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

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

17.09.2008 - 01.10.2008

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:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Version / remarks:

The method used followed that described in the US Environmental Protection Agency (EPA) Health Effects Test Guidelines, OPPTS 870.1300, Acute Inhalation Toxicity, August 1998. The method was also designed to meet OECD guideline 403 (May 1981) and EC Guideline (Method B2 of Commission Directive 92/69/EEC, as amended by 93/21/EEC).

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

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

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Male and female Wistar CRL:(WI) BR strain rats were obtained from Charles River (Europe) Laboratories Inc.(TOXI-COOP KFT, 1103 Budapest, Hungary). After arrival, the animal’s health was certified by the resident veterinarian and, after an acclimatisation period of seven days, the animals were accepted into this study. Prior to this acceptance the animals were randomised. At inclusion, the animals were young, adult animals, were aged eight to twelve weeks and in the weight range of 254 to 334 g. Females were nulliparous and non-pregnant.

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

air

Duration of exposure:

4 h

Concentrations:

0.5 mg/l

No. of animals per sex per dose:

5 female
5 male

Control animals:

no

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.05 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No mortality observed in male nor in female rats

Any other information on results incl. tables

CLINICAL OBSERVATIONS

Wet fur was commonly recorded both during and for several hours after exposure whilst fur staining was frequently noted both during and for some days after exposure. These observations were considered to be related to the restraint and exposure procedures and, in isolation, were considered not to be biologically significant. Significant clinical signs noted on day of exposure comprised a respiratory rate increase only. One incident lethargy and ataxia was recorded in one female animal on the day after exposure.

BODYWEIGHTS

Marked or slight bodyweight loss and inferior bodyweight gain was noted for three female animals during Week 1 of the study. During Week 2, normal bodyweight development was noted – variations in bodyweight gain or slight bodyweight loss are frequently seen in female rats of this age and the variations noted during Week 2 are considered not to be biologically significant.

NECROPSY

There was no evidence of MCPA-2EH-related findings at necropsy. In the lungs, focal red discoloration of the left or all lobes was observed in 1/5 males (1459) and 1/5 females (1476), respectively. These observations were regarded as agonal. In addition, uterus in estrus recorded in 3 females (1468, 1473, 1474) was considered as incidental.

Applicant's summary and conclusion

Executive summary:

Under the experimental conditions of this study, no deaths occurred in a group of ten rats exposed to a mean achieved atmosphere of 5.05 mg/L for four hours. The acute inhalation median lethal concentration (4hr LC50) of MCPA-2EH, in Wistar Crl:(WI) BR strain rats, was therefore considered to be greater than 5.05 mg/L.