Bronopol

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:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study conducted in accordance with GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 207 (Earthworm, Acute Toxicity Tests)

GLP compliance:

yes (incl. QA statement)

Vehicle:

no

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

- Supplier: Earthworm farm Tacke GmbH, Broken-Burlo, Germany
- Age of the animals at the begin of exposure: ca 9 months
- Weight of animals at the begin of the exposure (mean value): 515 mg
- Choice of the test animals: animals with a weight of 500 - 600 mg and a clear visible clitellum were taken out of the storage container and used for
the test.
- Adaptation of animals: 24 h before begin of exposure in the test substrate without test substance

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

14 d

Test temperature:

20.8 to 22.2 °C

pH:

6.4

Moisture:

Substrate: 32.8 g/100 g of dry weight

Details on test conditions:

TEST SUBSTRATE
- 10 % sphagnum peat
20 % kaolin clay
69.7 % quarz sand
0.3% calcium carbonate

TEST SYTSEM
- Test vessels: 1 L glass vessels covered with a lid
- Test volume: about 750 g (wet test substrate)
- Loading: 10 animals / test vessel (earthworms will be introduced into the test vessel impartially)
- Replicates/test concentration: 4
- Total number of animals/test concentration: 40
- Feeding: none

FURTHER TEST CONDITIONS
- Illumination: continuous light (400 - 800 lux)
- Application: exposure via test substrate, according to the natural exposure of earthworms

Nominal and measured concentrations:

Nominal test concentrations (mg/L): control, 12.8, 32, 80, 200, 500

Reference substance (positive control):

yes

Remarks:

2-chloroacetamide

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

> 500 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

> 500 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: weight

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

12.8 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

14 d LC0 = 12.8 mg/kg soil dw
14 d LC100 > 500 mg/kg soil dw
14 d LOEC = 32 mg/kg soil dw

- Further observations: at the test assays with the test concentrations of 500 mg/kg and 200 mg/kg a reduced activity of the earthworms was observed. Furthermore, by comparison with the other test concentrations, it seemed the earthworms at the test concentration of 500 mg/kg were skinnier.

Results with reference substance (positive control):

LC50 = 12.4 mg/kg; this result was slightly below the expected range of 15 to 35 mg/kg soil. This however did not affect the validity of the present study.

Mortalities after 14 days:

--------------------------------------------------

Test Conc. (mg/kg artificial soil) /Mortality (%)

0 (control)                    5% (2/40)

12.8                           8% (3/40)

32                            13% (5/40)

80                            10% (4/40)

200                           13% (5/40)

500                           15% (6/40)

-------------------------------------------------- 

Body weight (differences between test initiation and test ending):

-------------------------------------------------------

Test Conc.(mg/kg) MWi(mg/worm) MWe (mg/worm) Di/e(%)

Control           510 (Ni=40*) 484 (Ne=38**) 5

12.8              515 (Ni= 40) 386 (Ne=37)   25

32                511 (Ni=40)  335 (Ne=35)   34

80                503 (Ni=40)  396 (Ne=36)   21

200               528 (Ni=40)  401 (Ne=35)   24

500               521 (Ni=40)  276 (Ne=34)   47

-------------------------------------------------------

MWi: mean weight at test initiation

 

MWe: mean weight at test ending Di/e: difference between test initiation and ending

 

Additional findings: At 200 and 500 mg/kg soil the earthworms showed a reducted activity. At the highest test concentration, the animals furthermore appeared to be skinnier when compared to the remaining test groups.

 

Reference substance: an LC50 of 12.4 mg/ kg soil was obtained for 2-Chloroacetamide.

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:

500 mg/kg soil dw

Long-term EC10, LC10 or NOEC for soil macroorganisms:

62.5 mg/kg soil dw

Additional information

The acute toxicity of Bronopol to earthworms was examined in a GLP guideline study with Eisenia foetida according to OECD 207 [BASF AG 2006]. Adult earthworms were exposed to Bronopol-treated artificial soil for 14 days. At test termination a LC50 > 500 mg/kg dry weight and a NOEC = 12.8 mg/kg dry weight was determined.

 

The chronic toxicity of Bronopol to earthworms was examined in a GLP guideline study with Eisenia foetida according to OECD 222 [BASF SE 2021]. Adult earthworms were exposed to Bronopol-treated artificial soil for 28 days to investigate lethal effects resulting in an EC10 of 618.3 mg/kg (dw). The adult worms were removed thereafter and the reproduction by count of juvenile worms was investigated in the following. After 56 days a EC10 of 61.5 mg/kg (dw) regarding the reproduction was observed.