Fenitrothion

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

15 December 2009 - 1 April 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Version / remarks:

2001

Deviations:

no

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Fenitrothion

EC Number:

204-524-2

EC Name:

Fenitrothion

Cas Number:

122-14-5

Molecular formula:

C9H12NO5PS

IUPAC Name:

O,O-dimethyl O-3-methyl-4-nitrophenyl phosphorothioate

Test material form:

liquid

Specific details on test material used for the study:

Fenitrothion TG (SMT, sumithion)
Brown liquid
Lot No.: 070502

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: ORIENTBIO, Korea
- Females nulliparous and non-pregnant: yes
- Age at study initiation: 8 weeks
- Weight at study initiation: 173.3-217.8 g
- Fasting period before study: overnight (~16 hours)
- Housing: Individual
- Diet: ad libitum except prior to dosing
- Water: ad libitum
- Acclimation period: one week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.3-22.4
- Humidity (%): 27.8-65.1
- Air changes (per hr): 10-15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 22 December 2009 To: 14 January 2010

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

The test material was administered undiluted.

Doses:

300, 2000 mg/kg bw

No. of animals per sex per dose:

3 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations: 30 minutes, 1, 2, 4 and 6 hours after dosing and subsequently daily
- Frequency of weighing: Days 0, 1, 3, 7 and 14 (terminal)
- Necropsy of survivors performed: yes

Statistics:

Not required

Results and discussion

Preliminary study:

No details

Effect levels

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 300 - < 2 000 mg/kg bw

Based on:

test mat.

Mortality:

Two deaths occurred at 2000 mg/kg bw in the initial group of three females (Day 1 or 2). There was no mortality in either of the two groups of three females administered 300 mg/kg bw.

Clinical signs:

other: Clinical signs were observed in all rats at 2000 mg/kg bw and included reduced activity, lacrimation, salivation, tremor, chromaturia and perineal staining. All signs had resolved by Day 9. Signs at 300 mg/kg bw included perineal soiling, lacrimation, s

Gross pathology:

There were no treatment-related findings at necropsy.

Any other information on results incl. tables

Summary of mortality

Group	Dose level (mg/kg bw)	Number of rats	Mortality
1	2000	3F	2/3
2	300	3F	0/3
3	300	3F	0/3

Applicant's summary and conclusion

Interpretation of results:

Category 4 based on GHS criteria

Conclusions:

The acute oral LD50 of fenitrothion was found to be >300 -<2000 mg/kg bw;= fenitrothion therefore meets the criteria for classification for acute oral toxicity in Category 4 according to the CLP Regulation.

Executive summary:

The acute oral toxicity of fenitrothion was investigated in an Acute Toxic Class study according to OECD 423. Three females were initally administered a dose of 2000 mg/kg bw and observed for 14 days.  Due to mortality in this group, two additional groups of three females were administered 300 mg/kg bw in sequence, according to the study guideline. Two deaths occurred at 2000 mg/kg bw in the initial group of three females (Day 1 or 2).  There was no mortality in either of the two groups of three females administered 300 mg/kg bw. Clinical signs were observed in all rats at 2000 mg/kg bw and included reduced activity, lacrimation, salivation, tremor, chromaturia and perineal staining; all signs had resolved by Day 9.  Signs at 300 mg/kg bw included perineal soiling, lacrimation, salivation and tremor; all signs had resolved by Day 5. Transient slight reductions in bodyweight were seen in surviving animals of both dose groups. There were no treatment-related findings at necropsy. The acute oral LD50 of fenitrothion was found to be >300 -<2000 mg/kg bw; fenitrothion therefore meets the criteria for classification for acute oral toxicity in Category 4 according to the CLP Regulation.