pymetrozine (ISO); (E)-4,5-dihydro-6-methyl-4-(3-pyridylmethyleneamino)-1,2,4-triazin-3(2H)-one

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil macroorganisms except arthropods: short-term

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

01 Oct 1992 to 15 Oct 1992

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 207 (Earthworm, Acute Toxicity Tests)

Version / remarks:

1984

Deviations:

yes

Remarks:

Mean worm weight is 302 mg (288-323 mg) based on 60 worms. Humidity of the soil was 20 % resp. 22 % at test concentrations 333 and 1000 mg/kg at the end of exposure.

GLP compliance:

yes

Test organisms (species):

Eisenia fetida

Study type:

laboratory study

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

1 098 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CL.: 464-7724 mg/kg

Duration:

14 d

Dose descriptor:

LC100

Effect conc.:

> 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

14 d

Dose descriptor:

LC0

Effect conc.:

12.3 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Average live weight of test organisms

	Average live weight
Nominal concentration mg/kg dw of soil	Start of exposure	End of exposure
Blank	301	262
12.3	288	236
37	290	210
111	313	300
333	302	364
1000	323	333

  

Mortality (Initial numbers of worms= 40/test conc.)

Nominal concentration mg/kg dw of soil	7 days		14 days
	Number	%	Number	%
Blank	0		1	3
12.3	0		2	5
37	0		9	23
111	5	13	12	30
333	8	20	15	38
1000	14	35	18	45

 

 

 

Observations and symptoms on surviving organisms: Flaccidity

Nominal concentration mg/kg dw of soil	7 days		14 days
	Number	%	Number	%
Blank	0		1	3
12.3	0		0	-
37	8	25	3	11
111	6	21	4	17
333	11	52	8	47
1000	8	44	7	47

Validity criteria fulfilled:

yes

Conclusions:

The earthworms showed sublethal effects at concentrations of 37-1000 mg as/kg, such as flaccidity (11-47 % of the organisms with increasing concentration). The LC50 was calculated to be 1098 mg as/kg. The NOEC could not be determined as effects appeared at the lowest concentration tested.

Executive summary:

The acute effect of the test substance on earthworms was determined by performing a GLP compliant study according to the OECD guideline 207. The 14-day study was conducted using earth worms (Eisenia foetida foetida) as test system. Beakers of 1 L filled with 750 g soil (wet weight), covered with perforated plastic film were used for the study. 40 (4 replicates of 10 worms) test organisms per concentration and control were used. The test concentrations were prepared at nominal concatenations of: 12.3, 37, 111, 333 and 1000 mg/kg mg test substance/kg (dry weight of soil). Blanks were used as controls. Mortalities and flaccidity on surviving organisms were recorded after 7 and 14 days exposure. The LC50 values were calculated according to the maximum likelihood method, probit model. The study showed that the earthworms showed sublethal effects at concentrations of 37-1000 mg as/kg, such as flaccidity (11-47 % of the organisms with increasing concentration). The NOEC could not be determined as effects appeared at the lowest concentration tested.

Description of key information

The 14-d LC50 was calculated to be 1098 mg as/kg, OECD 207, Grade 1992

Information on this endpoint is not part of Annex VIII data requirements; all included studies are marked as supporting information and considered in the CSA.