Butanone oxime

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The test parameters evaluated in this study comply with a specific test guideline (EG-Richtlinie 79/831/EWG, Anhang V, C2), are well documented, scientifically acceptable, but not performed according to GLPs.

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

GLP compliance:

no

Analytical monitoring:

no

Details on test solutions:

Concentration tested was 500 mg/L.

Test organisms (species):

Daphnia magna

Details on test organisms:

5 daphnia/vessel (10 ml). 4 vessels per test concentration.

Test type:

not specified

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test temperature:

20 Degrees centigrade.

pH:

About 8.0 during testperiod.

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

<= 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

>= 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

>= 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Conclusions:

For the freshwater crurstacean Daphnia magna, the EC0, EC50 and EC100 (mobility) are estimated to be equal to 500, >500, and >500 mg MEKO/L, respectively.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to generally vaiid procedures and according to GLP guidelines. All parameters described are closely related or comparable to guideline methods.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations:all
- Sampling method:test item concentrations were measured using the solution mixed with equal volume taken out from the middle layer of the test solution in four test vessels in each exposure level

Details on test solutions:

Nominal concentrations of MEKO were 1000, 556, 309, 171, 95.3 or 52.9 mg/L. A laboratory water control was included. A solubilizer was not used. Concentrations of the test substance were kept close to the nominal concentrations (99.5 to 106%).

Test organisms (species):

Daphnia magna

Details on test organisms:

20 daphnids (4 replicates; 5 organisms per replicate) were exposed to various nominal concentrations of MEKO.

Test type:

static

Water media type:

freshwater

Total exposure duration:

48 h

Hardness:

40.5 mg/L (as CaC03)

Test temperature:

20±1°C

pH:

7.6

Details on test conditions:

TEST SYSTEM
- Test vessel:Petri dish (inside diameter 8.5 cm, depth 5.7 cm)
- Material, size, headspace, fill volume:
- No. of organisms per vessel:5
- No. of vessels per concentration (replicates):4
- No. of vessels per control (replicates):4

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod:16-hour light/8-hour dark
- Light intensity:Artificial light of white fluorescent lamp

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :

TEST CONCENTRATIONS
- Spacing factor for test concentrations:geometric series with a factor 1.8
- Justification for using less concentrations than requested by guideline:
- Range finding study: 30% immobility at 24 hours, 100% immobility at 48 hours in 500 mg/L; no immobilization at 62.5 mg/l
- Test concentrations:52.9, 95.3, 171, 309, 556, 1000

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

ca. 201 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

ca. 93 mg/L

Nominal / measured:

nominal

Details on results:

- Mortality of control: none
- Effect concentrations exceeding solubility of substance in test medium: none

The ratio of the measured concentration to the nominal value ranged from 103 to 106% at the start of the exposure, and from 99.5 to 104% at the end of the exposure

Validity criteria fulfilled:

yes

Conclusions:

For the freshwater crustacean Daphnia magna, the 48-hour EC50 (mobility) is 201 mg MEKO/mL.

Description of key information

The 48-h EC50 of 201 mg/L in Daphnia magna will be used in the assessment.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

201 mg/L

Additional information

Two short-term toxicity tests with Daphnia magna are available for MEKO. In the first one, a GLP-compliant static OECD Guideline 202 test with analytical monitoring, a 48-h EC50 of ca. 201 mg/L is reported (Kurume Laboratory, 1998c). In the second study, performed without GLP according to EU Method C2, a 48-h LC50 of = 500 mg/L is reported based on mobility (BASF, 1989). The most critical study of Kurume Laboratory (1998c) is regarded as the key study.