Avermectin A1a, 25-cyclohexyl-5-O-demethyl-25-de(1-methylpropyl)-

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 305 (Bioaccumulation in Fish: Aqueous and Dietary Exposure) -I: Aqueous Exposure Bioconcentration Fish Test

Deviations:

no

GLP compliance:

not specified

Details on sampling:

Sampling schedule for the definitive test with doramectin:
Uptake phase:
TRR Fish: d 1, 3, 7, 12, 14 and 20 (4 fish each), d 24 (6 fish)
TRR Water: daily (at least 2 samples)
PRP Fish: d 24 (28 fish)
PRP Water: d 24 (4 samples)
Depuration phase:
TRR Fish: d 0.17, 2, 4 and 8 (4 fish each), d 11 (6 fish)
TRR Water d 0–5, 8 and 11 (2 samples each)

Test organisms (species):

other: zebrafish

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

24 d

Total depuration duration:

11 d

Nominal and measured concentrations:

Pre-test: 0.0081 and 0.081 μg/L; definitive test: 0.041 μg/L

Details on estimation of bioconcentration:

The verification of the steady state was made based on fish sampled on days 20 and 24 as well as on day 7 (the last sampling day before the overdosage), which had similar accumulation factors.

Conc. / dose:

0.041 mg/L

Type:

BCF

Value:

70 L/kg

Basis:

whole body d.w.

Time of plateau:

2.88 d

Calculation basis:

steady state

Conc. / dose:

0.041 mg/L

Type:

BCF

Value:

71 L/kg

Basis:

whole body d.w.

Calculation basis:

kinetic

Details on results:

In the fish exposed to doramectin, no behavioural differences from the control fish were recorded. In all treatments and controls, no mortality was observed.
The doramectin concentrations measured in water were in the range of ± 20% of the mean measured concentration (1215 dpm/mL) on 20 of 23 sampling dates. In individual samples, the measured concentrations were outside of this range (between 56 and 190% of the mean value). On days 8 and 9, the application solution was 4-fold overdosed due to a human failure. This led to in-creased concentrations in water on days 8–10, and, subsequently, in fish on days 12 and 14. These values were excluded from estimation of kinetic parameters.

Conclusions:

The BCF value of the test substance was estimated as 70-71 L/kg in an OECD 305 study.

Description of key information

The BCF value of the test substance was estimated as 70-71 L/kg in an OECD 305 study.

Key value for chemical safety assessment

BCF (aquatic species):

70 L/kg ww