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

Toxicity to aquatic plants other than algae

Administrative data

Endpoint:

toxicity to aquatic plants other than algae

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13.09.2004 - 11.10.2004

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

Guideline:

OECD Guideline 221 (Lemna sp. Growth Inhibition 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

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

168 h

Dose descriptor:

other: ErC50

Remarks:

The median concentration causing 50% inhibition of average specific growth rates of Lemna

Effect conc.:

7.13 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Effect concentrations 2

Key result

Duration:

168 h

Dose descriptor:

other: EyC50

Remarks:

median concentration causing 50% inhibi¬tion of yield

Effect conc.:

6.53 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Effect concentrations 3

Key result

Duration:

168 h

Dose descriptor:

NOEC

Effect conc.:

0.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Effect concentrations 4

Key result

Duration:

168 h

Dose descriptor:

LOEC

Effect conc.:

0.32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Any other information on results incl. tables

ErC50. and EyC50 values:

All criterions validity of the test were met according the Guideline OECD 221:

·        Increase of frond number in control was 14-fold (criterion is at least seven-fold increase in seven days)

·        An average specific growth rate of 0,296 d-1 (criterion is at least 0,275 d-1).

Applicant's summary and conclusion

Executive summary:

Growth inhibition assessment of Lemna minor (Lemnaceae) was performed according to the OECD Guideline No 221 (accepted in May, 2004 by National Co¬ordinators) and Principles of Good Laboratory Practice (GLP, OECD 1997).

The aim of the study was determination of growth inhibition of Lemna exposed to the range of concentrations (after 48h, 96h and 168h, a x% inhibition of growth was determined based on average specific growth rates - the value ErCx and also a x % inhibition on of yield was determined – the value EyCx). The tested preparation was used in 7 concentrations in the range from 0.1 to 100 mg/I.

The median concentration causing 50% inhibition of average specific growth rates of Lemna (ErC50 after 168 h) is 7.13 mg/I and the median concentration causing 50% inhibition of yield (EyC50 after 168h) is 6.53 mg/I. NOEC and LOEC values are estimated 0.1 mg/I and 0.32 mg/I, respectively.