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

Short-term toxicity to fish

Administrative data

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24.11.2008 - 28.11.2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

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

EC Number:

249-636-2

EC Name:

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

Cas Number:

29450-45-1

Molecular formula:

C17H25ClO3

IUPAC Name:

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

impurity 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

Test material form:

liquid

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Effect concentrations 2

Key result

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

>= 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Effect concentrations 3

Key result

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Effect concentrations 4

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 0.328 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Effect concentrations 5

Key result

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

>= 0.328 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Effect concentrations 6

Key result

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

> 0.328 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Any other information on results incl. tables

Sublethal observations / clinical signs:

RESULTS AND DISCUSSION

According to the information from the Sponsor the test substance is insoluble in water (The test item description, Annex No 1 to contract No 23/PP/08). According to literature data the estimated limit of MCPA-2EH solubility is <0.17 mg/L and the ester is rapidly hydrolyzed. The test substance of low solubility should be tested up to the limit of solubility or at the concentration above the limit of solubility to ensure that the maximum soluble concentration has been obtained.

The acute toxicity of MCPA-2EH for carp test was performed at one test concentration 1.0 mg/L (limit test), i.e. above the estimated limit of solubility. Acetone was used at 0.1 mL/L concentration as auxiliary substance to prepare the test concentration. Therefore, in the test both standard control and control with acetone were conducted.

VALIDITY CRITERIA

The following validity criteria were met in the test:

·        Mortality in the control during test was 0 % (allowed 10 %),

·        Concentration of dissolved oxygen was kept within the range of 78.3 – 101.6 % (obligatory above 60 % of oxygen saturation).

DEVIATIONS FROM GUIDELINE

No deviations from Guideline occurred in the test performed.

The Guideline recommendations range also length of test fish and fish loading. The length of carp used in the experiment is above the range recommended by OECD Guideline No 203 and within the range recommended by test method EU C.1. The fish loading is above the value recommended for experiments in static test.

All validity criteria of the test mentioned in both OECD Guideline No 203 and test method EU C.1. were met.

 

MORTALITY AND INTOXICATION EFFECTS

The toxicity assessment of MCPA-2EH for carp is based on observations of mortality and intoxication effects.

 In the test concentration 1.0 mg/L as well as in the control and the control with acetone neither mortality nor intoxication effects were observed.

 

ENDPOINTS

The toxicity evaluation of MCPA-2EH for carp was performed in limit test with one test concentration 1.0 mg/L.

The contents of MCPA-2EH were chemically analyzed in the test. The test substance was detected in the test concentration and the control with acetone at the beginning and the end of exposure (t₀and t₉₆)_.

In the sample collected at the start of the test the content of MCPA-2EH was 89.7 % of nominal. This confirms that the test item was correctly applied.

The test substance is not stable in the test concentration during 96 h of exposure. The content of MCPA-2EH detected at the test end was 13.4 % of initial concentration.

The LC_xvalues were estimated based on nominal test item concentration, because the analytical results confirmed its correct application. The LC_xvalues are presented in Table 7. Median concentration causing 50 % fish mortality (LC50) after 96 hours of exposure is above 1.0 mg/L. The LC0/96 h is equal or above 1.0 mg/L and_LC100/96h is above 1.0 mg/L.

Based on the chemical analyses performed the content of MCPA-2EH is not stable in test conditions. Therefore, the geometric mean of measured test substance concentrations was calculated. The LC_xvalues were also determined based on the geometric mean.

Median concentration causing 50 % fish mortality (LC50) after 96 hours of exposure is above 0.328 mg/L. The LC0/96 h is equal or above 0.328 mg/L and_LC100/96h is above 0.328 mg/L.

Applicant's summary and conclusion

Executive summary:

The study was performed according to the OECD Guidelines for Testing of Chemicals No 203 (1992) and EU method C.1. as well as in compliance with Principles of GLP.

The aim of the study was evaluation of acute toxicity of test item for carp and determination of LC₅₀, LC₀and LC₁₀₀ values.

The test item was used in one test concentration 1.0 mg/L (limit test). The content of test substance was determined at the beginning and at the end of exposure. The results of chemical analyses confirmed the correct application of test item. The detected substance is not stable in experiment conditions.

Taking into account the obtained results after 96 hours of exposure the

LC₅₀ value is above 1.0 mg/L,

LC₀ is equal or above 1.0 mg/L and

LC₁₀₀ is above 1.0 mg/L based on test item nominal concentration.

 

Based on geometric mean of determined test substance concentrations the

LC₅₀ value is above 0.328 mg/L,

LC₀ is equal or above 0.328 mg/L

LC₁₀₀ is above 0.328 mg/L.