Chinomethionate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Test Period 25 - 27 October 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Remarks:

Weights and volumes may differ from those specified in OECD 202 in order to compensate for the water of crystallisation of chemicals used or the volumes of the stock solutions made/required on pro rata basis

GLP compliance:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Source: The Sponsor (Osaka Soda). Lot/batch no. 161120-01
- Expiration date of the lot/batch: 20 November 2018 (CofA)
- Purity test date: 97%

RADIOLABELLING INFORMATION (if applicable)
- Radiochemical purity: n/a
- Specific activity: n/a
- Locations of the label: n/a
- Expiration date of radiochemical substance: n/a

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Ambient (15±10°C), no specific protection from light
- Stability under test conditions: Stable under recommended storage condition as at room temperature (SDS)
- Solubility and stability of the test substance in the solvent/vehicle: Solubility 0.001 g/L (1 mg/L). Stability: Not specified
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: n/a

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: The definitive test concentrations were prepared from a 10 mg/L stock solution. The 10 mg/L stock was made by weighing 0.0101 g of homogenised test substance and adding to 1000 ml Elendt M4. This was stirred for 23 hours and 55 minutes and settled for 4 hours and 25 minutes. After settling the first 100ml (approximately) of aqueous phase was removed (avoiding all settled and floating material) and discarded. The test concentrations were made by measuring 2.5 ml, 4.5 ml, 8.0 ml, 14.5 ml and 26.0 ml of stock to 250 mL of Elendt M4. These made the concentration range of 0.1, 0.18, 0.32, 0.58 and 1.04 mg/L.
- Preliminary purification step (if any): Not specified
- Final dilution of a dissolved solid, stock liquid or gel: 0.1, 0.18, 0.32, 0.58 and 1.04 mg/L
- Final preparation of a solid: n/a

FORM AS APPLIED IN THE TEST (if different from that of starting material) Liquid

TYPE OF BIOCIDE/PESTICIDE FORMULATION (if applicable) n/a

OTHER SPECIFICS: n/a

Analytical monitoring:

not required

Details on sampling:

n/a

Vehicle:

yes

Remarks:

Water Accomodated Fraction (WAF)

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The definitive test concentrations were prepared from the same 10mg/L stock solution A. The 10 mg/L stock was made by weighing 0.0101 g of homogenised test substance and adding to 1000 ml Elendt M4. This was stirred for 23 hours and 55 minutes and settled for 4 hours and 25 minutes. After settling the first 100 ml (approximately) of aqueous phase was removed (avoiding all settled and floating material) and discarded. The test concentrations were made by measuring 2.5 ml, 4.5 ml, 8.0 ml, 14.5 ml and 26.0 ml of stock to 250 mL of Elendt M4. These made the concentration range of 0.1, 0.18, 0.32, 0.58 and 1.04 mg/L.
- Eluate: Not specified
- Differential loading: Not specified
- Controls: Not specified
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Water Accomodated Fraction (WAF)
- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)): 0.1, 0.18, 0.32, 0.58 and 1.04 mg/L.
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): Not specified

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia
- Strain/clone: Daphnia magna
- Justification for species other than prescribed by test guideline: n/a
- Source: From cultures maintained at Chemex Environmental International Ltd since July 2014 and originally sourced from a clone of genotype 5.
- Age of parental stock (mean and range, SD): Not specified. Test Daphnia <24 hours old.
- Feeding during test: The Daphnia in the test were not fed
- Food type: The Daphnia in the test were not fed. For the parental stock, each working day they were fed a suspension of Chlorella
vulgaris
- Amount: Not specified
- Frequency: The Daphnia in the test were not fed. For the parental stock, each working day

ACCLIMATION
- Acclimation period: Not specified, the Daphnia were cultured, and the tests performed in Elendt M4 reconstituted Daphnia water media
- Acclimation conditions (same as test or not): Not specified
- Type and amount of food: The Daphnia in the test were not fed
- Feeding frequency: n/a
- Health during acclimation (any mortality observed): n/a

QUARANTINE (wild caught)
- Duration: n/a
- Health/mortality: n/a

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES: n/a

Test type:

static

Water media type:

not specified

Total exposure duration:

48 h

Post exposure observation period:

n/a

Hardness:

n/a

Test temperature:

19.7 – 20.3 °C

pH:

6.79 – 7.97

Dissolved oxygen:

6.37 – 7.68 mg/l

Nominal and measured concentrations:

Nominal concentrations: 0.1, 0.18, 0.32, 0.58 and 1.04 mg/L
The Sponsor specified that analytical confirmation of exposure concentrations was not required. All effect concentrations have, therefore, been calculated from nominal concentrations.

Details on test conditions:

TEST SYSTEM
- Test vessel: 40ml glass dishes. To limit aerial contamination of the test vessels and reduce evaporative losses, the vessels were covered with a perspex sheet.
- Type (delete if not applicable): Closed
- Material, size, headspace, fill volume: 25 mL
- Aeration: Not specified
- Type of flow-through (e.g. peristaltic or proportional diluter): Not specified
- Renewal rate of test solution (frequency/flow rate): Not specified
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): Not specified
- No. of vessels per vehicle control (replicates): 4
- Biomass loading rate: n/a

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
- Total organic carbon: Not specified
- Particulate matter: Not specified
- Metals: Not specified
- Pesticides: Not specified
- Chlorine: Not specified
- Alkalinity: Not specified
- Ca/mg ratio: Not specified
- Conductivity: Not specified
- Salinity: Not specified
- Culture medium different from test medium: The Daphnia were cultured, and the tests performed in Elendt M4 media.
- Intervals of water quality measurement: 0 and 48 hours

OTHER TEST CONDITIONS
- Adjustment of pH: Not specified
- Photoperiod: 16 hours light, 8 hours dark cycle
- Light intensity: Not specified

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The number of immobilised Daphnia was recorded after
24 and 48-hour exposure periods.

