Methyl benzoylformate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

yes

Remarks:

See below

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

yes

Remarks:

See below

Principles of method if other than guideline:

Deviations to the study plan:
According to Study Plan:
The fish will be observed at test start and at least after 2 - 4, 24, 48, 72 and 96 hours after start of the test for sub-lethal effects and mortality.
Deviation to the Study Plan:
The time of observation on day 2 of the experiment was not documented. It can therefore not be shown that the observation was performed after exactly 48 hours. However, the timeframe in which the observation took place can be limited to 46.75 to 50.3 h test duration.
Reason for the Deviation:
Human Error
Presumed Effect on the Study:
None, since no effects occurred over the whole study period.

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

One sample from the freshly prepared stock solution and triplicate samples from the freshly prepared test medium of the only test concentration and the control were taken at the start of the test and on day 3.
For the determination of the stability of the test item under the test conditions, respectively the maintenance of the test item concentrations during the test period, samples were taken in triplicate out of the only test medium and the control at day 1 and at the end of the test (96 hours).
All test medium samples were taken from the approximate centre of the aquaria.
All samples were diluted with acetonitrile. Therefore one part of the sample was diluted with nine parts acetonitrile.
Additional samples of the control blank and the dilution solvent were taken at test start and test end without any sample treatment.

The concentrations of the test item Irgacure MBF were analysed in two of the triplicate test media samples from the only test concentration, and in two of the triplicate control samples, from all sampling times (0h, day 1, day3 and day 4).

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
With a semi-static test design, stock solutions of nominal 600 mg/L were prepared by dissolving 1305.0 mg (test start), 1314.8 mg (24h), 1304.7 (48 h) and 1314.1 mg of the test item homogeneously in 2175, 2191.3, 2174.5 and 2190.2 mL test water by intense stirring for 30 minutes. Then, an adequate volume of this stock solution was mixed into test water to obtain the desired test concentration. The test medium was prepared just before introduction of the test fish (= start of the test and test medium renewal on day 1, 2 and 3).

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: Zebrafish
- Strain:
- Source: The test fish were obtained from in-house breeding
- Age at study initiation (mean and range, SD): Juveniles
- Length at study initiation (length definition, mean, range and SD): The mean body length of the fish in the test was 2.40 cm ± 0.1 cm (Mean ± SD)
- Weight at study initiation (mean and range, SD): The mean body wet weight 111.93 mg ± 14.1 mg (Mean ± SD)
- Holding Conditions: All fish were obtained and held in the laboratory for at least 12 days before the start of the test. They were held in water of the quality to be used in the test for at least seven days immediately before testing under the following conditions:
Light: 16 hours photoperiod daily
Temperature: 21 - 25 °C
Oxygen concentration: at least 80 % of the air saturation value
Feeding: three times per week or daily until 24 hours before the test was started
During the last 7 days prior to the start of the test no fish died in the test fish batch. Therefore the mortalities in the fish batch were below 5 % and the fish batch was accepted.
- Feeding during test: No

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

2.5 mmol/L (= 250.0 mg/L) as CaCO3

Test temperature:

24 °C

pH:

7.7 to 8.1

Dissolved oxygen:

92 to 104 % of the air saturation value

Nominal and measured concentrations:

120 mg test item/L, corresponding to the initial mean measured concentration of 54.6 mg test item/L and a control.

Details on test conditions:

TEST SYSTEM
- Test vessel: 12 litre glass aquaria with 10 litre test medium
- Aeration: The test media were slightly aerated during the test.
- Renewal rate of test solution (frequency/flow rate): A semi static test procedure was chosen with a test medium renewal every 24 h to keep the concentrations of the test item in the test medium as constant as possible during the test period. During this test surviving fish were placed in a clean aquarium with freshly prepared test medium of the corresponding concentration every day. The test media were slightly aerated during the test period.
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: < 1 g fish/L test water

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
Reconstituted Water (ISO Medium)
In deionised water (conductivity ≤ 10 μScm-1) analytical grade salts were added to following nominal concentrations:
CaCl2 × 2H2O : 2.0 mmol/L (= 294.0 mg/L)
MgSO4 × 7H2O : 0.5 mmol/L (= 123.0 mg/L)
NaHCO3 : 0.75 mmol/L (= 65.0 mg/L)
KCl : 0.075 mmol/L (= 5.8 mg/L)
Water Hardness : 2.5 mmol/L (= 250.0 mg/L) as CaCO3
Alkalinity : 0.8 mmol/L
Ratio of Ca : Mg = 4 : 1 (based on molarity)
Na : K = 10 : 1 (based on molarity)
- Intervals of water quality measurement: The water temperature, pH-values and the dissolved oxygen concentrations were determined daily in the freshly prepared and aged test media of each treatment group.

OTHER TEST CONDITIONS
- Adjustment of pH: None
- Photoperiod: 16 h light : 8 h dark; 30 min dawn/dusk period was provided
- Light intensity: 200 to 250 lux; reduced light intensity to cope with specific substance properties of the test item (photoinitiator).

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
The test fish were observed at test start and after approximately 2, 24, 48, 72 and 96 hours test duration for sublethal effects and mortality

TEST CONCENTRATIONS
No pre-experiments were performed. An acute study with Daphnia magna showed no toxicity at nominal 120 mg test item/L, from which a similar result on fish might be concluded.
In order to reduce the number of fish used in the test, a limit study was performed.

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 120 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 54.6 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

> 120 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

> 54.6 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

In the control and the only test concentration of nominal 120 mg test item/L, corresponding to the initial mean measured concentration of 54.6 mg test item/L, all fish survived until the end of the experiment and showed no sublethal effects during the exposure time.

Sublethal observations / clinical signs:

The quantification of the test item was performed using liquid chromatography with UV detection. At the start of the test (0h) and at the test media renewal (day 3) recoveries of the only nominal test concentration varied between 43 and 49 %. In the aged test media (day 1 and day 4), the recovery was below the limit of quantification (LOQ: 0.1 mg test item/L). The rapid dissipation of the test item during the exposure period is conclusively explained by its specific substance properties (photoinitiator and hydrolytically unstable). Nevertheless, every effort (semi-static test design and reduced light intensity) has been taken to test the parent substance.

Validity criteria fulfilled:

yes

Conclusions:

The test item has an nominal LC50 of >120 mg/l (test material), this value is outside the criteria for classification under 1272/2008.

Executive summary:

In this guideline (OECD 203) study conducted with GLP certification, the test material (EC 239-263-3) was determined to have a nominal LC50 of >120 mg/l (test material) in Zebra fish. A single test concentration of 120 mg/l (nominal was tested (semi-static limit test) to confirm whether the substance posed a hazard to the aquatic environment. This LC50 value is outside the criteria for classification of substances hazardous to the aquatic environment, under the Classification, Labelling, and Packaging (CLP) regulation (1272/2008).

Description of key information

 Study carried out according to guideline and with GLP compliance.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

120 mg/L

Additional information

A semi-static GLP guideline study according OECD 203 including analytical monitoring has been conducted (ibacon GmbH 2015). Zebrafish have been exposed to the test substance for 96 h. Due to the photosensitivity of the test item the test has been conducted using reduced light intensity. After 96 h no effects could be observed and the LC50 was determined to be > 120 mg/L (nominal) respectively > 54.6 mg/L (measured initial).

Therefore, the test item is considered not to meet the criteria for classification as hazardous to the aquatic environment based upon this result.