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

Long-term toxicity to fish

Administrative data

Endpoint:

fish early-life stage toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

25.02.2005 - 24.02.2005

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:

2005

Report date:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 210 (Fish, Early-Life Stage Toxicity 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:

30 d

Dose descriptor:

NOEC

Effect conc.:

>= 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Effect concentrations 2

Key result

Duration:

30 d

Dose descriptor:

LOEC

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Any other information on results incl. tables

Results summary

All criteria of test validity were met, namely:

·        dissolved oxygen concentration was 83.0% - 89.2%, i.e. above 60% of air saturation value (i.e. above 4.9 mg 0₂/l) throughout the test duration,

·        the temperature was maintained at constant level of 24.5 ± 0.6 °C.

·        the concentration of the test material was at 86.2% - 97.1% as compared with nominal concentrations, i.e. it was maintained within ± 20% of the mean measured values,

·        survival of fertilized eggs in control was 76.7%, i.e. above the acceptable 70% thresh-old value.

Hatching per cent for control was 98.3% (one dead embryo) while 98.3% for 0.10 mg/l concentration (one dead embryo), 95.0% (three dead embryos) for 0.32 mg/l concentration, 93.3% (four dead embryos) for 1.0 mg/l concentration, 100.0% (no embryo mortality) for 3.2 mg/l concentration and 91.7% (five dead embryos) for 10.0 mg/l concentration. Dead embryos in control were observed on day four in replicate 2. In case of 0.10 mg/l concentration dead embryos were observed on day two only in replicate 2, while for concentration 0.32 mg/l on day two and four only in replicate 2, in concentration 1.0 mg/l on day two and three in replicates 1 and 2, in concentration 10.0 mg/l on day two and three in replicate 1 and 2.

Hatching started on day four of the test and ended on day six in control. In case of concentration 0.10 mg/l the hatching started on day four and ended on day six; for concentration 0.32 mg/l it was day two and six, respectively; for concentration 1.0 mg/l day two and six; for concentration 3.2 mg/l day two and six; and for concentration 10.0 mg/l day three and six.

The first dead larvae were observed in control on day 11 of the test while the last dead larvae were noticed on day 24. For concentration 0.10 mg/l the first dead larvae were observed on day 10 of the test while the last case of mortality on day 28. For concentration 0.32 mg/l the first dead larvae were noticed on day 11 and the last dead ones on day 30. For concentration 1.0 mg/l the first dead larvae were observed on day 11 and the last ones on day 30. For concentration 3.2 mg/l the first dead larvae were noticed on day 10 and the last case of mortality on day 30 but 100% mortality was observed after 27 days in case of replicate 2. For concentration 10.0 mg/l the first dead larvae were observed on day 10 and the last case on day 30. The mean survival for control was 78.3%, for concentration 0.10 mg/l the survival was 51.7%, for concentration 0.32 mg/l - 53.3%, for concentration 1.0 mg/l - 78.3%, for concentration 3.2 mg/l- 18.3% and for concentration 10.0 mg/l 51.7%.

The fish were weighed (blotted dry) and measured at the end of the test. The mean body weight of the control fish at the end of the test was 1.79 mg per fish, in concentration 0.10 mg/l the mean was 1.37 mg per fish, in concentration 0.32 mg/l - 2.38 mg per fish, in concentration 1.0 mg/l the mean weight was 2.06 mg per fish, in concentration 3.2 mg/l it was 0.7 mg per fish and in concentration 10.0 mg/l- 0.96 mg per fish. The mean length of control fish was 1.03 mm while in concentration 0.10 mg/l- 0.98 mm, in concentration 0.32 mg/l- 0.82 mm, in concentration 1.0 mg/l - 1.03 mm, in concentration 3.2 mg/l - 0.64 mm and in concentration 10.0 mg/l - 0.92 mm. There was no statistically significant differences in the mean weights and lengths between control and test concentrations except for concentration 3.2 mg/l.

No changes in appearance and behavior of fish (hyperventilation, uncoordinated swimming, atypical quiescence and atypical feeding behavior) were noticed throughout the test duration.

Since LOEC is above the highest used concentration of 10.0 mg/l (nominal concentration) then NOEC equals 10.0 mg/l or is above this concentration.

Applicant's summary and conclusion

Executive summary:

The test was performed according to the OECD Guidelines for Testing of Chemicals No 210 and Principles of Good Laboratory Practice (GLP, OECD 1997).

The aim of the study was to assess effects of prolonged exposure to MCPA technical of Brachy-danio rerio in early life stages (NOEC in mg/1 after 30 days).

The test material was used in five concentrations with separation factor 3.2 in range of 0.10 mg/1 to 10.0 mg/l. No observable effect concentration (NOEC) after 30 days exposure to MCPA technical equals or is above 10.0 mg/l (nominal concentration), LOEC is above the highest used concentration of 10.0 mg/l (nominal concentration).