VEHICLE CONTROL PERFORMED: yes

RANGE-FINDING STUDY
- Test concentrations: 0 (control), 0.1, 1.0, 10.0 and 100 mg/l.
- Results used to determine the conditions for the definitive study: Yes, data from the preliminary test identified the 48-hour EC50 as being between 0.1-1.0 mg/l.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate: test carried out in a seperate GLP study on 18 - 20 January 2017 (reference ENV 11395). 24 hour EC50 was 1.4 mg/L

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

ca. 0.444 mg/L

Nominal / measured:

nominal

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

ca. 0.233 mg/L

Nominal / measured:

nominal

Basis for effect:

mobility

Key result

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

ca. 0.18 mg/L

Nominal / measured:

nominal

Basis for effect:

mobility

Key result

Duration:

24 h

Dose descriptor:

LOEC

Effect conc.:

ca. 0.32 mg/L

Nominal / measured:

nominal

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

ca. 0.18 mg/L

Nominal / measured:

nominal

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

ca. 0.32 mg/L

Nominal / measured:

nominal

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities:
- Observations on body length and weight: Not specified
- Other biological observations: Not specified
- Mortality of control: None (0%) of the twenty control Daphnia maintained in dilution water were immobilised and none were trapped in the meniscus during the study.
- Other adverse effects control: None
- Abnormal responses: Abnormalities were observed during the test period, with 3 individuals having slower movement at 0.32mg/L and 8 individuals at 0.58mg/L at 24 hours. At 48 hours 7 individuals showed slower movement at 0.18mg/L.
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: Not specified
- Effect concentrations exceeding solubility of substance in test medium: Not specified

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Relevant effect levels: Acceptable range 0.6 mg/l to 2.1 mg/l
- Limit test: Not stated
- Dose-response test: Not stated
- ECx: 24 hour EC50 observed of 1.4 mg/L
- Other: Test carried out in a separate GLP study (ENV 11395) was conducted from 18 to 20 January 2017 to monitor the sensitivity of the test animals and test procedures.

Reported statistics and error estimates:

Where possible, the EC(r)10, EC(r)50 and EC(r)90 values with 95% confidence limits and NOEC(r) were calculated according to the statistical methods of ToxCalc™ Version 5.0 “Comprehensive Toxicity Data Analysis and Database Software”, copyright 1994-1996.

0-24 hr EC50: Estimated EC50 value = 0.44368mg/l (0.36896 – 0.53611mg/l). Determined by Maximum Likelihood-Probit (P = 0.1), using ToxCalc v5.0.
NOEC = 0.18mg/l, LOEC = 0.32mg/l. Determined by Steel's Many-One Rank Test, 1-tail, P=0.05, normality of distribution and equal variances could not be confirmed, using ToxCalc v5.0.

0-48 hr EC50: Estimated EC50 value = 0.2331mg/l (0.2203 – 0.2467mg/l). Determined by Trimmed Spearman-Karber, using ToxCalc v5.0.
NOEC = 0.18mg/l, LOEC = 0.32mg/l. Determined by Steel's Many-One Rank Test, 1-tail, P=0.05, normality of distribution and equal variances could not be confirmed, using ToxCalc v5.0.

Validity criteria fulfilled:

yes

Conclusions:

The 24-hour EC50 and 48-hour EC50 of Chinomethionate to Daphnia magna were 0.44368 mg/l and 0.2331 mg/l respectively.
The 0 to 24-hour NOEC and LOEC were 0.18 mg/l and 0.32 mg/l respectively.
The 0 to 48-hour NOEC and LOEC were 0.18 mg/l and 0.32 mg/l respectively.

The lowest test concentration which immobilised all twenty Daphnia after 48-hours was 0.32 mg/l. The highest concentration where no immobilisation occurred was 0.1 mg/l.

Executive summary:

A study has been performed to investigate the acute toxicity of Chinomethionate to Daphnia magna. The objective of this study

was to determine the 48-hour EC50, which is defined as the concentration that immobilises 50% of the exposed Daphnia after a 48-hour exposure period according to OECD test guideline 202.

Test concentrations were made by measuring 2.5 ml, 4.5 ml, 8.0 ml, 14.5 ml and 26.0 ml of a pre-made stock solution to 250mL of Elendt M4. These made the concentration range of 0.1, 0.18, 0.32, 0.58 and 1.04 mg/L. Control (0) and test concentrations were performed in 4 replicates, each with 5 Daphnia. The number of immobilised Daphnia was recorded after 24 and 48-hour exposure periods.

The 24-hour EC50 and 48-hour EC50 of Chinomethionate to Daphnia magna were 0.44368 mg/l and 0.2331 mg/l respectively.

The 0 to 24-hour NOEC and LOEC were 0.18 mg/l and 0.32 mg/l respectively.

The 0 to 48-hour NOEC and LOEC were 0.18 mg/l and 0.32 mg/l respectively.

The lowest test concentration which immobilised all twenty Daphnia after 48-hours was 0.32 mg/l. The highest concentration where no immobilisation occurred was 0.1 mg/l.

Description of key information

The 24-hour EC50 and 48-hour EC50 of Chinomethionate to Daphnia magna were 0.44368 mg/l and 0.2331 mg/l respectively.

The 0 to 24-hour NOEC and LOEC were 0.18 mg/l and 0.32 mg/l respectively.

The 0 to 48-hour NOEC and LOEC were 0.18 mg/l and 0.32 mg/l respectively.

The lowest test concentration which immobilised all twenty Daphnia after 48-hours was 0.32 mg/l. The highest concentration where no immobilisation occurred was 0.1 mg/l.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.44 mg/L