameter of meshes equal 1 millimetre, decantation last at least 60 minutes followed by draining of supernatant. Remaining sediment was introduced into 10 dm3 vessels where it was intensively washed with tap water. The sediment was intensively agitated with glass rod and allowed the sludge to settle for 60 minutes, drawed off the supernatant liquid and rinsed. Rinsing was made four or five times untill foam from the surface of water disappeared.

After last rinsing the sediment was decanted in period of time not shorter than 1 h, drained the supernatant and remaining sediment was carefully poured from vessel to tall beaker with a volume of 5 dm3 so that 3/4 of sediment volume was transferred. To vessels containing sediment was added mineral medium obtaining final volume equal 4.5 dm3. The sediment was intensively agitationed, and allowed the sludge to settle for 30 minutes followed by drawed off the supernatant. This operations were repeated three time. When the mineral medium was added for the third time the content of vessel was agitationed and intensively aerated to cased circulation of sludge suspended solids in volume of vessel. The compressed air came from aquarius aeration pump and was inflated through a cotton wool strainer and glass fit
After above operations in 100 ml samples measured dry weight of sludge suspended solids. It was measured according to Polish Standard PN-EN 12880:2002. Dry matter of sediment used in the study equal 6.32 g/dm3.

The fresh mineral medium was prepared according OECD guideline No 302B.
To find out of the sludge activity the studies with reference substance (ethylene glycol) were performed.

Reference substance

Reference substance:

ethylene glycol

Results and discussion

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Value:

100

Sampling time:

16 d

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Executive summary:

The aim of study was to determine of inherent biodegradation of MCPA TECHNICAL in water. The methodical bases of the studies were OECD Guidelines No 302B. The biodegradation process was monitored by determination of COD (Chemical Oxygen Demand) in samples at successive measurements time intervals.

Taking into account the obtained results it was assessed that tested preparation was degraded gradually and its inherent biodegradability was 100 % after 16 days of experiment.