Chlorpyrifos

Toxicity to terrestrial arthropods

Link to relevant study record(s)

Reference

Endpoint:

toxicity to terrestrial arthropods: short-term

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: United Kingdom Control of Pesticides Regulations 1986, Working Document 7/3

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPP 141-1 (Honey Bee Acute Contact Toxicity)

Deviations:

no

GLP compliance:

yes

Application method:

other: Contact and oral

Specific details on test material used for the study:

Batch Number: RMM 1946
Purity: 97.4%

Analytical monitoring:

no

Vehicle:

yes

Remarks:

acetone

Test organisms (species):

Apis mellifera

Animal group:

Hymenoptera (honeybees)

Study type:

laboratory study

Limit test:

no

Remarks:

Single dose

Post exposure observation period:

24 and 48 hours

Test temperature:

25-26°C

Humidity:

60-67%

Photoperiod and lighting:

The photoperiod was darkness except when essential procedures were conducted. During these procedures subdued light was used.

Nominal and measured concentrations:

0.015625, 0.03125, 0.0625, 0.125, 0.25, 0.5 and 1.0 µg/bee (contact administration)
0.0625, 0.125, 0.25, 0.5 and 1.0 µg/bee (oral administration)

Reference substance (positive control):

yes

Remarks:

dimethoate

Key result

Duration:

24 h

Dose descriptor:

LD50

Effect conc.:

0.36 µg per animal

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CL: 0.29-0.45 µg/bee

Remarks:

oral administration

Key result

Duration:

48 h

Dose descriptor:

LD50

Effect conc.:

0.36 µg per animal

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CL: 0.29-0.45 µg/bee

Remarks:

oral administration

Key result

Duration:

24 h

Dose descriptor:

LD50

Effect conc.:

0.072 µg per animal

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CL: 0.056-0.092 µg/bee

Remarks:

contact administration

Key result

Duration:

48 h

Dose descriptor:

LD50

Effect conc.:

0.07 µg per animal

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CL: 0.056-0.088 µg/bee

Remarks:

contact administration

Validity criteria fulfilled:

yes

Conclusions:

48 h LD50 (honey bee): 0.36 µg/bee (oral)
48 h LD50 (honey bee): 0.07 µg/bee (contact)

Executive summary:

A study was performed to assess the acute oral and contact toxicity of the test substance to honey bees (Apis mellifera). The study was conducted in accordance with EPA OPP 141 -1.

Groups of 30, sterile female worker bees were exposed by ingestion or contact (ventral thorax) to 1 of 5 (oral) or 1 of 7 (contact) concentrations of the test substance dispersed in sucrose or acetone solution as appropriate. The incidence of mortality was recorded for each test and control group 24 and 48 hours after administration.

The 48-hour LD50 values with 95 % confidence limits were:

Oral LD50: 0.36 µg/bee (0.29-0.45); Contact LD50: 0.07 µg/bee (0.056-0.088).

The 48-hour LD50 values with 95 % confidence limits for the reference substance, dimethoate were:

Oral LD50: 0.040 µg/bee (0.024-0.066); Contact LD50: 0.027 µg/bee (0.020-0.038).

All results were expressed in terms of nominal concentration.

Description of key information

48 h LD50 (honey bee): 0.36 µg/bee (oral), 48 h LD50 (honey bee): 0.07 µg/bee (contact); OPP 141 -1; Reliability = 1